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[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 grab video and audio from devices given that you specify the input
30format and device.
e99c4e10 31
9181577c 32@example
cc58300e 33ffmpeg -f audio_device -i /dev/dsp -f video4linux2 -i /dev/video0 /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
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42@section X11 grabbing
43
913e4081 44FFmpeg can grab the X11 display.
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45
46@example
9e0ab666 47ffmpeg -f x11grab -s cif -i :0.0 /tmp/out.mpg
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48@end example
49
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500.0 is display.screen number of your X11 server, same as
51the DISPLAY environment variable.
76d2efda 52
0cd4faf9 53@example
9e0ab666 54ffmpeg -f x11grab -s cif -i :0.0+10,20 /tmp/out.mpg
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55@end example
56
570.0 is display.screen number of your X11 server, same as the DISPLAY environment
58variable. 10 is the x-offset and 20 the y-offset for the grabbing.
59
6bf40f39 60@section Video and Audio file format conversion
9181577c 61
4c5f7207 62* FFmpeg can use any supported file format and protocol as input:
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63
64Examples:
65
4c5f7207 66* You can use YUV files as input:
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67
68@example
115329f1 69ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
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70@end example
71
115329f1 72It will use the files:
9181577c 73@example
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74/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
75/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
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76@end example
77
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78The Y files use twice the resolution of the U and V files. They are
79raw files, without header. They can be generated by all decent video
80decoders. You must specify the size of the image with the @option{-s} option
4c5f7207 81if FFmpeg cannot guess it.
9181577c 82
4c5f7207 83* You can input from a raw YUV420P file:
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84
85@example
e99c4e10 86ffmpeg -i /tmp/test.yuv /tmp/out.avi
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87@end example
88
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89test.yuv is a file containing raw YUV planar data. Each frame is composed
90of the Y plane followed by the U and V planes at half vertical and
e99c4e10 91horizontal resolution.
9181577c 92
4c5f7207 93* You can output to a raw YUV420P file:
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94
95@example
f926cbe7 96ffmpeg -i mydivx.avi hugefile.yuv
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97@end example
98
99* You can set several input files and output files:
100
101@example
e99c4e10 102ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
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103@end example
104
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105Converts the audio file a.wav and the raw YUV video file a.yuv
106to MPEG file a.mpg.
9181577c 107
6bf40f39 108* You can also do audio and video conversions at the same time:
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109
110@example
e99c4e10 111ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
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112@end example
113
4c5f7207 114Converts a.wav to MPEG audio at 22050Hz sample rate.
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115
116* You can encode to several formats at the same time and define a
e99c4e10 117mapping from input stream to output streams:
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118
119@example
5438308f 120ffmpeg -i /tmp/a.wav -ab 64k /tmp/a.mp2 -ab 128k /tmp/b.mp2 -map 0:0 -map 0:0
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121@end example
122
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123Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
124file:index' specifies which input stream is used for each output
e99c4e10 125stream, in the order of the definition of output streams.
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126
127* You can transcode decrypted VOBs
128
129@example
7b900f2d 130ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800k -g 300 -bf 2 -acodec libmp3lame -ab 128k snatch.avi
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131@end example
132
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133This is a typical DVD ripping example; the input is a VOB file, the
134output an AVI file with MPEG-4 video and MP3 audio. Note that in this
135command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
136GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
137input video. Furthermore, the audio stream is MP3-encoded so you need
1cc60c47 138to enable LAME support by passing @code{--enable-libmp3lame} to configure.
4c5f7207 139The mapping is particularly useful for DVD transcoding
e99c4e10 140to get the desired audio language.
9181577c 141
4c5f7207 142NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
e99c4e10 143@c man end
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144
145@chapter Invocation
146
147@section Syntax
148
e99c4e10 149The generic syntax is:
9181577c 150
115329f1 151@example
e99c4e10 152@c man begin SYNOPSIS
28f88dc8 153ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
e99c4e10 154@c man end
9181577c 155@end example
e99c4e10 156@c man begin DESCRIPTION
e99c4e10 157As a general rule, options are applied to the next specified
699e77b1 158file. Therefore, order is important, and you can have the same
8cc62264 159option on the command line multiple times. Each occurrence is
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160then applied to the next input or output file.
161
eb10acec 162* To set the video bitrate of the output file to 64kbit/s:
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163@example
164ffmpeg -i input.avi -b 64k output.avi
165@end example
166
167* To force the frame rate of the input and output file to 24 fps:
168@example
169ffmpeg -r 24 -i input.avi output.avi
170@end example
171
172* To force the frame rate of the output file to 24 fps:
173@example
174ffmpeg -i input.avi -r 24 output.avi
175@end example
176
177* To force the frame rate of input file to 1 fps and the output file to 24 fps:
178@example
179ffmpeg -r 1 -i input.avi -r 24 output.avi
180@end example
181
182The format option may be needed for raw input files.
9181577c 183
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184By default, FFmpeg tries to convert as losslessly as possible: It
185uses the same audio and video parameters for the outputs as the one
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186specified for the inputs.
187@c man end
9181577c 188
e99c4e10 189@c man begin OPTIONS
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190@section Main options
191
e99c4e10 192@table @option
9181577c 193@item -L
4c5f7207 194Show license.
18bff752 195
9181577c 196@item -h
4c5f7207 197Show help.
18bff752 198
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199@item -version
200Show version.
201
e99c4e10 202@item -formats
4c5f7207 203Show available formats, codecs, protocols, ...
18bff752 204
115329f1 205@item -f fmt
4c5f7207 206Force format.
18bff752 207
115329f1 208@item -i filename
4c5f7207 209input filename
9181577c 210
115329f1 211@item -y
4c5f7207 212Overwrite output files.
9181577c 213
115329f1 214@item -t duration
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215Set the recording time in seconds.
216@code{hh:mm:ss[.xxx]} syntax is also supported.
9181577c 217
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218@item -fs limit_size
219Set the file size limit.
220
e83a84ac 221@item -ss position
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222Seek to given time position in seconds.
223@code{hh:mm:ss[.xxx]} syntax is also supported.
e83a84ac 224
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225@item -itsoffset offset
226Set the input time offset in seconds.
227@code{[-]hh:mm:ss[.xxx]} syntax is also supported.
228This option affects all the input files that follow it.
229The offset is added to the timestamps of the input files.
230Specifying a positive offset means that the corresponding
231streams are delayed by 'offset' seconds.
232
115329f1 233@item -title string
4c5f7207 234Set the title.
9181577c 235
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236@item -timestamp time
237Set the timestamp.
238
115329f1 239@item -author string
4c5f7207 240Set the author.
9181577c 241
115329f1 242@item -copyright string
4c5f7207 243Set the copyright.
9181577c 244
115329f1 245@item -comment string
4c5f7207 246Set the comment.
9181577c 247
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248@item -album string
249Set the album.
250
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251@item -track number
252Set the track.
253
254@item -year number
255Set the year.
256
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257@item -v verbose
258Control amount of logging.
259
99db6420 260@item -target type
4386f941 261Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
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262"ntsc-svcd", ... ). All the format options (bitrate, codecs,
263buffer sizes) are then set automatically. You can just type:
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264
265@example
266ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
267@end example
268
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269Nevertheless you can specify additional options as long as you know
270they do not conflict with the standard, as in:
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271
272@example
273ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
274@end example
275
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276@item -dframes number
277Set the number of data frames to record.
278
279@item -scodec codec
280Force subtitle codec ('copy' to copy stream).
281
282@item -newsubtitle
283Add a new subtitle stream to the current output stream.
284
285@item -slang code
286Set the ISO 639 language code (3 letters) of the current subtitle stream.
401fbdde 287
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288@end table
289
290@section Video Options
291
e99c4e10 292@table @option
9181577c 293@item -b bitrate
3c0ba870 294Set the video bitrate in bit/s (default = 200 kb/s).
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295@item -vframes number
296Set the number of video frames to record.
115329f1 297@item -r fps
4386f941 298Set frame rate (Hz value, fraction or abbreviation), (default = 25).
