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NAMEffmpeg-bitstream-filters - FFmpeg bitstream filters
DESCRIPTIONThis 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 FILTERSWhen 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.
This filter creates an
This is required for example when copying an
chompRemove zero padding at the end of a packet.
dump_extraAdd extradata to the beginning of the filtered packets.
The additional argument specifies which packets should be filtered. It accepts the values:
- add extradata to all key packets, but only if local_header is set in the flags2 codec context field
- add extradata to all key packets
- add extradata to all packets
If not specified it is assumed k.
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
h264_mp4toannexbConvert 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
For example to remux an
ffmpeg -i INPUT.mp4 -codec copy -bsf:v h264_mp4toannexb OUTPUT.ts
imxdumpModifies the bitstream to fit in
For example, to remux 30 MB/sec
ffmpeg -i input.mxf -c copy -bsf:v imxdump -tag:v mx3n output.mov
ffmpeg -i ../some_mjpeg.avi -c:v copy frames_%d.jpg
Unfortunately, these chunks are incomplete
Avery Lee, writing in the rec.video.desktop newsgroup in 2001, commented that ``
This bitstream filter patches the header of frames extracted from an
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
mpeg4_unpack_bframesUnpack DivX-style packed B-frames.
DivX-style packed B-frames are not valid
For example to fix an
ffmpeg -i INPUT.avi -codec copy -bsf:v mpeg4_unpack_bframes OUTPUT.avi
noiseDamages the contents of packets without damaging the container. Can be used for fuzzing or testing error resilience/concealment.
Parameters: 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.
ffmpeg -i INPUT -c copy -bsf noise[=1] output.mkv
applies the modification to every byte.
SEE ALSOffmpeg(1), ffplay(1), ffprobe(1), ffserver(1), libavcodec(3)
AUTHORSThe 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 <source.ffmpeg.org>.
Maintainers for the specific components are listed in the file