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 The ff* tools have a -bsf option applied per stream, taking a
17 comma-separated list of filters, whose parameters follow the filter
21 ffmpeg -i INPUT -c:v copy -bsf:v filter1[=opt1=str1/opt2=str2][,filter2] OUTPUT
24 Below is a description of the currently available bitstream filters,
25 with their parameters, if any.
27 @section aac_adtstoasc
29 Convert MPEG-2/4 AAC ADTS to MPEG-4 Audio Specific Configuration
32 This filter creates an MPEG-4 AudioSpecificConfig from an MPEG-2/4
33 ADTS header and removes the ADTS header.
35 This is required for example when copying an AAC stream from a raw
36 ADTS AAC container to a FLV or a MOV/MP4 file.
40 Remove zero padding at the end of a packet.
44 Add extradata to the beginning of the filtered packets.
46 The additional argument specifies which packets should be filtered.
47 It accepts the values:
50 add extradata to all key packets, but only if @var{local_header} is
51 set in the @option{flags2} codec context field
54 add extradata to all key packets
57 add extradata to all packets
60 If not specified it is assumed @samp{k}.
62 For example the following @command{ffmpeg} command forces a global
63 header (thus disabling individual packet headers) in the H.264 packets
64 generated by the @code{libx264} encoder, but corrects them by adding
65 the header stored in extradata to the key packets:
67 ffmpeg -i INPUT -map 0 -flags:v +global_header -c:v libx264 -bsf:v dump_extra out.ts
70 @section h264_mp4toannexb
72 Convert an H.264 bitstream from length prefixed mode to start code
73 prefixed mode (as defined in the Annex B of the ITU-T H.264
76 This is required by some streaming formats, typically the MPEG-2
77 transport stream format ("mpegts").
79 For example to remux an MP4 file containing an H.264 stream to mpegts
80 format with @command{ffmpeg}, you can use the command:
83 ffmpeg -i INPUT.mp4 -codec copy -bsf:v h264_mp4toannexb OUTPUT.ts
88 Modifies the bitstream to fit in MOV and to be usable by the Final Cut
89 Pro decoder. This filter only applies to the mpeg2video codec, and is
90 likely not needed for Final Cut Pro 7 and newer with the appropriate
93 For example, to remux 30 MB/sec NTSC IMX to MOV:
96 ffmpeg -i input.mxf -c copy -bsf:v imxdump -tag:v mx3n output.mov
101 Convert MJPEG/AVI1 packets to full JPEG/JFIF packets.
103 MJPEG is a video codec wherein each video frame is essentially a
104 JPEG image. The individual frames can be extracted without loss,
108 ffmpeg -i ../some_mjpeg.avi -c:v copy frames_%d.jpg
111 Unfortunately, these chunks are incomplete JPEG images, because
112 they lack the DHT segment required for decoding. Quoting from
113 @url{http://www.digitalpreservation.gov/formats/fdd/fdd000063.shtml}:
115 Avery Lee, writing in the rec.video.desktop newsgroup in 2001,
116 commented that "MJPEG, or at least the MJPEG in AVIs having the
117 MJPG fourcc, is restricted JPEG with a fixed -- and *omitted* --
118 Huffman table. The JPEG must be YCbCr colorspace, it must be 4:2:2,
119 and it must use basic Huffman encoding, not arithmetic or
120 progressive. . . . You can indeed extract the MJPEG frames and
121 decode them with a regular JPEG decoder, but you have to prepend
122 the DHT segment to them, or else the decoder won't have any idea
123 how to decompress the data. The exact table necessary is given in
126 This bitstream filter patches the header of frames extracted from an MJPEG
127 stream (carrying the AVI1 header ID and lacking a DHT segment) to
128 produce fully qualified JPEG images.
131 ffmpeg -i mjpeg-movie.avi -c:v copy -bsf:v mjpeg2jpeg frame_%d.jpg
132 exiftran -i -9 frame*.jpg
133 ffmpeg -i frame_%d.jpg -c:v copy rotated.avi
136 @section mjpega_dump_header
140 @section mp3_header_decompress
142 @section mpeg4_unpack_bframes
144 Unpack DivX-style packed B-frames.
146 DivX-style packed B-frames are not valid MPEG-4 and were only a
147 workaround for the broken Video for Windows subsystem.
148 They use more space, can cause minor AV sync issues, require more
149 CPU power to decode (unless the player has some decoded picture queue
150 to compensate the 2,0,2,0 frame per packet style) and cause
151 trouble if copied into a standard container like mp4 or mpeg-ps/ts,
152 because MPEG-4 decoders may not be able to decode them, since they are
155 For example to fix an AVI file containing an MPEG-4 stream with
156 DivX-style packed B-frames using @command{ffmpeg}, you can use the command:
159 ffmpeg -i INPUT.avi -codec copy -bsf:v mpeg4_unpack_bframes OUTPUT.avi
164 Damages the contents of packets without damaging the container. Can be
165 used for fuzzing or testing error resilience/concealment.
168 A numeral string, whose value is related to how often output bytes will
169 be modified. Therefore, values below or equal to 0 are forbidden, and
170 the lower the more frequent bytes will be modified, with 1 meaning
171 every byte is modified.
174 ffmpeg -i INPUT -c copy -bsf noise[=1] output.mkv
176 applies the modification to every byte.
178 @section remove_extra
180 @c man end BITSTREAM FILTERS