115329f1 299@item -s size
67053c30 300Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
4c5f7207 301The following abbreviations are recognized:
5ee03c86 302@table @samp
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303@item sqcif
304128x96
305@item qcif
306176x144
307@item cif
308352x288
309@item 4cif
310704x576
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311@item qqvga
312160x120
313@item qvga
314320x240
315@item vga
316640x480
317@item svga
318800x600
319@item xga
3201024x768
321@item uxga
3221600x1200
323@item qxga
3242048x1536
325@item sxga
3261280x1024
327@item qsxga
3282560x2048
329@item hsxga
3305120x4096
331@item wvga
332852x480
333@item wxga
3341366x768
335@item wsxga
3361600x1024
337@item wuxga
3381920x1200
339@item woxga
3402560x1600
341@item wqsxga
3423200x2048
343@item wquxga
3443840x2400
345@item whsxga
3466400x4096
347@item whuxga
3487680x4800
349@item cga
350320x200
351@item ega
352640x350
353@item hd480
354852x480
355@item hd720
3561280x720
357@item hd1080
3581920x1080
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359@end table
360
361@item -aspect aspect
4c5f7207 362Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
18bff752 363@item -croptop size
4c5f7207 364Set top crop band size (in pixels).
18bff752 365@item -cropbottom size
4c5f7207 366Set bottom crop band size (in pixels).
18bff752 367@item -cropleft size
4c5f7207 368Set left crop band size (in pixels).
18bff752 369@item -cropright size
4c5f7207 370Set right crop band size (in pixels).
1ff93ffc 371@item -padtop size
4c5f7207 372Set top pad band size (in pixels).
1ff93ffc 373@item -padbottom size
4c5f7207 374Set bottom pad band size (in pixels).
1ff93ffc 375@item -padleft size
4c5f7207 376Set left pad band size (in pixels).
1ff93ffc 377@item -padright size
4c5f7207 378Set right pad band size (in pixels).
5b79a73e 379@item -padcolor (hex color)
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380Set color of padded bands. The value for padcolor is expressed
381as a six digit hexadecimal number where the first two digits
382represent red, the middle two digits green and last two digits
383blue (default = 000000 (black)).
9181577c 384@item -vn
4c5f7207 385Disable video recording.
115329f1 386@item -bt tolerance
dc5ee8bc 387Set video bitrate tolerance (in bit/s).
18bff752 388@item -maxrate bitrate
a5515106 389Set max video bitrate tolerance (in bit/s).
18bff752 390@item -minrate bitrate
a5515106 391Set min video bitrate tolerance (in bit/s).
18bff752 392@item -bufsize size
81d0618f 393Set rate control buffer size (in bits).
115329f1 394@item -vcodec codec
4c5f7207 395Force video codec to @var{codec}. Use the @code{copy} special value to
5ee03c86 396tell that the raw codec data must be copied as is.
18bff752 397@item -sameq
4c5f7207 398Use same video quality as source (implies VBR).
9181577c 399
115329f1 400@item -pass n
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401Select the pass number (1 or 2). It is useful to do two pass
402encoding. The statistics of the video are recorded in the first
403pass and the video is generated at the exact requested bitrate
404in the second pass.
9181577c 405
115329f1 406@item -passlogfile file
4c5f7207 407Set two pass logfile name to @var{file}.
9181577c 408
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409@item -newvideo
410Add a new video stream to the current output stream.
411
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412@end table
413
18bff752 414@section Advanced Video Options
9181577c 415
e99c4e10 416@table @option
4386f941 417@item -pix_fmt format
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418Set pixel format. Use 'list' as parameter to show all the supported
419pixel formats.
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420@item -sws_flags flags
421Set SwScaler flags (only available when compiled with SwScaler support).
115329f1 422@item -g gop_size
4c5f7207 423Set the group of pictures size.
115329f1 424@item -intra
4c5f7207 425Use only intra frames.
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426@item -vdt n
427Discard threshold.
115329f1 428@item -qscale q
4bef236b 429Use fixed video quantizer scale (VBR).
115329f1 430@item -qmin q
4bef236b 431minimum video quantizer scale (VBR)
115329f1 432@item -qmax q
4bef236b 433maximum video quantizer scale (VBR)
115329f1 434@item -qdiff q
4bef236b 435maximum difference between the quantizer scales (VBR)
115329f1 436@item -qblur blur
4bef236b 437video quantizer scale blur (VBR)
115329f1 438@item -qcomp compression
4bef236b 439video quantizer scale compression (VBR)
18bff752 440
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441@item -lmin lambda
442minimum video lagrange factor (VBR)
443@item -lmax lambda
444max video lagrange factor (VBR)
445@item -mblmin lambda
446minimum macroblock quantizer scale (VBR)
447@item -mblmax lambda
448maximum macroblock quantizer scale (VBR)
449
450These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
451but you may use the QP2LAMBDA constant to easily convert from 'q' units:
452@example
453ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
454@end example
455
18bff752 456@item -rc_init_cplx complexity
4c5f7207 457initial complexity for single pass encoding
18bff752 458@item -b_qfactor factor
4c5f7207 459qp factor between P- and B-frames
18bff752 460@item -i_qfactor factor
4c5f7207 461qp factor between P- and I-frames
18bff752 462@item -b_qoffset offset
4c5f7207 463qp offset between P- and B-frames
18bff752 464@item -i_qoffset offset
4c5f7207 465qp offset between P- and I-frames
18bff752 466@item -rc_eq equation
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467Set rate control equation (@pxref{FFmpeg formula
468evaluator}) (default = @code{tex^qComp}).
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469@item -rc_override override
470rate control override for specific intervals
18bff752 471@item -me method
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472Set motion estimation method to @var{method}.
473Available methods are (from lowest to best quality):
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474@table @samp
475@item zero
5ee03c86 476Try just the (0, 0) vector.
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477@item phods
478@item log
479@item x1
480@item epzs
481(default method)
482@item full
483exhaustive search (slow and marginally better than epzs)
484@end table
485
486@item -dct_algo algo
4c5f7207 487Set DCT algorithm to @var{algo}. Available values are:
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488@table @samp
489@item 0
490FF_DCT_AUTO (default)
491@item 1
492FF_DCT_FASTINT
493@item 2
494FF_DCT_INT
495@item 3
496FF_DCT_MMX
497@item 4
498FF_DCT_MLIB
499@item 5
500FF_DCT_ALTIVEC
501@end table
502
503@item -idct_algo algo
4c5f7207 504Set IDCT algorithm to @var{algo}. Available values are:
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505@table @samp
506@item 0
507FF_IDCT_AUTO (default)
508@item 1
115329f1 509FF_IDCT_INT
18bff752 510@item 2
115329f1 511FF_IDCT_SIMPLE
18bff752 512@item 3
115329f1 513FF_IDCT_SIMPLEMMX
18bff752 514@item 4
115329f1 515FF_IDCT_LIBMPEG2MMX
18bff752 516@item 5
115329f1 517FF_IDCT_PS2
18bff752 518@item 6
115329f1 519FF_IDCT_MLIB
18bff752 520@item 7
115329f1 521FF_IDCT_ARM
18bff752 522@item 8
115329f1 523FF_IDCT_ALTIVEC
18bff752 524@item 9
115329f1 525FF_IDCT_SH4
18bff752 526@item 10
115329f1 527FF_IDCT_SIMPLEARM
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528@end table
529
530@item -er n
4c5f7207 531Set error resilience to @var{n}.
18bff752 532@table @samp
115329f1 533@item 1
1471c6c2 534FF_ER_CAREFUL (default)
18bff752 535@item 2
5ee03c86 536FF_ER_COMPLIANT
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537@item 3
538FF_ER_AGGRESSIVE
539@item 4
540FF_ER_VERY_AGGRESSIVE
541@end table
542
5ee03c86 543@item -ec bit_mask
4c5f7207 544Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
5ee03c86 545the following values:
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546@table @samp
547@item 1
4c5f7207 548FF_EC_GUESS_MVS (default = enabled)
18bff752 549@item 2
4c5f7207 550FF_EC_DEBLOCK (default = enabled)
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551@end table
552
553@item -bf frames
4c5f7207 554Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
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555@item -mbd mode
556macroblock decision
557@table @samp
558@item 0
4c5f7207 559FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
18bff752 560@item 1
4c5f7207 561FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
18bff752 562@item 2
019c8838 563FF_MB_DECISION_RD: rate distortion
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564@end table
565
566@item -4mv
4c5f7207 567Use four motion vector by macroblock (MPEG-4 only).
