RealVideo 1.0/2.0 and TrueSpeech are supported.
[libav.git] / doc / ffmpeg-doc.texi
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1\input texinfo @c -*- texinfo -*-
2
3@settitle FFmpeg Documentation
4@titlepage
5@sp 7
6@center @titlefont{FFmpeg Documentation}
7@sp 3
8@end titlepage
9
10
11@chapter Introduction
12
13FFmpeg is a very fast video and audio converter. It can also grab from
14a live audio/video source.
115329f1 15
9181577c 16The command line interface is designed to be intuitive, in the sense
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17that FFmpeg tries to figure out all parameters that can possibly be
18derived automatically. You usually only have to specify the target
19bitrate you want.
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20
21FFmpeg can also convert from any sample rate to any other, and resize
22video on the fly with a high quality polyphase filter.
23
24@chapter Quick Start
25
e99c4e10 26@c man begin EXAMPLES
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27@section Video and Audio grabbing
28
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29FFmpeg can use a video4linux compatible video source and any Open Sound
30System audio source:
31
9181577c 32@example
115329f1 33ffmpeg /tmp/out.mpg
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34@end example
35
e99c4e10 36Note that you must activate the right video source and channel before
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37launching FFmpeg with any TV viewer such as xawtv
38(@url{http://bytesex.org/xawtv/}) by Gerd Knorr. You also
39have to set the audio recording levels correctly with a
e99c4e10 40standard mixer.
9181577c 41
6bf40f39 42@section Video and Audio file format conversion
9181577c 43
4c5f7207 44* FFmpeg can use any supported file format and protocol as input:
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45
46Examples:
47
4c5f7207 48* You can use YUV files as input:
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49
50@example
115329f1 51ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
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52@end example
53
115329f1 54It will use the files:
9181577c 55@example
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56/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
57/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
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58@end example
59
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60The Y files use twice the resolution of the U and V files. They are
61raw files, without header. They can be generated by all decent video
62decoders. You must specify the size of the image with the @option{-s} option
4c5f7207 63if FFmpeg cannot guess it.
9181577c 64
4c5f7207 65* You can input from a raw YUV420P file:
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66
67@example
e99c4e10 68ffmpeg -i /tmp/test.yuv /tmp/out.avi
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69@end example
70
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71test.yuv is a file containing raw YUV planar data. Each frame is composed
72of the Y plane followed by the U and V planes at half vertical and
e99c4e10 73horizontal resolution.
9181577c 74
4c5f7207 75* You can output to a raw YUV420P file:
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76
77@example
f926cbe7 78ffmpeg -i mydivx.avi hugefile.yuv
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79@end example
80
81* You can set several input files and output files:
82
83@example
e99c4e10 84ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
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85@end example
86
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87Converts the audio file a.wav and the raw YUV video file a.yuv
88to MPEG file a.mpg.
9181577c 89
6bf40f39 90* You can also do audio and video conversions at the same time:
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91
92@example
e99c4e10 93ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
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94@end example
95
4c5f7207 96Converts a.wav to MPEG audio at 22050Hz sample rate.
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97
98* You can encode to several formats at the same time and define a
e99c4e10 99mapping from input stream to output streams:
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100
101@example
e99c4e10 102ffmpeg -i /tmp/a.wav -ab 64 /tmp/a.mp2 -ab 128 /tmp/b.mp2 -map 0:0 -map 0:0
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103@end example
104
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105Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
106file:index' specifies which input stream is used for each output
e99c4e10 107stream, in the order of the definition of output streams.
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108
109* You can transcode decrypted VOBs
110
111@example
e99c4e10 112ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800 -g 300 -bf 2 -acodec mp3 -ab 128 snatch.avi
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113@end example
114
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115This is a typical DVD ripping example; the input is a VOB file, the
116output an AVI file with MPEG-4 video and MP3 audio. Note that in this
117command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
118GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
119input video. Furthermore, the audio stream is MP3-encoded so you need
120to enable LAME support by passing @code{--enable-mp3lame} to configure.
121The mapping is particularly useful for DVD transcoding
e99c4e10 122to get the desired audio language.
9181577c 123
4c5f7207 124NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
e99c4e10 125@c man end
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126
127@chapter Invocation
128
129@section Syntax
130
e99c4e10 131The generic syntax is:
9181577c 132
115329f1 133@example
e99c4e10 134@c man begin SYNOPSIS
28f88dc8 135ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
e99c4e10 136@c man end
9181577c 137@end example
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138@c man begin DESCRIPTION
139If no input file is given, audio/video grabbing is done.
9181577c 140
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141As a general rule, options are applied to the next specified
142file. For example, if you give the @option{-b 64} option, it sets the video
4c5f7207 143bitrate of the next file. The format option may be needed for raw input
e99c4e10 144files.
9181577c 145
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146By default, FFmpeg tries to convert as losslessly as possible: It
147uses the same audio and video parameters for the outputs as the one
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148specified for the inputs.
149@c man end
9181577c 150
e99c4e10 151@c man begin OPTIONS
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152@section Main options
153
e99c4e10 154@table @option
9181577c 155@item -L
4c5f7207 156Show license.
18bff752 157
9181577c 158@item -h
4c5f7207 159Show help.
18bff752 160
e99c4e10 161@item -formats
4c5f7207 162Show available formats, codecs, protocols, ...
18bff752 163
115329f1 164@item -f fmt
4c5f7207 165Force format.
18bff752 166
115329f1 167@item -i filename
4c5f7207 168input filename
9181577c 169
115329f1 170@item -y
4c5f7207 171Overwrite output files.
9181577c 172
115329f1 173@item -t duration
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174Set the recording time in seconds.
175@code{hh:mm:ss[.xxx]} syntax is also supported.
9181577c 176
e83a84ac 177@item -ss position
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178Seek to given time position in seconds.
179@code{hh:mm:ss[.xxx]} syntax is also supported.
e83a84ac 180
115329f1 181@item -title string
4c5f7207 182Set the title.
9181577c 183
115329f1 184@item -author string
4c5f7207 185Set the author.
9181577c 186
115329f1 187@item -copyright string
4c5f7207 188Set the copyright.
9181577c 189
115329f1 190@item -comment string
4c5f7207 191Set the comment.
9181577c 192
99db6420 193@item -target type
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194Specify target file type ("vcd", "svcd", "dvd", "dv", "pal-vcd",
195"ntsc-svcd", ... ). All the format options (bitrate, codecs,
196buffer sizes) are then set automatically. You can just type:
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197
198@example
199ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
200@end example
201
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202Nevertheless you can specify additional options as long as you know
203they do not conflict with the standard, as in:
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204
205@example
206ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
207@end example
208
99db6420 209@item -hq
4c5f7207 210Activate high quality settings.
18bff752 211
401fbdde 212@item -itsoffset offset
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213Set the input time offset in seconds.
