Hu Chunming / FFNvDecoder

  @chapter Bitstream Filters
  @c man begin 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 @code{--list-bsfs}.
  
  You can disable all the bitstream filters using the configure option
  @code{--disable-bsfs}, and selectively enable any bitstream filter using
  the option @code{--enable-bsf=BSF}, or you can disable a particular
  bitstream filter using the option @code{--disable-bsf=BSF}.
  
  The option @code{-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 '='.
  
  @example
  ffmpeg -i INPUT -c:v copy -bsf:v filter1[=opt1=str1:opt2=str2][,filter2] OUTPUT
  @end example
  
  Below is a description of the currently available bitstream filters,
  with their parameters, if any.
  
  @section 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.
  
  @section av1_metadata
  
  Modify metadata embedded in an AV1 stream.
  
  @table @option
  @item td
  Insert or remove temporal delimiter OBUs in all temporal units of the
  stream.
  
  @table @samp
  @item insert
  Insert a TD at the beginning of every TU which does not already have one.
  @item remove
  Remove the TD from the beginning of every TU which has one.
  @end table
  
  @item color_primaries
  @item transfer_characteristics
  @item matrix_coefficients
  Set the color description fields in the stream (see AV1 section 6.4.2).
  
  @item color_range
  Set the color range in the stream (see AV1 section 6.4.2; note that
  this cannot be set for streams using BT.709 primaries, sRGB transfer
  characteristic and identity (RGB) matrix coefficients).
  @table @samp
  @item tv
  Limited range.
  @item pc
  Full range.
  @end table
  
  @item 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.
  
  @table @samp
  @item vertical
  Left position (matching the default in MPEG-2 and H.264).
  @item colocated
  Top-left position.
  @end table
  
  @item tick_rate
  Set the tick rate (@emph{num_units_in_display_tick / time_scale}) in
  the timing info in the sequence header.
  @item num_ticks_per_picture
  Set the number of ticks in each picture, to indicate that the stream
  has a fixed framerate.  Ignored if @option{tick_rate} is not also set.
  
  @item delete_padding
  Deletes Padding OBUs.
  
  @end table
  
  @section chomp
  
  Remove zero padding at the end of a packet.
  
  @section dca_core
  
  Extract the core from a DCA/DTS stream, dropping extensions such as
  DTS-HD.
  
  @section dump_extra
  
  Add extradata to the beginning of the filtered packets except when
  said packets already exactly begin with the extradata that is intended
  to be added.
  
  @table @option
  @item freq
  The additional argument specifies which packets should be filtered.
  It accepts the values:
  @table @samp
  @item k
  @item keyframe
  add extradata to all key packets
  
  @item e
  @item all
  add extradata to all packets
  @end table
  @end table
  
  If not specified it is assumed @samp{k}.
  
  For example the following @command{ffmpeg} command forces a global
  header (thus disabling individual packet headers) in the H.264 packets
  generated by the @code{libx264} encoder, but corrects them by adding
  the header stored in extradata to the key packets:
  @example
  ffmpeg -i INPUT -map 0 -flags:v +global_header -c:v libx264 -bsf:v dump_extra out.ts
  @end example
  
  @section eac3_core
  
  Extract the core from a E-AC-3 stream, dropping extra channels.
  
  @section 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.
  
  @table @option
  @item remove
  When this option is enabled, the long-term headers are removed from the
  bitstream after extraction.
  @end table
  
  @section filter_units
  
  Remove units with types in or not in a given set from the stream.
  
  @table @option
  @item 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 '-'.
  
  @item remove_types
  Identical to @option{pass_types}, except the units in the given set
  removed and all others passed through.
  @end table
  
  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:
  @example
  ffmpeg -i INPUT -c:v copy -bsf:v 'filter_units=pass_types=1-5' OUTPUT
  @end example
  
  To remove all AUDs, SEI and filler from an H.265 stream:
  @example
  ffmpeg -i INPUT -c:v copy -bsf:v 'filter_units=remove_types=35|38-40' OUTPUT
  @end example
  
  @section hapqa_extract
  
  Extract Rgb or Alpha part of an HAPQA file, without recompression, in order to create an HAPQ or an HAPAlphaOnly file.
  
  @table @option
  @item texture
  Specifies the texture to keep.
  
  @table @option
  @item color
  @item alpha
  @end table
  
  @end table
  
  Convert HAPQA to HAPQ
  @example
  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
  @end example
  
  Convert HAPQA to HAPAlphaOnly
  @example
  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
  @end example
  
  @section h264_metadata
  
  Modify metadata embedded in an H.264 stream.
  