18bff752 568@item -part
4c5f7207 569Use data partitioning (MPEG-4 only).
18bff752 570@item -bug param
4c5f7207 571Work around encoder bugs that are not auto-detected.
18bff752 572@item -strict strictness
4c5f7207 573How strictly to follow the standards.
5ee03c86 574@item -aic
4c5f7207 575Enable Advanced intra coding (h263+).
5ee03c86 576@item -umv
4c5f7207 577Enable Unlimited Motion Vector (h263+)
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578
579@item -deinterlace
4c5f7207 580Deinterlace pictures.
3841e813 581@item -ilme
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582Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
583Use this option if your input file is interlaced and you want
584to keep the interlaced format for minimum losses.
585The alternative is to deinterlace the input stream with
586@option{-deinterlace}, but deinterlacing introduces losses.
18bff752 587@item -psnr
4c5f7207 588Calculate PSNR of compressed frames.
18bff752 589@item -vstats
4c5f7207 590Dump video coding statistics to @file{vstats_HHMMSS.log}.
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591@item -vstats_file file
592Dump video coding statistics to @var{file}.
18bff752 593@item -vhook module
4c5f7207 594Insert video processing @var{module}. @var{module} contains the module
18bff752 595name and its parameters separated by spaces.
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596@item -top n
597top=1/bottom=0/auto=-1 field first
598@item -dc precision
599Intra_dc_precision.
600@item -vtag fourcc/tag
601Force video tag/fourcc.
602@item -qphist
603Show QP histogram.
604@item -vbsf bitstream filter
605Bitstream filters available are "dump_extra", "remove_extra", "noise".
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606@end table
607
608@section Audio Options
609
610@table @option
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611@item -aframes number
612Set the number of audio frames to record.
115329f1 613@item -ar freq
4c5f7207 614Set the audio sampling frequency (default = 44100 Hz).
115329f1 615@item -ab bitrate
5438308f 616Set the audio bitrate in bit/s (default = 64k).
18bff752 617@item -ac channels
4c5f7207 618Set the number of audio channels (default = 1).
5ee03c86 619@item -an
4c5f7207 620Disable audio recording.
5ee03c86 621@item -acodec codec
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622Force audio codec to @var{codec}. Use the @code{copy} special value to
623specify that the raw codec data must be copied as is.
de62a89d 624@item -newaudio
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625Add a new audio track to the output file. If you want to specify parameters,
626do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
de62a89d 627
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628Mapping will be done automatically, if the number of output streams is equal to
629the number of input streams, else it will pick the first one that matches. You
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630can override the mapping using @code{-map} as usual.
631
632Example:
633@example
5438308f 634ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
de62a89d 635@end example
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636@item -alang code
637Set the ISO 639 language code (3 letters) of the current audio stream.
638@end table
639
640@section Advanced Audio options:
641
642@table @option
643@item -atag fourcc/tag
644Force audio tag/fourcc.
645@item -absf bitstream filter
646Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
647@end table
648
649@section Subtitle options:
650
651@table @option
652@item -scodec codec
653Force subtitle codec ('copy' to copy stream).
654@item -newsubtitle
655Add a new subtitle stream to the current output stream.
656@item -slang code
657Set the ISO 639 language code (3 letters) of the current subtitle stream.
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658@end table
659
660@section Audio/Video grab options
661
662@table @option
18bff752 663@item -vc channel
4c5f7207 664Set video grab channel (DV1394 only).
18bff752 665@item -tvstd standard
4c5f7207 666Set television standard (NTSC, PAL (SECAM)).
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667@item -isync
668Synchronize read on input.
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669@end table
670
671@section Advanced options
672
673@table @option
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674@item -map input stream id[:input stream id]
675Set stream mapping from input streams to output streams.
676Just enumerate the input streams in the order you want them in the output.
677[input stream id] sets the (input) stream to sync against.
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678@item -map_meta_data outfile:infile
679Set meta data information of outfile from infile.
18bff752 680@item -debug
4c5f7207 681Print specific debug info.
115329f1 682@item -benchmark
4c5f7207 683Add timings for benchmarking.
4386f941 684@item -dump
4c5f7207 685Dump each input packet.
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686@item -hex
687When dumping packets, also dump the payload.
18bff752 688@item -bitexact
4c5f7207 689Only use bit exact algorithms (for codec testing).
18bff752 690@item -ps size
4c5f7207 691Set packet size in bits.
5ee03c86 692@item -re
4c5f7207 693Read input at native frame rate. Mainly used to simulate a grab device.
4386f941 694@item -loop_input
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695Loop over the input stream. Currently it works only for image
696streams. This option is used for automatic FFserver testing.
8108551a 697@item -loop_output number_of_times
019c8838 698Repeatedly loop output for formats that support looping such as animated GIF
4c5f7207 699(0 will loop the output infinitely).
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700@item -threads count
701Thread count.
c52e13f1 702@item -vsync parameter
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703Video sync method. Video will be stretched/squeezed to match the timestamps,
704it is done by duplicating and dropping frames. With -map you can select from
705which stream the timestamps should be taken. You can leave either video or
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706audio unchanged and sync the remaining stream(s) to the unchanged one.
707@item -async samples_per_second
29c9183c 708Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
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709the parameter is the maximum samples per second by which the audio is changed.
710-async 1 is a special case where only the start of the audio stream is corrected
711without any later correction.
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712@item -copyts
713Copy timestamps from input to output.
714@item -shortest
715Finish encoding when the shortest input stream ends.
716@item -dts_delta_threshold
717Timestamp discontinuity delta threshold.
718@item -muxdelay seconds
719Set the maximum demux-decode delay.
720@item -muxpreload seconds
721Set the initial demux-decode delay.
9181577c 722@end table
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723
724@node FFmpeg formula evaluator
725@section FFmpeg formula evaluator
726
727When evaluating a rate control string, FFmpeg uses an internal formula
115329f1 728evaluator.
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729
730The following binary operators are available: @code{+}, @code{-},
731@code{*}, @code{/}, @code{^}.
732
733The following unary operators are available: @code{+}, @code{-},
734@code{(...)}.
735
736The following functions are available:
737@table @var
738@item sinh(x)
739@item cosh(x)
740@item tanh(x)
741@item sin(x)
742@item cos(x)
743@item tan(x)
744@item exp(x)
745@item log(x)
746@item squish(x)
747@item gauss(x)
748@item abs(x)
749@item max(x, y)
750@item min(x, y)
751@item gt(x, y)
752@item lt(x, y)
753@item eq(x, y)
754@item bits2qp(bits)
755@item qp2bits(qp)
756@end table
757
758The following constants are available:
759@table @var
760@item PI
761@item E
762@item iTex
763@item pTex
764@item tex
765@item mv
766@item fCode
767@item iCount
768@item mcVar
769@item var
770@item isI
771@item isP
772@item isB
773@item avgQP
774@item qComp
775@item avgIITex
776@item avgPITex
777@item avgPPTex
778@item avgBPTex
779@item avgTex
780@end table
781
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782@c man end
783
784@ignore
785
786@setfilename ffmpeg
787@settitle FFmpeg video converter
788
789@c man begin SEEALSO
019c8838 790ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
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791@c man end
792
793@c man begin AUTHOR
794Fabrice Bellard
795@c man end
796
797@end ignore
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798
799@section Protocols
800
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801The filename can be @file{-} to read from standard input or to write
802to standard output.
9181577c 803
4c5f7207 804FFmpeg also handles many protocols specified with an URL syntax.
9181577c 805
4c5f7207 806Use 'ffmpeg -formats' to see a list of the supported protocols.