214@code{[-]hh:mm:ss[.xxx]} syntax is also supported.
215This option affects all the input files that follow it.
216The offset is added to the timestamps of the input files.
217Specifying a positive offset means that the corresponding
218streams are delayed by 'offset' seconds.
401fbdde 219
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220@end table
221
222@section Video Options
223
e99c4e10 224@table @option
9181577c 225@item -b bitrate
4c5f7207 226Set the video bitrate in kbit/s (default = 200 kb/s).
115329f1 227@item -r fps
4c5f7207 228Set frame rate (default = 25).
115329f1 229@item -s size
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230Set frame size. The format is @samp{wxh} (default = 160x128).
231The following abbreviations are recognized:
5ee03c86 232@table @samp
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233@item sqcif
234128x96
235@item qcif
236176x144
237@item cif
238352x288
239@item 4cif
240704x576
241@end table
242
243@item -aspect aspect
4c5f7207 244Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
18bff752 245@item -croptop size
4c5f7207 246Set top crop band size (in pixels).
18bff752 247@item -cropbottom size
4c5f7207 248Set bottom crop band size (in pixels).
18bff752 249@item -cropleft size
4c5f7207 250Set left crop band size (in pixels).
18bff752 251@item -cropright size
4c5f7207 252Set right crop band size (in pixels).
1ff93ffc 253@item -padtop size
4c5f7207 254Set top pad band size (in pixels).
1ff93ffc 255@item -padbottom size
4c5f7207 256Set bottom pad band size (in pixels).
1ff93ffc 257@item -padleft size
4c5f7207 258Set left pad band size (in pixels).
1ff93ffc 259@item -padright size
4c5f7207 260Set right pad band size (in pixels).
5b79a73e 261@item -padcolor (hex color)
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262Set color of padded bands. The value for padcolor is expressed
263as a six digit hexadecimal number where the first two digits
264represent red, the middle two digits green and last two digits
265blue (default = 000000 (black)).
9181577c 266@item -vn
4c5f7207 267Disable video recording.
115329f1 268@item -bt tolerance
4c5f7207 269Set video bitrate tolerance (in kbit/s).
18bff752 270@item -maxrate bitrate
4c5f7207 271Set max video bitrate tolerance (in kbit/s).
18bff752 272@item -minrate bitrate
4c5f7207 273Set min video bitrate tolerance (in kbit/s).
18bff752 274@item -bufsize size
4c5f7207 275Set rate control buffer size (in kbit).
115329f1 276@item -vcodec codec
4c5f7207 277Force video codec to @var{codec}. Use the @code{copy} special value to
5ee03c86 278tell that the raw codec data must be copied as is.
18bff752 279@item -sameq
4c5f7207 280Use same video quality as source (implies VBR).
9181577c 281
115329f1 282@item -pass n
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283Select the pass number (1 or 2). It is useful to do two pass
284encoding. The statistics of the video are recorded in the first
285pass and the video is generated at the exact requested bitrate
286in the second pass.
9181577c 287
115329f1 288@item -passlogfile file
4c5f7207 289Set two pass logfile name to @var{file}.
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290
291@end table
292
18bff752 293@section Advanced Video Options
9181577c 294
e99c4e10 295@table @option
115329f1 296@item -g gop_size
4c5f7207 297Set the group of pictures size.
115329f1 298@item -intra
4c5f7207 299Use only intra frames.
115329f1 300@item -qscale q
4c5f7207 301Use fixed video quantiser scale (VBR).
115329f1 302@item -qmin q
4c5f7207 303minimum video quantiser scale (VBR)
115329f1 304@item -qmax q
4c5f7207 305maximum video quantiser scale (VBR)
115329f1 306@item -qdiff q
4c5f7207 307maximum difference between the quantiser scales (VBR)
115329f1 308@item -qblur blur
9181577c 309video quantiser scale blur (VBR)
115329f1 310@item -qcomp compression
9181577c 311video quantiser scale compression (VBR)
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312
313@item -rc_init_cplx complexity
4c5f7207 314initial complexity for single pass encoding
18bff752 315@item -b_qfactor factor
4c5f7207 316qp factor between P- and B-frames
18bff752 317@item -i_qfactor factor
4c5f7207 318qp factor between P- and I-frames
18bff752 319@item -b_qoffset offset
4c5f7207 320qp offset between P- and B-frames
18bff752 321@item -i_qoffset offset
4c5f7207 322qp offset between P- and I-frames
18bff752 323@item -rc_eq equation
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324Set rate control equation (@pxref{FFmpeg formula
325evaluator}) (default = @code{tex^qComp}).
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326@item -rc_override override
327rate control override for specific intervals
18bff752 328@item -me method
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329Set motion estimation method to @var{method}.
330Available methods are (from lowest to best quality):
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331@table @samp
332@item zero
5ee03c86 333Try just the (0, 0) vector.
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334@item phods
335@item log
336@item x1
337@item epzs
338(default method)
339@item full
340exhaustive search (slow and marginally better than epzs)
341@end table
342
343@item -dct_algo algo
4c5f7207 344Set DCT algorithm to @var{algo}. Available values are:
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345@table @samp
346@item 0
347FF_DCT_AUTO (default)
348@item 1
349FF_DCT_FASTINT
350@item 2
351FF_DCT_INT
352@item 3
353FF_DCT_MMX
354@item 4
355FF_DCT_MLIB
356@item 5
357FF_DCT_ALTIVEC
358@end table
359
360@item -idct_algo algo
4c5f7207 361Set IDCT algorithm to @var{algo}. Available values are:
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362@table @samp
363@item 0
364FF_IDCT_AUTO (default)
365@item 1
115329f1 366FF_IDCT_INT
18bff752 367@item 2
115329f1 368FF_IDCT_SIMPLE
18bff752 369@item 3
115329f1 370FF_IDCT_SIMPLEMMX
18bff752 371@item 4
115329f1 372FF_IDCT_LIBMPEG2MMX
18bff752 373@item 5
115329f1 374FF_IDCT_PS2
18bff752 375@item 6
115329f1 376FF_IDCT_MLIB
18bff752 377@item 7
115329f1 378FF_IDCT_ARM
18bff752 379@item 8
115329f1 380FF_IDCT_ALTIVEC
18bff752 381@item 9
115329f1 382FF_IDCT_SH4
18bff752 383@item 10
115329f1 384FF_IDCT_SIMPLEARM
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385@end table
386
387@item -er n
4c5f7207 388Set error resilience to @var{n}.
