mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-28 20:53:54 +02:00
c59b80c8d3
* qatar/master: isom: sort and pretty-print codec_movaudio_tags[] isom: remove pointless comments in codec_movaudio_tags[] isom: remove commented-out tag for vorbis movenc: write 'chan' tag for AC-3 in MOV mov: add support for reading and writing the 'chan' tag audioconvert: add some additional channel and channel layout macros audioconvert: change 7.1 "wide" layout to use side surround channels movenc: simplify handling of pcm vs. adpcm vs. other compressed codecs doc: update documentation to use avconv doc: update demuxers section doc: extend external library coverage doc: split platform specific information doc: port the git-howto to texinfo doc: provide fallback css and customize @float doc: document fate in a texinfo doxy: change hue value to match our green Conflicts: doc/fate.txt doc/ffserver.texi doc/general.texi doc/muxers.texi doc/protocols.texi doc/t2h.init libavformat/isom.c libavformat/mov.c libavutil/avutil.h tests/ref/acodec/pcm_s16be tests/ref/acodec/pcm_s24be tests/ref/acodec/pcm_s32be tests/ref/acodec/pcm_s8 tests/ref/lavf/mov Merged-by: Michael Niedermayer <michaelni@gmx.at>
78 lines
2.4 KiB
Plaintext
78 lines
2.4 KiB
Plaintext
@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.
|
|
|
|
Below is a description of the currently available bitstream filters.
|
|
|
|
@section aac_adtstoasc
|
|
|
|
@section chomp
|
|
|
|
@section dump_extradata
|
|
|
|
@section h264_mp4toannexb
|
|
|
|
@section imx_dump_header
|
|
|
|
@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 -vbsf mjpeg2jpeg frame_%d.jpg
|
|
exiftran -i -9 frame*.jpg
|
|
ffmpeg -i frame_%d.jpg -c:v copy rotated.avi
|
|
@end example
|
|
|
|
@section mjpega_dump_header
|
|
|
|
@section movsub
|
|
|
|
@section mp3_header_compress
|
|
|
|
@section mp3_header_decompress
|
|
|
|
@section noise
|
|
|
|
@section remove_extradata
|
|
|
|
@c man end BITSTREAM FILTERS
|