9181577c 807
e99c4e10 808The protocol @code{http:} is currently used only to communicate with
4c5f7207 809FFserver (see the FFserver documentation). When FFmpeg will be a
e99c4e10 810video player it will also be used for streaming :-)
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811
812@chapter Tips
813
814@itemize
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815@item For streaming at very low bitrate application, use a low frame rate
816and a small GOP size. This is especially true for RealVideo where
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817the Linux player does not seem to be very fast, so it can miss
818frames. An example is:
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819
820@example
3c0ba870 821ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
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822@end example
823
824@item The parameter 'q' which is displayed while encoding is the current
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825quantizer. The value 1 indicates that a very good quality could
826be achieved. The value 31 indicates the worst quality. If q=31 appears
e99c4e10 827too often, it means that the encoder cannot compress enough to meet
4c5f7207 828your bitrate. You must either increase the bitrate, decrease the
e99c4e10 829frame rate or decrease the frame size.
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830
831@item If your computer is not fast enough, you can speed up the
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832compression at the expense of the compression ratio. You can use
833'-me zero' to speed up motion estimation, and '-intra' to disable
4c5f7207 834motion estimation completely (you have only I-frames, which means it
e99c4e10 835is about as good as JPEG compression).
9181577c 836
4c5f7207 837@item To have very low audio bitrates, reduce the sampling frequency
019c8838 838(down to 22050 kHz for MPEG audio, 22050 or 11025 for AC3).
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839
840@item To have a constant quality (but a variable bitrate), use the option
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841'-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
842quality).
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843
844@item When converting video files, you can use the '-sameq' option which
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845uses the same quality factor in the encoder as in the decoder.
846It allows almost lossless encoding.
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847
848@end itemize
849
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850
851@chapter external libraries
852
853FFmpeg can be hooked up with a number of external libraries to add support
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854for more formats. None of them are used by default, their use has to be
855explicitly requested by passing the appropriate flags to @file{./configure}.
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856
857@section AMR
858
859AMR comes in two different flavors, WB and NB. FFmpeg can make use of the
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860AMR WB (floating-point mode) and the AMR NB (floating-point mode) reference
861decoders and encoders.
47404f9f 862
73508bc6 863Go to @url{http://www.penguin.cz/~utx/amr} and follow the instructions for
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864installing the libraries. Then pass @code{--enable-libamr-nb} and/or
865@code{--enable-libamr-wb} to configure to enable the libraries.
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866
867
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868@chapter Supported File Formats and Codecs
869
870You can use the @code{-formats} option to have an exhaustive list.
871
872@section File Formats
873
6bf40f39 874FFmpeg supports the following file formats through the @code{libavformat}
0699d2fe 875library:
9181577c 876
3fc9e78f 877@multitable @columnfractions .4 .1 .1 .4
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878@item Supported File Format @tab Encoding @tab Decoding @tab Comments
879@item MPEG audio @tab X @tab X
4c5f7207 880@item MPEG-1 systems @tab X @tab X
9181577c 881@tab muxed audio and video
4c5f7207 882@item MPEG-2 PS @tab X @tab X
9181577c 883@tab also known as @code{VOB} file
4c5f7207 884@item MPEG-2 TS @tab @tab X
9181577c 885@tab also known as DVB Transport Stream
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886@item ASF@tab X @tab X
887@item AVI@tab X @tab X
888@item WAV@tab X @tab X
9181577c 889@item Macromedia Flash@tab X @tab X
4c5f7207 890@tab Only embedded audio is decoded.
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891@item FLV @tab X @tab X
892@tab Macromedia Flash video files
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893@item Real Audio and Video @tab X @tab X
894@item Raw AC3 @tab X @tab X
895@item Raw MJPEG @tab X @tab X
896@item Raw MPEG video @tab X @tab X
897@item Raw PCM8/16 bits, mulaw/Alaw@tab X @tab X
898@item Raw CRI ADX audio @tab X @tab X
899@item Raw Shorten audio @tab @tab X
900@item SUN AU format @tab X @tab X
7fe4c823 901@item NUT @tab X @tab X @tab NUT Open Container Format
115329f1 902@item QuickTime @tab X @tab X
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903@item MPEG-4 @tab X @tab X
904@tab MPEG-4 is a variant of QuickTime.
115329f1 905@item Raw MPEG4 video @tab X @tab X
4fa1c4fa 906@item DV @tab X @tab X
701b603d 907@item 4xm @tab @tab X
4c5f7207 908@tab 4X Technologies format, used in some games.
4d3b1f8d 909@item Playstation STR @tab @tab X
13dec857 910@item Id RoQ @tab X @tab X
4c5f7207 911@tab Used in Quake III, Jedi Knight 2, other computer games.
4d3b1f8d 912@item Interplay MVE @tab @tab X
4c5f7207 913@tab Format used in various Interplay computer games.
b17e9c99 914@item WC3 Movie @tab @tab X
4c5f7207 915@tab Multimedia format used in Origin's Wing Commander III computer game.
2fdf638b 916@item Sega FILM/CPK @tab @tab X
4c5f7207 917@tab Used in many Sega Saturn console games.
2fdf638b 918@item Westwood Studios VQA/AUD @tab @tab X
4c5f7207 919@tab Multimedia formats used in Westwood Studios games.
4120a53a 920@item Id Cinematic (.cin) @tab @tab X
4c5f7207 921@tab Used in Quake II.
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922@item FLIC format @tab @tab X
923@tab .fli/.flc files
da00f30e 924@item Sierra VMD @tab @tab X
4c5f7207 925@tab Used in Sierra CD-ROM games.
d08d7142 926@item Sierra Online @tab @tab X
4c5f7207 927@tab .sol files used in Sierra Online games.
38088adf 928@item Matroska @tab @tab X
ad81a9fe 929@item Electronic Arts Multimedia @tab @tab X
4c5f7207 930@tab Used in various EA games; files have extensions like WVE and UV2.
353147ed 931@item Nullsoft Video (NSV) format @tab @tab X
4accd1fd 932@item ADTS AAC audio @tab X @tab X
ea395e8c 933@item Creative VOC @tab X @tab X @tab Created for the Sound Blaster Pro.
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934@item American Laser Games MM @tab @tab X
935@tab Multimedia format used in games like Mad Dog McCree
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936@item AVS @tab @tab X
937@tab Multimedia format used by the Creature Shock game.
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938@item Smacker @tab @tab X
939@tab Multimedia format used by many games.
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940@item GXF @tab X @tab X
941@tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley playout servers.
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942@item CIN @tab @tab X
943@tab Multimedia format used by Delphine Software games.
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944@item MXF @tab @tab X
945@tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
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946@item SEQ @tab @tab X
947@tab Tiertex .seq files used in the DOS CDROM version of the game Flashback.
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948@item DXA @tab @tab X
949@tab This format is used in non-Windows version of Feeble Files game and
950different game cutscenes repacked for use with ScummVM.
efb0c399 951@item THP @tab @tab X
d1e0d21f 952@tab Used on the Nintendo GameCube.
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953@item C93 @tab @tab X
954@tab Used in the game Cyberia from Interplay.
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955@item Bethsoft VID @tab @tab X
956@tab Used in some games from Bethesda Softworks.
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957@item CRYO APC @tab @tab X
958@tab Audio format used in some games by CRYO Interactive Entertainment.
353147ed 959@end multitable
9181577c 960
4c5f7207 961@code{X} means that encoding (resp. decoding) is supported.
9181577c 962
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963@section Image Formats
964
965FFmpeg can read and write images for each frame of a video sequence. The
966following image formats are supported:
967
3fc9e78f 968@multitable @columnfractions .4 .1 .1 .4
0699d2fe 969@item Supported Image Format @tab Encoding @tab Decoding @tab Comments
115329f1 970@item PGM, PPM @tab X @tab X
4c5f7207 971@item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
2eb5d024 972@item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
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973@item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
974@item .Y.U.V @tab X @tab X @tab one raw file per component
975@item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
976@item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
3689cf16 977@item Targa @tab @tab X @tab Targa (.TGA) image format.