18bff752 389@table @samp
115329f1 390@item 1
1471c6c2 391FF_ER_CAREFUL (default)
18bff752 392@item 2
5ee03c86 393FF_ER_COMPLIANT
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394@item 3
395FF_ER_AGGRESSIVE
396@item 4
397FF_ER_VERY_AGGRESSIVE
398@end table
399
5ee03c86 400@item -ec bit_mask
4c5f7207 401Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
5ee03c86 402the following values:
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403@table @samp
404@item 1
4c5f7207 405FF_EC_GUESS_MVS (default = enabled)
18bff752 406@item 2
4c5f7207 407FF_EC_DEBLOCK (default = enabled)
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408@end table
409
410@item -bf frames
4c5f7207 411Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
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412@item -mbd mode
413macroblock decision
414@table @samp
415@item 0
4c5f7207 416FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
18bff752 417@item 1
4c5f7207 418FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
18bff752 419@item 2
019c8838 420FF_MB_DECISION_RD: rate distortion
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421@end table
422
423@item -4mv
4c5f7207 424Use four motion vector by macroblock (MPEG-4 only).
18bff752 425@item -part
4c5f7207 426Use data partitioning (MPEG-4 only).
18bff752 427@item -bug param
4c5f7207 428Work around encoder bugs that are not auto-detected.
18bff752 429@item -strict strictness
4c5f7207 430How strictly to follow the standards.
5ee03c86 431@item -aic
4c5f7207 432Enable Advanced intra coding (h263+).
5ee03c86 433@item -umv
4c5f7207 434Enable Unlimited Motion Vector (h263+)
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435
436@item -deinterlace
4c5f7207 437Deinterlace pictures.
99db6420 438@item -interlace
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439Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
440Use this option if your input file is interlaced and you want
441to keep the interlaced format for minimum losses.
442The alternative is to deinterlace the input stream with
443@option{-deinterlace}, but deinterlacing introduces losses.
18bff752 444@item -psnr
4c5f7207 445Calculate PSNR of compressed frames.
18bff752 446@item -vstats
4c5f7207 447Dump video coding statistics to @file{vstats_HHMMSS.log}.
18bff752 448@item -vhook module
4c5f7207 449Insert video processing @var{module}. @var{module} contains the module
18bff752 450name and its parameters separated by spaces.
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451@end table
452
453@section Audio Options
454
455@table @option
115329f1 456@item -ar freq
4c5f7207 457Set the audio sampling frequency (default = 44100 Hz).
115329f1 458@item -ab bitrate
4c5f7207 459Set the audio bitrate in kbit/s (default = 64).
18bff752 460@item -ac channels
4c5f7207 461Set the number of audio channels (default = 1).
5ee03c86 462@item -an
4c5f7207 463Disable audio recording.
5ee03c86 464@item -acodec codec
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465Force audio codec to @var{codec}. Use the @code{copy} special value to
466specify that the raw codec data must be copied as is.
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467@end table
468
469@section Audio/Video grab options
470
471@table @option
472@item -vd device
4c5f7207 473sEt video grab device (e.g. @file{/dev/video0}).
18bff752 474@item -vc channel
4c5f7207 475Set video grab channel (DV1394 only).
18bff752 476@item -tvstd standard
4c5f7207 477Set television standard (NTSC, PAL (SECAM)).
18bff752 478@item -dv1394
4c5f7207 479Set DV1394 grab.
18bff752 480@item -ad device
4c5f7207 481Set audio device (e.g. @file{/dev/dsp}).
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482@end table
483
484@section Advanced options
485
486@table @option
115329f1 487@item -map file:stream
4c5f7207 488Set input stream mapping.
18bff752 489@item -debug
4c5f7207 490Print specific debug info.
115329f1 491@item -benchmark
4c5f7207 492Add timings for benchmarking.
115329f1 493@item -hex
4c5f7207 494Dump each input packet.
18bff752 495@item -bitexact
4c5f7207 496Only use bit exact algorithms (for codec testing).
18bff752 497@item -ps size
4c5f7207 498Set packet size in bits.
5ee03c86 499@item -re
4c5f7207 500Read input at native frame rate. Mainly used to simulate a grab device.
5ee03c86 501@item -loop
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502Loop over the input stream. Currently it works only for image
503streams. This option is used for automatic FFserver testing.
8108551a 504@item -loop_output number_of_times
019c8838 505Repeatedly loop output for formats that support looping such as animated GIF
4c5f7207 506(0 will loop the output infinitely).
9181577c 507@end table
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508
509@node FFmpeg formula evaluator
510@section FFmpeg formula evaluator
511
512When evaluating a rate control string, FFmpeg uses an internal formula
115329f1 513evaluator.
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514
515The following binary operators are available: @code{+}, @code{-},
516@code{*}, @code{/}, @code{^}.
517
518The following unary operators are available: @code{+}, @code{-},
519@code{(...)}.
520
521The following functions are available:
522@table @var
523@item sinh(x)
524@item cosh(x)
525@item tanh(x)
526@item sin(x)
527@item cos(x)
528@item tan(x)
529@item exp(x)
530@item log(x)
531@item squish(x)
532@item gauss(x)
533@item abs(x)
534@item max(x, y)
535@item min(x, y)
536@item gt(x, y)
537@item lt(x, y)
538@item eq(x, y)
539@item bits2qp(bits)
540@item qp2bits(qp)
541@end table
542
543The following constants are available:
544@table @var
545@item PI
546@item E
547@item iTex
548@item pTex
549@item tex
550@item mv
551@item fCode
552@item iCount
553@item mcVar
554@item var
555@item isI
556@item isP
557@item isB
558@item avgQP
559@item qComp
560@item avgIITex
561@item avgPITex
562@item avgPPTex
563@item avgBPTex
564@item avgTex
565@end table
566
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567@c man end
568
569@ignore
570
571@setfilename ffmpeg
572@settitle FFmpeg video converter
573
574@c man begin SEEALSO
019c8838 575ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
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576@c man end
577
578@c man begin AUTHOR
579Fabrice Bellard
580@c man end
581
582@end ignore
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583
584@section Protocols
585
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586The filename can be @file{-} to read from standard input or to write
587to standard output.
9181577c 588
4c5f7207 589FFmpeg also handles many protocols specified with an URL syntax.
9181577c 590
4c5f7207 591Use 'ffmpeg -formats' to see a list of the supported protocols.
9181577c 592
e99c4e10 593The protocol @code{http:} is currently used only to communicate with
4c5f7207 594FFserver (see the FFserver documentation). When FFmpeg will be a
e99c4e10 595video player it will also be used for streaming :-)
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596
597@chapter Tips
598
599@itemize
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600@item For streaming at very low bitrate application, use a low frame rate
601and a small GOP size. This is especially true for RealVideo where
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602the Linux player does not seem to be very fast, so it can miss
603frames. An example is:
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604
605@example
e99c4e10 606ffmpeg -g 3 -r 3 -t 10 -b 50 -s qcif -f rv10 /tmp/b.rm
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607@end example
608
609@item The parameter 'q' which is displayed while encoding is the current
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610quantizer. The value 1 indicates that a very good quality could
611be achieved. The value 31 indicates the worst quality. If q=31 appears
e99c4e10 612too often, it means that the encoder cannot compress enough to meet
4c5f7207 613your bitrate. You must either increase the bitrate, decrease the
e99c4e10 614frame rate or decrease the frame size.
