FFMPEG-CODECS(1)					      FFMPEG-CODECS(1)

NAME
       ffmpeg-codecs - FFmpeg codecs

DESCRIPTION
       This document describes the codecs (decoders and encoders) provided by
       the libavcodec library.

CODEC OPTIONS
       libavcodec provides some generic global options, which can be set on
       all the encoders and decoders. In addition, each codec may support so-
       called private options, which are specific for a given codec.

       Sometimes, a global option may only affect a specific kind of codec,
       and may be nonsensical or ignored by another, so you need to be aware
       of the meaning of the specified options. Also some options are meant
       only for decoding or encoding.

       Options may be set by specifying -option value in the FFmpeg tools, or
       by setting the value explicitly in the "AVCodecContext" options or
       using the libavutil/opt.h API for programmatic use.

       The list of supported options follow:

       b integer (encoding,audio,video)
	   Set bitrate in bits/s. Default value is 200K.

       ab integer (encoding,audio)
	   Set audio bitrate (in bits/s). Default value is 128K.

       bt integer (encoding,video)
	   Set video bitrate tolerance (in bits/s). In 1-pass mode, bitrate
	   tolerance specifies how far ratecontrol is willing to deviate from
	   the target average bitrate value. This is not related to min/max
	   bitrate. Lowering tolerance too much has an adverse effect on
	   quality.

       flags flags (decoding/encoding,audio,video,subtitles)
	   Set generic flags.

	   Possible values:

	   mv4 Use four motion vector by macroblock (mpeg4).

	   qpel
	       Use 1/4 pel motion compensation.

	   loop
	       Use loop filter.

	   qscale
	       Use fixed qscale.

	   pass1
	       Use internal 2pass ratecontrol in first pass mode.

	   pass2
	       Use internal 2pass ratecontrol in second pass mode.

	   gray
	       Only decode/encode grayscale.

	   psnr
	       Set error[?] variables during encoding.

	   truncated
	       Input bitstream might be randomly truncated.

	   drop_changed
	       Don't output frames whose parameters differ from first decoded
	       frame in stream.  Error AVERROR_INPUT_CHANGED is returned when
	       a frame is dropped.

	   ildct
	       Use interlaced DCT.

	   low_delay
	       Force low delay.

	   global_header
	       Place global headers in extradata instead of every keyframe.

	   bitexact
	       Only write platform-, build- and time-independent data. (except
	       (I)DCT).  This ensures that file and data checksums are
	       reproducible and match between platforms. Its primary use is
	       for regression testing.

	   aic Apply H263 advanced intra coding / mpeg4 ac prediction.

	   ilme
	       Apply interlaced motion estimation.

	   cgop
	       Use closed gop.

	   output_corrupt
	       Output even potentially corrupted frames.

       time_base rational number
	   Set codec time base.

	   It is the fundamental unit of time (in seconds) in terms of which
	   frame timestamps are represented. For fixed-fps content, timebase
	   should be "1 / frame_rate" and timestamp increments should be
	   identically 1.

       g integer (encoding,video)
	   Set the group of picture (GOP) size. Default value is 12.

       ar integer (decoding/encoding,audio)
	   Set audio sampling rate (in Hz).

       ac integer (decoding/encoding,audio)
	   Set number of audio channels.

       cutoff integer (encoding,audio)
	   Set cutoff bandwidth. (Supported only by selected encoders, see
	   their respective documentation sections.)

       frame_size integer (encoding,audio)
	   Set audio frame size.

	   Each submitted frame except the last must contain exactly
	   frame_size samples per channel. May be 0 when the codec has
	   CODEC_CAP_VARIABLE_FRAME_SIZE set, in that case the frame size is
	   not restricted. It is set by some decoders to indicate constant
	   frame size.

       frame_number integer
	   Set the frame number.

       delay integer
       qcomp float (encoding,video)
	   Set video quantizer scale compression (VBR). It is used as a
	   constant in the ratecontrol equation. Recommended range for default
	   rc_eq: 0.0-1.0.

       qblur float (encoding,video)
	   Set video quantizer scale blur (VBR).

       qmin integer (encoding,video)
	   Set min video quantizer scale (VBR). Must be included between -1
	   and 69, default value is 2.

       qmax integer (encoding,video)
	   Set max video quantizer scale (VBR). Must be included between -1
	   and 1024, default value is 31.

       qdiff integer (encoding,video)
	   Set max difference between the quantizer scale (VBR).

       bf integer (encoding,video)
	   Set max number of B frames between non-B-frames.

	   Must be an integer between -1 and 16. 0 means that B-frames are
	   disabled. If a value of -1 is used, it will choose an automatic
	   value depending on the encoder.

	   Default value is 0.

       b_qfactor float (encoding,video)
	   Set qp factor between P and B frames.

       codec_tag integer
       bug flags (decoding,video)
	   Workaround not auto detected encoder bugs.

	   Possible values:

	   autodetect
	   xvid_ilace
	       Xvid interlacing bug (autodetected if fourcc==XVIX)

	   ump4
	       (autodetected if fourcc==UMP4)

	   no_padding
	       padding bug (autodetected)

	   amv
	   qpel_chroma
	   std_qpel
	       old standard qpel (autodetected per fourcc/version)

	   qpel_chroma2
	   direct_blocksize
	       direct-qpel-blocksize bug (autodetected per fourcc/version)

	   edge
	       edge padding bug (autodetected per fourcc/version)

	   hpel_chroma
	   dc_clip
	   ms  Workaround various bugs in microsoft broken decoders.

	   trunc
	       trancated frames

       strict integer (decoding/encoding,audio,video)
	   Specify how strictly to follow the standards.

	   Possible values:

	   very
	       strictly conform to an older more strict version of the spec or
	       reference software

	   strict
	       strictly conform to all the things in the spec no matter what
	       consequences

	   normal
	   unofficial
	       allow unofficial extensions

	   experimental
	       allow non standardized experimental things, experimental
	       (unfinished/work in progress/not well tested) decoders and
	       encoders.  Note: experimental decoders can pose a security
	       risk, do not use this for decoding untrusted input.

       b_qoffset float (encoding,video)
	   Set QP offset between P and B frames.

       err_detect flags (decoding,audio,video)
	   Set error detection flags.

	   Possible values:

	   crccheck
	       verify embedded CRCs

	   bitstream
	       detect bitstream specification deviations

	   buffer
	       detect improper bitstream length

	   explode
	       abort decoding on minor error detection

	   ignore_err
	       ignore decoding errors, and continue decoding.  This is useful
	       if you want to analyze the content of a video and thus want
	       everything to be decoded no matter what. This option will not
	       result in a video that is pleasing to watch in case of errors.

	   careful
	       consider things that violate the spec and have not been seen in
	       the wild as errors

	   compliant
	       consider all spec non compliancies as errors

	   aggressive
	       consider things that a sane encoder should not do as an error

       has_b_frames integer
       block_align integer
       rc_override_count integer
       maxrate integer (encoding,audio,video)
	   Set max bitrate tolerance (in bits/s). Requires bufsize to be set.

       minrate integer (encoding,audio,video)
	   Set min bitrate tolerance (in bits/s). Most useful in setting up a
	   CBR encode. It is of little use elsewise.

       bufsize integer (encoding,audio,video)
	   Set ratecontrol buffer size (in bits).

       i_qfactor float (encoding,video)
	   Set QP factor between P and I frames.

       i_qoffset float (encoding,video)
	   Set QP offset between P and I frames.

       dct integer (encoding,video)
	   Set DCT algorithm.

	   Possible values:

	   auto
	       autoselect a good one (default)

	   fastint
	       fast integer

	   int accurate integer

	   mmx
	   altivec
	   faan
	       floating point AAN DCT

       lumi_mask float (encoding,video)
	   Compress bright areas stronger than medium ones.

       tcplx_mask float (encoding,video)
	   Set temporal complexity masking.

       scplx_mask float (encoding,video)
	   Set spatial complexity masking.

       p_mask float (encoding,video)
	   Set inter masking.

       dark_mask float (encoding,video)
	   Compress dark areas stronger than medium ones.

       idct integer (decoding/encoding,video)
	   Select IDCT implementation.

	   Possible values:

	   auto
	   int
	   simple
	   simplemmx
	   simpleauto
	       Automatically pick a IDCT compatible with the simple one

	   arm
	   altivec
	   sh4
	   simplearm
	   simplearmv5te
	   simplearmv6
	   simpleneon
	   xvid
	   faani
	       floating point AAN IDCT

       slice_count integer
       ec flags (decoding,video)
	   Set error concealment strategy.

	   Possible values:

	   guess_mvs
	       iterative motion vector (MV) search (slow)

	   deblock
	       use strong deblock filter for damaged MBs

	   favor_inter
	       favor predicting from the previous frame instead of the current

       bits_per_coded_sample integer
       aspect rational number (encoding,video)
	   Set sample aspect ratio.

       sar rational number (encoding,video)
	   Set sample aspect ratio. Alias to aspect.

       debug flags (decoding/encoding,audio,video,subtitles)
	   Print specific debug info.

	   Possible values:

	   pict
	       picture info

	   rc  rate control

	   bitstream
	   mb_type
	       macroblock (MB) type

	   qp  per-block quantization parameter (QP)

	   dct_coeff
	   green_metadata
	       display complexity metadata for the upcoming frame, GoP or for
	       a given duration.

	   skip
	   startcode
	   er  error recognition

	   mmco
	       memory management control operations (H.264)

	   bugs
	   buffers
	       picture buffer allocations

	   thread_ops
	       threading operations

	   nomc
	       skip motion compensation

       cmp integer (encoding,video)
	   Set full pel me compare function.

	   Possible values:

	   sad sum of absolute differences, fast (default)

	   sse sum of squared errors

	   satd
	       sum of absolute Hadamard transformed differences

	   dct sum of absolute DCT transformed differences

	   psnr
	       sum of squared quantization errors (avoid, low quality)

	   bit number of bits needed for the block

	   rd  rate distortion optimal, slow

	   zero
	       0

	   vsad
	       sum of absolute vertical differences

	   vsse
	       sum of squared vertical differences

	   nsse
	       noise preserving sum of squared differences

	   w53 5/3 wavelet, only used in snow

	   w97 9/7 wavelet, only used in snow

	   dctmax
	   chroma
       subcmp integer (encoding,video)
	   Set sub pel me compare function.

	   Possible values:

	   sad sum of absolute differences, fast (default)

	   sse sum of squared errors

	   satd
	       sum of absolute Hadamard transformed differences

	   dct sum of absolute DCT transformed differences

	   psnr
	       sum of squared quantization errors (avoid, low quality)

	   bit number of bits needed for the block

	   rd  rate distortion optimal, slow

	   zero
	       0

	   vsad
	       sum of absolute vertical differences

	   vsse
	       sum of squared vertical differences

	   nsse
	       noise preserving sum of squared differences

	   w53 5/3 wavelet, only used in snow

	   w97 9/7 wavelet, only used in snow

	   dctmax
	   chroma
       mbcmp integer (encoding,video)
	   Set macroblock compare function.

	   Possible values:

	   sad sum of absolute differences, fast (default)

	   sse sum of squared errors

	   satd
	       sum of absolute Hadamard transformed differences

	   dct sum of absolute DCT transformed differences

	   psnr
	       sum of squared quantization errors (avoid, low quality)

	   bit number of bits needed for the block

	   rd  rate distortion optimal, slow

	   zero
	       0

	   vsad
	       sum of absolute vertical differences

	   vsse
	       sum of squared vertical differences

	   nsse
	       noise preserving sum of squared differences

	   w53 5/3 wavelet, only used in snow

	   w97 9/7 wavelet, only used in snow

	   dctmax
	   chroma
       ildctcmp integer (encoding,video)
	   Set interlaced dct compare function.

	   Possible values:

	   sad sum of absolute differences, fast (default)

	   sse sum of squared errors

	   satd
	       sum of absolute Hadamard transformed differences

	   dct sum of absolute DCT transformed differences

	   psnr
	       sum of squared quantization errors (avoid, low quality)

	   bit number of bits needed for the block

	   rd  rate distortion optimal, slow

	   zero
	       0

	   vsad
	       sum of absolute vertical differences

	   vsse
	       sum of squared vertical differences

	   nsse
	       noise preserving sum of squared differences

	   w53 5/3 wavelet, only used in snow

	   w97 9/7 wavelet, only used in snow

	   dctmax
	   chroma
       dia_size integer (encoding,video)
	   Set diamond type & size for motion estimation.

	   (1024, INT_MAX)
	       full motion estimation(slowest)

	   (768, 1024]
	       umh motion estimation

	   (512, 768]
	       hex motion estimation

	   (256, 512]
	       l2s diamond motion estimation

	   [2,256]
	       var diamond motion estimation

	   (-1,  2)
	       small diamond motion estimation

	   -1  funny diamond motion estimation

	   (INT_MIN, -1)
	       sab diamond motion estimation

       last_pred integer (encoding,video)
	   Set amount of motion predictors from the previous frame.

       precmp integer (encoding,video)
	   Set pre motion estimation compare function.

	   Possible values:

	   sad sum of absolute differences, fast (default)

	   sse sum of squared errors

	   satd
	       sum of absolute Hadamard transformed differences

	   dct sum of absolute DCT transformed differences

	   psnr
	       sum of squared quantization errors (avoid, low quality)

	   bit number of bits needed for the block

	   rd  rate distortion optimal, slow

	   zero
	       0

	   vsad
	       sum of absolute vertical differences

	   vsse
	       sum of squared vertical differences

	   nsse
	       noise preserving sum of squared differences

	   w53 5/3 wavelet, only used in snow

	   w97 9/7 wavelet, only used in snow

	   dctmax
	   chroma
       pre_dia_size integer (encoding,video)
	   Set diamond type & size for motion estimation pre-pass.

       subq integer (encoding,video)
	   Set sub pel motion estimation quality.

       me_range integer (encoding,video)
	   Set limit motion vectors range (1023 for DivX player).

       global_quality integer (encoding,audio,video)
       slice_flags integer
       mbd integer (encoding,video)
	   Set macroblock decision algorithm (high quality mode).

	   Possible values:

	   simple
	       use mbcmp (default)

	   bits
	       use fewest bits

	   rd  use best rate distortion

       rc_init_occupancy integer (encoding,video)
	   Set number of bits which should be loaded into the rc buffer before
	   decoding starts.

       flags2 flags (decoding/encoding,audio,video,subtitles)
	   Possible values:

	   fast
	       Allow non spec compliant speedup tricks.

	   noout
	       Skip bitstream encoding.

	   ignorecrop
	       Ignore cropping information from sps.

	   local_header
	       Place global headers at every keyframe instead of in extradata.

	   chunks
	       Frame data might be split into multiple chunks.

	   showall
	       Show all frames before the first keyframe.

	   export_mvs
	       Export motion vectors into frame side-data (see
	       "AV_FRAME_DATA_MOTION_VECTORS") for codecs that support it. See
	       also doc/examples/export_mvs.c.

	   skip_manual
	       Do not skip samples and export skip information as frame side
	       data.

	   ass_ro_flush_noop
	       Do not reset ASS ReadOrder field on flush.

	   icc_profiles
	       Generate/parse embedded ICC profiles from/to colorimetry tags.

       export_side_data flags (decoding/encoding,audio,video,subtitles)
	   Possible values:

	   mvs Export motion vectors into frame side-data (see
	       "AV_FRAME_DATA_MOTION_VECTORS") for codecs that support it. See
	       also doc/examples/export_mvs.c.

	   prft
	       Export encoder Producer Reference Time into packet side-data
	       (see "AV_PKT_DATA_PRFT") for codecs that support it.

	   venc_params
	       Export video encoding parameters through frame side data (see
	       "AV_FRAME_DATA_VIDEO_ENC_PARAMS") for codecs that support it.
	       At present, those are H.264 and VP9.

	   film_grain
	       Export film grain parameters through frame side data (see
	       "AV_FRAME_DATA_FILM_GRAIN_PARAMS").  Supported at present by
	       AV1 decoders.

       threads integer (decoding/encoding,video)
	   Set the number of threads to be used, in case the selected codec
	   implementation supports multi-threading.

	   Possible values:

	   auto, 0
	       automatically select the number of threads to set

	   Default value is auto.

       dc integer (encoding,video)
	   Set intra_dc_precision.

       nssew integer (encoding,video)
	   Set nsse weight.

       skip_top integer (decoding,video)
	   Set number of macroblock rows at the top which are skipped.

       skip_bottom integer (decoding,video)
	   Set number of macroblock rows at the bottom which are skipped.

       profile integer (encoding,audio,video)
	   Set encoder codec profile. Default value is unknown. Encoder
	   specific profiles are documented in the relevant encoder
	   documentation.

       level integer (encoding,audio,video)
	   Set the encoder level. This level depends on the specific codec,
	   and might correspond to the profile level. It is set by default to
	   unknown.

	   Possible values:

	   unknown
       lowres integer (decoding,audio,video)
	   Decode at 1= 1/2, 2=1/4, 3=1/8 resolutions.

       mblmin integer (encoding,video)
	   Set min macroblock lagrange factor (VBR).

       mblmax integer (encoding,video)
	   Set max macroblock lagrange factor (VBR).

       skip_loop_filter integer (decoding,video)
       skip_idct	integer (decoding,video)
       skip_frame	integer (decoding,video)
	   Make decoder discard processing depending on the frame type
	   selected by the option value.

	   skip_loop_filter skips frame loop filtering, skip_idct skips frame
	   IDCT/dequantization, skip_frame skips decoding.

	   Possible values:

	   none
	       Discard no frame.

	   default
	       Discard useless frames like 0-sized frames.

	   noref
	       Discard all non-reference frames.

	   bidir
	       Discard all bidirectional frames.

	   nokey
	       Discard all frames excepts keyframes.

	   nointra
	       Discard all frames except I frames.

	   all Discard all frames.

