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FFMPEG-BITSTREAM-FILTERS

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Index

NAME

ffmpeg-bitstream-filters - FFmpeg bitstream filters

DESCRIPTION

This document describes the bitstream filters provided by thelibavcodec library.

A bitstream filter operates on the encoded stream data, and performsbitstream level modifications without performing decoding.

BITSTREAM FILTERS

When you configure your FFmpeg build, all the supported bitstreamfilters are enabled by default. You can list all available ones usingthe configure option "--list-bsfs".

You can disable all the bitstream filters using the configure option"--disable-bsfs", and selectively enable any bitstream filter usingthe option "--enable-bsf=BSF", or you can disable a particularbitstream filter using the option "--disable-bsf=BSF".

The option "-bsfs" of the ff* tools will display the list ofall the supported bitstream filters included in your build.

The ff* tools have a -bsf option applied per stream, taking acomma-separated list of filters, whose parameters follow the filtername after a '='.

        ffmpeg -i INPUT -c:v copy -bsf:v filter1[=opt1=str1:opt2=str2][,filter2] OUTPUT

Below is a description of the currently available bitstream filters,with their parameters, if any.

aac_adtstoasc

Convert MPEG-2/4 AAC ADTS to an MPEG-4 Audio Specific Configurationbitstream.

This filter creates an MPEG-4 AudioSpecificConfig from an MPEG-2/4ADTS header and removes the ADTS header.

This filter is required for example when copying an AAC stream from araw ADTS AAC or an MPEG-TS container to MP4A-LATM, to an FLV file, orto MOV/MP4 files and related formats such as 3GP or M4A. Please notethat it is auto-inserted for MP4A-LATM and MOV/MP4 and related formats.

av1_metadata

Modify metadata embedded in an AV1 stream.

td

Insert or remove temporal delimiter OBUs in all temporal units of thestream.

insert: Insert a TD at the beginning of every TU which does not already have one.
remove: Remove the TD from the beginning of every TU which has one.

color_primaries

transfer_characteristics

matrix_coefficients

Set the color description fields in the stream (see AV1 section 6.4.2).

color_range

Set the color range in the stream (see AV1 section 6.4.2; note thatthis cannot be set for streams using BT.709 primaries, sRGB transfercharacteristic and identity (RGB) matrix coefficients).

tv: Limited range.
pc: Full range.

chroma_sample_position

Set the chroma sample location in the stream (see AV1 section 6.4.2).This can only be set for 4:2:0 streams.

vertical: Left position (matching the default in MPEG-2 and H.264).
colocated: Top-left position.

tick_rate

Set the tick rate (num_units_in_display_tick / time_scale) inthe timing info in the sequence header.

num_ticks_per_picture

Set the number of ticks in each picture, to indicate that the streamhas a fixed framerate. Ignored if tick_rate is not also set.

chomp

Remove zero padding at the end of a packet.

dca_core

Extract the core from a DCA/DTS stream, dropping extensions such asDTS-HD.

dump_extra

Add extradata to the beginning of the filtered packets.

freq

The additional argument specifies which packets should be filtered.It accepts the values:

k
keyframe: add extradata to all key packets
e
all: add extradata to all packets

If not specified it is assumed e.

For example the following ffmpeg command forces a globalheader (thus disabling individual packet headers) in the H.264 packetsgenerated by the "libx264" encoder, but corrects them by addingthe header stored in extradata to the key packets:

        ffmpeg -i INPUT -map 0 -flags:v +global_header -c:v libx264 -bsf:v dump_extra out.ts

eac3_core

Extract the core from a E-AC-3 stream, dropping extra channels.

extract_extradata

Extract the in-band extradata.

Certain codecs allow the long-term headers (e.g. MPEG-2 sequence headers,or H.264/HEVC (VPS/)SPS/PPS) to be transmitted either ``in-band'' (i.e. as a partof the bitstream containing the coded frames) or ``out of band'' (e.g. on thecontainer level). This latter form is called ``extradata'' in FFmpeg terminology.

This bitstream filter detects the in-band headers and makes them available asextradata.

remove: When this option is enabled, the long-term headers are removed from thebitstream after extraction.

filter_units

Remove units with types in or not in a given set from the stream.

pass_types: List of unit types or ranges of unit types to pass through while removingall others. This is specified as a '|'-separated list of unit type valuesor ranges of values with '-'.
remove_types: Identical to pass_types, except the units in the given setremoved and all others passed through.