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615
616@item If your computer is not fast enough, you can speed up the
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617compression at the expense of the compression ratio. You can use
618'-me zero' to speed up motion estimation, and '-intra' to disable
4c5f7207 619motion estimation completely (you have only I-frames, which means it
e99c4e10 620is about as good as JPEG compression).
9181577c 621
4c5f7207 622@item To have very low audio bitrates, reduce the sampling frequency
019c8838 623(down to 22050 kHz for MPEG audio, 22050 or 11025 for AC3).
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624
625@item To have a constant quality (but a variable bitrate), use the option
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626'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
627quality).
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628
629@item When converting video files, you can use the '-sameq' option which
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630uses the same quality factor in the encoder as in the decoder.
631It allows almost lossless encoding.
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632
633@end itemize
634
635@chapter Supported File Formats and Codecs
636
637You can use the @code{-formats} option to have an exhaustive list.
638
639@section File Formats
640
6bf40f39 641FFmpeg supports the following file formats through the @code{libavformat}
0699d2fe 642library:
9181577c 643
3fc9e78f 644@multitable @columnfractions .4 .1 .1 .4
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645@item Supported File Format @tab Encoding @tab Decoding @tab Comments
646@item MPEG audio @tab X @tab X
4c5f7207 647@item MPEG-1 systems @tab X @tab X
9181577c 648@tab muxed audio and video
4c5f7207 649@item MPEG-2 PS @tab X @tab X
9181577c 650@tab also known as @code{VOB} file
4c5f7207 651@item MPEG-2 TS @tab @tab X
9181577c 652@tab also known as DVB Transport Stream
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653@item ASF@tab X @tab X
654@item AVI@tab X @tab X
655@item WAV@tab X @tab X
9181577c 656@item Macromedia Flash@tab X @tab X
4c5f7207 657@tab Only embedded audio is decoded.
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658@item FLV @tab X @tab X
659@tab Macromedia Flash video files
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660@item Real Audio and Video @tab X @tab X
661@item Raw AC3 @tab X @tab X
662@item Raw MJPEG @tab X @tab X
663@item Raw MPEG video @tab X @tab X
664@item Raw PCM8/16 bits, mulaw/Alaw@tab X @tab X
665@item Raw CRI ADX audio @tab X @tab X
666@item Raw Shorten audio @tab @tab X
667@item SUN AU format @tab X @tab X
7fe4c823 668@item NUT @tab X @tab X @tab NUT Open Container Format
115329f1 669@item QuickTime @tab X @tab X
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670@item MPEG-4 @tab X @tab X
671@tab MPEG-4 is a variant of QuickTime.
115329f1 672@item Raw MPEG4 video @tab X @tab X
4fa1c4fa 673@item DV @tab X @tab X
701b603d 674@item 4xm @tab @tab X
4c5f7207 675@tab 4X Technologies format, used in some games.
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676@item Playstation STR @tab @tab X
677@item Id RoQ @tab @tab X
4c5f7207 678@tab Used in Quake III, Jedi Knight 2, other computer games.
4d3b1f8d 679@item Interplay MVE @tab @tab X
4c5f7207 680@tab Format used in various Interplay computer games.
b17e9c99 681@item WC3 Movie @tab @tab X
4c5f7207 682@tab Multimedia format used in Origin's Wing Commander III computer game.
2fdf638b 683@item Sega FILM/CPK @tab @tab X
4c5f7207 684@tab Used in many Sega Saturn console games.
2fdf638b 685@item Westwood Studios VQA/AUD @tab @tab X
4c5f7207 686@tab Multimedia formats used in Westwood Studios games.
4120a53a 687@item Id Cinematic (.cin) @tab @tab X
4c5f7207 688@tab Used in Quake II.
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689@item FLIC format @tab @tab X
690@tab .fli/.flc files
da00f30e 691@item Sierra VMD @tab @tab X
4c5f7207 692@tab Used in Sierra CD-ROM games.
d08d7142 693@item Sierra Online @tab @tab X
4c5f7207 694@tab .sol files used in Sierra Online games.
38088adf 695@item Matroska @tab @tab X
ad81a9fe 696@item Electronic Arts Multimedia @tab @tab X
4c5f7207 697@tab Used in various EA games; files have extensions like WVE and UV2.
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698@item Nullsoft Video (NSV) format @tab @tab X
699@end multitable
9181577c 700
4c5f7207 701@code{X} means that encoding (resp. decoding) is supported.
9181577c 702
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703@section Image Formats
704
705FFmpeg can read and write images for each frame of a video sequence. The
706following image formats are supported:
707
3fc9e78f 708@multitable @columnfractions .4 .1 .1 .4
0699d2fe 709@item Supported Image Format @tab Encoding @tab Decoding @tab Comments
115329f1 710@item PGM, PPM @tab X @tab X
4c5f7207 711@item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
2eb5d024 712@item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
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713@item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
714@item .Y.U.V @tab X @tab X @tab one raw file per component
715@item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
716@item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
6a91ec51 717@item SGI @tab X @tab X @tab SGI RGB image format
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718@end multitable
719
4c5f7207 720@code{X} means that encoding (resp. decoding) is supported.
0699d2fe 721
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722@section Video Codecs
723
3fc9e78f 724@multitable @columnfractions .4 .1 .1 .4
9181577c 725@item Supported Codec @tab Encoding @tab Decoding @tab Comments
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726@item MPEG-1 video @tab X @tab X
727@item MPEG-2 video @tab X @tab X
728@item MPEG-4 @tab X @tab X @tab also known as DivX4/5
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729@item MSMPEG4 V1 @tab X @tab X
730@item MSMPEG4 V2 @tab X @tab X
4c5f7207 731@item MSMPEG4 V3 @tab X @tab X @tab also known as DivX3
9181577c 732@item WMV7 @tab X @tab X
4c5f7207 733@item WMV8 @tab X @tab X @tab not completely working
b06b45c4 734@item H.261 @tab X @tab X
4c5f7207 735@item H.263(+) @tab X @tab X @tab also known as RealVideo 1.0
b06b45c4 736@item H.264 @tab @tab X
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737@item RealVideo 1.0 @tab X @tab X
738@item RealVideo 2.0 @tab X @tab X
115329f1 739@item MJPEG @tab X @tab X
4c5f7207 740@item lossless MJPEG @tab X @tab X
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741@item Apple MJPEG-B @tab @tab X
742@item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
115329f1 743@item DV @tab X @tab X
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744@item HuffYUV @tab X @tab X
745@item FFmpeg Video 1 @tab X @tab X @tab experimental lossless codec (fourcc: FFV1)
746@item FFmpeg Snow @tab X @tab X @tab experimental wavelet codec (fourcc: SNOW)
701b603d 747@item Asus v1 @tab X @tab X @tab fourcc: ASV1
4d3b1f8d 748@item Asus v2 @tab X @tab X @tab fourcc: ASV2
701b603d 749@item Creative YUV @tab @tab X @tab fourcc: CYUV
d2bfadc0 750@item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
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751@item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
752@item On2 VP3 @tab @tab X @tab still experimental
d6896c49 753@item Theora @tab @tab X @tab still experimental
cdb2c1ca 754@item Intel Indeo 3 @tab @tab X
9303d49c 755@item FLV @tab X @tab X @tab Sorenson H.263 used in Flash
4d3b1f8d 756@item ATI VCR1 @tab @tab X @tab fourcc: VCR1
7fe4c823 757@item ATI VCR2 @tab @tab X @tab fourcc: VCR2
4d3b1f8d 758@item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
4c5f7207 759@item 4X Video @tab @tab X @tab Used in certain computer games.