	   Default value is default.

       bidir_refine integer (encoding,video)
	   Refine the two motion vectors used in bidirectional macroblocks.

       keyint_min integer (encoding,video)
	   Set minimum interval between IDR-frames.

       refs integer (encoding,video)
	   Set reference frames to consider for motion compensation.

       trellis integer (encoding,audio,video)
	   Set rate-distortion optimal quantization.

       mv0_threshold integer (encoding,video)
       compression_level integer (encoding,audio,video)
       bits_per_raw_sample integer
       channel_layout integer (decoding/encoding,audio)
	   See the Channel Layout section in the ffmpeg-utils(1) manual for
	   the required syntax.

       rc_max_vbv_use float (encoding,video)
       rc_min_vbv_use float (encoding,video)
       color_primaries integer (decoding/encoding,video)
	   Possible values:

	   bt709
	       BT.709

	   bt470m
	       BT.470 M

	   bt470bg
	       BT.470 BG

	   smpte170m
	       SMPTE 170 M

	   smpte240m
	       SMPTE 240 M

	   film
	       Film

	   bt2020
	       BT.2020

	   smpte428
	   smpte428_1
	       SMPTE ST 428-1

	   smpte431
	       SMPTE 431-2

	   smpte432
	       SMPTE 432-1

	   jedec-p22
	       JEDEC P22

       color_trc integer (decoding/encoding,video)
	   Possible values:

	   bt709
	       BT.709

	   gamma22
	       BT.470 M

	   gamma28
	       BT.470 BG

	   smpte170m
	       SMPTE 170 M

	   smpte240m
	       SMPTE 240 M

	   linear
	       Linear

	   log
	   log100
	       Log

	   log_sqrt
	   log316
	       Log square root

	   iec61966_2_4
	   iec61966-2-4
	       IEC 61966-2-4

	   bt1361
	   bt1361e
	       BT.1361

	   iec61966_2_1
	   iec61966-2-1
	       IEC 61966-2-1

	   bt2020_10
	   bt2020_10bit
	       BT.2020 - 10 bit

	   bt2020_12
	   bt2020_12bit
	       BT.2020 - 12 bit

	   smpte2084
	       SMPTE ST 2084

	   smpte428
	   smpte428_1
	       SMPTE ST 428-1

	   arib-std-b67
	       ARIB STD-B67

       colorspace integer (decoding/encoding,video)
	   Possible values:

	   rgb RGB

	   bt709
	       BT.709

	   fcc FCC

	   bt470bg
	       BT.470 BG

	   smpte170m
	       SMPTE 170 M

	   smpte240m
	       SMPTE 240 M

	   ycocg
	       YCOCG

	   bt2020nc
	   bt2020_ncl
	       BT.2020 NCL

	   bt2020c
	   bt2020_cl
	       BT.2020 CL

	   smpte2085
	       SMPTE 2085

	   chroma-derived-nc
	       Chroma-derived NCL

	   chroma-derived-c
	       Chroma-derived CL

	   ictcp
	       ICtCp

       color_range integer (decoding/encoding,video)
	   If used as input parameter, it serves as a hint to the decoder,
	   which color_range the input has.  Possible values:

	   tv
	   mpeg
	   limited
	       MPEG (219*2^(n-8))

	   pc
	   jpeg
	   full
	       JPEG (2^n-1)

       chroma_sample_location integer (decoding/encoding,video)
	   Possible values:

	   left
	   center
	   topleft
	   top
	   bottomleft
	   bottom
       log_level_offset integer
	   Set the log level offset.

       slices integer (encoding,video)
	   Number of slices, used in parallelized encoding.

       thread_type flags (decoding/encoding,video)
	   Select which multithreading methods to use.

	   Use of frame will increase decoding delay by one frame per thread,
	   so clients which cannot provide future frames should not use it.

	   Possible values:

	   slice
	       Decode more than one part of a single frame at once.

	       Multithreading using slices works only when the video was
	       encoded with slices.

	   frame
	       Decode more than one frame at once.

	   Default value is slice+frame.

       audio_service_type integer (encoding,audio)
	   Set audio service type.

	   Possible values:

	   ma  Main Audio Service

	   ef  Effects

	   vi  Visually Impaired

	   hi  Hearing Impaired

	   di  Dialogue

	   co  Commentary

	   em  Emergency

	   vo  Voice Over

	   ka  Karaoke

       request_sample_fmt sample_fmt (decoding,audio)
	   Set sample format audio decoders should prefer. Default value is
	   "none".

       pkt_timebase rational number
       sub_charenc encoding (decoding,subtitles)
	   Set the input subtitles character encoding.

       field_order  field_order (video)
	   Set/override the field order of the video.  Possible values:

	   progressive
	       Progressive video

	   tt  Interlaced video, top field coded and displayed first

	   bb  Interlaced video, bottom field coded and displayed first

	   tb  Interlaced video, top coded first, bottom displayed first

	   bt  Interlaced video, bottom coded first, top displayed first

       skip_alpha bool (decoding,video)
	   Set to 1 to disable processing alpha (transparency). This works
	   like the gray flag in the flags option which skips chroma
	   information instead of alpha. Default is 0.

       codec_whitelist list (input)
	   "," separated list of allowed decoders. By default all are allowed.

       dump_separator string (input)
	   Separator used to separate the fields printed on the command line
	   about the Stream parameters.  For example, to separate the fields
	   with newlines and indentation:

		   ffprobe -dump_separator "
					     "	-i ~/videos/matrixbench_mpeg2.mpg

       max_pixels integer (decoding/encoding,video)
	   Maximum number of pixels per image. This value can be used to avoid
	   out of memory failures due to large images.

       apply_cropping bool (decoding,video)
	   Enable cropping if cropping parameters are multiples of the
	   required alignment for the left and top parameters. If the
	   alignment is not met the cropping will be partially applied to
	   maintain alignment.	Default is 1 (enabled).  Note: The required
	   alignment depends on if "AV_CODEC_FLAG_UNALIGNED" is set and the
	   CPU. "AV_CODEC_FLAG_UNALIGNED" cannot be changed from the command
	   line. Also hardware decoders will not apply left/top Cropping.

DECODERS
       Decoders are configured elements in FFmpeg which allow the decoding of
       multimedia streams.

       When you configure your FFmpeg build, all the supported native decoders
       are enabled by default. Decoders requiring an external library must be
       enabled manually via the corresponding "--enable-lib" option. You can
       list all available decoders using the configure option
       "--list-decoders".

       You can disable all the decoders with the configure option
       "--disable-decoders" and selectively enable / disable single decoders
       with the options "--enable-decoder=DECODER" /
       "--disable-decoder=DECODER".

       The option "-decoders" of the ff* tools will display the list of
       enabled decoders.

VIDEO DECODERS
       A description of some of the currently available video decoders
       follows.

   av1
       AOMedia Video 1 (AV1) decoder.

       Options

       operating_point
	   Select an operating point of a scalable AV1 bitstream (0 - 31).
	   Default is 0.

   rawvideo
       Raw video decoder.

       This decoder decodes rawvideo streams.

       Options

       top top_field_first
	   Specify the assumed field type of the input video.

	   -1  the video is assumed to be progressive (default)

	   0   bottom-field-first is assumed

	   1   top-field-first is assumed

   libdav1d
       dav1d AV1 decoder.

       libdav1d allows libavcodec to decode the AOMedia Video 1 (AV1) codec.
       Requires the presence of the libdav1d headers and library during
       configuration.  You need to explicitly configure the build with
       "--enable-libdav1d".

       Options

       The following options are supported by the libdav1d wrapper.

       framethreads
	   Set amount of frame threads to use during decoding. The default
	   value is 0 (autodetect).  This option is deprecated for libdav1d >=
	   1.0 and will be removed in the future. Use the option
	   "max_frame_delay" and the global option "threads" instead.

       tilethreads
	   Set amount of tile threads to use during decoding. The default
	   value is 0 (autodetect).  This option is deprecated for libdav1d >=
	   1.0 and will be removed in the future. Use the global option
	   "threads" instead.

       max_frame_delay
	   Set max amount of frames the decoder may buffer internally. The
	   default value is 0 (autodetect).

       filmgrain
	   Apply film grain to the decoded video if present in the bitstream.
	   Defaults to the internal default of the library.  This option is
	   deprecated and will be removed in the future. See the global option
	   "export_side_data" to export Film Grain parameters instead of
	   applying it.

       oppoint
	   Select an operating point of a scalable AV1 bitstream (0 - 31).
	   Defaults to the internal default of the library.

       alllayers
	   Output all spatial layers of a scalable AV1 bitstream. The default
	   value is false.

   libdavs2
       AVS2-P2/IEEE1857.4 video decoder wrapper.

       This decoder allows libavcodec to decode AVS2 streams with davs2
       library.

   libuavs3d
       AVS3-P2/IEEE1857.10 video decoder.

       libuavs3d allows libavcodec to decode AVS3 streams.  Requires the
       presence of the libuavs3d headers and library during configuration.
       You need to explicitly configure the build with "--enable-libuavs3d".

       Options

       The following option is supported by the libuavs3d wrapper.

       frame_threads
	   Set amount of frame threads to use during decoding. The default
	   value is 0 (autodetect).

   libxevd
       eXtra-fast Essential Video Decoder (XEVD) MPEG-5 EVC decoder wrapper.

       This decoder requires the presence of the libxevd headers and library
       during configuration. You need to explicitly configure the build with
       --enable-libxevd.

       The xevd project website is at <https://github.com/mpeg5/xevd>.

       Options

       The following options are supported by the libxevd wrapper.  The xevd-
       equivalent options or values are listed in parentheses for easy
       migration.

       To get a more accurate and extensive documentation of the libxevd
       options, invoke the command  "xevd_app --help" or consult the libxevd
       documentation.

       threads (threads)
	   Force to use a specific number of threads

   QSV Decoders
       The family of Intel QuickSync Video decoders (VC1, MPEG-2, H.264, HEVC,
       JPEG/MJPEG, VP8, VP9, AV1).

       Common Options

       The following options are supported by all qsv decoders.

       async_depth
	   Internal parallelization depth, the higher the value the higher the
	   latency.

       gpu_copy
	   A GPU-accelerated copy between video and system memory

	   default
	   on
	   off

       HEVC Options

       Extra options for hevc_qsv.

       load_plugin
	   A user plugin to load in an internal session

	   none
	   hevc_sw
	   hevc_hw
       load_plugins
	   A :-separate list of hexadecimal plugin UIDs to load in an internal
	   session

   v210
       Uncompressed 4:2:2 10-bit decoder.

       Options

       custom_stride
	   Set the line size of the v210 data in bytes. The default value is 0
	   (autodetect). You can use the special -1 value for a strideless
	   v210 as seen in BOXX files.

AUDIO DECODERS
       A description of some of the currently available audio decoders
       follows.

   ac3
       AC-3 audio decoder.

       This decoder implements part of ATSC A/52:2010 and ETSI TS 102 366, as
       well as the undocumented RealAudio 3 (a.k.a. dnet).

       AC-3 Decoder Options

       -drc_scale value
	   Dynamic Range Scale Factor. The factor to apply to dynamic range
	   values from the AC-3 stream. This factor is applied exponentially.
	   The default value is 1.  There are 3 notable scale factor ranges:

	   drc_scale == 0
	       DRC disabled. Produces full range audio.

	   0 < drc_scale <= 1
	       DRC enabled.  Applies a fraction of the stream DRC value.
	       Audio reproduction is between full range and full compression.

	   drc_scale > 1
	       DRC enabled. Applies drc_scale asymmetrically.  Loud sounds are
	       fully compressed.  Soft sounds are enhanced.

   flac
       FLAC audio decoder.

       This decoder aims to implement the complete FLAC specification from
       Xiph.

       FLAC Decoder options

       -use_buggy_lpc
	   The lavc FLAC encoder used to produce buggy streams with high lpc
	   values (like the default value). This option makes it possible to
	   decode such streams correctly by using lavc's old buggy lpc logic
	   for decoding.

   ffwavesynth
       Internal wave synthesizer.

       This decoder generates wave patterns according to predefined sequences.
       Its use is purely internal and the format of the data it accepts is not
       publicly documented.

   libcelt
       libcelt decoder wrapper.

       libcelt allows libavcodec to decode the Xiph CELT ultra-low delay audio
       codec.  Requires the presence of the libcelt headers and library during
       configuration.  You need to explicitly configure the build with
       "--enable-libcelt".

   libgsm
       libgsm decoder wrapper.

       libgsm allows libavcodec to decode the GSM full rate audio codec.
       Requires the presence of the libgsm headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libgsm".

       This decoder supports both the ordinary GSM and the Microsoft variant.

   libilbc
       libilbc decoder wrapper.

       libilbc allows libavcodec to decode the Internet Low Bitrate Codec
       (iLBC) audio codec. Requires the presence of the libilbc headers and
       library during configuration. You need to explicitly configure the
       build with "--enable-libilbc".

       Options

       The following option is supported by the libilbc wrapper.

       enhance
	   Enable the enhancement of the decoded audio when set to 1. The
	   default value is 0 (disabled).

   libopencore-amrnb
       libopencore-amrnb decoder wrapper.

       libopencore-amrnb allows libavcodec to decode the Adaptive Multi-Rate
       Narrowband audio codec. Using it requires the presence of the
       libopencore-amrnb headers and library during configuration. You need to
       explicitly configure the build with "--enable-libopencore-amrnb".

       An FFmpeg native decoder for AMR-NB exists, so users can decode AMR-NB
       without this library.

   libopencore-amrwb
       libopencore-amrwb decoder wrapper.

       libopencore-amrwb allows libavcodec to decode the Adaptive Multi-Rate
       Wideband audio codec. Using it requires the presence of the
       libopencore-amrwb headers and library during configuration. You need to
       explicitly configure the build with "--enable-libopencore-amrwb".

       An FFmpeg native decoder for AMR-WB exists, so users can decode AMR-WB
       without this library.

   libopus
       libopus decoder wrapper.

       libopus allows libavcodec to decode the Opus Interactive Audio Codec.
       Requires the presence of the libopus headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libopus".

       An FFmpeg native decoder for Opus exists, so users can decode Opus
       without this library.

SUBTITLES DECODERS
   libaribb24
       ARIB STD-B24 caption decoder.

       Implements profiles A and C of the ARIB STD-B24 standard.

       libaribb24 Decoder Options

       -aribb24-base-path path
	   Sets the base path for the libaribb24 library. This is utilized for
	   reading of configuration files (for custom unicode conversions),
	   and for dumping of non-text symbols as images under that location.

	   Unset by default.

       -aribb24-skip-ruby-text boolean
	   Tells the decoder wrapper to skip text blocks that contain half-
	   height ruby text.

	   Enabled by default.

   libaribcaption
       Yet another ARIB STD-B24 caption decoder using external libaribcaption
       library.

       Implements profiles A and C of the Japanse ARIB STD-B24 standard,
       Brazilian ABNT NBR 15606-1, and Philippines version of ISDB-T.

       Requires the presence of the libaribcaption headers and library
       (<https://github.com/xqq/libaribcaption>) during configuration.	You
       need to explicitly configure the build with "--enable-libaribcaption".
       If both libaribb24 and libaribcaption are enabled, libaribcaption
       decoder precedes.

       libaribcaption Decoder Options

       -sub_type subtitle_type
	   Specifies the format of the decoded subtitles.

	   bitmap
	       Graphical image.

	   ass ASS formatted text.

	   text
	       Simple text based output without formatting.

	   The default is ass as same as libaribb24 decoder.  Some present
	   players (e.g., mpv) expect ASS format for ARIB caption.

       -caption_encoding encoding_scheme
	   Specifies the encoding scheme of input subtitle text.

	   auto
	       Automatically detect text encoding (default).

	   jis 8bit-char JIS encoding defined in ARIB STD B24.	This encoding
	       used in Japan for ISDB captions.

	   utf8
	       UTF-8 encoding defined in ARIB STD B24.	This encoding is used
	       in Philippines for ISDB-T captions.

	   latin
	       Latin character encoding defined in ABNT NBR 15606-1.  This
	       encoding is used in South America for SBTVD / ISDB-Tb captions.

       -font font_name[,font_name2,...]
	   Specify comma-separated list of font family names to be used for
	   bitmap or ass type subtitle rendering.  Only first font name is
	   used for ass type subtitle.

	   If not specified, use internaly defined default font family.

       -ass_single_rect boolean
	   ARIB STD-B24 specifies that some captions may be displayed at
	   different positions at a time (multi-rectangle subtitle).  Since
	   some players (e.g., old mpv) can't handle multiple ASS rectangles
	   in a single AVSubtitle, or multiple ASS rectangles of indeterminate
	   duration with the same start timestamp, this option can change the
	   behavior so that all the texts are displayed in a single ASS
	   rectangle.

	   The default is false.

	   If your player cannot handle AVSubtitles with multiple ASS
	   rectangles properly, set this option to true or define
	   ASS_SINGLE_RECT=1 to change default behavior at compilation.

       -force_outline_text boolean
	   Specify whether always render outline text for all characters
	   regardless of the indication by charactor style.

	   The default is false.

       -outline_width number (0.0 - 3.0)
	   Specify width for outline text, in dots (relative).

	   The default is 1.5.

       -ignore_background boolean
	   Specify whether to ignore background color rendering.

	   The default is false.

       -ignore_ruby boolean
	   Specify whether to ignore rendering for ruby-like (furigana)
	   characters.

	   The default is false.

       -replace_drcs boolean
	   Specify whether to render replaced DRCS characters as Unicode
	   characters.

	   The default is true.

       -replace_msz_ascii boolean
	   Specify whether to replace MSZ (Middle Size; half width) fullwidth
	   alphanumerics with halfwidth alphanumerics.

	   The default is true.

       -replace_msz_japanese boolean
	   Specify whether to replace some MSZ (Middle Size; half width)
	   fullwidth japanese special characters with halfwidth ones.

	   The default is true.

       -replace_msz_glyph boolean
	   Specify whether to replace MSZ (Middle Size; half width) characters
	   with halfwidth glyphs if the fonts supports it.  This option works
	   under FreeType or DirectWrite renderer with Adobe-Japan1 compliant
	   fonts.  e.g., IBM Plex Sans JP, Morisawa BIZ UDGothic, Morisawa BIZ
	   UDMincho, Yu Gothic, Yu Mincho, and Meiryo.

	   The default is true.

       -canvas_size image_size
	   Specify the resolution of the canvas to render subtitles to;
	   usually, this should be frame size of input video.  This only
	   applies when "-subtitle_type" is set to bitmap.

	   The libaribcaption decoder assumes input frame size for bitmap
	   rendering as below:

	   1.  PROFILE_A : 1440 x 1080 with SAR (PAR) 4:3

	   2.  PROFILE_C : 320 x 180 with SAR (PAR) 1:1

	   If actual frame size of input video does not match above
	   assumption, the rendered captions may be distorted.	To make the
	   captions undistorted, add "-canvas_size" option to specify actual
	   input video size.

	   Note that the "-canvas_size" option is not required for video with
	   different size but same aspect ratio.  In such cases, the caption
	   will be stretched or shrunk to actual video size if "-canvas_size"
	   option is not specified.  If "-canvas_size" option is specified
	   with different size, the caption will be stretched or shrunk as
	   specified size with calculated SAR.

       libaribcaption decoder usage examples

       Display MPEG-TS file with ARIB subtitle by "ffplay" tool:

	       ffplay -sub_type bitmap MPEG.TS

       Display MPEG-TS file with input frame size 1920x1080 by "ffplay" tool:

	       ffplay -sub_type bitmap -canvas_size 1920x1080 MPEG.TS

       Embed ARIB subtitle in transcoded video:

	       ffmpeg -sub_type bitmap -i src.m2t -filter_complex "[0:v][0:s]overlay" -vcodec h264 dest.mp4

   dvbsub
       Options

       compute_clut
	   -2  Compute clut once if no matching CLUT is in the stream.

	   -1  Compute clut if no matching CLUT is in the stream.

	   0   Never compute CLUT

	   1   Always compute CLUT and override the one provided in the
	       stream.

       dvb_substream
	   Selects the dvb substream, or all substreams if -1 which is
	   default.

   dvdsub
       This codec decodes the bitmap subtitles used in DVDs; the same
       subtitles can also be found in VobSub file pairs and in some Matroska
       files.

       Options

       palette
	   Specify the global palette used by the bitmaps. When stored in
	   VobSub, the palette is normally specified in the index file; in
	   Matroska, the palette is stored in the codec extra-data in the same
	   format as in VobSub. In DVDs, the palette is stored in the IFO
	   file, and therefore not available when reading from dumped VOB
	   files.