716222db 978@item TIFF @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
6a91ec51 979@item SGI @tab X @tab X @tab SGI RGB image format
d58bbf81 980@item PTX @tab @tab X @tab V.Flash PTX format
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981@end multitable
982
4c5f7207 983@code{X} means that encoding (resp. decoding) is supported.
0699d2fe 984
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985@section Video Codecs
986
3fc9e78f 987@multitable @columnfractions .4 .1 .1 .4
9181577c 988@item Supported Codec @tab Encoding @tab Decoding @tab Comments
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989@item MPEG-1 video @tab X @tab X
990@item MPEG-2 video @tab X @tab X
2bc5da7b 991@item MPEG-4 @tab X @tab X
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992@item MSMPEG4 V1 @tab X @tab X
993@item MSMPEG4 V2 @tab X @tab X
2bc5da7b 994@item MSMPEG4 V3 @tab X @tab X
9181577c 995@item WMV7 @tab X @tab X
4c5f7207 996@item WMV8 @tab X @tab X @tab not completely working
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997@item WMV9 @tab @tab X @tab not completely working
998@item VC1 @tab @tab X
b06b45c4 999@item H.261 @tab X @tab X
4c5f7207 1000@item H.263(+) @tab X @tab X @tab also known as RealVideo 1.0
b06b45c4 1001@item H.264 @tab @tab X
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1002@item RealVideo 1.0 @tab X @tab X
1003@item RealVideo 2.0 @tab X @tab X
115329f1 1004@item MJPEG @tab X @tab X
4c5f7207 1005@item lossless MJPEG @tab X @tab X
26d6d032 1006@item JPEG-LS @tab X @tab X @tab fourcc: MJLS, lossless and near-lossless is supported
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1007@item Apple MJPEG-B @tab @tab X
1008@item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
115329f1 1009@item DV @tab X @tab X
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1010@item HuffYUV @tab X @tab X
1011@item FFmpeg Video 1 @tab X @tab X @tab experimental lossless codec (fourcc: FFV1)
1012@item FFmpeg Snow @tab X @tab X @tab experimental wavelet codec (fourcc: SNOW)
701b603d 1013@item Asus v1 @tab X @tab X @tab fourcc: ASV1
4d3b1f8d 1014@item Asus v2 @tab X @tab X @tab fourcc: ASV2
701b603d 1015@item Creative YUV @tab @tab X @tab fourcc: CYUV
d2bfadc0 1016@item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
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1017@item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
1018@item On2 VP3 @tab @tab X @tab still experimental
5ce117c3 1019@item On2 VP5 @tab @tab X @tab fourcc: VP50
9110a0e3 1020@item On2 VP6 @tab @tab X @tab fourcc: VP60,VP61,VP62
150d2772 1021@item Theora @tab X @tab X @tab still experimental
cdb2c1ca 1022@item Intel Indeo 3 @tab @tab X
9303d49c 1023@item FLV @tab X @tab X @tab Sorenson H.263 used in Flash
15419468 1024@item Flash Screen Video @tab X @tab X @tab fourcc: FSV1
4d3b1f8d 1025@item ATI VCR1 @tab @tab X @tab fourcc: VCR1
7fe4c823 1026@item ATI VCR2 @tab @tab X @tab fourcc: VCR2
4d3b1f8d 1027@item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
4c5f7207 1028@item 4X Video @tab @tab X @tab Used in certain computer games.
115329f1 1029@item Sony Playstation MDEC @tab @tab X
03e3e765 1030@item Id RoQ @tab X @tab X @tab Used in Quake III, Jedi Knight 2, other computer games.
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1031@item Xan/WC3 @tab @tab X @tab Used in Wing Commander III .MVE files.
1032@item Interplay Video @tab @tab X @tab Used in Interplay .MVE files.
d3b7406c 1033@item Apple Animation @tab X @tab X @tab fourcc: 'rle '
42cad81a 1034@item Apple Graphics @tab @tab X @tab fourcc: 'smc '
2fdf638b 1035@item Apple Video @tab @tab X @tab fourcc: rpza
d08d7142 1036@item Apple QuickDraw @tab @tab X @tab fourcc: qdrw
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1037@item Cinepak @tab @tab X
1038@item Microsoft RLE @tab @tab X
1039@item Microsoft Video-1 @tab @tab X
4120a53a 1040@item Westwood VQA @tab @tab X
4c5f7207 1041@item Id Cinematic Video @tab @tab X @tab Used in Quake II.
1dc1ed99 1042@item Planar RGB @tab @tab X @tab fourcc: 8BPS
42cad81a 1043@item FLIC video @tab @tab X
9a4117d5 1044@item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK
dce76c20 1045@item Duck TrueMotion v2 @tab @tab X @tab fourcc: TM20
4c5f7207 1046@item VMD Video @tab @tab X @tab Used in Sierra VMD files.
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1047@item MSZH @tab @tab X @tab Part of LCL
1048@item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental
9d53d58e 1049@item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC
d0a0bbd2 1050@item IBM Ultimotion @tab @tab X @tab fourcc: ULTI
ab711b3c 1051@item Miro VideoXL @tab @tab X @tab fourcc: VIXL
acfd8f0f 1052@item QPEG @tab @tab X @tab fourccs: QPEG, Q1.0, Q1.1
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1053@item LOCO @tab @tab X @tab
1054@item Winnov WNV1 @tab @tab X @tab
589f8220 1055@item Autodesk Animator Studio Codec @tab @tab X @tab fourcc: AASC
115329f1 1056@item Fraps FPS1 @tab @tab X @tab
2b6c1d80 1057@item CamStudio @tab @tab X @tab fourcc: CSCD
4e114829 1058@item American Laser Games Video @tab @tab X @tab Used in games like Mad Dog McCree
f48d6e1b 1059@item ZMBV @tab X @tab X @tab Encoder works only on PAL8
26376701 1060@item AVS Video @tab @tab X @tab Video encoding used by the Creature Shock game.
348efc18 1061@item Smacker Video @tab @tab X @tab Video encoding used in Smacker.
dfca23e3 1062@item RTjpeg @tab @tab X @tab Video encoding used in NuppelVideo files.
fd7b1991 1063@item KMVC @tab @tab X @tab Codec used in Worms games.
eb57c889 1064@item VMware Video @tab @tab X @tab Codec used in videos captured by VMware.
dc56e0de 1065@item Cin Video @tab @tab X @tab Codec used in Delphine Software games.
29f86228 1066@item Tiertex Seq Video @tab @tab X @tab Codec used in DOS CDROM FlashBack game.
33a0dd37 1067@item DXA Video @tab @tab X @tab Codec originally used in Feeble Files game.
52b6bad2 1068@item AVID DNxHD @tab @tab X @tab aka SMPTE VC3
9a0ddd09 1069@item C93 Video @tab @tab X @tab Codec used in Cyberia game.
8845202e 1070@item THP @tab @tab X @tab Used on the Nintendo GameCube.
1e6c6759 1071@item Bethsoft VID @tab @tab X @tab Used in some games from Bethesda Softworks.
12b6d7c0 1072@item Renderware TXD @tab @tab X @tab Texture dictionaries used by the Renderware Engine.
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1073@end multitable
1074
4c5f7207 1075@code{X} means that encoding (resp. decoding) is supported.
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1076
1077@section Audio Codecs
1078
1079@multitable @columnfractions .4 .1 .1 .1 .7
1080@item Supported Codec @tab Encoding @tab Decoding @tab Comments
115329f1 1081@item MPEG audio layer 2 @tab IX @tab IX
9181577c 1082@item MPEG audio layer 1/3 @tab IX @tab IX
4c5f7207 1083@tab MP3 encoding is supported through the external library LAME.
37776c3b 1084@item AC3 @tab IX @tab IX
4c5f7207 1085@tab liba52 is used internally for decoding.