115329f1 760@item Sony Playstation MDEC @tab @tab X
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761@item Id RoQ @tab @tab X @tab Used in Quake III, Jedi Knight 2, other computer games.
762@item Xan/WC3 @tab @tab X @tab Used in Wing Commander III .MVE files.
763@item Interplay Video @tab @tab X @tab Used in Interplay .MVE files.
070ed1bc 764@item Apple Animation @tab @tab X @tab fourcc: 'rle '
42cad81a 765@item Apple Graphics @tab @tab X @tab fourcc: 'smc '
2fdf638b 766@item Apple Video @tab @tab X @tab fourcc: rpza
d08d7142 767@item Apple QuickDraw @tab @tab X @tab fourcc: qdrw
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768@item Cinepak @tab @tab X
769@item Microsoft RLE @tab @tab X
770@item Microsoft Video-1 @tab @tab X
4120a53a 771@item Westwood VQA @tab @tab X
4c5f7207 772@item Id Cinematic Video @tab @tab X @tab Used in Quake II.
1dc1ed99 773@item Planar RGB @tab @tab X @tab fourcc: 8BPS
42cad81a 774@item FLIC video @tab @tab X
9a4117d5 775@item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK
dce76c20 776@item Duck TrueMotion v2 @tab @tab X @tab fourcc: TM20
4c5f7207 777@item VMD Video @tab @tab X @tab Used in Sierra VMD files.
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778@item MSZH @tab @tab X @tab Part of LCL
779@item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental
9d53d58e 780@item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC
d0a0bbd2 781@item IBM Ultimotion @tab @tab X @tab fourcc: ULTI
ab711b3c 782@item Miro VideoXL @tab @tab X @tab fourcc: VIXL
acfd8f0f 783@item QPEG @tab @tab X @tab fourccs: QPEG, Q1.0, Q1.1
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784@item LOCO @tab @tab X @tab
785@item Winnov WNV1 @tab @tab X @tab
589f8220 786@item Autodesk Animator Studio Codec @tab @tab X @tab fourcc: AASC
115329f1 787@item Fraps FPS1 @tab @tab X @tab
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788@end multitable
789
4c5f7207 790@code{X} means that encoding (resp. decoding) is supported.
9181577c 791
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792See @url{http://www.mplayerhq.hu/~michael/codec-features.html} to
793get a precise comparison of the FFmpeg MPEG-4 codec compared to
794other implementations.
60837265 795
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796@section Audio Codecs
797
798@multitable @columnfractions .4 .1 .1 .1 .7
799@item Supported Codec @tab Encoding @tab Decoding @tab Comments
115329f1 800@item MPEG audio layer 2 @tab IX @tab IX
9181577c 801@item MPEG audio layer 1/3 @tab IX @tab IX
4c5f7207 802@tab MP3 encoding is supported through the external library LAME.
37776c3b 803@item AC3 @tab IX @tab IX
4c5f7207 804@tab liba52 is used internally for decoding.
34d7008d 805@item Vorbis @tab X @tab X
4c5f7207 806@tab Supported through the external library libvorbis.
4745b5bf 807@item WMA V1/V2 @tab @tab X
f6fa7a6c 808@item AAC @tab X @tab X
4c5f7207 809@tab Supported through the external library libfaac/libfaad.
d4c3c5a6 810@item Microsoft ADPCM @tab X @tab X
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811@item MS IMA ADPCM @tab X @tab X
812@item QT IMA ADPCM @tab @tab X
813@item 4X IMA ADPCM @tab @tab X
d4e437df 814@item G.726 ADPCM @tab X @tab X
b17e9c99 815@item Duck DK3 IMA ADPCM @tab @tab X
4c5f7207 816@tab Used in some Sega Saturn console games.
b17e9c99 817@item Duck DK4 IMA ADPCM @tab @tab X
4c5f7207 818@tab Used in some Sega Saturn console games.
2fdf638b 819@item Westwood Studios IMA ADPCM @tab @tab X
4c5f7207 820@tab Used in Westwood Studios games like Command and Conquer.
7d8379f2 821@item SMJPEG IMA ADPCM @tab @tab X
4c5f7207 822@tab Used in certain Loki game ports.
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823@item CD-ROM XA ADPCM @tab @tab X
824@item CRI ADX ADPCM @tab X @tab X
4c5f7207 825@tab Used in Sega Dreamcast games.
7d8379f2 826@item Electronic Arts ADPCM @tab @tab X
4c5f7207 827@tab Used in various EA titles.
b3bfb299 828@item Creative ADPCM @tab @tab X
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829@item RA144 @tab @tab X
830@tab Real 14400 bit/s codec
831@item RA288 @tab @tab X
832@tab Real 28800 bit/s codec
37776c3b 833@item RADnet @tab X @tab IX
4c5f7207 834@tab Real low bitrate AC3 codec, liba52 is used for decoding.
2eb5d024 835@item AMR-NB @tab X @tab X
4c5f7207 836@tab Supported through an external library.
d663a1fd 837@item AMR-WB @tab X @tab X
4c5f7207 838@tab Supported through an external library.
2eb5d024 839@item DV audio @tab @tab X
4d3b1f8d 840@item Id RoQ DPCM @tab @tab X
4c5f7207 841@tab Used in Quake III, Jedi Knight 2, other computer games.
4d3b1f8d 842@item Interplay MVE DPCM @tab @tab X
4c5f7207 843@tab Used in various Interplay computer games.
b17e9c99 844@item Xan DPCM @tab @tab X
4c5f7207 845@tab Used in Origin's Wing Commander IV AVI files.
d08d7142 846@item Sierra Online DPCM @tab @tab X
4c5f7207 847@tab Used in Sierra Online game audio files.