	   The format for this option is a string containing 16 24-bits
	   hexadecimal numbers (without 0x prefix) separated by commas, for
	   example "0d00ee, ee450d, 101010, eaeaea, 0ce60b, ec14ed, ebff0b,
	   0d617a, 7b7b7b, d1d1d1, 7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c,
	   7c127b".

       ifo_palette
	   Specify the IFO file from which the global palette is obtained.
	   (experimental)

       forced_subs_only
	   Only decode subtitle entries marked as forced. Some titles have
	   forced and non-forced subtitles in the same track. Setting this
	   flag to 1 will only keep the forced subtitles. Default value is 0.

   libzvbi-teletext
       Libzvbi allows libavcodec to decode DVB teletext pages and DVB teletext
       subtitles. Requires the presence of the libzvbi headers and library
       during configuration. You need to explicitly configure the build with
       "--enable-libzvbi".

       Options

       txt_page
	   List of teletext page numbers to decode. Pages that do not match
	   the specified list are dropped. You may use the special "*" string
	   to match all pages, or "subtitle" to match all subtitle pages.
	   Default value is *.

       txt_default_region
	   Set default character set used for decoding, a value between 0 and
	   87 (see ETS 300 706, Section 15, Table 32). Default value is -1,
	   which does not override the libzvbi default. This option is needed
	   for some legacy level 1.0 transmissions which cannot signal the
	   proper charset.

       txt_chop_top
	   Discards the top teletext line. Default value is 1.

       txt_format
	   Specifies the format of the decoded subtitles.

	   bitmap
	       The default format, you should use this for teletext pages,
	       because certain graphics and colors cannot be expressed in
	       simple text or even ASS.

	   text
	       Simple text based output without formatting.

	   ass Formatted ASS output, subtitle pages and teletext pages are
	       returned in different styles, subtitle pages are stripped down
	       to text, but an effort is made to keep the text alignment and
	       the formatting.

       txt_left
	   X offset of generated bitmaps, default is 0.

       txt_top
	   Y offset of generated bitmaps, default is 0.

       txt_chop_spaces
	   Chops leading and trailing spaces and removes empty lines from the
	   generated text. This option is useful for teletext based subtitles
	   where empty spaces may be present at the start or at the end of the
	   lines or empty lines may be present between the subtitle lines
	   because of double-sized teletext characters.  Default value is 1.

       txt_duration
	   Sets the display duration of the decoded teletext pages or
	   subtitles in milliseconds. Default value is -1 which means infinity
	   or until the next subtitle event comes.

       txt_transparent
	   Force transparent background of the generated teletext bitmaps.
	   Default value is 0 which means an opaque background.

       txt_opacity
	   Sets the opacity (0-255) of the teletext background. If
	   txt_transparent is not set, it only affects characters between a
	   start box and an end box, typically subtitles. Default value is 0
	   if txt_transparent is set, 255 otherwise.

ENCODERS
       Encoders are configured elements in FFmpeg which allow the encoding of
       multimedia streams.

       When you configure your FFmpeg build, all the supported native encoders
       are enabled by default. Encoders requiring an external library must be
       enabled manually via the corresponding "--enable-lib" option. You can
       list all available encoders using the configure option
       "--list-encoders".

       You can disable all the encoders with the configure option
       "--disable-encoders" and selectively enable / disable single encoders
       with the options "--enable-encoder=ENCODER" /
       "--disable-encoder=ENCODER".

       The option "-encoders" of the ff* tools will display the list of
       enabled encoders.

AUDIO ENCODERS
       A description of some of the currently available audio encoders
       follows.

   aac
       Advanced Audio Coding (AAC) encoder.

       This encoder is the default AAC encoder, natively implemented into
       FFmpeg.

       Options

       b   Set bit rate in bits/s. Setting this automatically activates
	   constant bit rate (CBR) mode. If this option is unspecified it is
	   set to 128kbps.

       q   Set quality for variable bit rate (VBR) mode. This option is valid
	   only using the ffmpeg command-line tool. For library interface
	   users, use global_quality.

       cutoff
	   Set cutoff frequency. If unspecified will allow the encoder to
	   dynamically adjust the cutoff to improve clarity on low bitrates.

       aac_coder
	   Set AAC encoder coding method. Possible values:

	   twoloop
	       Two loop searching (TLS) method. This is the default method.

	       This method first sets quantizers depending on band thresholds
	       and then tries to find an optimal combination by adding or
	       subtracting a specific value from all quantizers and adjusting
	       some individual quantizer a little.  Will tune itself based on
	       whether aac_is, aac_ms and aac_pns are enabled.

	   anmr
	       Average noise to mask ratio (ANMR) trellis-based solution.

	       This is an experimental coder which currently produces a lower
	       quality, is more unstable and is slower than the default
	       twoloop coder but has potential.  Currently has no support for
	       the aac_is or aac_pns options.  Not currently recommended.

	   fast
	       Constant quantizer method.

	       Uses a cheaper version of twoloop algorithm that doesn't try to
	       do as many clever adjustments. Worse with low bitrates (less
	       than 64kbps), but is better and much faster at higher bitrates.

       aac_ms
	   Sets mid/side coding mode. The default value of "auto" will
	   automatically use M/S with bands which will benefit from such
	   coding. Can be forced for all bands using the value "enable", which
	   is mainly useful for debugging or disabled using "disable".

       aac_is
	   Sets intensity stereo coding tool usage. By default, it's enabled
	   and will automatically toggle IS for similar pairs of stereo bands
	   if it's beneficial.	Can be disabled for debugging by setting the
	   value to "disable".

       aac_pns
	   Uses perceptual noise substitution to replace low entropy high
	   frequency bands with imperceptible white noise during the decoding
	   process. By default, it's enabled, but can be disabled for
	   debugging purposes by using "disable".

       aac_tns
	   Enables the use of a multitap FIR filter which spans through the
	   high frequency bands to hide quantization noise during the encoding
	   process and is reverted by the decoder. As well as decreasing
	   unpleasant artifacts in the high range this also reduces the
	   entropy in the high bands and allows for more bits to be used by
	   the mid-low bands. By default it's enabled but can be disabled for
	   debugging by setting the option to "disable".

       aac_ltp
	   Enables the use of the long term prediction extension which
	   increases coding efficiency in very low bandwidth situations such
	   as encoding of voice or solo piano music by extending constant
	   harmonic peaks in bands throughout frames. This option is implied
	   by profile:a aac_low and is incompatible with aac_pred. Use in
	   conjunction with -ar to decrease the samplerate.

       aac_pred
	   Enables the use of a more traditional style of prediction where the
	   spectral coefficients transmitted are replaced by the difference of
	   the current coefficients minus the previous "predicted"
	   coefficients. In theory and sometimes in practice this can improve
	   quality for low to mid bitrate audio.  This option implies the
	   aac_main profile and is incompatible with aac_ltp.

       profile
	   Sets the encoding profile, possible values:

	   aac_low
	       The default, AAC "Low-complexity" profile. Is the most
	       compatible and produces decent quality.

	   mpeg2_aac_low
	       Equivalent to "-profile:a aac_low -aac_pns 0". PNS was
	       introduced with the MPEG4 specifications.

	   aac_ltp
	       Long term prediction profile, is enabled by and will enable the
	       aac_ltp option. Introduced in MPEG4.

	   aac_main
	       Main-type prediction profile, is enabled by and will enable the
	       aac_pred option. Introduced in MPEG2.

	   If this option is unspecified it is set to aac_low.

   ac3 and ac3_fixed
       AC-3 audio encoders.

       These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as
       well as the undocumented RealAudio 3 (a.k.a. dnet).

       The ac3 encoder uses floating-point math, while the ac3_fixed encoder
       only uses fixed-point integer math. This does not mean that one is
       always faster, just that one or the other may be better suited to a
       particular system. The ac3_fixed encoder is not the default codec for
       any of the output formats, so it must be specified explicitly using the
       option "-acodec ac3_fixed" in order to use it.

       AC-3 Metadata

       The AC-3 metadata options are used to set parameters that describe the
       audio, but in most cases do not affect the audio encoding itself. Some
       of the options do directly affect or influence the decoding and
       playback of the resulting bitstream, while others are just for
       informational purposes. A few of the options will add bits to the
       output stream that could otherwise be used for audio data, and will
       thus affect the quality of the output. Those will be indicated
       accordingly with a note in the option list below.

       These parameters are described in detail in several publicly-available
       documents.

       *<<http://www.atsc.org/cms/standards/a_52-2010.pdf>>
       *<<http://www.atsc.org/cms/standards/a_54a_with_corr_1.pdf>>
       *<<http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf>>
       *<<http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf>>

       Metadata Control Options

       -per_frame_metadata boolean
	   Allow Per-Frame Metadata. Specifies if the encoder should check for
	   changing metadata for each frame.

	   0   The metadata values set at initialization will be used for
	       every frame in the stream. (default)

	   1   Metadata values can be changed before encoding each frame.

       Downmix Levels

       -center_mixlev level
	   Center Mix Level. The amount of gain the decoder should apply to
	   the center channel when downmixing to stereo. This field will only
	   be written to the bitstream if a center channel is present. The
	   value is specified as a scale factor. There are 3 valid values:

	   0.707
	       Apply -3dB gain

	   0.595
	       Apply -4.5dB gain (default)

	   0.500
	       Apply -6dB gain

       -surround_mixlev level
	   Surround Mix Level. The amount of gain the decoder should apply to
	   the surround channel(s) when downmixing to stereo. This field will
	   only be written to the bitstream if one or more surround channels
	   are present. The value is specified as a scale factor.  There are 3
	   valid values:

	   0.707
	       Apply -3dB gain

	   0.500
	       Apply -6dB gain (default)

	   0.000
	       Silence Surround Channel(s)

       Audio Production Information

       Audio Production Information is optional information describing the
       mixing environment.  Either none or both of the fields are written to
       the bitstream.

       -mixing_level number
	   Mixing Level. Specifies peak sound pressure level (SPL) in the
	   production environment when the mix was mastered. Valid values are
	   80 to 111, or -1 for unknown or not indicated. The default value is
	   -1, but that value cannot be used if the Audio Production
	   Information is written to the bitstream. Therefore, if the
	   "room_type" option is not the default value, the "mixing_level"
	   option must not be -1.

       -room_type type
	   Room Type. Describes the equalization used during the final mixing
	   session at the studio or on the dubbing stage. A large room is a
	   dubbing stage with the industry standard X-curve equalization; a
	   small room has flat equalization.  This field will not be written
	   to the bitstream if both the "mixing_level" option and the
	   "room_type" option have the default values.

	   0
	   notindicated
	       Not Indicated (default)

	   1
	   large
	       Large Room

	   2
	   small
	       Small Room

       Other Metadata Options

       -copyright boolean
	   Copyright Indicator. Specifies whether a copyright exists for this
	   audio.

	   0
	   off No Copyright Exists (default)

	   1
	   on  Copyright Exists

       -dialnorm value
	   Dialogue Normalization. Indicates how far the average dialogue
	   level of the program is below digital 100% full scale (0 dBFS).
	   This parameter determines a level shift during audio reproduction
	   that sets the average volume of the dialogue to a preset level. The
	   goal is to match volume level between program sources. A value of
	   -31dB will result in no volume level change, relative to the source
	   volume, during audio reproduction. Valid values are whole numbers
	   in the range -31 to -1, with -31 being the default.

       -dsur_mode mode
	   Dolby Surround Mode. Specifies whether the stereo signal uses Dolby
	   Surround (Pro Logic). This field will only be written to the
	   bitstream if the audio stream is stereo. Using this option does NOT
	   mean the encoder will actually apply Dolby Surround processing.

	   0
	   notindicated
	       Not Indicated (default)

	   1
	   off Not Dolby Surround Encoded

	   2
	   on  Dolby Surround Encoded

       -original boolean
	   Original Bit Stream Indicator. Specifies whether this audio is from
	   the original source and not a copy.

	   0
	   off Not Original Source

	   1
	   on  Original Source (default)

       Extended Bitstream Information

       The extended bitstream options are part of the Alternate Bit Stream
       Syntax as specified in Annex D of the A/52:2010 standard. It is grouped
       into 2 parts.  If any one parameter in a group is specified, all values
       in that group will be written to the bitstream.	Default values are
       used for those that are written but have not been specified.  If the
       mixing levels are written, the decoder will use these values instead of
       the ones specified in the "center_mixlev" and "surround_mixlev" options
       if it supports the Alternate Bit Stream Syntax.

       Extended Bitstream Information - Part 1

       -dmix_mode mode
	   Preferred Stereo Downmix Mode. Allows the user to select either
	   Lt/Rt (Dolby Surround) or Lo/Ro (normal stereo) as the preferred
	   stereo downmix mode.

	   0
	   notindicated
	       Not Indicated (default)

	   1
	   ltrt
	       Lt/Rt Downmix Preferred

	   2
	   loro
	       Lo/Ro Downmix Preferred

       -ltrt_cmixlev level
	   Lt/Rt Center Mix Level. The amount of gain the decoder should apply
	   to the center channel when downmixing to stereo in Lt/Rt mode.

	   1.414
	       Apply +3dB gain

	   1.189
	       Apply +1.5dB gain

	   1.000
	       Apply 0dB gain

	   0.841
	       Apply -1.5dB gain

	   0.707
	       Apply -3.0dB gain

	   0.595
	       Apply -4.5dB gain (default)

	   0.500
	       Apply -6.0dB gain

	   0.000
	       Silence Center Channel

       -ltrt_surmixlev level
	   Lt/Rt Surround Mix Level. The amount of gain the decoder should
	   apply to the surround channel(s) when downmixing to stereo in Lt/Rt
	   mode.

	   0.841
	       Apply -1.5dB gain

	   0.707
	       Apply -3.0dB gain

	   0.595
	       Apply -4.5dB gain

	   0.500
	       Apply -6.0dB gain (default)

	   0.000
	       Silence Surround Channel(s)

       -loro_cmixlev level
	   Lo/Ro Center Mix Level. The amount of gain the decoder should apply
	   to the center channel when downmixing to stereo in Lo/Ro mode.

	   1.414
	       Apply +3dB gain

	   1.189
	       Apply +1.5dB gain

	   1.000
	       Apply 0dB gain

	   0.841
	       Apply -1.5dB gain

	   0.707
	       Apply -3.0dB gain

	   0.595
	       Apply -4.5dB gain (default)

	   0.500
	       Apply -6.0dB gain

	   0.000
	       Silence Center Channel

       -loro_surmixlev level
	   Lo/Ro Surround Mix Level. The amount of gain the decoder should
	   apply to the surround channel(s) when downmixing to stereo in Lo/Ro
	   mode.

	   0.841
	       Apply -1.5dB gain

	   0.707
	       Apply -3.0dB gain

	   0.595
	       Apply -4.5dB gain

	   0.500
	       Apply -6.0dB gain (default)

	   0.000
	       Silence Surround Channel(s)

       Extended Bitstream Information - Part 2

       -dsurex_mode mode
	   Dolby Surround EX Mode. Indicates whether the stream uses Dolby
	   Surround EX (7.1 matrixed to 5.1). Using this option does NOT mean
	   the encoder will actually apply Dolby Surround EX processing.

	   0
	   notindicated
	       Not Indicated (default)

	   1
	   on  Dolby Surround EX Off

	   2
	   off Dolby Surround EX On

       -dheadphone_mode mode
	   Dolby Headphone Mode. Indicates whether the stream uses Dolby
	   Headphone encoding (multi-channel matrixed to 2.0 for use with
	   headphones). Using this option does NOT mean the encoder will
	   actually apply Dolby Headphone processing.

	   0
	   notindicated
	       Not Indicated (default)

	   1
	   on  Dolby Headphone Off

	   2
	   off Dolby Headphone On

       -ad_conv_type type
	   A/D Converter Type. Indicates whether the audio has passed through
	   HDCD A/D conversion.

	   0
	   standard
	       Standard A/D Converter (default)

	   1
	   hdcd
	       HDCD A/D Converter

       Other AC-3 Encoding Options

       -stereo_rematrixing boolean
	   Stereo Rematrixing. Enables/Disables use of rematrixing for stereo
	   input. This is an optional AC-3 feature that increases quality by
	   selectively encoding the left/right channels as mid/side. This
	   option is enabled by default, and it is highly recommended that it
	   be left as enabled except for testing purposes.

       cutoff frequency
	   Set lowpass cutoff frequency. If unspecified, the encoder selects a
	   default determined by various other encoding parameters.

       Floating-Point-Only AC-3 Encoding Options

       These options are only valid for the floating-point encoder and do not
       exist for the fixed-point encoder due to the corresponding features not
       being implemented in fixed-point.

       -channel_coupling boolean
	   Enables/Disables use of channel coupling, which is an optional AC-3
	   feature that increases quality by combining high frequency
	   information from multiple channels into a single channel. The per-
	   channel high frequency information is sent with less accuracy in
	   both the frequency and time domains. This allows more bits to be
	   used for lower frequencies while preserving enough information to
	   reconstruct the high frequencies. This option is enabled by default
	   for the floating-point encoder and should generally be left as
	   enabled except for testing purposes or to increase encoding speed.

	   -1
	   auto
	       Selected by Encoder (default)

	   0
	   off Disable Channel Coupling

	   1
	   on  Enable Channel Coupling

       -cpl_start_band number
	   Coupling Start Band. Sets the channel coupling start band, from 1
	   to 15. If a value higher than the bandwidth is used, it will be
	   reduced to 1 less than the coupling end band. If auto is used, the
	   start band will be determined by the encoder based on the bit rate,
	   sample rate, and channel layout. This option has no effect if
	   channel coupling is disabled.

	   -1
	   auto
	       Selected by Encoder (default)

   flac
       FLAC (Free Lossless Audio Codec) Encoder

       Options

       The following options are supported by FFmpeg's flac encoder.

       compression_level
	   Sets the compression level, which chooses defaults for many other
	   options if they are not set explicitly. Valid values are from 0 to
	   12, 5 is the default.

       frame_size
	   Sets the size of the frames in samples per channel.

       lpc_coeff_precision
	   Sets the LPC coefficient precision, valid values are from 1 to 15,
	   15 is the default.

       lpc_type
	   Sets the first stage LPC algorithm

	   none
	       LPC is not used

	   fixed
	       fixed LPC coefficients

	   levinson
	   cholesky
       lpc_passes
	   Number of passes to use for Cholesky factorization during LPC
	   analysis

       min_partition_order
	   The minimum partition order

       max_partition_order
	   The maximum partition order

       prediction_order_method
	   estimation
	   2level
	   4level
	   8level
	   search
	       Bruteforce search

	   log
       ch_mode
	   Channel mode

	   auto
	       The mode is chosen automatically for each frame

	   indep
	       Channels are independently coded

	   left_side
	   right_side
	   mid_side
       exact_rice_parameters
	   Chooses if rice parameters are calculated exactly or approximately.
	   if set to 1 then they are chosen exactly, which slows the code down
	   slightly and improves compression slightly.

       multi_dim_quant
	   Multi Dimensional Quantization. If set to 1 then a 2nd stage LPC
	   algorithm is applied after the first stage to finetune the
	   coefficients. This is quite slow and slightly improves compression.

   opus
       Opus encoder.

       This is a native FFmpeg encoder for the Opus format. Currently, it's in
       development and only implements the CELT part of the codec. Its quality
       is usually worse and at best is equal to the libopus encoder.

       Options

       b   Set bit rate in bits/s. If unspecified it uses the number of
	   channels and the layout to make a good guess.

       opus_delay
	   Sets the maximum delay in milliseconds. Lower delays than 20ms will
	   very quickly decrease quality.

   libfdk_aac
       libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.