34d7008d 1086@item Vorbis @tab X @tab X
74882049 1087@item WMA V1/V2 @tab X @tab X
f6fa7a6c 1088@item AAC @tab X @tab X
4c5f7207 1089@tab Supported through the external library libfaac/libfaad.
d4c3c5a6 1090@item Microsoft ADPCM @tab X @tab X
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1091@item MS IMA ADPCM @tab X @tab X
1092@item QT IMA ADPCM @tab @tab X
1093@item 4X IMA ADPCM @tab @tab X
d4e437df 1094@item G.726 ADPCM @tab X @tab X
b17e9c99 1095@item Duck DK3 IMA ADPCM @tab @tab X
4c5f7207 1096@tab Used in some Sega Saturn console games.
b17e9c99 1097@item Duck DK4 IMA ADPCM @tab @tab X
4c5f7207 1098@tab Used in some Sega Saturn console games.
2fdf638b 1099@item Westwood Studios IMA ADPCM @tab @tab X
4c5f7207 1100@tab Used in Westwood Studios games like Command and Conquer.
7d8379f2 1101@item SMJPEG IMA ADPCM @tab @tab X
4c5f7207 1102@tab Used in certain Loki game ports.
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1103@item CD-ROM XA ADPCM @tab @tab X
1104@item CRI ADX ADPCM @tab X @tab X
4c5f7207 1105@tab Used in Sega Dreamcast games.
7d8379f2 1106@item Electronic Arts ADPCM @tab @tab X
4c5f7207 1107@tab Used in various EA titles.
b3bfb299 1108@item Creative ADPCM @tab @tab X
2433f24f 1109@tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
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1110@item THP ADPCM @tab @tab X
1111@tab Used on the Nintendo GameCube.
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1112@item RA144 @tab @tab X
1113@tab Real 14400 bit/s codec
1114@item RA288 @tab @tab X
1115@tab Real 28800 bit/s codec
37776c3b 1116@item RADnet @tab X @tab IX
4c5f7207 1117@tab Real low bitrate AC3 codec, liba52 is used for decoding.
2eb5d024 1118@item AMR-NB @tab X @tab X
4c5f7207 1119@tab Supported through an external library.
d663a1fd 1120@item AMR-WB @tab X @tab X
4c5f7207 1121@tab Supported through an external library.
2eb5d024 1122@item DV audio @tab @tab X
b09432ad 1123@item Id RoQ DPCM @tab X @tab X
4c5f7207 1124@tab Used in Quake III, Jedi Knight 2, other computer games.
4d3b1f8d 1125@item Interplay MVE DPCM @tab @tab X
4c5f7207 1126@tab Used in various Interplay computer games.
b17e9c99 1127@item Xan DPCM @tab @tab X
4c5f7207 1128@tab Used in Origin's Wing Commander IV AVI files.
d08d7142 1129@item Sierra Online DPCM @tab @tab X
4c5f7207 1130@tab Used in Sierra Online game audio files.
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1131@item Apple MACE 3 @tab @tab X
1132@item Apple MACE 6 @tab @tab X
bfd9a00f 1133@item FLAC lossless audio @tab X @tab X
13dfd2b9 1134@item Shorten lossless audio @tab @tab X
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1135@item Apple lossless audio @tab @tab X
1136@tab QuickTime fourcc 'alac'
33a4d8b1 1137@item FFmpeg Sonic @tab X @tab X
4c5f7207 1138@tab experimental lossy/lossless codec
d9b1c197
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1139@item Qdesign QDM2 @tab @tab X
1140@tab there are still some distortions
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1141@item Real COOK @tab @tab X
1142@tab All versions except 5.1 are supported
e839a994 1143@item DSP Group TrueSpeech @tab @tab X
3dc411c0 1144@item True Audio (TTA) @tab @tab X
348efc18 1145@item Smacker Audio @tab @tab X
730581f3 1146@item WavPack Audio @tab @tab X
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1147@item Cin Audio @tab @tab X
1148@tab Codec used in Delphine Software games.
84ed36da 1149@item Intel Music Coder @tab @tab X
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1150@item Musepack @tab @tab X
1151@tab Only SV7 is supported
01ca9ac3 1152@item DT$ Coherent Audio @tab @tab X
10e26bc7 1153@item ATRAC 3 @tab @tab X
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1154@end multitable
1155
4c5f7207 1156@code{X} means that encoding (resp. decoding) is supported.
9181577c 1157
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1158@code{I} means that an integer-only version is available, too (ensures high
1159performance on systems without hardware floating point support).
9181577c 1160
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1161@chapter Platform Specific information
1162
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1163@section BSD
1164
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1165BSD make will not build FFmpeg, you need to install and use GNU Make
1166(@file{gmake}).
1167
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1168@section Windows
1169
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1170To get help and instructions for using FFmpeg under Windows, check out
1171the FFmpeg Windows Help Forum at
1172@url{http://arrozcru.no-ip.org/ffmpeg/}.
1173
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1174@subsection Native Windows compilation
1175
1176@itemize
1177@item Install the current versions of MSYS and MinGW from
1178@url{http://www.mingw.org/}. You can find detailed installation
1179instructions in the download section and the FAQ.
1180
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1181NOTE: Use at least bash 3.1. Older versions are known to be failing on the
1182configure script.
1183
4c5f7207 1184@item If you want to test the FFplay, also download
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1185the MinGW development library of SDL 1.2.x
1186(@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
4c5f7207 1187@url{http://www.libsdl.org}. Unpack it in a temporary directory, and
50f52fcd 1188unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
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1189directory. Edit the @file{sdl-config} script so that it gives the
1190correct SDL directory when invoked.
50f52fcd 1191
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1192@item If you want to use vhooks, you must have a POSIX compliant libdl in your
1193MinGW system. Get dlfcn-win32 from @url{http://code.google.com/p/dlfcn-win32}.
1194
e926e391 1195@item Extract the current version of FFmpeg.
115329f1 1196
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1197@item Start the MSYS shell (file @file{msys.bat}).
1198
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1199@item Change to the FFmpeg directory and follow
1200 the instructions of how to compile FFmpeg (file
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1201@file{INSTALL}). Usually, launching @file{./configure} and @file{make}
1202suffices. If you have problems using SDL, verify that
1203@file{sdl-config} can be launched from the MSYS command line.
1204
4c5f7207 1205@item You can install FFmpeg in @file{Program Files/FFmpeg} by typing
ce10ff8e 1206@file{make install}. Do not forget to copy @file{SDL.dll} to the place
4c5f7207 1207you launch @file{ffplay} from.
50f52fcd 1208
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1209@end itemize
1210
115329f1 1211Notes:
988a9f9e 1212@itemize
50f52fcd 1213
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1214@item The target @file{make wininstaller} can be used to create a
1215Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
4c5f7207 1216must be copied to the FFmpeg directory in order to build the
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1217installer.
1218
4c5f7207 1219@item By using @code{./configure --enable-shared} when configuring FFmpeg,
988a9f9e
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1220you can build @file{avcodec.dll} and @file{avformat.dll}. With
1221@code{make install} you install the FFmpeg DLLs and the associated
115329f1 1222headers in @file{Program Files/FFmpeg}.
988a9f9e 1223
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1224@item Visual C++ compatibility: If you used @code{./configure --enable-shared}
1225when configuring FFmpeg, FFmpeg tries to use the Microsoft Visual
988a9f9e 1226C++ @code{lib} tool to build @code{avcodec.lib} and
4c5f7207 1227@code{avformat.lib}. With these libraries you can link your Visual C++
be0efc0c 1228code directly with the FFmpeg DLLs (see below).
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1229
1230@end itemize
b030b284 1231
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1232@subsection Visual C++ compatibility
1233
1234FFmpeg will not compile under Visual C++ -- and it has too many
1235dependencies on the GCC compiler to make a port viable. However,
1236if you want to use the FFmpeg libraries in your own applications,
1237you can still compile those applications using Visual C++. An
1238important restriction to this is that you have to use the
1239dynamically linked versions of the FFmpeg libraries (i.e. the
1240DLLs), and you have to make sure that Visual-C++-compatible
1241import libraries are created during the FFmpeg build process.