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848@item Apple MACE 3 @tab @tab X
849@item Apple MACE 6 @tab @tab X
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850@item FLAC lossless audio @tab @tab X
851@item Shorten lossless audio @tab @tab X
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852@item Apple lossless audio @tab @tab X
853@tab QuickTime fourcc 'alac'
33a4d8b1 854@item FFmpeg Sonic @tab X @tab X
4c5f7207 855@tab experimental lossy/lossless codec
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856@item Qdesign QDM2 @tab @tab X
857@tab there are still some distortions
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858@item Real COOK @tab @tab X
859@tab All versions except 5.1 are supported
e839a994 860@item DSP Group TrueSpeech @tab @tab X
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861@end multitable
862
4c5f7207 863@code{X} means that encoding (resp. decoding) is supported.
9181577c 864
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865@code{I} means that an integer-only version is available, too (ensures high
866performance on systems without hardware floating point support).
9181577c 867
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868@chapter Platform Specific information
869
870@section Linux
871
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872FFmpeg should be compiled with at least GCC 2.95.3. GCC 3.2 is the
873preferred compiler now for FFmpeg. All future optimizations will depend on
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874features only found in GCC 3.2.
875
876@section BSD
877
878@section Windows
879
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880@subsection Native Windows compilation
881
882@itemize
883@item Install the current versions of MSYS and MinGW from
884@url{http://www.mingw.org/}. You can find detailed installation
885instructions in the download section and the FAQ.
886
4c5f7207 887@item If you want to test the FFplay, also download
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888the MinGW development library of SDL 1.2.x
889(@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
4c5f7207 890@url{http://www.libsdl.org}. Unpack it in a temporary directory, and
50f52fcd 891unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
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892directory. Edit the @file{sdl-config} script so that it gives the
893correct SDL directory when invoked.
50f52fcd 894
e926e391 895@item Extract the current version of FFmpeg.
115329f1 896
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897@item Start the MSYS shell (file @file{msys.bat}).
898
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899@item Change to the FFmpeg directory and follow
900 the instructions of how to compile FFmpeg (file
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901@file{INSTALL}). Usually, launching @file{./configure} and @file{make}
902suffices. If you have problems using SDL, verify that
903@file{sdl-config} can be launched from the MSYS command line.
904
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905@item You can install FFmpeg in @file{Program Files/FFmpeg} by typing
906@file{make install}. Don't forget to copy @file{SDL.dll} to the place
907you launch @file{ffplay} from.
50f52fcd 908
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909@end itemize
910
115329f1 911Notes:
988a9f9e 912@itemize
50f52fcd 913
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914@item The target @file{make wininstaller} can be used to create a
915Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
4c5f7207 916must be copied to the FFmpeg directory in order to build the
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917installer.
918
4c5f7207 919@item By using @code{./configure --enable-shared} when configuring FFmpeg,
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920you can build @file{avcodec.dll} and @file{avformat.dll}. With
921@code{make install} you install the FFmpeg DLLs and the associated
115329f1 922headers in @file{Program Files/FFmpeg}.
988a9f9e 923
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924@item Visual C++ compatibility: If you used @code{./configure --enable-shared}
925when configuring FFmpeg, FFmpeg tries to use the Microsoft Visual
988a9f9e 926C++ @code{lib} tool to build @code{avcodec.lib} and
4c5f7207 927@code{avformat.lib}. With these libraries you can link your Visual C++
be0efc0c 928code directly with the FFmpeg DLLs (see below).
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929
930@end itemize
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932@subsection Visual C++ compatibility
933
934FFmpeg will not compile under Visual C++ -- and it has too many
935dependencies on the GCC compiler to make a port viable. However,
936if you want to use the FFmpeg libraries in your own applications,
937you can still compile those applications using Visual C++. An
938important restriction to this is that you have to use the
939dynamically linked versions of the FFmpeg libraries (i.e. the
940DLLs), and you have to make sure that Visual-C++-compatible
941import libraries are created during the FFmpeg build process.
942
943This description of how to use the FFmpeg libraries with Visual C++ is
944based on Visual C++ 2005 Express Edition Beta 2. If you have a different
945version, you might have to modify the procedures slightly.
946
947Here are the step-by-step instructions for building the FFmpeg libraries
948so they can be used with Visual C++:
949
950@enumerate
951
952@item Install Visual C++ (if you haven't done so already).
953
954@item Install MinGW and MSYS as described above.
955
956@item Add a call to @file{vcvars32.bat} (which sets up the environment
957variables for the Visual C++ tools) as the first line of
958@file{msys.bat}. The standard location for @file{vcvars32.bat} is
959@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
960and the standard location for @file{msys.bat} is
961@file{C:\msys\1.0\msys.bat}. If this corresponds to your setup, add the
962following line as the first line of @file{msys.bat}:
963
964@code{call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"}
965
966@item Start the MSYS shell (file @file{msys.bat}) and type @code{link.exe}.
967If you get a help message with the command line options of @code{link.exe},
968this means your environment variables are set up correctly, the
969Microsoft linker is on the path and will be used by FFmpeg to
970create Visual-C++-compatible import libraries.
971
e926e391 972@item Extract the current version of FFmpeg and change to the FFmpeg directory.
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973
974@item Type the command
975@code{./configure --enable-shared --enable-memalign-hack} to configure and,
976if that didn't produce any errors, type @code{make} to build FFmpeg.
977
978@item The subdirectories @file{libavformat}, @file{libavcodec}, and
979@file{libavutil} should now contain the files @file{avformat.dll},
980@file{avformat.lib}, @file{avcodec.dll}, @file{avcodec.lib},
981@file{avutil.dll}, and @file{avutil.lib}, respectively. Copy the three
982DLLs to your System32 directory (typically @file{C:\Windows\System32}).
983
984@end enumerate
985
986And here is how to use these libraries with Visual C++:
987
988@enumerate
989
990@item Create a new console application ("File / New / Project") and then
991select "Win32 Console Application". On the appropriate page of the
992Application Wizard, uncheck the "Precompiled headers" option.
993
994@item Write the source code for your application, or, for testing, just
995copy the code from an existing sample application into the source file
996that Visual C++ has already created for you. (Note that your source
997filehas to have a @code{.cpp} extension; otherwise, Visual C++ won't
998compile the FFmpeg headers correctly because in C mode, it doesn't
999recognize the @code{inline} keyword.) For example, you can copy
1000@file{output_example.c} from the FFmpeg distribution (but you will
1001have to make minor modifications so the code will compile under
1002C++, see below).
1003
1004@item Open the "Project / Properties" dialog box. In the "Configuration"
1005combo box, select "All Configurations" so that the changes you make will
1006affect both debug and release builds. In the tree view on the left hand
1007side, select "C/C++ / General", then edit the "Additional Include
1008Directories" setting to contain the complete paths to the
1009@file{libavformat}, @file{libavcodec}, and @file{libavutil}
1010subdirectories of your FFmpeg directory. Note that the directories have
1011to be separated using semicolons. Now select "Linker / General" from the
1012tree view and edit the "Additional Library Directories" setting to
1013contain the same three directories.