       The libfdk-aac library is based on the Fraunhofer FDK AAC code from the
       Android project.

       Requires the presence of the libfdk-aac headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libfdk-aac". The library is also incompatible with GPL, so if
       you allow the use of GPL, you should configure with "--enable-gpl
       --enable-nonfree --enable-libfdk-aac".

       This encoder has support for the AAC-HE profiles.

       VBR encoding, enabled through the vbr or flags +qscale options, is
       experimental and only works with some combinations of parameters.

       Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3
       or higher.

       For more information see the fdk-aac project at
       <http://sourceforge.net/p/opencore-amr/fdk-aac/>.

       Options

       The following options are mapped on the shared FFmpeg codec options.

       b   Set bit rate in bits/s. If the bitrate is not explicitly specified,
	   it is automatically set to a suitable value depending on the
	   selected profile.

	   In case VBR mode is enabled the option is ignored.

       ar  Set audio sampling rate (in Hz).

       channels
	   Set the number of audio channels.

       flags +qscale
	   Enable fixed quality, VBR (Variable Bit Rate) mode.	Note that VBR
	   is implicitly enabled when the vbr value is positive.

       cutoff
	   Set cutoff frequency. If not specified (or explicitly set to 0) it
	   will use a value automatically computed by the library. Default
	   value is 0.

       profile
	   Set audio profile.

	   The following profiles are recognized:

	   aac_low
	       Low Complexity AAC (LC)

	   aac_he
	       High Efficiency AAC (HE-AAC)

	   aac_he_v2
	       High Efficiency AAC version 2 (HE-AACv2)

	   aac_ld
	       Low Delay AAC (LD)

	   aac_eld
	       Enhanced Low Delay AAC (ELD)

	   If not specified it is set to aac_low.

       The following are private options of the libfdk_aac encoder.

       afterburner
	   Enable afterburner feature if set to 1, disabled if set to 0. This
	   improves the quality but also the required processing power.

	   Default value is 1.

       eld_sbr
	   Enable SBR (Spectral Band Replication) for ELD if set to 1,
	   disabled if set to 0.

	   Default value is 0.

       eld_v2
	   Enable ELDv2 (LD-MPS extension for ELD stereo signals) for ELDv2 if
	   set to 1, disabled if set to 0.

	   Note that option is available when fdk-aac version
	   (AACENCODER_LIB_VL0.AACENCODER_LIB_VL1.AACENCODER_LIB_VL2) >
	   (4.0.0).

	   Default value is 0.

       signaling
	   Set SBR/PS signaling style.

	   It can assume one of the following values:

	   default
	       choose signaling implicitly (explicit hierarchical by default,
	       implicit if global header is disabled)

	   implicit
	       implicit backwards compatible signaling

	   explicit_sbr
	       explicit SBR, implicit PS signaling

	   explicit_hierarchical
	       explicit hierarchical signaling

	   Default value is default.

       latm
	   Output LATM/LOAS encapsulated data if set to 1, disabled if set to
	   0.

	   Default value is 0.

       header_period
	   Set StreamMuxConfig and PCE repetition period (in frames) for
	   sending in-band configuration buffers within LATM/LOAS transport
	   layer.

	   Must be a 16-bits non-negative integer.

	   Default value is 0.

       vbr Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
	   good) and 5 is highest quality. A value of 0 will disable VBR, and
	   CBR (Constant Bit Rate) is enabled.

	   Currently only the aac_low profile supports VBR encoding.

	   VBR modes 1-5 correspond to roughly the following average bit
	   rates:

	   1   32 kbps/channel

	   2   40 kbps/channel

	   3   48-56 kbps/channel

	   4   64 kbps/channel

	   5   about 80-96 kbps/channel

	   Default value is 0.

       frame_length
	   Set the audio frame length in samples. Default value is the
	   internal default of the library. Refer to the library's
	   documentation for information about supported values.

       Examples

       o   Use ffmpeg to convert an audio file to VBR AAC in an M4A (MP4)
	   container:

		   ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a

       o   Use ffmpeg to convert an audio file to CBR 64k kbps AAC, using the
	   High-Efficiency AAC profile:

		   ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a

   libmp3lame
       LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.

       Requires the presence of the libmp3lame headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libmp3lame".

       See libshine for a fixed-point MP3 encoder, although with a lower
       quality.

       Options

       The following options are supported by the libmp3lame wrapper. The
       lame-equivalent of the options are listed in parentheses.

       b (-b)
	   Set bitrate expressed in bits/s for CBR or ABR. LAME "bitrate" is
	   expressed in kilobits/s.

       q (-V)
	   Set constant quality setting for VBR. This option is valid only
	   using the ffmpeg command-line tool. For library interface users,
	   use global_quality.

       compression_level (-q)
	   Set algorithm quality. Valid arguments are integers in the 0-9
	   range, with 0 meaning highest quality but slowest, and 9 meaning
	   fastest while producing the worst quality.

       cutoff (--lowpass)
	   Set lowpass cutoff frequency. If unspecified, the encoder
	   dynamically adjusts the cutoff.

       reservoir
	   Enable use of bit reservoir when set to 1. Default value is 1. LAME
	   has this enabled by default, but can be overridden by use --nores
	   option.

       joint_stereo (-m j)
	   Enable the encoder to use (on a frame by frame basis) either L/R
	   stereo or mid/side stereo. Default value is 1.

       abr (--abr)
	   Enable the encoder to use ABR when set to 1. The lame --abr sets
	   the target bitrate, while this options only tells FFmpeg to use ABR
	   still relies on b to set bitrate.

       copyright (-c)
	   Set MPEG audio copyright flag when set to 1. The default value is 0
	   (disabled).

       original (-o)
	   Set MPEG audio original flag when set to 1. The default value is 1
	   (enabled).

   libopencore-amrnb
       OpenCORE Adaptive Multi-Rate Narrowband encoder.

       Requires the presence of the libopencore-amrnb headers and library
       during configuration. You need to explicitly configure the build with
       "--enable-libopencore-amrnb --enable-version3".

       This is a mono-only encoder. Officially it only supports 8000Hz sample
       rate, but you can override it by setting strict to unofficial or lower.

       Options

       b   Set bitrate in bits per second. Only the following bitrates are
	   supported, otherwise libavcodec will round to the nearest valid
	   bitrate.

	   4750
	   5150
	   5900
	   6700
	   7400
	   7950
	   10200
	   12200
       dtx Allow discontinuous transmission (generate comfort noise) when set
	   to 1. The default value is 0 (disabled).

   libopus
       libopus Opus Interactive Audio Codec encoder wrapper.

       Requires the presence of the libopus headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libopus".

       Option Mapping

       Most libopus options are modelled after the opusenc utility from opus-
       tools. The following is an option mapping chart describing options
       supported by the libopus wrapper, and their opusenc-equivalent in
       parentheses.

       b (bitrate)
	   Set the bit rate in bits/s.	FFmpeg's b option is expressed in
	   bits/s, while opusenc's bitrate in kilobits/s.

       vbr (vbr, hard-cbr, and cvbr)
	   Set VBR mode. The FFmpeg vbr option has the following valid
	   arguments, with the opusenc equivalent options in parentheses:

	   off (hard-cbr)
	       Use constant bit rate encoding.

	   on (vbr)
	       Use variable bit rate encoding (the default).

	   constrained (cvbr)
	       Use constrained variable bit rate encoding.

       compression_level (comp)
	   Set encoding algorithm complexity. Valid options are integers in
	   the 0-10 range. 0 gives the fastest encodes but lower quality,
	   while 10 gives the highest quality but slowest encoding. The
	   default is 10.

       frame_duration (framesize)
	   Set maximum frame size, or duration of a frame in milliseconds. The
	   argument must be exactly the following: 2.5, 5, 10, 20, 40, 60.
	   Smaller frame sizes achieve lower latency but less quality at a
	   given bitrate.  Sizes greater than 20ms are only interesting at
	   fairly low bitrates.  The default is 20ms.

       packet_loss (expect-loss)
	   Set expected packet loss percentage. The default is 0.

       fec (n/a)
	   Enable inband forward error correction. packet_loss must be non-
	   zero to take advantage - frequency of FEC 'side-data' is
	   proportional to expected packet loss.  Default is disabled.

       application (N.A.)
	   Set intended application type. Valid options are listed below:

	   voip
	       Favor improved speech intelligibility.

	   audio
	       Favor faithfulness to the input (the default).

	   lowdelay
	       Restrict to only the lowest delay modes by disabling voice-
	       optimized modes.

       cutoff (N.A.)
	   Set cutoff bandwidth in Hz. The argument must be exactly one of the
	   following: 4000, 6000, 8000, 12000, or 20000, corresponding to
	   narrowband, mediumband, wideband, super wideband, and fullband
	   respectively. The default is 0 (cutoff disabled). Note that libopus
	   forces a wideband cutoff for bitrates < 15 kbps, unless CELT-only
	   (application set to lowdelay) mode is used.

       mapping_family (mapping_family)
	   Set channel mapping family to be used by the encoder. The default
	   value of -1 uses mapping family 0 for mono and stereo inputs, and
	   mapping family 1 otherwise. The default also disables the surround
	   masking and LFE bandwidth optimzations in libopus, and requires
	   that the input contains 8 channels or fewer.

	   Other values include 0 for mono and stereo, 1 for surround sound
	   with masking and LFE bandwidth optimizations, and 255 for
	   independent streams with an unspecified channel layout.

       apply_phase_inv (N.A.) (requires libopus >= 1.2)
	   If set to 0, disables the use of phase inversion for intensity
	   stereo, improving the quality of mono downmixes, but slightly
	   reducing normal stereo quality. The default is 1 (phase inversion
	   enabled).

   libshine
       Shine Fixed-Point MP3 encoder wrapper.

       Shine is a fixed-point MP3 encoder. It has a far better performance on
       platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
       However, as it is more targeted on performance than quality, it is not
       on par with LAME and other production-grade encoders quality-wise.
       Also, according to the project's homepage, this encoder may not be free
       of bugs as the code was written a long time ago and the project was
       dead for at least 5 years.

       This encoder only supports stereo and mono input. This is also CBR-
       only.

       The original project (last updated in early 2007) is at
       <http://sourceforge.net/projects/libshine-fxp/>. We only support the
       updated fork by the Savonet/Liquidsoap project at
       <https://github.com/savonet/shine>.

       Requires the presence of the libshine headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libshine".

       See also libmp3lame.

       Options

       The following options are supported by the libshine wrapper. The
       shineenc-equivalent of the options are listed in parentheses.

       b (-b)
	   Set bitrate expressed in bits/s for CBR. shineenc -b option is
	   expressed in kilobits/s.

   libtwolame
       TwoLAME MP2 encoder wrapper.

       Requires the presence of the libtwolame headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libtwolame".

       Options

       The following options are supported by the libtwolame wrapper. The
       twolame-equivalent options follow the FFmpeg ones and are in
       parentheses.

       b (-b)
	   Set bitrate expressed in bits/s for CBR. twolame b option is
	   expressed in kilobits/s. Default value is 128k.

       q (-V)
	   Set quality for experimental VBR support. Maximum value range is
	   from -50 to 50, useful range is from -10 to 10. The higher the
	   value, the better the quality. This option is valid only using the
	   ffmpeg command-line tool. For library interface users, use
	   global_quality.

       mode (--mode)
	   Set the mode of the resulting audio. Possible values:

	   auto
	       Choose mode automatically based on the input. This is the
	       default.

	   stereo
	       Stereo

	   joint_stereo
	       Joint stereo

	   dual_channel
	       Dual channel

	   mono
	       Mono

       psymodel (--psyc-mode)
	   Set psychoacoustic model to use in encoding. The argument must be
	   an integer between -1 and 4, inclusive. The higher the value, the
	   better the quality. The default value is 3.

       energy_levels (--energy)
	   Enable energy levels extensions when set to 1. The default value is
	   0 (disabled).

       error_protection (--protect)
	   Enable CRC error protection when set to 1. The default value is 0
	   (disabled).

       copyright (--copyright)
	   Set MPEG audio copyright flag when set to 1. The default value is 0
	   (disabled).

       original (--original)
	   Set MPEG audio original flag when set to 1. The default value is 0
	   (disabled).

   libvo-amrwbenc
       VisualOn Adaptive Multi-Rate Wideband encoder.

       Requires the presence of the libvo-amrwbenc headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libvo-amrwbenc --enable-version3".

       This is a mono-only encoder. Officially it only supports 16000Hz sample
       rate, but you can override it by setting strict to unofficial or lower.

       Options

       b   Set bitrate in bits/s. Only the following bitrates are supported,
	   otherwise libavcodec will round to the nearest valid bitrate.

	   6600
	   8850
	   12650
	   14250
	   15850
	   18250
	   19850
	   23050
	   23850
       dtx Allow discontinuous transmission (generate comfort noise) when set
	   to 1. The default value is 0 (disabled).

   libvorbis
       libvorbis encoder wrapper.

       Requires the presence of the libvorbisenc headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libvorbis".

       Options

       The following options are supported by the libvorbis wrapper. The
       oggenc-equivalent of the options are listed in parentheses.

       To get a more accurate and extensive documentation of the libvorbis
       options, consult the libvorbisenc's and oggenc's documentations.  See
       <http://xiph.org/vorbis/>, <http://wiki.xiph.org/Vorbis-tools>, and
       oggenc(1).

       b (-b)
	   Set bitrate expressed in bits/s for ABR. oggenc -b is expressed in
	   kilobits/s.

       q (-q)
	   Set constant quality setting for VBR. The value should be a float
	   number in the range of -1.0 to 10.0. The higher the value, the
	   better the quality. The default value is 3.0.

	   This option is valid only using the ffmpeg command-line tool.  For
	   library interface users, use global_quality.

       cutoff (--advanced-encode-option lowpass_frequency=N)
	   Set cutoff bandwidth in Hz, a value of 0 disables cutoff. oggenc's
	   related option is expressed in kHz. The default value is 0 (cutoff
	   disabled).

       minrate (-m)
	   Set minimum bitrate expressed in bits/s. oggenc -m is expressed in
	   kilobits/s.

       maxrate (-M)
	   Set maximum bitrate expressed in bits/s. oggenc -M is expressed in
	   kilobits/s. This only has effect on ABR mode.

       iblock (--advanced-encode-option impulse_noisetune=N)
	   Set noise floor bias for impulse blocks. The value is a float
	   number from -15.0 to 0.0. A negative bias instructs the encoder to
	   pay special attention to the crispness of transients in the encoded
	   audio. The tradeoff for better transient response is a higher
	   bitrate.

   mjpeg
       Motion JPEG encoder.

       Options

       huffman
	   Set the huffman encoding strategy. Possible values:

	   default
	       Use the default huffman tables. This is the default strategy.

	   optimal
	       Compute and use optimal huffman tables.

   wavpack
       WavPack lossless audio encoder.

       Options

       The equivalent options for wavpack command line utility are listed in
       parentheses.

       Shared options

       The following shared options are effective for this encoder. Only
       special notes about this particular encoder will be documented here.
       For the general meaning of the options, see the Codec Options chapter.

       frame_size (--blocksize)
	   For this encoder, the range for this option is between 128 and
	   131072. Default is automatically decided based on sample rate and
	   number of channel.

	   For the complete formula of calculating default, see
	   libavcodec/wavpackenc.c.

       compression_level (-f, -h, -hh, and -x)

       Private options

       joint_stereo (-j)
	   Set whether to enable joint stereo. Valid values are:

	   on (1)
	       Force mid/side audio encoding.

	   off (0)
	       Force left/right audio encoding.

	   auto
	       Let the encoder decide automatically.

       optimize_mono
	   Set whether to enable optimization for mono. This option is only
	   effective for non-mono streams. Available values:

	   on  enabled

	   off disabled

VIDEO ENCODERS
       A description of some of the currently available video encoders
       follows.

   a64_multi, a64_multi5
       A64 / Commodore 64 multicolor charset encoder. "a64_multi5" is extended
       with 5th color (colram).

   Cinepak
       Cinepak aka CVID encoder.  Compatible with Windows 3.1 and vintage
       MacOS.

       Options

       g integer
	   Keyframe interval.  A keyframe is inserted at least every "-g"
	   frames, sometimes sooner.

       q:v integer
	   Quality factor. Lower is better. Higher gives lower bitrate.  The
	   following table lists bitrates when encoding akiyo_cif.y4m for
	   various values of "-q:v" with "-g 100":

	   "-q:v 1" 1918 kb/s
	   "-q:v 2" 1735 kb/s
	   "-q:v 4" 1500 kb/s
	   "-q:v 10" 1041 kb/s
	   "-q:v 20" 826 kb/s
	   "-q:v 40" 553 kb/s
	   "-q:v 100" 394 kb/s
	   "-q:v 200" 312 kb/s
	   "-q:v 400" 266 kb/s
	   "-q:v 1000" 237 kb/s
       max_extra_cb_iterations integer
	   Max extra codebook recalculation passes, more is better and slower.

       skip_empty_cb boolean
	   Avoid wasting bytes, ignore vintage MacOS decoder.

       max_strips integer
       min_strips integer
	   The minimum and maximum number of strips to use.  Wider range
	   sometimes improves quality.	More strips is generally better
	   quality but costs more bits.  Fewer strips tend to yield more
	   keyframes.  Vintage compatible is 1..3.

       strip_number_adaptivity integer
	   How much number of strips is allowed to change between frames.
	   Higher is better but slower.

   GIF
       GIF image/animation encoder.

       Options

       gifflags integer
	   Sets the flags used for GIF encoding.

	   offsetting
	       Enables picture offsetting.

	       Default is enabled.

	   transdiff
	       Enables transparency detection between frames.

	       Default is enabled.

       gifimage integer
	   Enables encoding one full GIF image per frame, rather than an
	   animated GIF.

	   Default value is 0.

       global_palette integer
	   Writes a palette to the global GIF header where feasible.

	   If disabled, every frame will always have a palette written, even
	   if there is a global palette supplied.

	   Default value is 1.

   Hap
       Vidvox Hap video encoder.

       Options

       format integer
	   Specifies the Hap format to encode.

	   hap
	   hap_alpha
	   hap_q

	   Default value is hap.

       chunks integer
	   Specifies the number of chunks to split frames into, between 1 and
	   64. This permits multithreaded decoding of large frames,
	   potentially at the cost of data-rate. The encoder may modify this
	   value to divide frames evenly.

	   Default value is 1.

       compressor integer
	   Specifies the second-stage compressor to use. If set to none,
	   chunks will be limited to 1, as chunked uncompressed frames offer
	   no benefit.

	   none
	   snappy

	   Default value is snappy.

   jpeg2000
       The native jpeg 2000 encoder is lossy by default, the "-q:v" option can
       be used to set the encoding quality. Lossless encoding can be selected
       with "-pred 1".

       Options

       format integer
	   Can be set to either "j2k" or "jp2" (the default) that makes it
	   possible to store non-rgb pix_fmts.

       tile_width integer
	   Sets tile width. Range is 1 to 1073741824. Default is 256.

       tile_height integer
	   Sets tile height. Range is 1 to 1073741824. Default is 256.

       pred integer
	   Allows setting the discrete wavelet transform (DWT) type

	   dwt97int (Lossy)
	   dwt53 (Lossless)

	   Default is "dwt97int"

       sop boolean
	   Enable this to add SOP marker at the start of each packet. Disabled
	   by default.

       eph boolean
	   Enable this to add EPH marker at the end of each packet header.
	   Disabled by default.

       prog integer
	   Sets the progression order to be used by the encoder.  Possible
	   values are:

	   lrcp
	   rlcp
	   rpcl
	   pcrl
	   cprl

	   Set to "lrcp" by default.

       layer_rates string
	   By default, when this option is not used, compression is done using
	   the quality metric.	This option allows for compression using
	   compression ratio. The compression ratio for each level could be
	   specified. The compression ratio of a layer "l" species the what
	   ratio of total file size is contained in the first "l" layers.

