1 @chapter Bitstream Filters
2 @c man begin BITSTREAM FILTERS
4 When you configure your FFmpeg build, all the supported bitstream
5 filters are enabled by default. You can list all available ones using
6 the configure option @code{--list-bsfs}.
8 You can disable all the bitstream filters using the configure option
9 @code{--disable-bsfs}, and selectively enable any bitstream filter using
10 the option @code{--enable-bsf=BSF}, or you can disable a particular
11 bitstream filter using the option @code{--disable-bsf=BSF}.
13 The option @code{-bsfs} of the ff* tools will display the list of
14 all the supported bitstream filters included in your build.
16 Below is a description of the currently available bitstream filters.
18 @section aac_adtstoasc
20 Convert MPEG-2/4 AAC ADTS to MPEG-4 Audio Specific Configuration
23 This filter creates an MPEG-4 AudioSpecificConfig from an MPEG-2/4
24 ADTS header and removes the ADTS header.
26 This is required for example when copying an AAC stream from a raw
27 ADTS AAC container to a FLV or a MOV/MP4 file.
31 Remove zero padding at the end of a packet.
35 Add extradata to the beginning of the filtered packets.
37 The additional argument specifies which packets should be filtered.
38 It accepts the values:
41 add extradata to all key packets, but only if @var{local_header} is
42 set in the @option{flags2} codec context field
45 add extradata to all key packets
48 add extradata to all packets
51 If not specified it is assumed @samp{k}.
53 For example the following @command{ffmpeg} command forces a global
54 header (thus disabling individual packet headers) in the H.264 packets
55 generated by the @code{libx264} encoder, but corrects them by adding
56 the header stored in extradata to the key packets:
58 ffmpeg -i INPUT -map 0 -flags:v +global_header -c:v libx264 -bsf:v dump_extra out.ts
61 @section h264_mp4toannexb
63 Convert an H.264 bitstream from length prefixed mode to start code
64 prefixed mode (as defined in the Annex B of the ITU-T H.264
67 This is required by some streaming formats, typically the MPEG-2
68 transport stream format ("mpegts").
70 For example to remux an MP4 file containing an H.264 stream to mpegts
71 format with @command{ffmpeg}, you can use the command:
74 ffmpeg -i INPUT.mp4 -codec copy -bsf:v h264_mp4toannexb OUTPUT.ts
79 Modifies the bitstream to fit in MOV and to be usable by the Final Cut
80 Pro decoder. This filter only applies to the mpeg2video codec, and is
81 likely not needed for Final Cut Pro 7 and newer with the appropriate
84 For example, to remux 30 MB/sec NTSC IMX to MOV:
87 ffmpeg -i input.mxf -c copy -bsf:v imxdump -tag:v mx3n output.mov
92 Convert MJPEG/AVI1 packets to full JPEG/JFIF packets.
94 MJPEG is a video codec wherein each video frame is essentially a
95 JPEG image. The individual frames can be extracted without loss,
99 ffmpeg -i ../some_mjpeg.avi -c:v copy frames_%d.jpg
102 Unfortunately, these chunks are incomplete JPEG images, because
103 they lack the DHT segment required for decoding. Quoting from
104 @url{http://www.digitalpreservation.gov/formats/fdd/fdd000063.shtml}:
106 Avery Lee, writing in the rec.video.desktop newsgroup in 2001,
107 commented that "MJPEG, or at least the MJPEG in AVIs having the
108 MJPG fourcc, is restricted JPEG with a fixed -- and *omitted* --
109 Huffman table. The JPEG must be YCbCr colorspace, it must be 4:2:2,
110 and it must use basic Huffman encoding, not arithmetic or
111 progressive. . . . You can indeed extract the MJPEG frames and
112 decode them with a regular JPEG decoder, but you have to prepend
113 the DHT segment to them, or else the decoder won't have any idea
114 how to decompress the data. The exact table necessary is given in
117 This bitstream filter patches the header of frames extracted from an MJPEG
118 stream (carrying the AVI1 header ID and lacking a DHT segment) to
119 produce fully qualified JPEG images.
122 ffmpeg -i mjpeg-movie.avi -c:v copy -bsf:v mjpeg2jpeg frame_%d.jpg
123 exiftran -i -9 frame*.jpg
124 ffmpeg -i frame_%d.jpg -c:v copy rotated.avi
127 @section mjpega_dump_header
131 @section mp3_header_decompress
135 Damages the contents of packets without damaging the container. Can be
136 used for fuzzing or testing error resilience/concealment.
139 ffmpeg -i INPUT -c copy -bsf noise output.mkv
142 @section remove_extra
144 @c man end BITSTREAM FILTERS