1014
1015@item Still in the "Project / Properties" dialog box, select "Linker / Input"
1016from the tree view, then add the files @file{avformat.lib},
1017@file{avcodec.lib}, and @file{avutil.lib} to the end of the "Additional
1018Dependencies". Note that the names of the libraries have to be separated
1019using spaces.
1020
765c3440 1021@item Now, select "C/C++ / Code Generation" from the tree view. Select
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1022"Debug" in the "Configuration" combo box. Make sure that "Runtime
1023Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
1024the "Configuration" combo box and make sure that "Runtime Library" is
1025set to "Multi-threaded DLL".
1026
1027@item Click "OK" to close the "Project / Properties" dialog box and build
1028the application. Hopefully, it should compile and run cleanly. If you
1029used @file{output_example.c} as your sample application, you will get a
1030few compiler errors, but they are easy to fix. The first type of error
1031occurs because Visual C++ doesn't allow an @code{int} to be converted to
1032an @code{enum} without a cast. To solve the problem, insert the required
1033casts (this error occurs once for a @code{CodecID} and once for a
1034@code{CodecType}). The second type of error occurs because C++ requires
1035the return value of @code{malloc} to be cast to the exact type of the
1036pointer it is being assigned to. Visual C++ will complain that, for
1037example, @code{(void *)} is being assigned to @code{(uint8_t *)} without
1038an explicit cast. So insert an explicit cast in these places to silence
1039the compiler. The third type of error occurs because the @code{snprintf}
1040library function is called @code{_snprintf} under Visual C++. So just
1041add an underscore to fix the problem. With these changes,
1042@file{output_example.c} should compile under Visual C++, and the
1043resulting executable should produce valid video files.
1044
1045@end enumerate
1046
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1047@subsection Cross compilation for Windows with Linux
1048
1049You must use the MinGW cross compilation tools available at
1050@url{http://www.mingw.org/}.
1051
4c5f7207 1052Then configure FFmpeg with the following options:
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1053@example
1054./configure --enable-mingw32 --cross-prefix=i386-mingw32msvc-
1055@end example
019c8838 1056(you can change the cross-prefix according to the prefix chosen for the
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1057MinGW tools).
1058
4c5f7207 1059Then you can easily test FFmpeg with Wine
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1060(@url{http://www.winehq.com/}).
1061
019c8838 1062@section Mac OS X
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1063
1064@section BeOS
1065
1066The configure script should guess the configuration itself.
1067Networking support is currently not finished.
1068errno issues fixed by Andrew Bachmann.
1069
1070Old stuff:
1071
7dd611c9 1072François Revol - revol at free dot fr - April 2002
47d944d2 1073
115329f1 1074The configure script should guess the configuration itself,
4c5f7207 1075however I still didn't test building on the net_server version of BeOS.
47d944d2 1076
4c5f7207 1077FFserver is broken (needs poll() implementation).
47d944d2 1078
4c5f7207 1079There are still issues with errno codes, which are negative in BeOS, and
115329f1 1080that FFmpeg negates when returning. This ends up turning errors into
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1081valid results, then crashes.
1082(To be fixed)
1083
34d7008d 1084@chapter Developers Guide
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1085
1086@section API
1087@itemize
1088@item libavcodec is the library containing the codecs (both encoding and
4c5f7207 1089decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
9181577c 1090
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1091@item libavformat is the library containing the file format handling (mux and
1092demux code for several formats). Look at @file{ffplay.c} to use it in a
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1093player. See @file{output_example.c} to use it to generate audio or video
1094streams.
1095
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1096@end itemize
1097
1098@section Integrating libavcodec or libavformat in your program
1099
1100You can integrate all the source code of the libraries to link them
1101statically to avoid any version problem. All you need is to provide a
1102'config.mak' and a 'config.h' in the parent directory. See the defines
1103generated by ./configure to understand what is needed.
1104
1105You can use libavcodec or libavformat in your commercial program, but
1106@emph{any patch you make must be published}. The best way to proceed is
4c5f7207 1107to send your patches to the FFmpeg mailing list.
9181577c 1108
80d1c272 1109@node Coding Rules
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1110@section Coding Rules
1111
4c5f7207 1112FFmpeg is programmed in the ISO C90 language with a few additional
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1113features from ISO C99, namely:
1114@itemize @bullet
1115@item
1116the @samp{inline} keyword;
1117@item
1118@samp{//} comments;
1119@item
1120designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
1121@item
114afa9c 1122compound literals (@samp{x = (struct s) @{ 17, 23 @};})
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1123@end itemize
1124
1125These features are supported by all compilers we care about, so we won't
1126accept patches to remove their use unless they absolutely don't impair
1127clarity and performance.
1128
4c5f7207 1129All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
cb6e87c1
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1130compiles with several other compilers, such as the Compaq ccc compiler
1131or Sun Studio 9, and we would like to keep it that way unless it would
1132be exceedingly involved. To ensure compatibility, please don't use any
4c5f7207 1133additional C99 features or GCC extensions. Especially watch out for:
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1134@itemize @bullet
1135@item
1136mixing statements and declarations;
1137@item
1138@samp{long long} (use @samp{int64_t} instead);
1139@item
1140@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
1141@item
019c8838 1142GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
cb6e87c1 1143@end itemize
9181577c 1144
cb6e87c1 1145Indent size is 4. The TAB character should not be used.
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1146The presentation is the one specified by 'indent -i4 -kr'.
1147
4c5f7207 1148Main priority in FFmpeg is simplicity and small code size (=less
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1149bugs).
1150
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1151Comments: Use the JavaDoc/Doxygen
1152format (see examples below) so that code documentation
1153can be generated automatically. All nontrivial functions should have a comment
1154above them explaining what the function does, even if it's just one sentence.
1155All structures and their member variables should be documented, too.
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1156@example
1157/**
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1158 * @@file mpeg.c
1159 * MPEG codec.
1160 * @@author ...
1161 */
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1162
1163/**
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1164 * Summary sentence.
1165 * more text ...
1166 * ...
1167 */
114afa9c 1168typedef struct Foobar@{
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1169 int var1; /**< var1 description */
1170 int var2; ///< var2 description
1171 /** var3 description */
1172 int var3;
114afa9c 1173@} Foobar;
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1174
1175/**
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1176 * Summary sentence.
1177 * more text ...
1178 * ...
1179 * @@param my_parameter description of my_parameter
1180 * @@return return value description
1181 */
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1182int myfunc(int my_parameter)
1183...
1184@end example
9181577c 1185
115329f1 1186fprintf and printf are forbidden in libavformat and libavcodec,
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1187please use av_log() instead.