	   Example usage:

		   ffmpeg -i input.bmp -c:v jpeg2000 -layer_rates "100,10,1" output.j2k

	   This would compress the image to contain 3 layers, where the data
	   contained in the first layer would be compressed by 1000 times,
	   compressed by 100 in the first two layers, and shall contain all
	   data while using all 3 layers.

   librav1e
       rav1e AV1 encoder wrapper.

       Requires the presence of the rav1e headers and library during
       configuration.  You need to explicitly configure the build with
       "--enable-librav1e".

       Options

       qmax
	   Sets the maximum quantizer to use when using bitrate mode.

       qmin
	   Sets the minimum quantizer to use when using bitrate mode.

       qp  Uses quantizer mode to encode at the given quantizer (0-255).

       speed
	   Selects the speed preset (0-10) to encode with.

       tiles
	   Selects how many tiles to encode with.

       tile-rows
	   Selects how many rows of tiles to encode with.

       tile-columns
	   Selects how many columns of tiles to encode with.

       rav1e-params
	   Set rav1e options using a list of key=value pairs separated by ":".
	   See rav1e --help for a list of options.

	   For example to specify librav1e encoding options with
	   -rav1e-params:

		   ffmpeg -i input -c:v librav1e -b:v 500K -rav1e-params speed=5:low_latency=true output.mp4

   libaom-av1
       libaom AV1 encoder wrapper.

       Requires the presence of the libaom headers and library during
       configuration.  You need to explicitly configure the build with
       "--enable-libaom".

       Options

       The wrapper supports the following standard libavcodec options:

       b   Set bitrate target in bits/second.  By default this will use
	   variable-bitrate mode.  If maxrate and minrate are also set to the
	   same value then it will use constant-bitrate mode, otherwise if crf
	   is set as well then it will use constrained-quality mode.

       g keyint_min
	   Set key frame placement.  The GOP size sets the maximum distance
	   between key frames; if zero the output stream will be intra-only.
	   The minimum distance is ignored unless it is the same as the GOP
	   size, in which case key frames will always appear at a fixed
	   interval.  Not set by default, so without this option the library
	   has completely free choice about where to place key frames.

       qmin qmax
	   Set minimum/maximum quantisation values.  Valid range is from 0 to
	   63 (warning: this does not match the quantiser values actually used
	   by AV1 - divide by four to map real quantiser values to this
	   range).  Defaults to min/max (no constraint).

       minrate maxrate bufsize rc_init_occupancy
	   Set rate control buffering parameters.  Not used if not set -
	   defaults to unconstrained variable bitrate.

       threads
	   Set the number of threads to use while encoding.  This may require
	   the tiles or row-mt options to also be set to actually use the
	   specified number of threads fully. Defaults to the number of
	   hardware threads supported by the host machine.

       profile
	   Set the encoding profile.  Defaults to using the profile which
	   matches the bit depth and chroma subsampling of the input.

       The wrapper also has some specific options:

       cpu-used
	   Set the quality/encoding speed tradeoff.  Valid range is from 0 to
	   8, higher numbers indicating greater speed and lower quality.  The
	   default value is 1, which will be slow and high quality.

       auto-alt-ref
	   Enable use of alternate reference frames.  Defaults to the internal
	   default of the library.

       arnr-max-frames (frames)
	   Set altref noise reduction max frame count. Default is -1.

       arnr-strength (strength)
	   Set altref noise reduction filter strength. Range is -1 to 6.
	   Default is -1.

       aq-mode (aq-mode)
	   Set adaptive quantization mode. Possible values:

	   none (0)
	       Disabled.

	   variance (1)
	       Variance-based.

	   complexity (2)
	       Complexity-based.

	   cyclic (3)
	       Cyclic refresh.

       tune (tune)
	   Set the distortion metric the encoder is tuned with. Default is
	   "psnr".

	   psnr (0)
	   ssim (1)
       lag-in-frames
	   Set the maximum number of frames which the encoder may keep in
	   flight at any one time for lookahead purposes.  Defaults to the
	   internal default of the library.

       error-resilience
	   Enable error resilience features:

	   default
	       Improve resilience against losses of whole frames.

	   Not enabled by default.

       crf Set the quality/size tradeoff for constant-quality (no bitrate
	   target) and constrained-quality (with maximum bitrate target)
	   modes. Valid range is 0 to 63, higher numbers indicating lower
	   quality and smaller output size.  Only used if set; by default only
	   the bitrate target is used.

       static-thresh
	   Set a change threshold on blocks below which they will be skipped
	   by the encoder.  Defined in arbitrary units as a nonnegative
	   integer, defaulting to zero (no blocks are skipped).

       drop-threshold
	   Set a threshold for dropping frames when close to rate control
	   bounds.  Defined as a percentage of the target buffer - when the
	   rate control buffer falls below this percentage, frames will be
	   dropped until it has refilled above the threshold.  Defaults to
	   zero (no frames are dropped).

       denoise-noise-level (level)
	   Amount of noise to be removed for grain synthesis. Grain synthesis
	   is disabled if this option is not set or set to 0.

       denoise-block-size (pixels)
	   Block size used for denoising for grain synthesis. If not set, AV1
	   codec uses the default value of 32.

       undershoot-pct (pct)
	   Set datarate undershoot (min) percentage of the target bitrate.
	   Range is -1 to 100.	Default is -1.

       overshoot-pct (pct)
	   Set datarate overshoot (max) percentage of the target bitrate.
	   Range is -1 to 1000.  Default is -1.

       minsection-pct (pct)
	   Minimum percentage variation of the GOP bitrate from the target
	   bitrate. If minsection-pct is not set, the libaomenc wrapper
	   computes it as follows: "(minrate * 100 / bitrate)".  Range is -1
	   to 100. Default is -1 (unset).

       maxsection-pct (pct)
	   Maximum percentage variation of the GOP bitrate from the target
	   bitrate. If maxsection-pct is not set, the libaomenc wrapper
	   computes it as follows: "(maxrate * 100 / bitrate)".  Range is -1
	   to 5000. Default is -1 (unset).

       frame-parallel (boolean)
	   Enable frame parallel decodability features. Default is true.

       tiles
	   Set the number of tiles to encode the input video with, as columns
	   x rows.  Larger numbers allow greater parallelism in both encoding
	   and decoding, but may decrease coding efficiency.  Defaults to the
	   minimum number of tiles required by the size of the input video
	   (this is 1x1 (that is, a single tile) for sizes up to and including
	   4K).

       tile-columns tile-rows
	   Set the number of tiles as log2 of the number of tile rows and
	   columns.  Provided for compatibility with libvpx/VP9.

       row-mt (Requires libaom >= 1.0.0-759-g90a15f4f2)
	   Enable row based multi-threading. Disabled by default.

       enable-cdef (boolean)
	   Enable Constrained Directional Enhancement Filter. The libaom-av1
	   encoder enables CDEF by default.

       enable-restoration (boolean)
	   Enable Loop Restoration Filter. Default is true for libaom-av1.

       enable-global-motion (boolean)
	   Enable the use of global motion for block prediction. Default is
	   true.

       enable-intrabc (boolean)
	   Enable block copy mode for intra block prediction. This mode is
	   useful for screen content. Default is true.

       enable-rect-partitions (boolean) (Requires libaom >= v2.0.0)
	   Enable rectangular partitions. Default is true.

       enable-1to4-partitions (boolean) (Requires libaom >= v2.0.0)
	   Enable 1:4/4:1 partitions. Default is true.

       enable-ab-partitions (boolean) (Requires libaom >= v2.0.0)
	   Enable AB shape partitions. Default is true.

       enable-angle-delta (boolean) (Requires libaom >= v2.0.0)
	   Enable angle delta intra prediction. Default is true.

       enable-cfl-intra (boolean) (Requires libaom >= v2.0.0)
	   Enable chroma predicted from luma intra prediction. Default is
	   true.

       enable-filter-intra (boolean) (Requires libaom >= v2.0.0)
	   Enable filter intra predictor. Default is true.

       enable-intra-edge-filter (boolean) (Requires libaom >= v2.0.0)
	   Enable intra edge filter. Default is true.

       enable-smooth-intra (boolean) (Requires libaom >= v2.0.0)
	   Enable smooth intra prediction mode. Default is true.

       enable-paeth-intra (boolean) (Requires libaom >= v2.0.0)
	   Enable paeth predictor in intra prediction. Default is true.

       enable-palette (boolean) (Requires libaom >= v2.0.0)
	   Enable palette prediction mode. Default is true.

       enable-flip-idtx (boolean) (Requires libaom >= v2.0.0)
	   Enable extended transform type, including FLIPADST_DCT,
	   DCT_FLIPADST, FLIPADST_FLIPADST, ADST_FLIPADST, FLIPADST_ADST,
	   IDTX, V_DCT, H_DCT, V_ADST, H_ADST, V_FLIPADST, H_FLIPADST. Default
	   is true.

       enable-tx64 (boolean) (Requires libaom >= v2.0.0)
	   Enable 64-pt transform. Default is true.

       reduced-tx-type-set (boolean) (Requires libaom >= v2.0.0)
	   Use reduced set of transform types. Default is false.

       use-intra-dct-only (boolean) (Requires libaom >= v2.0.0)
	   Use DCT only for INTRA modes. Default is false.

       use-inter-dct-only (boolean) (Requires libaom >= v2.0.0)
	   Use DCT only for INTER modes. Default is false.

       use-intra-default-tx-only (boolean) (Requires libaom >= v2.0.0)
	   Use Default-transform only for INTRA modes. Default is false.

       enable-ref-frame-mvs (boolean) (Requires libaom >= v2.0.0)
	   Enable temporal mv prediction. Default is true.

       enable-reduced-reference-set (boolean) (Requires libaom >= v2.0.0)
	   Use reduced set of single and compound references. Default is
	   false.

       enable-obmc (boolean) (Requires libaom >= v2.0.0)
	   Enable obmc. Default is true.

       enable-dual-filter (boolean) (Requires libaom >= v2.0.0)
	   Enable dual filter. Default is true.

       enable-diff-wtd-comp (boolean) (Requires libaom >= v2.0.0)
	   Enable difference-weighted compound. Default is true.

       enable-dist-wtd-comp (boolean) (Requires libaom >= v2.0.0)
	   Enable distance-weighted compound. Default is true.

       enable-onesided-comp (boolean) (Requires libaom >= v2.0.0)
	   Enable one sided compound. Default is true.

       enable-interinter-wedge (boolean) (Requires libaom >= v2.0.0)
	   Enable interinter wedge compound. Default is true.

       enable-interintra-wedge (boolean) (Requires libaom >= v2.0.0)
	   Enable interintra wedge compound. Default is true.

       enable-masked-comp (boolean) (Requires libaom >= v2.0.0)
	   Enable masked compound. Default is true.

       enable-interintra-comp (boolean) (Requires libaom >= v2.0.0)
	   Enable interintra compound. Default is true.

       enable-smooth-interintra (boolean) (Requires libaom >= v2.0.0)
	   Enable smooth interintra mode. Default is true.

       aom-params
	   Set libaom options using a list of key=value pairs separated by
	   ":". For a list of supported options, see aomenc --help under the
	   section "AV1 Specific Options".

	   For example to specify libaom encoding options with -aom-params:

		   ffmpeg -i input -c:v libaom-av1 -b:v 500K -aom-params tune=psnr:enable-tpl-model=1 output.mp4

   libsvtav1
       SVT-AV1 encoder wrapper.

       Requires the presence of the SVT-AV1 headers and library during
       configuration.  You need to explicitly configure the build with
       "--enable-libsvtav1".

       Options

       profile
	   Set the encoding profile.

	   main
	   high
	   professional
       level
	   Set the operating point level. For example: '4.0'

       hielevel
	   Set the Hierarchical prediction levels.

	   3level
	   4level
	       This is the default.

       tier
	   Set the operating point tier.

	   main
	       This is the default.

	   high
       qmax
	   Set the maximum quantizer to use when using a bitrate mode.

       qmin
	   Set the minimum quantizer to use when using a bitrate mode.

       crf Constant rate factor value used in crf rate control mode (0-63).

       qp  Set the quantizer used in cqp rate control mode (0-63).

       sc_detection
	   Enable scene change detection.

       la_depth
	   Set number of frames to look ahead (0-120).

       preset
	   Set the quality-speed tradeoff, in the range 0 to 13.  Higher
	   values are faster but lower quality.

       tile_rows
	   Set log2 of the number of rows of tiles to use (0-6).

       tile_columns
	   Set log2 of the number of columns of tiles to use (0-4).

       svtav1-params
	   Set SVT-AV1 options using a list of key=value pairs separated by
	   ":". See the SVT-AV1 encoder user guide for a list of accepted
	   parameters.

   libjxl
       libjxl JPEG XL encoder wrapper.

       Requires the presence of the libjxl headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libjxl".

       Options

       The libjxl wrapper supports the following options:

       distance
	   Set the target Butteraugli distance. This is a quality setting:
	   lower distance yields higher quality, with distance=1.0 roughly
	   comparable to libjpeg Quality 90 for photographic content. Setting
	   distance=0.0 yields true lossless encoding. Valid values range
	   between 0.0 and 15.0, and sane values rarely exceed 5.0. Setting
	   distance=0.1 usually attains transparency for most input. The
	   default is 1.0.

       effort
	   Set the encoding effort used. Higher effort values produce more
	   consistent quality and usually produces a better quality/bpp curve,
	   at the cost of more CPU time required. Valid values range from 1 to
	   9, and the default is 7.

       modular
	   Force the encoder to use Modular mode instead of choosing
	   automatically. The default is to use VarDCT for lossy encoding and
	   Modular for lossless. VarDCT is generally superior to Modular for
	   lossy encoding but does not support lossless encoding.

   libkvazaar
       Kvazaar H.265/HEVC encoder.

       Requires the presence of the libkvazaar headers and library during
       configuration. You need to explicitly configure the build with
       --enable-libkvazaar.

       Options

       b   Set target video bitrate in bit/s and enable rate control.

       kvazaar-params
	   Set kvazaar parameters as a list of name=value pairs separated by
	   commas (,). See kvazaar documentation for a list of options.

   libopenh264
       Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.

       This encoder requires the presence of the libopenh264 headers and
       library during configuration. You need to explicitly configure the
       build with "--enable-libopenh264". The library is detected using pkg-
       config.

       For more information about the library see <http://www.openh264.org>.

       Options

       The following FFmpeg global options affect the configurations of the
       libopenh264 encoder.

       b   Set the bitrate (as a number of bits per second).

       g   Set the GOP size.

       maxrate
	   Set the max bitrate (as a number of bits per second).

       flags +global_header
	   Set global header in the bitstream.

       slices
	   Set the number of slices, used in parallelized encoding. Default
	   value is 0. This is only used when slice_mode is set to fixed.

       loopfilter
	   Enable loop filter, if set to 1 (automatically enabled). To disable
	   set a value of 0.

       profile
	   Set profile restrictions. If set to the value of main enable CABAC
	   (set the "SEncParamExt.iEntropyCodingModeFlag" flag to 1).

       max_nal_size
	   Set maximum NAL size in bytes.

       allow_skip_frames
	   Allow skipping frames to hit the target bitrate if set to 1.

   libtheora
       libtheora Theora encoder wrapper.

       Requires the presence of the libtheora headers and library during
       configuration. You need to explicitly configure the build with
       "--enable-libtheora".

       For more information about the libtheora project see
       <http://www.theora.org/>.

       Options

       The following global options are mapped to internal libtheora options
       which affect the quality and the bitrate of the encoded stream.

       b   Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode.
	   In case VBR (Variable Bit Rate) mode is enabled this option is
	   ignored.

       flags
	   Used to enable constant quality mode (VBR) encoding through the
	   qscale flag, and to enable the "pass1" and "pass2" modes.

       g   Set the GOP size.

       global_quality
	   Set the global quality as an integer in lambda units.

	   Only relevant when VBR mode is enabled with "flags +qscale". The
	   value is converted to QP units by dividing it by "FF_QP2LAMBDA",
	   clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
	   value in the native libtheora range [0-63]. A higher value
	   corresponds to a higher quality.

       q   Enable VBR mode when set to a non-negative value, and set constant
	   quality value as a double floating point value in QP units.

	   The value is clipped in the [0-10] range, and then multiplied by
	   6.3 to get a value in the native libtheora range [0-63].

	   This option is valid only using the ffmpeg command-line tool. For
	   library interface users, use global_quality.

       Examples

       o   Set maximum constant quality (VBR) encoding with ffmpeg:

		   ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg

       o   Use ffmpeg to convert a CBR 1000 kbps Theora video stream:

		   ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg

   libvpx
       VP8/VP9 format supported through libvpx.

       Requires the presence of the libvpx headers and library during
       configuration.  You need to explicitly configure the build with
       "--enable-libvpx".

       Options

       The following options are supported by the libvpx wrapper. The
       vpxenc-equivalent options or values are listed in parentheses for easy
       migration.

       To reduce the duplication of documentation, only the private options
       and some others requiring special attention are documented here. For
       the documentation of the undocumented generic options, see the Codec
       Options chapter.