  @table @option
  @item aud
  Insert or remove AUD NAL units in all access units of the stream.
  
  @table @samp
  @item insert
  @item remove
  @end table
  
  @item sample_aspect_ratio
  Set the sample aspect ratio of the stream in the VUI parameters.
  
  @item video_format
  @item video_full_range_flag
  Set the video format in the stream (see H.264 section E.2.1 and
  table E-2).
  
  @item colour_primaries
  @item transfer_characteristics
  @item 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).
  
  @item chroma_sample_loc_type
  Set the chroma sample location in the stream (see H.264 section
  E.2.1 and figure E-1).
  
  @item 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).
  @item 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).
  
  @item crop_left
  @item crop_right
  @item crop_top
  @item 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).
  
  @item sei_user_data
  Insert a string as SEI unregistered user data.  The argument must
  be of the form @emph{UUID+string}, where the UUID is as hex digits
  possibly separated by hyphens, and the string can be anything.
  
  For example, @samp{086f3693-b7b3-4f2c-9653-21492feee5b8+hello} will
  insert the string ``hello'' associated with the given UUID.
  
  @item delete_filler
  Deletes both filler NAL units and filler SEI messages.
  
  @item level
  Set the level in the SPS.  Refer to H.264 section A.3 and tables A-1
  to A-5.
  
  The argument must be the name of a level (for example, @samp{4.2}), a
  level_idc value (for example, @samp{42}), or the special name @samp{auto}
  indicating that the filter should attempt to guess the level from the
  input stream properties.
  
  @end table
  
  @section 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 @code{mpegts}).
  
  For example to remux an MP4 file containing an H.264 stream to mpegts
  format with @command{ffmpeg}, you can use the command:
  
  @example
  ffmpeg -i INPUT.mp4 -codec copy -bsf:v h264_mp4toannexb OUTPUT.ts
  @end example
  
  Please note that this filter is auto-inserted for MPEG-TS (muxer
  @code{mpegts}) and raw H.264 (muxer @code{h264}) output formats.
  
  @section 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.
  
  @section hevc_metadata
  
  Modify metadata embedded in an HEVC stream.
  
  @table @option
  @item aud
  Insert or remove AUD NAL units in all access units of the stream.
  
  @table @samp
  @item insert
  @item remove
  @end table
  
  @item sample_aspect_ratio
  Set the sample aspect ratio in the stream in the VUI parameters.
  
  @item video_format
  @item video_full_range_flag
  Set the video format in the stream (see H.265 section E.3.1 and
  table E.2).
  
  @item colour_primaries
  @item transfer_characteristics
  @item 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).
  
  @item chroma_sample_loc_type
  Set the chroma sample location in the stream (see H.265 section
  E.3.1 and figure E.1).
  
  @item tick_rate
  Set the tick rate in the VPS and VUI parameters (num_units_in_tick /
  time_scale).  Combined with @option{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.
  
  @item 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 @option{tick_rate} is not also set.
  
  @item crop_left
  @item crop_right
  @item crop_top
  @item 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).
  
  @item level
  Set the level in the VPS and SPS.  See H.265 section A.4 and tables
  A.6 and A.7.
  
  The argument must be the name of a level (for example, @samp{5.1}), a
  @emph{general_level_idc} value (for example, @samp{153} for level 5.1),
  or the special name @samp{auto} indicating that the filter should
  attempt to guess the level from the input stream properties.
  
  @end table
  
  @section 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 @code{mpegts}).
  
  For example to remux an MP4 file containing an HEVC stream to mpegts
  format with @command{ffmpeg}, you can use the command:
  
  @example
  ffmpeg -i INPUT.mp4 -codec copy -bsf:v hevc_mp4toannexb OUTPUT.ts
  @end example
  
  Please note that this filter is auto-inserted for MPEG-TS (muxer
  @code{mpegts}) and raw HEVC/H.265 (muxer @code{h265} or
  @code{hevc}) output formats.
  
  @section 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
  @option{-tag:v}.
  
  For example, to remux 30 MB/sec NTSC IMX to MOV:
  
  @example
  ffmpeg -i input.mxf -c copy -bsf:v imxdump -tag:v mx3n output.mov
  @end example
  
  @section 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
  
  @example
  ffmpeg -i ../some_mjpeg.avi -c:v copy frames_%d.jpg
  @end example
  
  Unfortunately, these chunks are incomplete JPEG images, because
  they lack the DHT segment required for decoding. Quoting from
  @url{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.
  