Extradata is unchanged by this transformation, but note that if the streamcontains inline parameter sets then the output may be unusable if they areremoved.

For example, to remove all non-VCL NAL units from an H.264 stream:

        ffmpeg -i INPUT -c:v copy -bsf:v 'filter_units=pass_types=1-5' OUTPUT

To remove all AUDs, SEI and filler from an H.265 stream:

        ffmpeg -i INPUT -c:v copy -bsf:v 'filter_units=remove_types=35|38-40' OUTPUT

hapqa_extract

Extract Rgb or Alpha part of an HAPQA file, without recompression, in order to create an HAPQ or an HAPAlphaOnly file.

texture

Specifies the texture to keep.

color
alpha

Convert HAPQA to HAPQ

        ffmpeg -i hapqa_inputfile.mov -c copy -bsf:v hapqa_extract=texture=color -tag:v HapY -metadata:s:v:0 encoder="HAPQ" hapq_file.mov

Convert HAPQA to HAPAlphaOnly

        ffmpeg -i hapqa_inputfile.mov -c copy -bsf:v hapqa_extract=texture=alpha -tag:v HapA -metadata:s:v:0 encoder="HAPAlpha Only" hapalphaonly_file.mov

h264_metadata

Modify metadata embedded in an H.264 stream.

aud

Insert or remove AUD NAL units in all access units of the stream.

insert
remove

sample_aspect_ratio

Set the sample aspect ratio of the stream in the VUI parameters.

video_format

video_full_range_flag

Set the video format in the stream (see H.264 section E.2.1 andtable E-2).

colour_primaries

transfer_characteristics

matrix_coefficients

Set the colour description in the stream (see H.264 section E.2.1and tables E-3, E-4 and E-5).

chroma_sample_loc_type

Set the chroma sample location in the stream (see H.264 sectionE.2.1 and figure E-1).

tick_rate

Set the tick rate (num_units_in_tick / time_scale) in the VUIparameters. This is the smallest time unit representable in thestream, and in many cases represents the field rate of the stream(double the frame rate).

fixed_frame_rate_flag

Set whether the stream has fixed framerate - typically this indicatesthat the framerate is exactly half the tick rate, but the exactmeaning is dependent on interlacing and the picture structure (seeH.264 section E.2.1 and table E-6).

crop_left

crop_right

crop_top

crop_bottom

Set the frame cropping offsets in the SPS. These values will replacethe current ones if the stream is already cropped.

These fields are set in pixels. Note that some sizes may not berepresentable if the chroma is subsampled or the stream is interlaced(see H.264 section 7.4.2.1.1).

sei_user_data

Insert a string as SEI unregistered user data. The argument mustbe of the form UUID+string, where the UUID is as hex digitspossibly separated by hyphens, and the string can be anything.

For example, 086f3693-b7b3-4f2c-9653-21492feee5b8+hello willinsert the string ``hello'' associated with the given UUID.

delete_filler

Deletes both filler NAL units and filler SEI messages.

level

Set the level in the SPS. Refer to H.264 section A.3 and tables A-1to A-5.

The argument must be the name of a level (for example, 4.2), alevel_idc value (for example, 42), or the special name autoindicating that the filter should attempt to guess the level from theinput stream properties.

h264_mp4toannexb

Convert an H.264 bitstream from length prefixed mode to start codeprefixed mode (as defined in the Annex B of the ITU-T H.264specification).

This is required by some streaming formats, typically the MPEG-2transport stream format (muxer "mpegts").

For example to remux an MP4 file containing an H.264 stream to mpegtsformat with ffmpeg, you can use the command:

        ffmpeg -i INPUT.mp4 -codec copy -bsf:v h264_mp4toannexb OUTPUT.ts

Please note that this filter is auto-inserted for MPEG-TS (muxer"mpegts") and raw H.264 (muxer "h264") output formats.

h264_redundant_pps

This applies a specific fixup to some Blu-ray streams which containredundant PPSs modifying irrelevant parameters of the stream whichconfuse other transformations which require correct extradata.