1242
1243This description of how to use the FFmpeg libraries with Visual C++ is
1244based on Visual C++ 2005 Express Edition Beta 2. If you have a different
1245version, you might have to modify the procedures slightly.
1246
1247Here are the step-by-step instructions for building the FFmpeg libraries
1248so they can be used with Visual C++:
1249
1250@enumerate
1251
ce10ff8e 1252@item Install Visual C++ (if you have not done so already).
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1253
1254@item Install MinGW and MSYS as described above.
1255
1256@item Add a call to @file{vcvars32.bat} (which sets up the environment
1257variables for the Visual C++ tools) as the first line of
1258@file{msys.bat}. The standard location for @file{vcvars32.bat} is
1259@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
1260and the standard location for @file{msys.bat} is
1261@file{C:\msys\1.0\msys.bat}. If this corresponds to your setup, add the
1262following line as the first line of @file{msys.bat}:
1263
1264@code{call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"}
1265
1266@item Start the MSYS shell (file @file{msys.bat}) and type @code{link.exe}.
1267If you get a help message with the command line options of @code{link.exe},
1268this means your environment variables are set up correctly, the
1269Microsoft linker is on the path and will be used by FFmpeg to
1270create Visual-C++-compatible import libraries.
1271
e926e391 1272@item Extract the current version of FFmpeg and change to the FFmpeg directory.
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1273
1274@item Type the command
51d8321d 1275@code{./configure --enable-shared --disable-static --enable-memalign-hack}
ce10ff8e 1276to configure and, if that did not produce any errors,
51d8321d 1277type @code{make} to build FFmpeg.
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1278
1279@item The subdirectories @file{libavformat}, @file{libavcodec}, and
1280@file{libavutil} should now contain the files @file{avformat.dll},
1281@file{avformat.lib}, @file{avcodec.dll}, @file{avcodec.lib},
1282@file{avutil.dll}, and @file{avutil.lib}, respectively. Copy the three
1283DLLs to your System32 directory (typically @file{C:\Windows\System32}).
1284
1285@end enumerate
1286
1287And here is how to use these libraries with Visual C++:
1288
1289@enumerate
1290
1291@item Create a new console application ("File / New / Project") and then
1292select "Win32 Console Application". On the appropriate page of the
1293Application Wizard, uncheck the "Precompiled headers" option.
1294
1295@item Write the source code for your application, or, for testing, just
1296copy the code from an existing sample application into the source file
1297that Visual C++ has already created for you. (Note that your source
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DB
1298filehas to have a @code{.cpp} extension; otherwise, Visual C++ will not
1299compile the FFmpeg headers correctly because in C mode, it does not
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1300recognize the @code{inline} keyword.) For example, you can copy
1301@file{output_example.c} from the FFmpeg distribution (but you will
1302have to make minor modifications so the code will compile under
1303C++, see below).
1304
1305@item Open the "Project / Properties" dialog box. In the "Configuration"
1306combo box, select "All Configurations" so that the changes you make will
1307affect both debug and release builds. In the tree view on the left hand
1308side, select "C/C++ / General", then edit the "Additional Include
1309Directories" setting to contain the complete paths to the
1310@file{libavformat}, @file{libavcodec}, and @file{libavutil}
1311subdirectories of your FFmpeg directory. Note that the directories have
1312to be separated using semicolons. Now select "Linker / General" from the
1313tree view and edit the "Additional Library Directories" setting to
1314contain the same three directories.
1315
1316@item Still in the "Project / Properties" dialog box, select "Linker / Input"
1317from the tree view, then add the files @file{avformat.lib},
1318@file{avcodec.lib}, and @file{avutil.lib} to the end of the "Additional
1319Dependencies". Note that the names of the libraries have to be separated
1320using spaces.
1321
765c3440 1322@item Now, select "C/C++ / Code Generation" from the tree view. Select
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1323"Debug" in the "Configuration" combo box. Make sure that "Runtime
1324Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
1325the "Configuration" combo box and make sure that "Runtime Library" is
1326set to "Multi-threaded DLL".
1327
1328@item Click "OK" to close the "Project / Properties" dialog box and build
1329the application. Hopefully, it should compile and run cleanly. If you
1330used @file{output_example.c} as your sample application, you will get a
1331few compiler errors, but they are easy to fix. The first type of error
ce10ff8e 1332occurs because Visual C++ does not allow an @code{int} to be converted to
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MB
1333an @code{enum} without a cast. To solve the problem, insert the required
1334casts (this error occurs once for a @code{CodecID} and once for a
1335@code{CodecType}). The second type of error occurs because C++ requires
1336the return value of @code{malloc} to be cast to the exact type of the
1337pointer it is being assigned to. Visual C++ will complain that, for
1338example, @code{(void *)} is being assigned to @code{(uint8_t *)} without
1339an explicit cast. So insert an explicit cast in these places to silence
1340the compiler. The third type of error occurs because the @code{snprintf}
1341library function is called @code{_snprintf} under Visual C++. So just
1342add an underscore to fix the problem. With these changes,
1343@file{output_example.c} should compile under Visual C++, and the
1344resulting executable should produce valid video files.
1345
1346@end enumerate
1347
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1348@subsection Cross compilation for Windows with Linux
1349
1350You must use the MinGW cross compilation tools available at
1351@url{http://www.mingw.org/}.
1352
4c5f7207 1353Then configure FFmpeg with the following options:
b030b284 1354@example
6b74787b 1355./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
b030b284 1356@end example
019c8838 1357(you can change the cross-prefix according to the prefix chosen for the
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1358MinGW tools).
1359
4c5f7207 1360Then you can easily test FFmpeg with Wine
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1361(@url{http://www.winehq.com/}).
1362
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1363@subsection Compilation under Cygwin
1364
1365Cygwin works very much like Unix.
1366
1367Just install your Cygwin with all the "Base" packages, plus the
1368following "Devel" ones:
1369@example
1370binutils, gcc-core, make, subversion
1371@end example
1372
1373Do not install binutils-20060709-1 (they are buggy on shared builds);
1374use binutils-20050610-1 instead.
1375
1376Then run
1377
1378@example
1379./configure --enable-static --disable-shared
1380@end example
1381
1382to make a static build or
1383
1384@example
1385./configure --enable-shared --disable-static
1386@end example
1387
1388to build shared libraries.
1389
1390If you want to build FFmpeg with additional libraries, download Cygwin
1391"Devel" packages for Ogg and Vorbis from any Cygwin packages repository
1392and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
1393(@url{http://cygwinports.dotsrc.org/}).
1394
1395@subsection Crosscompilation for Windows under Cygwin
1396
ce10ff8e 1397With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
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1398
1399Just install your Cygwin as explained before, plus these additional
1400"Devel" packages:
1401@example
1402gcc-mingw-core, mingw-runtime, mingw-zlib
1403@end example
1404
1405and add some special flags to your configure invocation.
1406
1407For a static build run
1408@example
6b74787b 1409./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
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1410@end example
1411
1412and for a build with shared libraries
1413@example
6b74787b 1414./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
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1415@end example
1416
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1417@section BeOS
1418
1419The configure script should guess the configuration itself.
1420Networking support is currently not finished.
1421errno issues fixed by Andrew Bachmann.
1422
1423Old stuff:
1424
7dd611c9 1425François Revol - revol at free dot fr - April 2002
47d944d2 1426
115329f1 1427The configure script should guess the configuration itself,
ce10ff8e 1428however I still did not test building on the net_server version of BeOS.
47d944d2 1429
4c5f7207 1430FFserver is broken (needs poll() implementation).
47d944d2 1431
4c5f7207 1432There are still issues with errno codes, which are negative in BeOS, and
115329f1 1433that FFmpeg negates when returning. This ends up turning errors into
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1434valid results, then crashes.
1435(To be fixed)
1436
34d7008d 1437@chapter Developers Guide
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1438
1439@section API
a0b72f90 1440@itemize @bullet
9181577c 1441@item libavcodec is the library containing the codecs (both encoding and
4c5f7207 1442decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
9181577c 1443
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1444@item libavformat is the library containing the file format handling (mux and
1445demux code for several formats). Look at @file{ffplay.c} to use it in a
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1446player. See @file{output_example.c} to use it to generate audio or video
1447streams.
