@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{time_scale / num_units_in_display_tick}) 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 dv_error_marker Blocks in DV which are marked as damaged are replaced by blocks of the specified color. @table @option @item color The color to replace damaged blocks by @item sta A 16 bit mask which specifies which of the 16 possible error status values are to be replaced by colored blocks. 0xFFFE is the default which replaces all non 0 error status values. @table @samp @item ok No error, no concealment @item err Error, No concealment @item res Reserved @item notok Error or concealment @item notres Not reserved @item Aa, Ba, Ca, Ab, Bb, Cb, A, B, C, a, b, erri, erru The specific error status code @end table see page 44-46 or section 5.5 of @url{http://web.archive.org/web/20060927044735/http://www.smpte.org/smpte_store/standards/pdf/s314m.pdf} @end table @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 pass @item insert @item remove @end table Default is pass. @item sample_aspect_ratio Set the sample aspect ratio of the stream in the VUI parameters. See H.264 table E-1. @item overscan_appropriate_flag Set whether the stream is suitable for display using overscan or not (see H.264 section E.2.1). @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 (time_scale / num_units_in_tick) 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 zero_new_constraint_set_flags Zero constraint_set4_flag and constraint_set5_flag in the SPS. These bits were reserved in a previous version of the H.264 spec, and thus some hardware decoders require these to be zero. The result of zeroing this is still a valid bitstream. @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 display_orientation Insert, extract or remove Display orientation SEI messages. See H.264 section D.1.27 and D.2.27 for syntax and semantics. @table @samp @item pass @item insert @item remove @item extract @end table Default is pass. Insert mode works in conjunction with @code{rotate} and @code{flip} options. Any pre-existing Display orientation messages will be removed in insert or remove mode. Extract mode attaches the display matrix to the packet as side data. @item rotate Set rotation in display orientation SEI (anticlockwise angle in degrees). Range is -360 to +360. Default is NaN. @item flip Set flip in display orientation SEI. @table @samp @item horizontal @item vertical @end table Default is unset. @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. @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 (time_scale / num_units_in_tick). 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 Accepts an expression whose evaluation per-packet determines how often bytes in that packet will be modified. A value below 0 will result in a variable frequency. Default is 0 which results in no modification. However, if neither amount nor drop is specified, amount will be set to @var{-1}. See below for accepted variables. @item drop Accepts an expression evaluated per-packet whose value determines whether that packet is dropped. Evaluation to a positive value results in the packet being dropped. Evaluation to a negative value results in a variable chance of it being dropped, roughly inverse in proportion to the magnitude of the value. Default is 0 which results in no drops. See below for accepted variables. @item dropamount Accepts a non-negative integer, which assigns a variable chance of it being dropped, roughly inverse in proportion to the value. Default is 0 which results in no drops. This option is kept for backwards compatibility and is equivalent to setting drop to a negative value with the same magnitude i.e. @code{dropamount=4} is the same as @code{drop=-4}. Ignored if drop is also specified. @end table Both @code{amount} and @code{drop} accept expressions containing the following variables: @table @samp @item n The index of the packet, starting from zero. @item tb The timebase for packet timestamps. @item pts Packet presentation timestamp. @item dts Packet decoding timestamp. @item nopts Constant representing AV_NOPTS_VALUE. @item startpts First non-AV_NOPTS_VALUE PTS seen in the stream. @item startdts First non-AV_NOPTS_VALUE DTS seen in the stream. @item duration @itemx d Packet duration, in timebase units. @item pos Packet position in input; may be -1 when unknown or not set. @item size Packet size, in bytes. @item key Whether packet is marked as a keyframe. @item state A pseudo random integer, primarily derived from the content of packet payload. @end table @subsection Examples Apply modification to every byte but don't drop any packets. @example ffmpeg -i INPUT -c copy -bsf noise=1 output.mkv @end example Drop every video packet not marked as a keyframe after timestamp 30s but do not modify any of the remaining packets. @example ffmpeg -i INPUT -c copy -bsf:v noise=drop='gt(t\,30)*not(key)' output.mkv @end example Drop one second of audio every 10 seconds and add some random noise to the rest. @example ffmpeg -i INPUT -c copy -bsf:a noise=amount=-1:drop='between(mod(t\,10)\,9\,10)' output.mkv @end example @section null This bitstream filter passes the packets through unchanged. @section pcm_rechunk Repacketize PCM audio to a fixed number of samples per packet or a fixed packet rate per second. This is similar to the @ref{asetnsamples,,asetnsamples audio filter,ffmpeg-filters} but works on audio packets instead of audio frames. @table @option @item nb_out_samples, n Set the number of samples per each output audio packet. The number is intended as the number of samples @emph{per each channel}. Default value is 1024. @item pad, p If set to 1, the filter will pad the last audio packet with silence, so that it will contain the same number of samples (or roughly the same number of samples, see @option{frame_rate}) as the previous ones. Default value is 1. @item frame_rate, r This option makes the filter output a fixed number of packets per second instead of a fixed number of samples per packet. If the audio sample rate is not divisible by the frame rate then the number of samples will not be constant but will vary slightly so that each packet will start as close to the frame boundary as possible. Using this option has precedence over @option{nb_out_samples}. @end table You can generate the well known 1602-1601-1602-1601-1602 pattern of 48kHz audio for NTSC frame rate using the @option{frame_rate} option. @example ffmpeg -f lavfi -i sine=r=48000:d=1 -c pcm_s16le -bsf pcm_rechunk=r=30000/1001 -f framecrc - @end example @section pgs_frame_merge Merge a sequence of PGS Subtitle segments ending with an "end of display set" segment into a single packet. This is required by some containers that support PGS subtitles (muxer @code{matroska}). @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 @item smpte2084 SMPTE ST 2084 @item arib-std-b67 ARIB STD-B67 @end table @item matrix_coefficients Set the matrix coefficient. Available values are: @table @samp @item auto Keep the same colorspace 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 Set Hybrid Log-Gamma parameters for each frame of the file @example ffmpeg -i INPUT -c copy -bsf:v prores_metadata=color_primaries=bt2020:color_trc=arib-std-b67:colorspace=bt2020nc 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 @section setts Set PTS and DTS in packets. It accepts the following parameters: @table @option @item ts @item pts @item dts Set expressions for PTS, DTS or both. @item duration Set expression for duration. @item time_base Set output time base. @end table The expressions are evaluated through the eval API and can contain the following constants: @table @option @item N The count of the input packet. Starting from 0. @item TS The demux timestamp in input in case of @code{ts} or @code{dts} option or presentation timestamp in case of @code{pts} option. @item POS The original position in the file of the packet, or undefined if undefined for the current packet @item DTS The demux timestamp in input. @item PTS The presentation timestamp in input. @item DURATION The duration in input. @item STARTDTS The DTS of the first packet. @item STARTPTS The PTS of the first packet. @item PREV_INDTS The previous input DTS. @item PREV_INPTS The previous input PTS. @item PREV_INDURATION The previous input duration. @item PREV_OUTDTS The previous output DTS. @item PREV_OUTPTS The previous output PTS. @item PREV_OUTDURATION The previous output duration. @item NEXT_DTS The next input DTS. @item NEXT_PTS The next input PTS. @item NEXT_DURATION The next input duration. @item TB The timebase of stream packet belongs. @item TB_OUT The output timebase. @item SR The sample rate of stream packet belongs. @item NOPTS The AV_NOPTS_VALUE constant. @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. Note that any frame set to RGB will be implicitly set to PC range and that RGB is incompatible with profiles 0 and 2. @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 any value imposed by the color space will take precedence over this value. @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