A new single global PPS is created, and all of the redundant PPSswithin the stream are removed.

hevc_metadata

Modify metadata embedded in an HEVC stream.

aud

Insert or remove AUD NAL units in all access units of the stream.

insert
remove

sample_aspect_ratio

Set the sample aspect ratio in the stream in the VUI parameters.

video_format

video_full_range_flag

Set the video format in the stream (see H.265 section E.3.1 andtable E.2).

colour_primaries

transfer_characteristics

matrix_coefficients

Set the colour description in the stream (see H.265 section E.3.1and tables E.3, E.4 and E.5).

chroma_sample_loc_type

Set the chroma sample location in the stream (see H.265 sectionE.3.1 and figure E.1).

tick_rate

Set the tick rate in the VPS and VUI parameters (num_units_in_tick /time_scale). Combined with num_ticks_poc_diff_one, this canset a constant framerate in the stream. Note that it is likely to beoverridden by container parameters when the stream is in a container.

num_ticks_poc_diff_one

Set poc_proportional_to_timing_flag in VPS and VUI and use this valueto set num_ticks_poc_diff_one_minus1 (see H.265 sections 7.4.3.1 andE.3.1). Ignored if tick_rate is not also set.

crop_left

crop_right

crop_top

crop_bottom

Set the conformance window cropping offsets in the SPS. These valueswill replace the current ones if the stream is already cropped.

These fields are set in pixels. Note that some sizes may not berepresentable if the chroma is subsampled (H.265 section 7.4.3.2.1).

hevc_mp4toannexb

Convert an HEVC/H.265 bitstream from length prefixed mode to start codeprefixed mode (as defined in the Annex B of the ITU-T H.265specification).

This is required by some streaming formats, typically the MPEG-2transport stream format (muxer "mpegts").

For example to remux an MP4 file containing an HEVC stream to mpegtsformat with ffmpeg, you can use the command:

        ffmpeg -i INPUT.mp4 -codec copy -bsf:v hevc_mp4toannexb OUTPUT.ts

Please note that this filter is auto-inserted for MPEG-TS (muxer"mpegts") and raw HEVC/H.265 (muxer "h265" or"hevc") output formats.

imxdump

Modifies the bitstream to fit in MOV and to be usable by the Final CutPro decoder. This filter only applies to the mpeg2video codec, and islikely not needed for Final Cut Pro 7 and newer with the appropriate-tag:v.

For example, to remux 30 MB/sec NTSC IMX to MOV:

        ffmpeg -i input.mxf -c copy -bsf:v imxdump -tag:v mx3n output.mov

mjpeg2jpeg

Convert MJPEG/AVI1 packets to full JPEG/JFIF packets.

MJPEG is a video codec wherein each video frame is essentially aJPEG image. The individual frames can be extracted without loss,e.g. by

        ffmpeg -i ../some_mjpeg.avi -c:v copy frames_%d.jpg

Unfortunately, these chunks are incomplete JPEG images, becausethey lack the DHT segment required for decoding. Quoting from<http://www.digitalpreservation.gov/formats/fdd/fdd000063.shtml>:

Avery Lee, writing in the rec.video.desktop newsgroup in 2001,commented that ``MJPEG, or at least the MJPEG in AVIs having theMJPG fourcc, is restricted JPEG with a fixed --- and *omitted* ---Huffman table. The JPEG must be YCbCr colorspace, it must be 4:2:2,and it must use basic Huffman encoding, not arithmetic orprogressive. . . . You can indeed extract the MJPEG frames anddecode them with a regular JPEG decoder, but you have to prependthe DHT segment to them, or else the decoder won't have any ideahow to decompress the data. The exact table necessary is given inthe OpenDML spec.''

This bitstream filter patches the header of frames extracted from an MJPEGstream (carrying the AVI1 header ID and lacking a DHT segment) toproduce fully qualified JPEG images.

        ffmpeg -i mjpeg-movie.avi -c:v copy -bsf:v mjpeg2jpeg frame_%d.jpg        exiftran -i -9 frame*.jpg        ffmpeg -i frame_%d.jpg -c:v copy rotated.avi

mjpegadump

Add an MJPEG A header to the bitstream, to enable decoding byQuicktime.

mov2textsub

Extract a representable text file from MOV subtitles, stripping themetadata header from each subtitle packet.

mp3decomp

Decompress non-standard compressed MP3 audio headers.

mpeg2_metadata

Modify metadata embedded in an MPEG-2 stream.

display_aspect_ratio

Set the display aspect ratio in the stream.