       To get more documentation of the libvpx options, invoke the command
       ffmpeg -h encoder=libvpx, ffmpeg -h encoder=libvpx-vp9 or vpxenc
       --help. Further information is available in the libvpx API
       documentation.

       b (target-bitrate)
	   Set bitrate in bits/s. Note that FFmpeg's b option is expressed in
	   bits/s, while vpxenc's target-bitrate is in kilobits/s.

       g (kf-max-dist)
       keyint_min (kf-min-dist)
       qmin (min-q)
	   Minimum (Best Quality) Quantizer.

       qmax (max-q)
	   Maximum (Worst Quality) Quantizer.  Can be changed per-frame.

       bufsize (buf-sz, buf-optimal-sz)
	   Set ratecontrol buffer size (in bits). Note vpxenc's options are
	   specified in milliseconds, the libvpx wrapper converts this value
	   as follows: "buf-sz = bufsize * 1000 / bitrate", "buf-optimal-sz =
	   bufsize * 1000 / bitrate * 5 / 6".

       rc_init_occupancy (buf-initial-sz)
	   Set number of bits which should be loaded into the rc buffer before
	   decoding starts. Note vpxenc's option is specified in milliseconds,
	   the libvpx wrapper converts this value as follows:
	   "rc_init_occupancy * 1000 / bitrate".

       undershoot-pct
	   Set datarate undershoot (min) percentage of the target bitrate.

       overshoot-pct
	   Set datarate overshoot (max) percentage of the target bitrate.

       skip_threshold (drop-frame)
       qcomp (bias-pct)
       maxrate (maxsection-pct)
	   Set GOP max bitrate in bits/s. Note vpxenc's option is specified as
	   a percentage of the target bitrate, the libvpx wrapper converts
	   this value as follows: "(maxrate * 100 / bitrate)".

       minrate (minsection-pct)
	   Set GOP min bitrate in bits/s. Note vpxenc's option is specified as
	   a percentage of the target bitrate, the libvpx wrapper converts
	   this value as follows: "(minrate * 100 / bitrate)".

       minrate, maxrate, b end-usage=cbr
	   "(minrate == maxrate == bitrate)".

       crf (end-usage=cq, cq-level)
       tune (tune)
	   psnr (psnr)
	   ssim (ssim)
       quality, deadline (deadline)
	   best
	       Use best quality deadline. Poorly named and quite slow, this
	       option should be avoided as it may give worse quality output
	       than good.

	   good
	       Use good quality deadline. This is a good trade-off between
	       speed and quality when used with the cpu-used option.

	   realtime
	       Use realtime quality deadline.

       speed, cpu-used (cpu-used)
	   Set quality/speed ratio modifier. Higher values speed up the encode
	   at the cost of quality.

       nr (noise-sensitivity)
       static-thresh
	   Set a change threshold on blocks below which they will be skipped
	   by the encoder.

       slices (token-parts)
	   Note that FFmpeg's slices option gives the total number of
	   partitions, while vpxenc's token-parts is given as
	   "log2(partitions)".

       max-intra-rate
	   Set maximum I-frame bitrate as a percentage of the target bitrate.
	   A value of 0 means unlimited.

       force_key_frames
	   "VPX_EFLAG_FORCE_KF"

       Alternate reference frame related
	   auto-alt-ref
	       Enable use of alternate reference frames (2-pass only).	Values
	       greater than 1 enable multi-layer alternate reference frames
	       (VP9 only).

	   arnr-maxframes
	       Set altref noise reduction max frame count.

	   arnr-type
	       Set altref noise reduction filter type: backward, forward,
	       centered.

	   arnr-strength
	       Set altref noise reduction filter strength.

	   rc-lookahead, lag-in-frames (lag-in-frames)
	       Set number of frames to look ahead for frametype and
	       ratecontrol.

	   min-gf-interval
	       Set minimum golden/alternate reference frame interval (VP9
	       only).

       error-resilient
	   Enable error resiliency features.

       sharpness integer
	   Increase sharpness at the expense of lower PSNR.  The valid range
	   is [0, 7].

       ts-parameters
	   Sets the temporal scalability configuration using a :-separated
	   list of key=value pairs. For example, to specify temporal
	   scalability parameters with "ffmpeg":

		   ffmpeg -i INPUT -c:v libvpx -ts-parameters ts_number_layers=3:\
		   ts_target_bitrate=250,500,1000:ts_rate_decimator=4,2,1:\
		   ts_periodicity=4:ts_layer_id=0,2,1,2:ts_layering_mode=3 OUTPUT

	   Below is a brief explanation of each of the parameters, please
	   refer to "struct vpx_codec_enc_cfg" in "vpx/vpx_encoder.h" for more
	   details.

	   ts_number_layers
	       Number of temporal coding layers.

	   ts_target_bitrate
	       Target bitrate for each temporal layer (in kbps).  (bitrate
	       should be inclusive of the lower temporal layer).

	   ts_rate_decimator
	       Frame rate decimation factor for each temporal layer.

	   ts_periodicity
	       Length of the sequence defining frame temporal layer
	       membership.

	   ts_layer_id
	       Template defining the membership of frames to temporal layers.

	   ts_layering_mode
	       (optional) Selecting the temporal structure from a set of pre-
	       defined temporal layering modes.  Currently supports the
	       following options.

	       0   No temporal layering flags are provided internally, relies
		   on flags being passed in using "metadata" field in
		   "AVFrame" with following keys.

		   vp8-flags
		       Sets the flags passed into the encoder to indicate the
		       referencing scheme for the current frame.  Refer to
		       function "vpx_codec_encode" in "vpx/vpx_encoder.h" for
		       more details.

		   temporal_id
		       Explicitly sets the temporal id of the current frame to
		       encode.

	       2   Two temporal layers. 0-1...

	       3   Three temporal layers. 0-2-1-2...; with single reference
		   frame.

	       4   Same as option "3", except there is a dependency between
		   the two temporal layer 2 frames within the temporal period.

       VP8-specific options
	   screen-content-mode
	       Screen content mode, one of: 0 (off), 1 (screen), 2 (screen
	       with more aggressive rate control).

       VP9-specific options
	   lossless
	       Enable lossless mode.

	   tile-columns
	       Set number of tile columns to use. Note this is given as
	       "log2(tile_columns)". For example, 8 tile columns would be
	       requested by setting the tile-columns option to 3.

	   tile-rows
	       Set number of tile rows to use. Note this is given as
	       "log2(tile_rows)".  For example, 4 tile rows would be requested
	       by setting the tile-rows option to 2.

	   frame-parallel
	       Enable frame parallel decodability features.

	   aq-mode
	       Set adaptive quantization mode (0: off (default), 1: variance
	       2: complexity, 3: cyclic refresh, 4: equator360).

	   colorspace color-space
	       Set input color space. The VP9 bitstream supports signaling the
	       following colorspaces:

	       rgb sRGB
	       bt709 bt709
	       unspecified unknown
	       bt470bg bt601
	       smpte170m smpte170
	       smpte240m smpte240
	       bt2020_ncl bt2020
	   row-mt boolean
	       Enable row based multi-threading.

	   tune-content
	       Set content type: default (0), screen (1), film (2).

	   corpus-complexity
	       Corpus VBR mode is a variant of standard VBR where the
	       complexity distribution midpoint is passed in rather than
	       calculated for a specific clip or chunk.

	       The valid range is [0, 10000]. 0 (default) uses standard VBR.

	   enable-tpl boolean
	       Enable temporal dependency model.

	   ref-frame-config
	       Using per-frame metadata, set members of the structure
	       "vpx_svc_ref_frame_config_t" in "vpx/vp8cx.h" to fine-control
	       referencing schemes and frame buffer management.  Use a
	       :-separated list of key=value pairs.  For example,

		       av_dict_set(&av_frame->metadata, "ref-frame-config", \
		       "rfc_update_buffer_slot=7:rfc_lst_fb_idx=0:rfc_gld_fb_idx=1:rfc_alt_fb_idx=2:rfc_reference_last=0:rfc_reference_golden=0:rfc_reference_alt_ref=0");

	       rfc_update_buffer_slot
		   Indicates the buffer slot number to update

	       rfc_update_last
		   Indicates whether to update the LAST frame

	       rfc_update_golden
		   Indicates whether to update GOLDEN frame

	       rfc_update_alt_ref
		   Indicates whether to update ALT_REF frame

	       rfc_lst_fb_idx
		   LAST frame buffer index

	       rfc_gld_fb_idx
		   GOLDEN frame buffer index

	       rfc_alt_fb_idx
		   ALT_REF frame buffer index

	       rfc_reference_last
		   Indicates whether to reference LAST frame

	       rfc_reference_golden
		   Indicates whether to reference GOLDEN frame

	       rfc_reference_alt_ref
		   Indicates whether to reference ALT_REF frame

	       rfc_reference_duration
		   Indicates frame duration

       For more information about libvpx see: <http://www.webmproject.org/>

   libwebp
       libwebp WebP Image encoder wrapper

       libwebp is Google's official encoder for WebP images. It can encode in
       either lossy or lossless mode. Lossy images are essentially a wrapper
       around a VP8 frame. Lossless images are a separate codec developed by
       Google.

       Pixel Format

       Currently, libwebp only supports YUV420 for lossy and RGB for lossless
       due to limitations of the format and libwebp. Alpha is supported for
       either mode.  Because of API limitations, if RGB is passed in when
       encoding lossy or YUV is passed in for encoding lossless, the pixel
       format will automatically be converted using functions from libwebp.
       This is not ideal and is done only for convenience.

       Options

       -lossless boolean
	   Enables/Disables use of lossless mode. Default is 0.

       -compression_level integer
	   For lossy, this is a quality/speed tradeoff. Higher values give
	   better quality for a given size at the cost of increased encoding
	   time. For lossless, this is a size/speed tradeoff. Higher values
	   give smaller size at the cost of increased encoding time. More
	   specifically, it controls the number of extra algorithms and
	   compression tools used, and varies the combination of these tools.
	   This maps to the method option in libwebp. The valid range is 0 to
	   6.  Default is 4.

       -quality float
	   For lossy encoding, this controls image quality. For lossless
	   encoding, this controls the effort and time spent in compression.
	   Range is 0 to 100. Default is 75.

       -preset type
	   Configuration preset. This does some automatic settings based on
	   the general type of the image.

	   none
	       Do not use a preset.

	   default
	       Use the encoder default.

	   picture
	       Digital picture, like portrait, inner shot

	   photo
	       Outdoor photograph, with natural lighting

	   drawing
	       Hand or line drawing, with high-contrast details

	   icon
	       Small-sized colorful images

	   text
	       Text-like

   libx264, libx264rgb
       x264 H.264/MPEG-4 AVC encoder wrapper.

       This encoder requires the presence of the libx264 headers and library
       during configuration. You need to explicitly configure the build with
       "--enable-libx264".

       libx264 supports an impressive number of features, including 8x8 and
       4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
       entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
       for detail retention (adaptive quantization, psy-RD, psy-trellis).

       Many libx264 encoder options are mapped to FFmpeg global codec options,
       while unique encoder options are provided through private options.
       Additionally the x264opts and x264-params private options allows one to
       pass a list of key=value tuples as accepted by the libx264
       "x264_param_parse" function.

       The x264 project website is at
       <http://www.videolan.org/developers/x264.html>.

       The libx264rgb encoder is the same as libx264, except it accepts packed
       RGB pixel formats as input instead of YUV.

       Supported Pixel Formats

       x264 supports 8- to 10-bit color spaces. The exact bit depth is
       controlled at x264's configure time.

       Options

       The following options are supported by the libx264 wrapper. The
       x264-equivalent options or values are listed in parentheses for easy
       migration.

       To reduce the duplication of documentation, only the private options
       and some others requiring special attention are documented here. For
       the documentation of the undocumented generic options, see the Codec
       Options chapter.

       To get a more accurate and extensive documentation of the libx264
       options, invoke the command x264 --fullhelp or consult the libx264
       documentation.

       In the list below, note that the x264 option name is shown in
       parentheses after the libavcodec corresponding name, in case there is a
       direct mapping.

       b (bitrate)
	   Set bitrate in bits/s. Note that FFmpeg's b option is expressed in
	   bits/s, while x264's bitrate is in kilobits/s.

       bf (bframes)
	   Number of B-frames between I and P-frames

       g (keyint)
	   Maximum GOP size

       qmin (qpmin)
	   Minimum quantizer scale

       qmax (qpmax)
	   Maximum quantizer scale

       qdiff (qpstep)
	   Maximum difference between quantizer scales

       qblur (qblur)
	   Quantizer curve blur

       qcomp (qcomp)
	   Quantizer curve compression factor

       refs (ref)
	   Number of reference frames each P-frame can use. The range is 0-16.

       level (level)
	   Set the "x264_param_t.i_level_idc" value in case the value is
	   positive, it is ignored otherwise.

	   This value can be set using the "AVCodecContext" API (e.g. by
	   setting the "AVCodecContext" value directly), and is specified as
	   an integer mapped on a corresponding level (e.g. the value 31 maps
	   to H.264 level IDC "3.1", as defined in the "x264_levels" table).
	   It is ignored when set to a non positive value.

	   Alternatively it can be set as a private option, overriding the
	   value set in "AVCodecContext", and in this case must be specified
	   as the level IDC identifier (e.g. "3.1"), as defined by H.264 Annex
	   A.

       sc_threshold (scenecut)
	   Sets the threshold for the scene change detection.

       trellis (trellis)
	   Performs Trellis quantization to increase efficiency. Enabled by
	   default.

       nr (nr)
	   Noise reduction

       me_range (merange)
	   Maximum range of the motion search in pixels.

       me_method (me)
	   Set motion estimation method. Possible values in the decreasing
	   order of speed:

	   dia (dia)
	   epzs (dia)
	       Diamond search with radius 1 (fastest). epzs is an alias for
	       dia.

	   hex (hex)
	       Hexagonal search with radius 2.

	   umh (umh)
	       Uneven multi-hexagon search.

	   esa (esa)
	       Exhaustive search.

	   tesa (tesa)
	       Hadamard exhaustive search (slowest).

       forced-idr
	   Normally, when forcing a I-frame type, the encoder can select any
	   type of I-frame. This option forces it to choose an IDR-frame.

       subq (subme)
	   Sub-pixel motion estimation method.

       b_strategy (b-adapt)
	   Adaptive B-frame placement decision algorithm. Use only on first-
	   pass.

       keyint_min (min-keyint)
	   Minimum GOP size.

       coder
	   Set entropy encoder. Possible values:

	   ac  Enable CABAC.

	   vlc Enable CAVLC and disable CABAC. It generates the same effect as
	       x264's --no-cabac option.

       cmp Set full pixel motion estimation comparison algorithm. Possible
	   values:

	   chroma
	       Enable chroma in motion estimation.

	   sad Ignore chroma in motion estimation. It generates the same
	       effect as x264's --no-chroma-me option.

       threads (threads)
	   Number of encoding threads.

       thread_type
	   Set multithreading technique. Possible values:

	   slice
	       Slice-based multithreading. It generates the same effect as
	       x264's --sliced-threads option.

	   frame
	       Frame-based multithreading.

       flags
	   Set encoding flags. It can be used to disable closed GOP and enable
	   open GOP by setting it to "-cgop". The result is similar to the
	   behavior of x264's --open-gop option.

       rc_init_occupancy (vbv-init)
	   Initial VBV buffer occupancy

       preset (preset)
	   Set the encoding preset.

       tune (tune)
	   Set tuning of the encoding params.

       profile (profile)
	   Set profile restrictions.

       fastfirstpass
	   Enable fast settings when encoding first pass, when set to 1. When
	   set to 0, it has the same effect of x264's --slow-firstpass option.

       crf (crf)
	   Set the quality for constant quality mode.

       crf_max (crf-max)
	   In CRF mode, prevents VBV from lowering quality beyond this point.

       qp (qp)
	   Set constant quantization rate control method parameter.

       aq-mode (aq-mode)
	   Set AQ method. Possible values:

	   none (0)
	       Disabled.

	   variance (1)
	       Variance AQ (complexity mask).

	   autovariance (2)
	       Auto-variance AQ (experimental).

       aq-strength (aq-strength)
	   Set AQ strength, reduce blocking and blurring in flat and textured
	   areas.

       psy Use psychovisual optimizations when set to 1. When set to 0, it has
	   the same effect as x264's --no-psy option.

       psy-rd (psy-rd)
	   Set strength of psychovisual optimization, in psy-rd:psy-trellis
	   format.

       rc-lookahead (rc-lookahead)
	   Set number of frames to look ahead for frametype and ratecontrol.

       weightb
	   Enable weighted prediction for B-frames when set to 1. When set to
	   0, it has the same effect as x264's --no-weightb option.

       weightp (weightp)
	   Set weighted prediction method for P-frames. Possible values:

	   none (0)
	       Disabled

	   simple (1)
	       Enable only weighted refs

	   smart (2)
	       Enable both weighted refs and duplicates

       ssim (ssim)
	   Enable calculation and printing SSIM stats after the encoding.

       intra-refresh (intra-refresh)
	   Enable the use of Periodic Intra Refresh instead of IDR frames when
	   set to 1.

       avcintra-class (class)
	   Configure the encoder to generate AVC-Intra.  Valid values are 50,
	   100 and 200

       bluray-compat (bluray-compat)
	   Configure the encoder to be compatible with the bluray standard.
	   It is a shorthand for setting "bluray-compat=1 force-cfr=1".

       b-bias (b-bias)
	   Set the influence on how often B-frames are used.

       b-pyramid (b-pyramid)
	   Set method for keeping of some B-frames as references. Possible
	   values:

	   none (none)
	       Disabled.

	   strict (strict)
	       Strictly hierarchical pyramid.

	   normal (normal)
	       Non-strict (not Blu-ray compatible).

       mixed-refs
	   Enable the use of one reference per partition, as opposed to one
	   reference per macroblock when set to 1. When set to 0, it has the
	   same effect as x264's --no-mixed-refs option.

       8x8dct
	   Enable adaptive spatial transform (high profile 8x8 transform) when
	   set to 1. When set to 0, it has the same effect as x264's
	   --no-8x8dct option.

       fast-pskip
	   Enable early SKIP detection on P-frames when set to 1. When set to
	   0, it has the same effect as x264's --no-fast-pskip option.

       aud (aud)
	   Enable use of access unit delimiters when set to 1.

       mbtree
	   Enable use macroblock tree ratecontrol when set to 1. When set to
	   0, it has the same effect as x264's --no-mbtree option.

       deblock (deblock)
	   Set loop filter parameters, in alpha:beta form.

       cplxblur (cplxblur)
	   Set fluctuations reduction in QP (before curve compression).

       partitions (partitions)
	   Set partitions to consider as a comma-separated list of values.
	   Possible values in the list:

	   p8x8
	       8x8 P-frame partition.

	   p4x4
	       4x4 P-frame partition.

	   b8x8
	       4x4 B-frame partition.

	   i8x8
	       8x8 I-frame partition.

	   i4x4
	       4x4 I-frame partition.  (Enabling p4x4 requires p8x8 to be
	       enabled. Enabling i8x8 requires adaptive spatial transform
	       (8x8dct option) to be enabled.)

	   none (none)
	       Do not consider any partitions.

	   all (all)
	       Consider every partition.

       direct-pred (direct)
	   Set direct MV prediction mode. Possible values:

	   none (none)
	       Disable MV prediction.

	   spatial (spatial)
	       Enable spatial predicting.

	   temporal (temporal)
	       Enable temporal predicting.

	   auto (auto)
	       Automatically decided.

       slice-max-size (slice-max-size)
	   Set the limit of the size of each slice in bytes. If not specified
	   but RTP payload size (ps) is specified, that is used.

       stats (stats)
	   Set the file name for multi-pass stats.

       nal-hrd (nal-hrd)
	   Set signal HRD information (requires vbv-bufsize to be set).
	   Possible values:

	   none (none)
	       Disable HRD information signaling.

	   vbr (vbr)
	       Variable bit rate.

	   cbr (cbr)
	       Constant bit rate (not allowed in MP4 container).

       x264opts opts
       x264-params opts
	   Override the x264 configuration using a :-separated list of
	   key=value options.

	   The argument for both options is a list of key=value couples
	   separated by ":". With x264opts the value can be omitted, and the
	   value 1 is assumed in that case.

	   For filter and psy-rd options values that use ":" as a separator
	   themselves, use "," instead. They accept it as well since long ago
	   but this is kept undocumented for some reason.

	   For example, the options might be provided as:

		   level=30:bframes=0:weightp=0:cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:no-fast-pskip=1:subq=6:8x8dct=0:trellis=0

	   For example to specify libx264 encoding options with ffmpeg:

		   ffmpeg -i foo.mpg -c:v libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv

	   To get the complete list of the libx264 options, invoke the command
	   x264 --fullhelp or consult the libx264 documentation.

       a53cc boolean
	   Import closed captions (which must be ATSC compatible format) into
	   output.  Only the mpeg2 and h264 decoders provide these. Default is
	   1 (on).

       udu_sei boolean
	   Import user data unregistered SEI if available into output. Default
	   is 0 (off).

       mb_info boolean
	   Set mb_info data through AVFrameSideData, only useful when used
	   from the API. Default is 0 (off).