  @example
  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
  @end example
  
  @section mjpegadump
  
  Add an MJPEG A header to the bitstream, to enable decoding by
  Quicktime.
  
  @anchor{mov2textsub}
  @section mov2textsub
  
  Extract a representable text file from MOV subtitles, stripping the
  metadata header from each subtitle packet.
  
  See also the @ref{text2movsub} filter.
  
  @section mp3decomp
  
  Decompress non-standard compressed MP3 audio headers.
  
  @section mpeg2_metadata
  
  Modify metadata embedded in an MPEG-2 stream.
  
  @table @option
  @item display_aspect_ratio
  Set the display aspect ratio in the stream.
  
  The following fixed values are supported:
  @table @option
  @item 4/3
  @item 16/9
  @item 221/100
  @end table
  Any other value will result in square pixels being signalled instead
  (see H.262 section 6.3.3 and table 6-3).
  
  @item 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).
  
  @item video_format
  Set the video format in the stream (see H.262 section 6.3.6 and
  table 6-6).
  
  @item colour_primaries
  @item transfer_characteristics
  @item 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).
  
  @end table
  
  @section 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 @command{ffmpeg}, you can use the command:
  
  @example
  ffmpeg -i INPUT.avi -codec copy -bsf:v mpeg4_unpack_bframes OUTPUT.avi
  @end example
  
  @section 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:
  @table @option
  @item 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.
  @item 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.
  @end table
  
  The following example applies the modification to every byte but does not drop
  any packets.
  @example
  ffmpeg -i INPUT -c copy -bsf noise[=1] output.mkv
  @end example
  
  @section null
  This bitstream filter passes the packets through unchanged.
  
  @section prores_metadata
  
  Modify color property metadata embedded in prores stream.
  
  @table @option
  @item color_primaries
  Set the color primaries.
  Available values are:
  
  @table @samp
  @item auto
  Keep the same color primaries property (default).
  
  @item unknown
  @item bt709
  @item bt470bg
  BT601 625
  
  @item smpte170m
  BT601 525
  
  @item bt2020
  @item smpte431
  DCI P3
  
  @item smpte432
  P3 D65
  
  @end table
  
  @item transfer_characteristics
  Set the color transfer.
  Available values are:
  
  @table @samp
  @item auto
  Keep the same transfer characteristics property (default).
  
  @item unknown
  @item bt709
  BT 601, BT 709, BT 2020
  @end table
  
  
  @item matrix_coefficients
  Set the matrix coefficient.
  Available values are:
  
  @table @samp
  @item auto
  Keep the same transfer characteristics property (default).
  
  @item unknown
  @item bt709
  @item smpte170m
  BT 601
  
  @item bt2020nc
  @end table
  @end table
  
  Set Rec709 colorspace for each frame of the file
  @example
  ffmpeg -i INPUT -c copy -bsf:v prores_metadata=color_primaries=bt709:color_trc=bt709:colorspace=bt709 output.mov
  @end example
  
  @section remove_extra
  
  Remove extradata from packets.
  
  It accepts the following parameter:
  @table @option
  @item freq
  Set which frame types to remove extradata from.
  
  @table @samp
  @item k
  Remove extradata from non-keyframes only.
  
  @item keyframe
  Remove extradata from keyframes only.
  
  @item e, all
  Remove extradata from all frames.
  
  @end table
  @end table
  
  @anchor{text2movsub}
  @section text2movsub
  
  Convert text subtitles to MOV subtitles (as used by the @code{mov_text}
  codec) with metadata headers.
  
  See also the @ref{mov2textsub} filter.
  
  @section 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 AV1, H.264, H.265, (M)JPEG, MPEG-2 and VP9, but depending
  on the build only a subset of these may be available.
  
  @section truehd_core
  
  Extract the core from a TrueHD stream, dropping ATMOS data.
  
  @section vp9_metadata
  
  Modify metadata embedded in a VP9 stream.
  
  @table @option
  @item color_space
  Set the color space value in the frame header.
  @table @samp
  @item unknown
  @item bt601
  @item bt709
  @item smpte170
  @item smpte240
  @item bt2020
  @item rgb
  @end table
  
  @item color_range
  Set the color range value in the frame header.  Note that this cannot
  be set in RGB streams.
  @table @samp
  @item tv
  @item pc
  @end table
  @end table
  
  @section 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.
  
  @section vp9_superframe_split
  
  Split VP9 superframes into single frames.
  
  @section 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.
  
  @c man end BITSTREAM FILTERS