The following fixed values are supported:

4/3
16/9
221/100

: Any other value will result in square pixels being signalled instead(see H.262 section 6.3.3 and table 6-3).

frame_rate

Set the frame rate in the stream. This is constructed from a tableof known values combined with a small multiplier and divisor - ifthe supplied value is not exactly representable, the nearestrepresentable value will be used instead (see H.262 section 6.3.3and table 6-4).

video_format

Set the video format in the stream (see H.262 section 6.3.6 andtable 6-6).

colour_primaries

transfer_characteristics

matrix_coefficients

Set the colour description in the stream (see H.262 section 6.3.6and tables 6-7, 6-8 and 6-9).

mpeg4_unpack_bframes

Unpack DivX-style packed B-frames.

DivX-style packed B-frames are not valid MPEG-4 and were only aworkaround for the broken Video for Windows subsystem.They use more space, can cause minor AV sync issues, require moreCPU power to decode (unless the player has some decoded picture queueto compensate the 2,0,2,0 frame per packet style) and causetrouble if copied into a standard container like mp4 or mpeg-ps/ts,because MPEG-4 decoders may not be able to decode them, since they arenot valid MPEG-4.

For example to fix an AVI file containing an MPEG-4 stream withDivX-style packed B-frames using ffmpeg, you can use the command:

        ffmpeg -i INPUT.avi -codec copy -bsf:v mpeg4_unpack_bframes OUTPUT.avi

noise

Damages the contents of packets or simply drops them without damaging thecontainer. Can be used for fuzzing or testing error resilience/concealment.

Parameters:

amount: A numeral string, whose value is related to how often output bytes willbe modified. Therefore, values below or equal to 0 are forbidden, andthe lower the more frequent bytes will be modified, with 1 meaningevery byte is modified.
dropamount: A numeral string, whose value is related to how often packets will be dropped.Therefore, values below or equal to 0 are forbidden, and the lower the morefrequent packets will be dropped, with 1 meaning every packet is dropped.

The following example applies the modification to every byte but does not dropany packets.

        ffmpeg -i INPUT -c copy -bsf noise[=1] output.mkv

null

This bitstream filter passes the packets through unchanged.

remove_extra

Remove extradata from packets.

It accepts the following parameter:

freq

Set which frame types to remove extradata from.

k: Remove extradata from non-keyframes only.
keyframe: Remove extradata from keyframes only.
e, all: Remove extradata from all frames.

text2movsub

Convert text subtitles to MOV subtitles (as used by the "mov_text"codec) with metadata headers.

trace_headers

Log trace output containing all syntax elements in the coded streamheaders (everything above the level of individual coded blocks).This can be useful for debugging low-level stream issues.

Supports H.264, H.265, MPEG-2 and VP9.

vp9_metadata

Modify metadata embedded in a VP9 stream.

color_space

Set the color space value in the frame header.

unknown
bt601
bt709
smpte170
smpte240
bt2020
rgb

color_range

Set the color range value in the frame header. Note that this cannotbe set in RGB streams.

tv
pc

vp9_superframe

Merge VP9 invisible (alt-ref) frames back into VP9 superframes. Thisfixes merging of split/segmented VP9 streams where the alt-ref framewas split from its visible counterpart.

vp9_superframe_split

Split VP9 superframes into single frames.

vp9_raw_reorder

Given a VP9 stream with correct timestamps but possibly out of order,insert additional show-existing-frame packets to correct the ordering.

AUTHORS

The FFmpeg developers.

For details about the authorship, see the Git history of the project(git://source.ffmpeg.org/ffmpeg), e.g. by typing the commandgit log in the FFmpeg source directory, or browsing theonline repository at <http://source.ffmpeg.org>.

Maintainers for the specific components are listed in the fileMAINTAINERS in the source code tree.

Index

NAME

DESCRIPTION

BITSTREAM FILTERS

aac_adtstoasc
av1_metadata
chomp
dca_core
dump_extra
eac3_core
extract_extradata
filter_units
hapqa_extract
h264_metadata
h264_mp4toannexb
h264_redundant_pps
hevc_metadata
hevc_mp4toannexb
imxdump
mjpeg2jpeg
mjpegadump
mov2textsub
mp3decomp
mpeg2_metadata
mpeg4_unpack_bframes
noise
null
remove_extra
text2movsub
trace_headers
vp9_metadata
vp9_superframe
vp9_superframe_split
vp9_raw_reorder

SEE ALSO

AUTHORS

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