       Encoding ffpresets for common usages are provided so they can be used
       with the general presets system (e.g. passing the pre option).

   libx265
       x265 H.265/HEVC encoder wrapper.

       This encoder requires the presence of the libx265 headers and library
       during configuration. You need to explicitly configure the build with
       --enable-libx265.

       Options

       b   Sets target video bitrate.

       bf
       g   Set the GOP size.

       keyint_min
	   Minimum GOP size.

       refs
	   Number of reference frames each P-frame can use. The range is from
	   1-16.

       preset
	   Set the x265 preset.

       tune
	   Set the x265 tune parameter.

       profile
	   Set profile restrictions.

       crf Set the quality for constant quality mode.

       qp  Set constant quantization rate control method parameter.

       qmin
	   Minimum quantizer scale.

       qmax
	   Maximum quantizer scale.

       qdiff
	   Maximum difference between quantizer scales.

       qblur
	   Quantizer curve blur

       qcomp
	   Quantizer curve compression factor

       i_qfactor
       b_qfactor
       forced-idr
	   Normally, when forcing a I-frame type, the encoder can select any
	   type of I-frame. This option forces it to choose an IDR-frame.

       udu_sei boolean
	   Import user data unregistered SEI if available into output. Default
	   is 0 (off).

       x265-params
	   Set x265 options using a list of key=value couples separated by
	   ":". See x265 --help for a list of options.

	   For example to specify libx265 encoding options with -x265-params:

		   ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4

   libxavs2
       xavs2 AVS2-P2/IEEE1857.4 encoder wrapper.

       This encoder requires the presence of the libxavs2 headers and library
       during configuration. You need to explicitly configure the build with
       --enable-libxavs2.

       The following standard libavcodec options are used:

       o   b / bit_rate

       o   g / gop_size

       o   bf / max_b_frames

       The encoder also has its own specific options:

       Options

       lcu_row_threads
	   Set the number of parallel threads for rows from 1 to 8 (default
	   5).

       initial_qp
	   Set the xavs2 quantization parameter from 1 to 63 (default 34).
	   This is used to set the initial qp for the first frame.

       qp  Set the xavs2 quantization parameter from 1 to 63 (default 34).
	   This is used to set the qp value under constant-QP mode.

       max_qp
	   Set the max qp for rate control from 1 to 63 (default 55).

       min_qp
	   Set the min qp for rate control from 1 to 63 (default 20).

       speed_level
	   Set the Speed level from 0 to 9 (default 0). Higher is better but
	   slower.

       log_level
	   Set the log level from -1 to 3 (default 0). -1: none, 0: error, 1:
	   warning, 2: info, 3: debug.

       xavs2-params
	   Set xavs2 options using a list of key=value couples separated by
	   ":".

	   For example to specify libxavs2 encoding options with
	   -xavs2-params:

		   ffmpeg -i input -c:v libxavs2 -xavs2-params RdoqLevel=0 output.avs2

   libxeve
       eXtra-fast Essential Video Encoder (XEVE) MPEG-5 EVC encoder wrapper.
       The xeve-equivalent options or values are listed in parentheses for
       easy migration.

       This encoder requires the presence of the libxeve headers and library
       during configuration. You need to explicitly configure the build with
       --enable-libxeve.

	   Many libxeve encoder options are mapped to FFmpeg global codec
	   options, while unique encoder options are provided through private
	   options.  Additionally the xeve-params private options allows one
	   to pass a list of key=value tuples as accepted by the libxeve
	   "parse_xeve_params" function.

       The xeve project website is at <https://github.com/mpeg5/xeve>.

       Options

       The following options are supported by the libxeve wrapper.  The xeve-
       equivalent options or values are listed in parentheses for easy
       migration.

	   To reduce the duplication of documentation, only the private
	   options and some others requiring special attention are documented
	   here. For the documentation of the undocumented generic options,
	   see the Codec Options chapter.

	   To get a more accurate and extensive documentation of the libxeve
	   options, invoke the command	"xeve_app --help" or consult the
	   libxeve documentation.

       b (bitrate)
	   Set target video bitrate in bits/s.	Note that FFmpeg's b option is
	   expressed in bits/s, while xeve's bitrate is in kilobits/s.

       bf (bframes)
	   Set the maximum number of B frames (1,3,7,15).

       g (keyint)
	   Set the GOP size (I-picture period).

       preset (preset)
	   Set the xeve preset.  Set the encoder preset value to determine
	   encoding speed [fast, medium, slow, placebo]

       tune (tune)
	   Set the encoder tune parameter [psnr, zerolatency]

       profile (profile)
	   Set the encoder profile [0: baseline; 1: main]

       crf (crf)
	   Set the quality for constant quality mode.  Constant rate factor
	   <10..49> [default: 32]

       qp (qp)
	   Set constant quantization rate control method parameter.
	   Quantization parameter qp <0..51> [default: 32]

       threads (threads)
	   Force to use a specific number of threads

   libxvid
       Xvid MPEG-4 Part 2 encoder wrapper.

       This encoder requires the presence of the libxvidcore headers and
       library during configuration. You need to explicitly configure the
       build with "--enable-libxvid --enable-gpl".

       The native "mpeg4" encoder supports the MPEG-4 Part 2 format, so users
       can encode to this format without this library.

       Options

       The following options are supported by the libxvid wrapper. Some of the
       following options are listed but are not documented, and correspond to
       shared codec options. See the Codec Options chapter for their
       documentation. The other shared options which are not listed have no
       effect for the libxvid encoder.

       b
       g
       qmin
       qmax
       mpeg_quant
       threads
       bf
       b_qfactor
       b_qoffset
       flags
	   Set specific encoding flags. Possible values:

	   mv4 Use four motion vector by macroblock.

	   aic Enable high quality AC prediction.

	   gray
	       Only encode grayscale.

	   qpel
	       Enable quarter-pixel motion compensation.

	   cgop
	       Enable closed GOP.

	   global_header
	       Place global headers in extradata instead of every keyframe.

       gmc Enable the use of global motion compensation (GMC).	Default is 0
	   (disabled).

       me_quality
	   Set motion estimation quality level. Possible values in decreasing
	   order of speed and increasing order of quality:

	   0   Use no motion estimation (default).

	   1, 2
	       Enable advanced diamond zonal search for 16x16 blocks and half-
	       pixel refinement for 16x16 blocks.

	   3, 4
	       Enable all of the things described above, plus advanced diamond
	       zonal search for 8x8 blocks and half-pixel refinement for 8x8
	       blocks, also enable motion estimation on chroma planes for P
	       and B-frames.

	   5, 6
	       Enable all of the things described above, plus extended 16x16
	       and 8x8 blocks search.

       mbd Set macroblock decision algorithm. Possible values in the
	   increasing order of quality:

	   simple
	       Use macroblock comparing function algorithm (default).

	   bits
	       Enable rate distortion-based half pixel and quarter pixel
	       refinement for 16x16 blocks.

	   rd  Enable all of the things described above, plus rate distortion-
	       based half pixel and quarter pixel refinement for 8x8 blocks,
	       and rate distortion-based search using square pattern.

       lumi_aq
	   Enable lumi masking adaptive quantization when set to 1. Default is
	   0 (disabled).

       variance_aq
	   Enable variance adaptive quantization when set to 1. Default is 0
	   (disabled).

	   When combined with lumi_aq, the resulting quality will not be
	   better than any of the two specified individually. In other words,
	   the resulting quality will be the worse one of the two effects.

       trellis
	   Set rate-distortion optimal quantization.

       ssim
	   Set structural similarity (SSIM) displaying method. Possible
	   values:

	   off Disable displaying of SSIM information.

	   avg Output average SSIM at the end of encoding to stdout. The
	       format of showing the average SSIM is:

		       Average SSIM: %f

	       For users who are not familiar with C, %f means a float number,
	       or a decimal (e.g. 0.939232).

	   frame
	       Output both per-frame SSIM data during encoding and average
	       SSIM at the end of encoding to stdout. The format of per-frame
	       information is:

			      SSIM: avg: %1.3f min: %1.3f max: %1.3f

	       For users who are not familiar with C, %1.3f means a float
	       number rounded to 3 digits after the dot (e.g. 0.932).

       ssim_acc
	   Set SSIM accuracy. Valid options are integers within the range of
	   0-4, while 0 gives the most accurate result and 4 computes the
	   fastest.

   MediaFoundation
       This provides wrappers to encoders (both audio and video) in the
       MediaFoundation framework. It can access both SW and HW encoders.
       Video encoders can take input in either of nv12 or yuv420p form (some
       encoders support both, some support only either - in practice, nv12 is
       the safer choice, especially among HW encoders).

   Microsoft RLE
       Microsoft RLE aka MSRLE encoder.  Only 8-bit palette mode supported.
       Compatible with Windows 3.1 and Windows 95.

       Options

       g integer
	   Keyframe interval.  A keyframe is inserted at least every "-g"
	   frames, sometimes sooner.

   mpeg2
       MPEG-2 video encoder.

       Options

       profile
	   Select the mpeg2 profile to encode:

	   422
	   high
	   ss  Spatially Scalable

	   snr SNR Scalable

	   main
	   simple
       level
	   Select the mpeg2 level to encode:

	   high
	   high1440
	   main
	   low
       seq_disp_ext integer
	   Specifies if the encoder should write a sequence_display_extension
	   to the output.

	   -1
	   auto
	       Decide automatically to write it or not (this is the default)
	       by checking if the data to be written is different from the
	       default or unspecified values.

	   0
	   never
	       Never write it.

	   1
	   always
	       Always write it.

       video_format integer
	   Specifies the video_format written into the sequence display
	   extension indicating the source of the video pictures. The default
	   is unspecified, can be component, pal, ntsc, secam or mac.  For
	   maximum compatibility, use component.

       a53cc boolean
	   Import closed captions (which must be ATSC compatible format) into
	   output.  Default is 1 (on).

   png
       PNG image encoder.

       Private options

       dpi integer
	   Set physical density of pixels, in dots per inch, unset by default

       dpm integer
	   Set physical density of pixels, in dots per meter, unset by default

   ProRes
       Apple ProRes encoder.

       FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
       The used encoder can be chosen with the "-vcodec" option.

       Private Options for prores-ks

       profile integer
	   Select the ProRes profile to encode

	   proxy
	   lt
	   standard
	   hq
	   4444
	   4444xq
       quant_mat integer
	   Select quantization matrix.

	   auto
	   default
	   proxy
	   lt
	   standard
	   hq

	   If set to auto, the matrix matching the profile will be picked.  If
	   not set, the matrix providing the highest quality, default, will be
	   picked.

       bits_per_mb integer
	   How many bits to allot for coding one macroblock. Different
	   profiles use between 200 and 2400 bits per macroblock, the maximum
	   is 8000.

       mbs_per_slice integer
	   Number of macroblocks in each slice (1-8); the default value (8)
	   should be good in almost all situations.

       vendor string
	   Override the 4-byte vendor ID.  A custom vendor ID like apl0 would
	   claim the stream was produced by the Apple encoder.

       alpha_bits integer
	   Specify number of bits for alpha component.	Possible values are 0,
	   8 and 16.  Use 0 to disable alpha plane coding.

       Speed considerations

       In the default mode of operation the encoder has to honor frame
       constraints (i.e. not produce frames with size bigger than requested)
       while still making output picture as good as possible.  A frame
       containing a lot of small details is harder to compress and the encoder
       would spend more time searching for appropriate quantizers for each
       slice.

       Setting a higher bits_per_mb limit will improve the speed.

       For the fastest encoding speed set the qscale parameter (4 is the
       recommended value) and do not set a size constraint.

   QSV Encoders
       The family of Intel QuickSync Video encoders (MPEG-2, H.264, HEVC,
       JPEG/MJPEG, VP9, AV1)

       Ratecontrol Method

       The ratecontrol method is selected as follows:

       o   When global_quality is specified, a quality-based mode is used.
	   Specifically this means either

	   -   CQP - constant quantizer scale, when the qscale codec flag is
	       also set (the -qscale ffmpeg option).

	   -   LA_ICQ - intelligent constant quality with lookahead, when the
	       look_ahead option is also set.

	   -   ICQ -- intelligent constant quality otherwise. For the ICQ
	       modes, global quality range is 1 to 51, with 1 being the best
	       quality.

       o   Otherwise when the desired average bitrate is specified with the b
	   option, a bitrate-based mode is used.

	   -   LA - VBR with lookahead, when the look_ahead option is
	       specified.

	   -   VCM - video conferencing mode, when the vcm option is set.

	   -   CBR - constant bitrate, when maxrate is specified and equal to
	       the average bitrate.

	   -   VBR - variable bitrate, when maxrate is specified, but is
	       higher than the average bitrate.

	   -   AVBR - average VBR mode, when maxrate is not specified, both
	       avbr_accuracy and avbr_convergence are set to non-zero. This
	       mode is available for H264 and HEVC on Windows.

       o   Otherwise the default ratecontrol method CQP is used.

       Note that depending on your system, a different mode than the one you
       specified may be selected by the encoder. Set the verbosity level to
       verbose or higher to see the actual settings used by the QSV runtime.

       Global Options -> MSDK Options

       Additional libavcodec global options are mapped to MSDK options as
       follows:

       o   g/gop_size -> GopPicSize

       o   bf/max_b_frames+1 -> GopRefDist

       o   rc_init_occupancy/rc_initial_buffer_occupancy -> InitialDelayInKB

       o   slices -> NumSlice

       o   refs -> NumRefFrame

       o   b_strategy/b_frame_strategy -> BRefType

       o   cgop/CLOSED_GOP codec flag -> GopOptFlag

       o   For the CQP mode, the i_qfactor/i_qoffset and b_qfactor/b_qoffset
	   set the difference between QPP and QPI, and QPP and QPB
	   respectively.

       o   Setting the coder option to the value vlc will make the H.264
	   encoder use CAVLC instead of CABAC.

       Common Options

       Following options are used by all qsv encoders.

       async_depth
	   Specifies how many asynchronous operations an application performs
	   before the application explicitly synchronizes the result. If zero,
	   the value is not specified.

       preset
	   This option itemizes a range of choices from veryfast (best speed)
	   to veryslow (best quality).

	   veryfast
	   faster
	   fast
	   medium
	   slow
	   slower
	   veryslow
       forced_idr
	   Forcing I frames as IDR frames.

       low_power
	   For encoders set this flag to ON to reduce power consumption and
	   GPU usage.

       Runtime Options

       Following options can be used durning qsv encoding.

       global_quality
       i_quant_factor
       i_quant_offset
       b_quant_factor
       b_quant_offset
	   Supported in h264_qsv and hevc_qsv.	Change these value to reset
	   qsv codec's qp configuration.

       max_frame_size
	   Supported in h264_qsv and hevc_qsv.	Change this value to reset qsv
	   codec's MaxFrameSize configuration.

       gop_size
	   Change this value to reset qsv codec's gop configuration.

       int_ref_type
       int_ref_cycle_size
       int_ref_qp_delta
       int_ref_cycle_dist
	   Supported in h264_qsv and hevc_qsv.	Change these value to reset
	   qsv codec's Intra Refresh configuration.

       qmax
       qmin
       max_qp_i
       min_qp_i
       max_qp_p
       min_qp_p
       max_qp_b
       min_qp_b
	   Supported in h264_qsv.  Change these value to reset qsv codec's
	   max/min qp configuration.

       low_delay_brc
	   Supported in h264_qsv, hevc_qsv and av1_qsv.  Change this value to
	   reset qsv codec's low_delay_brc configuration.

       framerate
	   Change this value to reset qsv codec's framerate configuration.

       bit_rate
       rc_buffer_size
       rc_initial_buffer_occupancy
       rc_max_rate
	   Change these value to reset qsv codec's bitrate control
	   configuration.

       pic_timing_sei
	   Supported in h264_qsv and hevc_qsv.	Change this value to reset qsv
	   codec's pic_timing_sei configuration.

       H264 options

       These options are used by h264_qsv

       extbrc
	   Extended bitrate control.

       recovery_point_sei
	   Set this flag to insert the recovery point SEI message at the
	   beginning of every intra refresh cycle.

       rdo Enable rate distortion optimization.

       max_frame_size
	   Maximum encoded frame size in bytes.

       max_frame_size_i
	   Maximum encoded frame size for I frames in bytes. If this value is
	   set as larger than zero, then for I frames the value set by
	   max_frame_size is ignored.

       max_frame_size_p
	   Maximum encoded frame size for P frames in bytes. If this value is
	   set as larger than zero, then for P frames the value set by
	   max_frame_size is ignored.

       max_slice_size
	   Maximum encoded slice size in bytes.

       bitrate_limit
	   Toggle bitrate limitations.	Modifies bitrate to be in the range
	   imposed by the QSV encoder. Setting this flag off may lead to
	   violation of HRD conformance. Mind that specifying bitrate below
	   the QSV encoder range might significantly affect quality. If on
	   this option takes effect in non CQP modes: if bitrate is not in the
	   range imposed by the QSV encoder, it will be changed to be in the
	   range.

       mbbrc
	   Setting this flag enables macroblock level bitrate control that
	   generally improves subjective visual quality. Enabling this flag
	   may have negative impact on performance and objective visual
	   quality metric.

       low_delay_brc
	   Setting this flag turns on or off LowDelayBRC feautre in qsv
	   plugin, which provides more accurate bitrate control to minimize
	   the variance of bitstream size frame by frame. Value: -1-default
	   0-off 1-on

       adaptive_i
	   This flag controls insertion of I frames by the QSV encoder. Turn
	   ON this flag to allow changing of frame type from P and B to I.

       adaptive_b
	   This flag controls changing of frame type from B to P.

       p_strategy
	   Enable P-pyramid: 0-default 1-simple 2-pyramid(bf need to be set to
	   0).

       b_strategy
	   This option controls usage of B frames as reference.

       dblk_idc
	   This option disable deblocking. It has value in range 0~2.

       cavlc
	   If set, CAVLC is used; if unset, CABAC is used for encoding.

       vcm Video conferencing mode, please see ratecontrol method.

       idr_interval
	   Distance (in I-frames) between IDR frames.

       pic_timing_sei
	   Insert picture timing SEI with pic_struct_syntax element.

       single_sei_nal_unit
	   Put all the SEI messages into one NALU.

       max_dec_frame_buffering
	   Maximum number of frames buffered in the DPB.

       look_ahead
	   Use VBR algorithm with look ahead.

       look_ahead_depth
	   Depth of look ahead in number frames.

       look_ahead_downsampling
	   Downscaling factor for the frames saved for the lookahead analysis.

	   unknown
	   auto
	   off
	   2x
	   4x
       int_ref_type
	   Specifies intra refresh type. The major goal of intra refresh is
	   improvement of error resilience without significant impact on
	   encoded bitstream size caused by I frames. The SDK encoder achieves
	   this by encoding part of each frame in refresh cycle using intra
	   MBs. none means no refresh. vertical means vertical refresh, by
	   column of MBs. horizontal means horizontal refresh, by rows of MBs.
	   slice means horizontal refresh by slices without overlapping. In
	   case of slice, in_ref_cycle_size is ignored. To enable intra
	   refresh, B frame should be set to 0.

       int_ref_cycle_size
	   Specifies number of pictures within refresh cycle starting from 2.
	   0 and 1 are invalid values.

       int_ref_qp_delta
	   Specifies QP difference for inserted intra MBs. This is signed
	   value in [-51, 51] range if target encoding bit-depth for luma
	   samples is 8 and this range is [-63, 63] for 10 bit-depth or [-75,
	   75] for 12 bit-depth respectively.

       int_ref_cycle_dist
	   Distance between the beginnings of the intra-refresh cycles in
	   frames.

       profile
	   unknown
	   baseline
	   main
	   high
       a53cc
	   Use A53 Closed Captions (if available).

       aud Insert the Access Unit Delimiter NAL.

       mfmode
	   Multi-Frame Mode.

	   off
	   auto
       repeat_pps
	   Repeat pps for every frame.

       max_qp_i
	   Maximum video quantizer scale for I frame.

       min_qp_i
	   Minimum video quantizer scale for I frame.

       max_qp_p
	   Maximum video quantizer scale for P frame.

       min_qp_p
	   Minimum video quantizer scale for P frame.

       max_qp_b
	   Maximum video quantizer scale for B frame.

       min_qp_b
	   Minimum video quantizer scale for B frame.

       scenario
	   Provides a hint to encoder about the scenario for the encoding
	   session.

	   unknown
	   displayremoting
	   videoconference
	   archive
	   livestreaming
	   cameracapture
	   videosurveillance
	   gamestreaming
	   remotegaming
       avbr_accuracy
	   Accuracy of the AVBR ratecontrol (unit of tenth of percent).

       avbr_convergence
	   Convergence of the AVBR ratecontrol (unit of 100 frames)

	   The parameters avbr_accuracy and avbr_convergence are for the
	   average variable bitrate control (AVBR) algorithm.  The algorithm
	   focuses on overall encoding quality while meeting the specified
	   bitrate, target_bitrate, within the accuracy range avbr_accuracy,
	   after a avbr_Convergence period. This method does not follow HRD
	   and the instant bitrate is not capped or padded.

       skip_frame
	   Use per-frame metadata "qsv_skip_frame" to skip frame when
	   encoding. This option defines the usage of this metadata.

	   no_skip
	       Frame skipping is disabled.

	   insert_dummy
	       Encoder inserts into bitstream frame where all macroblocks are
	       encoded as skipped.

	   insert_nothing
	       Similar to insert_dummy, but encoder inserts nothing into
	       bitstream. The skipped frames are still used in brc. For
	       example, gop still include skipped frames, and the frames after
	       skipped frames will be larger in size.

	   brc_only
	       skip_frame metadata indicates the number of missed frames
	       before the current frame.

