Table of Contents

1 Description

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

2 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

‘`h264_dp_nnz`’
:   H.264 nC derivation for partitioned slices, as done by JM rather than by
    9.2.1 (autodetected)

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.

‘`fixed_frame_size`’
:   Force audio encoders to use a fixed frame size.

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.

‘`enhancements`’
:   Export picture enhancement metadata through frame side data, e.g. LCEVC (see `AV_FRAME_DATA_LCEVC`).

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_pred 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_pred` skips prediction
(intra prediction and motion compensation), `skip_frame` skips
decoding.

With both `skip_pred` and `skip_idct` set to ‘`all`’
the decoder may skip all pixel operations and output frames with
undefined pixels but valid metadata, such as timestamps and frame
types.

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`’

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

‘`premultiplied`’

‘`straight`’

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.

lcevc-dec-params string (decoding,video) : A :-separated list of key=value parameters passed to liblcevc-dec to initialize it.

3 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.

4 Video Decoders

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

4.1 av1

AOMedia Video 1 (AV1) decoder.

4.1.1 Options

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

4.2 hevc

HEVC (AKA ITU-T H.265 or ISO/IEC 23008-2) decoder.

The decoder supports MV-HEVC multiview streams with at most two views. Views to be output are selected by supplying a list of view IDs to the decoder (the view_ids option). This option may be set either statically before decoder init, or from the get_format() callback - useful for the case when the view count or IDs change dynamically during decoding.

Only the base layer is decoded by default.

Note that if you are using the ffmpeg CLI tool, you should be using view specifiers as documented in its manual, rather than the options documented here.

4.2.1 Options

view_ids (MV-HEVC) : Specify a list of view IDs that should be output. This option can also be set to a single ’-1’, which will cause all views defined in the VPS to be decoded and output.

view_ids_available (MV-HEVC) : This option may be read by the caller to retrieve an array of view IDs available in the active VPS. The array is empty for single-layer video.

The value of this option is guaranteed to be accurate when read from the
`get_format()` callback. It may also be set at other times (e.g. after
opening the decoder), but the value is informational only and may be incorrect
(e.g. when the stream contains multiple distinct VPS NALUs).

view_pos_available (MV-HEVC) : This option may be read by the caller to retrieve an array of view positions (left, right, or unspecified) available in the active VPS, as AVStereo3DView values. When the array is available, its elements apply to the corresponding elements of view_ids_available, i.e. view_pos_available[i] contains the position of view with ID view_ids_available[i].

Same validity restrictions as for `view_ids_available` apply to
this option.

4.3 rawvideo

Raw video decoder.

This decoder decodes rawvideo streams.

4.3.1 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

4.4 libastcenc

ARM ASTC Encoder wrapper for decoding ASTC textures.

This decoder requires the Arm ASTC Encoder (astc-encoder) library version 5.4 or newer, installed as astcenc/astcenc.h next to a library that -lastcenc finds. Pass --enable-version3 together with --enable-libastcenc to configure.

The .astc header does not record the intended decoding profile. Individual blocks identify their endpoint encodings, but this does not establish the sRGB versus linear interpretation. The decoder therefore uses the container metadata or dec_profile: a KTX sRGB texture is decoded as ldr-srgb, while a KTX texture in the linear format is sampled with HDR precision (hdr-ldr-a, half-float output) because the linear GL internal format says nothing about LDR. A raw .astc file carries no profile at all, so it falls back to ldr-srgb; use dec_profile for a raw HDR image:

ffmpeg -dec_profile hdr-ldr-a -i input.astc output.png

4.4.1 Options

dec_profile int : Color profile to decode with, overriding the container metadata. It must match the profile the texture was encoded with: astcenc substitutes a fixed magenta error color for blocks whose endpoints do not fit the selected profile. The values are ldr, ldr-srgb, hdr-ldr-a and hdr. Without this option the profile published by the container is used; a raw .astc stream, which publishes none, falls back to ldr-srgb.

4.5 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.

4.5.1 Options

The following options are supported by the libdav1d wrapper.

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.

4.6 libdavs2

AVS2-P2/IEEE1857.4 video decoder wrapper.

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

4.7 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.

4.7.1 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).

4.8 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>.

4.8.1 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

4.9 QSV Decoders

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

4.9.1 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`’

4.9.2 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

4.10 v210

Uncompressed 4:2:2 10-bit decoder.

4.10.1 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.

5 Audio Decoders

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

5.1 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).

5.1.1 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.

5.2 dca

DCA (DTS Coherent Acoustics) audio decoder, including the DTS-HD extensions.

5.2.1 DCA Decoder Options

-downmix channel_layout : Request a smaller channel layout from the decoder: ‘stereo’, ‘5.0(side)’, ‘5.1(side)’ or ‘7.1’.

A DTS:X stream in the standard presentation decodes to 7.1.4 by default. Its
four height channels are carried in an extension at the end of each lossless
(XLL) frame, and the encoder also folds them into the 7.1 bed, so the decoder
removes them from the bed when it outputs them. Requesting ‘`7.1`’ outputs
the bed as coded instead, with the heights folded in, and so does every
smaller layout. A ‘`7.1`’ request has no effect on other streams.

5.3 flac

FLAC audio decoder.

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

5.3.1 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.

5.4 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.

5.5 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.

5.6 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.

5.6.1 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).

5.7 libmpeghdec

libmpeghdec decoder wrapper.

libmpeghdec allows libmpeghdec to decode the MPEG-H 3D audio codec. Requires the presence of the libmpeghdec headers and library during configuration. You need to explicitly configure the build with --enable-libmpeghdec --enable-nonfree.

5.8 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.

5.9 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.

5.10 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.

5.11 pcm_dvda

PCM DVD-Audio decoder.

Decodes the LPCM variant stored in DVD-Audio AOB files. Unlike DVD-Video LPCM it supports sample rates up to 192 kHz and allows splitting the channels into two groups with different quantization.

6 Subtitles Decoders

6.1 libaribb24

ARIB STD-B24 caption decoder.

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

6.1.1 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.

6.2 libaribcaption

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

Implements profiles A and C of the Japanese 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.

6.2.1 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 internally 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 character 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.

6.2.2 li

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