FFMPEG-BITSTREAM-FILTERS(1)			   FFMPEG-BITSTREAM-FILTERS(1)

NAME
       ffmpeg-bitstream-filters - FFmpeg bitstream filters

DESCRIPTION
       This document describes the bitstream filters provided by the
       libavcodec library.

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

BITSTREAM FILTERS
       When you configure your FFmpeg build, all the supported bitstream
       filters are enabled by default. You can list all available ones using
       the configure option "--list-bsfs".

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

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

       The ff* tools have a -bsf option applied per stream, taking a comma-
       separated list of filters, whose parameters follow the filter name
       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 Configuration
       bitstream.

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

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

   chomp
       Remove zero padding at the end of a packet.

   dca_core
       Extract the core from a DCA/DTS stream, dropping extensions such as
       DTS-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 global header (thus
       disabling individual packet headers) in the H.264 packets generated by
       the "libx264" encoder, but corrects them by adding the 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 part of the bitstream containing the coded frames) or
       "out of band" (e.g. on the container level). This latter form is called
       "extradata" in FFmpeg terminology.

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

       remove
	   When this option is enabled, the long-term headers are removed from
	   the bitstream 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
	   removing all others.  This is specified as a '|'-separated list of
	   unit type values or ranges of values with '-'.

       remove_types
	   Identical to pass_types, except the units in the given set removed
	   and all others passed through.

       Extradata is unchanged by this transformation, but note that if the
       stream contains inline parameter sets then the output may be unusable
       if they are removed.

       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 and
	   table E-2).

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

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

       tick_rate
	   Set the tick rate (num_units_in_tick / time_scale) in the VUI
	   parameters.	This is the smallest time unit representable in the
	   stream, 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
	   indicates that the framerate is exactly half the tick rate, but the
	   exact meaning is dependent on interlacing and the picture structure
	   (see H.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
	   replace the current ones if the stream is already cropped.

	   These fields are set in pixels.  Note that some sizes may not be
	   representable 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 must
	   be of the form UUID+string, where the UUID is as hex digits
	   possibly separated by hyphens, and the string can be anything.

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

       delete_filler
	   Deletes both filler NAL units and filler SEI messages.

   h264_mp4toannexb
       Convert an H.264 bitstream from length prefixed mode to start code
       prefixed mode (as defined in the Annex B of the ITU-T H.264
       specification).

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

       For example to remux an MP4 file containing an H.264 stream to mpegts
       format 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 contain
       redundant PPSs modifying irrelevant parameters of the stream which
       confuse other transformations which require correct extradata.

       A new single global PPS is created, and all of the redundant PPSs
       within 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 and
	   table E.2).

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

       chroma_sample_loc_type
	   Set the chroma sample location in the stream (see H.265 section
	   E.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 can set
	   a constant framerate in the stream.	Note that it is likely to be
	   overridden 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
	   value to set num_ticks_poc_diff_one_minus1 (see H.265 sections
	   7.4.3.1 and E.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
	   values will replace the current ones if the stream is already
	   cropped.

	   These fields are set in pixels.  Note that some sizes may not be
	   representable 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 code
       prefixed mode (as defined in the Annex B of the ITU-T H.265
       specification).

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

       For example to remux an MP4 file containing an HEVC stream to mpegts
       format 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 Cut
       Pro decoder. This filter only applies to the mpeg2video codec, and is
       likely 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 a JPEG
       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, because they
       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 the MJPG
       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 or progressive. . . . You
       can indeed extract the MJPEG frames and decode them with a regular JPEG
       decoder, but you have to prepend the DHT segment to them, or else the
       decoder won't have any idea how to decompress the data. The exact table
       necessary is given in the OpenDML spec."

       This bitstream filter patches the header of frames extracted from an
       MJPEG stream (carrying the AVI1 header ID and lacking a DHT segment) to
       produce 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 by
       Quicktime.

   mov2textsub
       Extract a representable text file from MOV subtitles, stripping the
       metadata header from each subtitle packet.

       See also the text2movsub filter.

   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 table
	   of known values combined with a small multiplier and divisor - if
	   the supplied value is not exactly representable, the nearest
	   representable value will be used instead (see H.262 section 6.3.3
	   and table 6-4).

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

       colour_primaries
       transfer_characteristics
       matrix_coefficients
	   Set the colour description in the stream (see H.262 section 6.3.6
	   and 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 a
       workaround for the broken Video for Windows subsystem.  They use more
       space, can cause minor AV sync issues, require more CPU power to decode
       (unless the player has some decoded picture queue to compensate the
       2,0,2,0 frame per packet style) and cause trouble 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 are not valid MPEG-4.

       For example to fix an AVI file containing an MPEG-4 stream with DivX-
       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
       the container. Can be used for fuzzing or testing error
       resilience/concealment.

       Parameters:

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

       The following example applies the modification to every byte but does
       not drop any 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.

       See also the mov2textsub filter.

   trace_headers
       Log trace output containing all syntax elements in the coded stream
       headers (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
	   cannot be set in RGB streams.

	   tv
	   pc

   vp9_superframe
       Merge VP9 invisible (alt-ref) frames back into VP9 superframes. This
       fixes merging of split/segmented VP9 streams where the alt-ref frame
       was 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.

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
       (git://source.ffmpeg.org/ffmpeg), e.g. by typing the command git log in
       the FFmpeg source directory, or browsing the online repository at
       <http://source.ffmpeg.org>.

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

						   FFMPEG-BITSTREAM-FILTERS(1)