       HEVC Options

       These options are used by hevc_qsv

       extbrc
	   Extended bitrate control.

       recovery_point_sei
	   Set this flag to insert the recovery point SEI message at the
	   beginning of every intra refresh cycle.

       rdo Enable rate distortion optimization.

       max_frame_size
	   Maximum encoded frame size in bytes.

       max_frame_size_i
	   Maximum encoded frame size for I frames in bytes. If this value is
	   set as larger than zero, then for I frames the value set by
	   max_frame_size is ignored.

       max_frame_size_p
	   Maximum encoded frame size for P frames in bytes. If this value is
	   set as larger than zero, then for P frames the value set by
	   max_frame_size is ignored.

       max_slice_size
	   Maximum encoded slice size in bytes.

       mbbrc
	   Setting this flag enables macroblock level bitrate control that
	   generally improves subjective visual quality. Enabling this flag
	   may have negative impact on performance and objective visual
	   quality metric.

       low_delay_brc
	   Setting this flag turns on or off LowDelayBRC feautre in qsv
	   plugin, which provides more accurate bitrate control to minimize
	   the variance of bitstream size frame by frame. Value: -1-default
	   0-off 1-on

       adaptive_i
	   This flag controls insertion of I frames by the QSV encoder. Turn
	   ON this flag to allow changing of frame type from P and B to I.

       adaptive_b
	   This flag controls changing of frame type from B to P.

       p_strategy
	   Enable P-pyramid: 0-default 1-simple 2-pyramid(bf need to be set to
	   0).

       b_strategy
	   This option controls usage of B frames as reference.

       dblk_idc
	   This option disable deblocking. It has value in range 0~2.

       idr_interval
	   Distance (in I-frames) between IDR frames.

	   begin_only
	       Output an IDR-frame only at the beginning of the stream.

       load_plugin
	   A user plugin to load in an internal session.

	   none
	   hevc_sw
	   hevc_hw
       load_plugins
	   A :-separate list of hexadecimal plugin UIDs to load in an internal
	   session.

       look_ahead_depth
	   Depth of look ahead in number frames, available when extbrc option
	   is enabled.

       profile
	   Set the encoding profile (scc requires libmfx >= 1.32).

	   unknown
	   main
	   main10
	   mainsp
	   rext
	   scc
       tier
	   Set the encoding tier (only level >= 4 can support high tier).
	   This option only takes effect when the level option is specified.

	   main
	   high
       gpb 1: GPB (generalized P/B frame)

	   0: regular P frame.

       tile_cols
	   Number of columns for tiled encoding.

       tile_rows
	   Number of rows for tiled encoding.

       aud Insert the Access Unit Delimiter NAL.

       pic_timing_sei
	   Insert picture timing SEI with pic_struct_syntax element.

       transform_skip
	   Turn this option ON to enable transformskip. It is supported on
	   platform equal or newer than ICL.

       int_ref_type
	   Specifies intra refresh type. The major goal of intra refresh is
	   improvement of error resilience without significant impact on
	   encoded bitstream size caused by I frames. The SDK encoder achieves
	   this by encoding part of each frame in refresh cycle using intra
	   MBs. none means no refresh. vertical means vertical refresh, by
	   column of MBs. horizontal means horizontal refresh, by rows of MBs.
	   slice means horizontal refresh by slices without overlapping. In
	   case of slice, in_ref_cycle_size is ignored. To enable intra
	   refresh, B frame should be set to 0.

       int_ref_cycle_size
	   Specifies number of pictures within refresh cycle starting from 2.
	   0 and 1 are invalid values.

       int_ref_qp_delta
	   Specifies QP difference for inserted intra MBs. This is signed
	   value in [-51, 51] range if target encoding bit-depth for luma
	   samples is 8 and this range is [-63, 63] for 10 bit-depth or [-75,
	   75] for 12 bit-depth respectively.

       int_ref_cycle_dist
	   Distance between the beginnings of the intra-refresh cycles in
	   frames.

       max_qp_i
	   Maximum video quantizer scale for I frame.

       min_qp_i
	   Minimum video quantizer scale for I frame.

       max_qp_p
	   Maximum video quantizer scale for P frame.

       min_qp_p
	   Minimum video quantizer scale for P frame.

       max_qp_b
	   Maximum video quantizer scale for B frame.

       min_qp_b
	   Minimum video quantizer scale for B frame.

       scenario
	   Provides a hint to encoder about the scenario for the encoding
	   session.

	   unknown
	   displayremoting
	   videoconference
	   archive
	   livestreaming
	   cameracapture
	   videosurveillance
	   gamestreaming
	   remotegaming
       avbr_accuracy
	   Accuracy of the AVBR ratecontrol (unit of tenth of percent).

       avbr_convergence
	   Convergence of the AVBR ratecontrol (unit of 100 frames)

	   The parameters avbr_accuracy and avbr_convergence are for the
	   average variable bitrate control (AVBR) algorithm.  The algorithm
	   focuses on overall encoding quality while meeting the specified
	   bitrate, target_bitrate, within the accuracy range avbr_accuracy,
	   after a avbr_Convergence period. This method does not follow HRD
	   and the instant bitrate is not capped or padded.

       skip_frame
	   Use per-frame metadata "qsv_skip_frame" to skip frame when
	   encoding. This option defines the usage of this metadata.

	   no_skip
	       Frame skipping is disabled.

	   insert_dummy
	       Encoder inserts into bitstream frame where all macroblocks are
	       encoded as skipped.

	   insert_nothing
	       Similar to insert_dummy, but encoder inserts nothing into
	       bitstream. The skipped frames are still used in brc. For
	       example, gop still include skipped frames, and the frames after
	       skipped frames will be larger in size.

	   brc_only
	       skip_frame metadata indicates the number of missed frames
	       before the current frame.

       MPEG2 Options

       These options are used by mpeg2_qsv

       profile
	   unknown
	   simple
	   main
	   high

       VP9 Options

       These options are used by vp9_qsv

       profile
	   unknown
	   profile0
	   profile1
	   profile2
	   profile3
       tile_cols
	   Number of columns for tiled encoding (requires libmfx >= 1.29).

       tile_rows
	   Number of rows for tiled encoding (requires libmfx  >= 1.29).

       AV1 Options

       These options are used by av1_qsv (requires libvpl).

       profile
	   unknown
	   main
       tile_cols
	   Number of columns for tiled encoding.

       tile_rows
	   Number of rows for tiled encoding.

       adaptive_i
	   This flag controls insertion of I frames by the QSV encoder. Turn
	   ON this flag to allow changing of frame type from P and B to I.

       adaptive_b
	   This flag controls changing of frame type from B to P.

       b_strategy
	   This option controls usage of B frames as reference.

       extbrc
	   Extended bitrate control.

       look_ahead_depth
	   Depth of look ahead in number frames, available when extbrc option
	   is enabled.

       low_delay_brc
	   Setting this flag turns on or off LowDelayBRC feautre in qsv
	   plugin, which provides more accurate bitrate control to minimize
	   the variance of bitstream size frame by frame. Value: -1-default
	   0-off 1-on

       max_frame_size
	   Set the allowed max size in bytes for each frame. If the frame size
	   exceeds the limitation, encoder will adjust the QP value to control
	   the frame size.  Invalid in CQP rate control mode.

   snow
       Options

       iterative_dia_size
	   dia size for the iterative motion estimation

   VAAPI encoders
       Wrappers for hardware encoders accessible via VAAPI.

       These encoders only accept input in VAAPI hardware surfaces.  If you
       have input in software frames, use the hwupload filter to upload them
       to the GPU.

       The following standard libavcodec options are used:

       o   g / gop_size

       o   bf / max_b_frames

       o   profile

	   If not set, this will be determined automatically from the format
	   of the input frames and the profiles supported by the driver.

       o   level

       o   b / bit_rate

       o   maxrate / rc_max_rate

       o   bufsize / rc_buffer_size

       o   rc_init_occupancy / rc_initial_buffer_occupancy

       o   compression_level

	   Speed / quality tradeoff: higher values are faster / worse quality.

       o   q / global_quality

	   Size / quality tradeoff: higher values are smaller / worse quality.

       o   qmin

       o   qmax

       o   i_qfactor / i_quant_factor

       o   i_qoffset / i_quant_offset

       o   b_qfactor / b_quant_factor

       o   b_qoffset / b_quant_offset

       o   slices

       All encoders support the following options:

       low_power
	   Some drivers/platforms offer a second encoder for some codecs
	   intended to use less power than the default encoder; setting this
	   option will attempt to use that encoder.  Note that it may support
	   a reduced feature set, so some other options may not be available
	   in this mode.

       idr_interval
	   Set the number of normal intra frames between full-refresh (IDR)
	   frames in open-GOP mode.  The intra frames are still IRAPs, but
	   will not include global headers and may have non-decodable leading
	   pictures.

       b_depth
	   Set the B-frame reference depth.  When set to one (the default),
	   all B-frames will refer only to P- or I-frames.  When set to
	   greater values multiple layers of B-frames will be present, frames
	   in each layer only referring to frames in higher layers.

       async_depth
	   Maximum processing parallelism. Increase this to improve single
	   channel performance. This option doesn't work if driver doesn't
	   implement vaSyncBuffer function. Please make sure there are enough
	   hw_frames allocated if a large number of async_depth is used.

       max_frame_size
	   Set the allowed max size in bytes for each frame. If the frame size
	   exceeds the limitation, encoder will adjust the QP value to control
	   the frame size.  Invalid in CQP rate control mode.

       rc_mode
	   Set the rate control mode to use.  A given driver may only support
	   a subset of modes.

	   Possible modes:

	   auto
	       Choose the mode automatically based on driver support and the
	       other options.  This is the default.

	   CQP Constant-quality.

	   CBR Constant-bitrate.

	   VBR Variable-bitrate.

	   ICQ Intelligent constant-quality.

	   QVBR
	       Quality-defined variable-bitrate.

	   AVBR
	       Average variable bitrate.

       blbrc
	   Enable block level rate control, which assigns different bitrate
	   block by block.  Invalid for CQP mode.

       Each encoder also has its own specific options:

       av1_vaapi
	   profile sets the value of seq_profile.  tier sets the value of
	   seq_tier.  level sets the value of seq_level_idx.

	   tiles
	       Set the number of tiles to encode the input video with, as
	       columns x rows.	(default is auto, which means use minimal tile
	       column/row number).

	   tile_groups
	       Set tile groups number. All the tiles will be distributed as
	       evenly as possible to each tile group. (default is 1).

       h264_vaapi
	   profile sets the value of profile_idc and the
	   constraint_set*_flags.  level sets the value of level_idc.

	   coder
	       Set entropy encoder (default is cabac).	Possible values:

	       ac
	       cabac
		   Use CABAC.

	       vlc
	       cavlc
		   Use CAVLC.

	   aud Include access unit delimiters in the stream (not included by
	       default).

	   sei Set SEI message types to include.  Some combination of the
	       following values:

	       identifier
		   Include a user_data_unregistered message containing
		   information about the encoder.

	       timing
		   Include picture timing parameters (buffering_period and
		   pic_timing messages).

	       recovery_point
		   Include recovery points where appropriate (recovery_point
		   messages).

       hevc_vaapi
	   profile and level set the values of general_profile_idc and
	   general_level_idc respectively.

	   aud Include access unit delimiters in the stream (not included by
	       default).

	   tier
	       Set general_tier_flag.  This may affect the level chosen for
	       the stream if it is not explicitly specified.

	   sei Set SEI message types to include.  Some combination of the
	       following values:

	       hdr Include HDR metadata if the input frames have it
		   (mastering_display_colour_volume and content_light_level
		   messages).

	   tiles
	       Set the number of tiles to encode the input video with, as
	       columns x rows.	Larger numbers allow greater parallelism in
	       both encoding and decoding, but may decrease coding efficiency.

       mjpeg_vaapi
	   Only baseline DCT encoding is supported.  The encoder always uses
	   the standard quantisation and huffman tables - global_quality
	   scales the standard quantisation table (range 1-100).

	   For YUV, 4:2:0, 4:2:2 and 4:4:4 subsampling modes are supported.
	   RGB is also supported, and will create an RGB JPEG.

	   jfif
	       Include JFIF header in each frame (not included by default).

	   huffman
	       Include standard huffman tables (on by default).  Turning this
	       off will save a few hundred bytes in each output frame, but may
	       lose compatibility with some JPEG decoders which don't fully
	       handle MJPEG.

       mpeg2_vaapi
	   profile and level set the value of profile_and_level_indication.

       vp8_vaapi
	   B-frames are not supported.

	   global_quality sets the q_idx used for non-key frames (range
	   0-127).

	   loop_filter_level
	   loop_filter_sharpness
	       Manually set the loop filter parameters.

       vp9_vaapi
	   global_quality sets the q_idx used for P-frames (range 0-255).

	   loop_filter_level
	   loop_filter_sharpness
	       Manually set the loop filter parameters.

	   B-frames are supported, but the output stream is always in encode
	   order rather than display order.  If B-frames are enabled, it may
	   be necessary to use the vp9_raw_reorder bitstream filter to modify
	   the output stream to display frames in the correct order.

	   Only normal frames are produced - the vp9_superframe bitstream
	   filter may be required to produce a stream usable with all
	   decoders.

   vbn
       Vizrt Binary Image encoder.

       This format is used by the broadcast vendor Vizrt for quick texture
       streaming.  Advanced features of the format such as LZW compression of
       texture data or generation of mipmaps are not supported.

       Options

       format string
	   Sets the texture compression used by the VBN file. Can be dxt1,
	   dxt5 or raw. Default is dxt5.

   vc2
       SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed
       at professional broadcasting but since it supports yuv420, yuv422 and
       yuv444 at 8 (limited range or full range), 10 or 12 bits, this makes it
       suitable for other tasks which require low overhead and low compression
       (like screen recording).

       Options

       b   Sets target video bitrate. Usually that's around 1:6 of the
	   uncompressed video bitrate (e.g. for 1920x1080 50fps yuv422p10
	   that's around 400Mbps). Higher values (close to the uncompressed
	   bitrate) turn on lossless compression mode.

       field_order
	   Enables field coding when set (e.g. to tt - top field first) for
	   interlaced inputs. Should increase compression with interlaced
	   content as it splits the fields and encodes each separately.

       wavelet_depth
	   Sets the total amount of wavelet transforms to apply, between 1 and
	   5 (default).  Lower values reduce compression and quality. Less
	   capable decoders may not be able to handle values of wavelet_depth
	   over 3.

       wavelet_type
	   Sets the transform type. Currently only 5_3 (LeGall) and 9_7
	   (Deslauriers-Dubuc) are implemented, with 9_7 being the one with
	   better compression and thus is the default.

       slice_width
       slice_height
	   Sets the slice size for each slice. Larger values result in better
	   compression.  For compatibility with other more limited decoders
	   use slice_width of 32 and slice_height of 8.

       tolerance
	   Sets the undershoot tolerance of the rate control system in
	   percent. This is to prevent an expensive search from being run.

       qm  Sets the quantization matrix preset to use by default or when
	   wavelet_depth is set to 5

	   -   default Uses the default quantization matrix from the
	       specifications, extended with values for the fifth level. This
	       provides a good balance between keeping detail and omitting
	       artifacts.

	   -   flat Use a completely zeroed out quantization matrix. This
	       increases PSNR but might reduce perception. Use in bogus
	       benchmarks.

	   -   color Reduces detail but attempts to preserve color at
	       extremely low bitrates.

SUBTITLES ENCODERS
   dvdsub
       This codec encodes the bitmap subtitle format that is used in DVDs.
       Typically they are stored in VOBSUB file pairs (*.idx + *.sub), and
       they can also be used in Matroska files.

       Options

       palette
	   Specify the global palette used by the bitmaps.

	   The format for this option is a string containing 16 24-bits
	   hexadecimal numbers (without 0x prefix) separated by commas, for
	   example "0d00ee, ee450d, 101010, eaeaea, 0ce60b, ec14ed, ebff0b,
	   0d617a, 7b7b7b, d1d1d1, 7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c,
	   7c127b".

       even_rows_fix
	   When set to 1, enable a work-around that makes the number of pixel
	   rows even in all subtitles.	This fixes a problem with some players
	   that cut off the bottom row if the number is odd.  The work-around
	   just adds a fully transparent row if needed.  The overhead is low,
	   typically one byte per subtitle on average.

	   By default, this work-around is disabled.

SEE ALSO
       ffmpeg(1), ffplay(1), ffprobe(1), libavcodec(3)

AUTHORS
       The FFmpeg developers.

       For details about the authorship, see the Git history of the project
       (https://git.ffmpeg.org/ffmpeg), e.g. by typing the command git log in
       the FFmpeg source directory, or browsing the online repository at
       <https://git.ffmpeg.org/ffmpeg>.

       Maintainers for the specific components are listed in the file
       MAINTAINERS in the source code tree.

							      FFMPEG-CODECS(1)