1188
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1189@node CVS Policy
1190@section CVS Policy
1191
1192@enumerate
115329f1 1193@item
7a57b90c 1194 You must not commit code which breaks FFmpeg! (Meaning unfinished but
4c5f7207 1195 enabled code which breaks compilation or compiles but does not work or
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1196 breaks the regression tests)
1197 You can commit unfinished stuff (for testing etc), but it must be disabled
1198 (#ifdef etc) by default so it does not interfere with other developers'
1199 work.
115329f1 1200@item
7a57b90c 1201 You don't have to over-test things. If it works for you, and you think it
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1202 should work for others, then commit. If your code has problems
1203 (portability, triggers compiler bugs, unusual environment etc) they will be
7a57b90c 1204 reported and eventually fixed.
115329f1 1205@item
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1206 Do not commit unrelated changes together, split them into self-contained
1207 pieces.
1208@item
1209 Do not change behavior of the program (renaming options etc) without
019c8838 1210 first discussing it on the ffmpeg-devel mailing list. Do not remove
7a57b90c 1211 functionality from the code. Just improve!
115329f1 1212
4c5f7207 1213 Note: Redundant code can be removed.
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1214@item
1215 Do not commit changes to the build system (Makefiles, configure script)
019c8838 1216 which change behavior, defaults etc, without asking first. The same
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1217 applies to compiler warning fixes, trivial looking fixes and to code
1218 maintained by other developers. We usually have a reason for doing things
019c8838 1219 the way we do. Send your changes as patches to the ffmpeg-devel mailing
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1220 list, and if the code maintainers say OK, you may commit. This does not
1221 apply to files you wrote and/or maintain.
1222@item
1223 We refuse source indentation and other cosmetic changes if they are mixed
1224 with functional changes, such commits will be rejected and removed. Every
1225 developer has his own indentation style, you should not change it. Of course
1226 if you (re)write something, you can use your own style, even though we would
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1227 prefer if the indentation throughout FFmpeg was consistent (Many projects
1228 force a given indentation style - we don't.). If you really need to make
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1229 indentation changes (try to avoid this), separate them strictly from real
1230 changes.
1231
114afa9c 1232 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
115329f1 1233 then either do NOT change the indentation of the inner part within (don't
019c8838 1234 move it to the right)! or do so in a separate commit
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1235@item
1236 Always fill out the commit log message. Describe in a few lines what you
1237 changed and why. You can refer to mailing list postings if you fix a
1238 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1239@item
1240 If you apply a patch by someone else, include the name and email address in
1241 the CVS log message. Since the ffmpeg-cvslog mailing list is publicly
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1242 archived you should add some SPAM protection to the email address. Send an
1243 answer to ffmpeg-devel (or wherever you got the patch from) saying that
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1244 you applied the patch.
1245@item
1246 Do NOT commit to code actively maintained by others without permission. Send
019c8838 1247 a patch to ffmpeg-devel instead.
7a57b90c
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1248@item
1249 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all CVS commits
1250 are sent there and reviewed by all the other developers. Bugs and possible
1251 improvements or general questions regarding commits are discussed there. We
1252 expect you to react if problems with your code are uncovered.
1253@item
1254 Update the documentation if you change behavior or add features. If you are
019c8838 1255 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
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1256 maintainer(s) will review and commit your stuff.
1257@item
1258 Revert a commit ONLY in case of a big blunder like committing something not
1259 intended to be committed or committing a wrong file, the wrong version of a
019c8838 1260 patch, CVS policy violation or broken code and you are going to recommit the
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1261 right thing immediately.
1262
1263 Never revert changes made a long time ago or buggy code. Fix it in the
1264 normal way instead.
52f4aea0 1265@item
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1266 Never write to unallocated memory, never write over the end of arrays,
1267 always check values read from some untrusted source before using them
1268 as array index or other risky things.
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1269@item
1270 Remember to check if you need to bump versions for the specific libav
f0efbde7 1271 parts (libavutil, libavcodec, libavformat) you are changing. You need
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1272 to change the version integer and the version string.
1273 Incrementing the first component means no backward compatibility to
f0efbde7 1274 previous versions (e.g. removal of a function).
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1275 Incrementing the second component means backward compatible change
1276 (e.g. addition of a function).
1277 Incrementing the third component means a noteworthy binary compatible
1278 change (e.g. encoder bug fix that matters for the decoder).
114afa9c 1279@end enumerate
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1280
1281We think our rules are not too hard. If you have comments, contact us.
1282
1283Note, these rules are mostly borrowed from the MPlayer project.
1284
1285@subsection Renaming/moving files or content of files
019c8838 1286 You CANNOT do that. Post a request for such a change to the mailing list
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1287 Do NOT remove & readd a file - it will kill the changelog!!!!
1288
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1289@section Submitting patches
1290
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1291First, (@pxref{Coding Rules}) above if you didn't yet.
1292
6a6810b1 1293When you submit your patch, try to send a unified diff (diff '-up'
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1294option). I cannot read other diffs :-)
1295
6e5c1877 1296Also please do not submit patches which contain several unrelated changes.
115329f1 1297Split them into individual self-contained patches; this makes reviewing
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1298them much easier.
1299
9181577c 1300Run the regression tests before submitting a patch so that you can
6bf40f39 1301verify that there are no big problems.
9181577c 1302
9181577c 1303Patches should be posted as base64 encoded attachments (or any other
4c5f7207 1304encoding which ensures that the patch won't be trashed during
115329f1 1305transmission) to the ffmpeg-devel mailing list, see
67c311fa 1306@url{http://www1.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
9181577c 1307
54fcf429 1308It also helps quite a bit if you tell us what the patch does (for example
4c5f7207 1309'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
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1310and has no lrint()')
1311
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1312We reply to all submitted patches and either apply or reject with some
1313explanation why, but sometimes we are quite busy so it can take a week or two.
cf7f2b16 1314
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1315@section Regression tests
1316
4c5f7207 1317Before submitting a patch (or committing to CVS), you should at least
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1318test that you did not break anything.
1319
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1320The regression tests build a synthetic video stream and a synthetic
1321audio stream. These are then encoded and decoded with all codecs or
9181577c 1322formats. The CRC (or MD5) of each generated file is recorded in a
4c5f7207 1323result file. A 'diff' is launched to compare the reference results and
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1324the result file.
1325
4c5f7207 1326The regression tests then go on to test the FFserver code with a
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1327limited set of streams. It is important that this step runs correctly
1328as well.
1329
36d9b4e8 1330Run 'make test' to test all the codecs and formats.
9181577c 1331
4c5f7207 1332Run 'make fulltest' to test all the codecs, formats and FFserver.
9181577c 1333
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1334[Of course, some patches may change the results of the regression tests. In
1335this case, the reference results of the regression tests shall be modified
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1336accordingly].
1337
1338@bye