Provided by: ffmpeg_2.8.6-1ubuntu2_amd64 bug

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 MPEG-4 Audio Specific Configuration bitstream filter.

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

       This is required for example when copying an AAC stream from a raw ADTS AAC container to a
       FLV or a MOV/MP4 file.

   chomp
       Remove zero padding at the end of a packet.

   dump_extra
       Add extradata to the beginning of the filtered packets.

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

       a   add extradata to all key packets, but only if local_header is set in the flags2 codec
           context field

       k   add extradata to all key packets

       e   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_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
       ("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

   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

   mjpega_dump_header
   movsub
   mp3_header_decompress
   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 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.

   remove_extra

SEE ALSO

       ffmpeg(1), ffplay(1), ffprobe(1), ffserver(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)