1448
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1449@end itemize
1450
1451@section Integrating libavcodec or libavformat in your program
1452
1453You can integrate all the source code of the libraries to link them
1454statically to avoid any version problem. All you need is to provide a
1455'config.mak' and a 'config.h' in the parent directory. See the defines
1456generated by ./configure to understand what is needed.
1457
1458You can use libavcodec or libavformat in your commercial program, but
1459@emph{any patch you make must be published}. The best way to proceed is
4c5f7207 1460to send your patches to the FFmpeg mailing list.
9181577c 1461
80d1c272 1462@node Coding Rules
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1463@section Coding Rules
1464
4c5f7207 1465FFmpeg is programmed in the ISO C90 language with a few additional
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1466features from ISO C99, namely:
1467@itemize @bullet
1468@item
1469the @samp{inline} keyword;
1470@item
1471@samp{//} comments;
1472@item
1473designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
1474@item
114afa9c 1475compound literals (@samp{x = (struct s) @{ 17, 23 @};})
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1476@end itemize
1477
ce10ff8e
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1478These features are supported by all compilers we care about, so we will not
1479accept patches to remove their use unless they absolutely do not impair
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1480clarity and performance.
1481
4c5f7207 1482All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
cb6e87c1
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1483compiles with several other compilers, such as the Compaq ccc compiler
1484or Sun Studio 9, and we would like to keep it that way unless it would
ce10ff8e 1485be exceedingly involved. To ensure compatibility, please do not use any
4c5f7207 1486additional C99 features or GCC extensions. Especially watch out for:
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1487@itemize @bullet
1488@item
1489mixing statements and declarations;
1490@item
1491@samp{long long} (use @samp{int64_t} instead);
1492@item
1493@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
1494@item
019c8838 1495GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
cb6e87c1 1496@end itemize
9181577c 1497
53862e0f 1498Indent size is 4.
b86e38a0 1499The presentation is the one specified by 'indent -i4 -kr -nut'.
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1500The TAB character is forbidden outside of Makefiles as is any
1501form of trailing whitespace. Commits containing either will be
1c1b5a40 1502rejected by the Subversion repository.
9181577c 1503
4c5f7207 1504Main priority in FFmpeg is simplicity and small code size (=less
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1505bugs).
1506
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1507Comments: Use the JavaDoc/Doxygen
1508format (see examples below) so that code documentation
1509can be generated automatically. All nontrivial functions should have a comment
ce10ff8e 1510above them explaining what the function does, even if it is just one sentence.
4c5f7207 1511All structures and their member variables should be documented, too.
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1512@example
1513/**
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1514 * @@file mpeg.c
1515 * MPEG codec.
1516 * @@author ...
1517 */
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1518
1519/**
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1520 * Summary sentence.
1521 * more text ...
1522 * ...
1523 */
114afa9c 1524typedef struct Foobar@{
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1525 int var1; /**< var1 description */
1526 int var2; ///< var2 description
1527 /** var3 description */
1528 int var3;
114afa9c 1529@} Foobar;
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1530
1531/**
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1532 * Summary sentence.
1533 * more text ...
1534 * ...
1535 * @@param my_parameter description of my_parameter
1536 * @@return return value description
1537 */
f4888b83
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1538int myfunc(int my_parameter)
1539...
1540@end example
9181577c 1541
115329f1 1542fprintf and printf are forbidden in libavformat and libavcodec,
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1543please use av_log() instead.
1544
7cbf432d
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1545Casts should be used only when necessary. Unneeded parentheses
1546should also be avoided if they don't make the code easier to understand.
1547
1c1b5a40 1548@section Development Policy
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1549
1550@enumerate
115329f1 1551@item
7a57b90c 1552 You must not commit code which breaks FFmpeg! (Meaning unfinished but
4c5f7207 1553 enabled code which breaks compilation or compiles but does not work or
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MN
1554 breaks the regression tests)
1555 You can commit unfinished stuff (for testing etc), but it must be disabled
1556 (#ifdef etc) by default so it does not interfere with other developers'
1557 work.
115329f1 1558@item
ce10ff8e 1559 You do not have to over-test things. If it works for you, and you think it
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1560 should work for others, then commit. If your code has problems
1561 (portability, triggers compiler bugs, unusual environment etc) they will be
7a57b90c 1562 reported and eventually fixed.
115329f1 1563@item
7a57b90c 1564 Do not commit unrelated changes together, split them into self-contained
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1565 pieces. Also do not forget that if part B depends on part A, but A does not
1566 depend on B, then A can and should be committed first and separate from B.
1567 Keeping changes well split into self-contained parts makes reviewing and
1568 understanding them on the commit log mailing list easier. This also helps
1569 in case of debugging later on.
1570 Also if you have doubts about splitting or not splitting, do not hesitate to
442d1598 1571 ask/discuss it on the developer mailing list.
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1572@item
1573 Do not change behavior of the program (renaming options etc) without
019c8838 1574 first discussing it on the ffmpeg-devel mailing list. Do not remove
7a57b90c 1575 functionality from the code. Just improve!
115329f1 1576
4c5f7207 1577 Note: Redundant code can be removed.
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1578@item
1579 Do not commit changes to the build system (Makefiles, configure script)
019c8838 1580 which change behavior, defaults etc, without asking first. The same
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1581 applies to compiler warning fixes, trivial looking fixes and to code
1582 maintained by other developers. We usually have a reason for doing things
019c8838 1583 the way we do. Send your changes as patches to the ffmpeg-devel mailing
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1584 list, and if the code maintainers say OK, you may commit. This does not
1585 apply to files you wrote and/or maintain.
1586@item
1587 We refuse source indentation and other cosmetic changes if they are mixed
1588 with functional changes, such commits will be rejected and removed. Every
1589 developer has his own indentation style, you should not change it. Of course
1590 if you (re)write something, you can use your own style, even though we would
4c5f7207 1591 prefer if the indentation throughout FFmpeg was consistent (Many projects
ce10ff8e 1592 force a given indentation style - we do not.). If you really need to make
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1593 indentation changes (try to avoid this), separate them strictly from real
1594 changes.
1595
114afa9c 1596 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
ce10ff8e 1597 then either do NOT change the indentation of the inner part within (do not
019c8838 1598 move it to the right)! or do so in a separate commit
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1599@item
1600 Always fill out the commit log message. Describe in a few lines what you
1601 changed and why. You can refer to mailing list postings if you fix a
1602 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1603@item
1604 If you apply a patch by someone else, include the name and email address in
1c1b5a40 1605 the log message. Since the ffmpeg-cvslog mailing list is publicly
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1606 archived you should add some SPAM protection to the email address. Send an
1607 answer to ffmpeg-devel (or wherever you got the patch from) saying that
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1608 you applied the patch.
1609@item
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1610 When applying patches that have been discussed (at length) on the mailing
1611 list, reference the thread in the log message.
1612@item
5ab0f204 1613 Do NOT commit to code actively maintained by others without permission.
755bfeab 1614 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
5ab0f204 1615 timeframe (12h for build failures and security fixes, 3 days small changes,
ce10ff8e 1616 1 week for big patches) then commit your patch if you think it is OK.
5ab0f204 1617 Also note, the maintainer can simply ask for more time to review!
7a57b90c 1618@item
1c1b5a40 1619 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
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1620 are sent there and reviewed by all the other developers. Bugs and possible
1621 improvements or general questions regarding commits are discussed there. We
1622 expect you to react if problems with your code are uncovered.
1623@item
1624 Update the documentation if you change behavior or add features. If you are
019c8838 1625 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
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1626 maintainer(s) will review and commit your stuff.
1627@item
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1628 Try to keep important discussions and requests (also) on the public
1629 developer mailing list, so that all developers can benefit from them.
1630@item
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1631 Never write to unallocated memory, never write over the end of arrays,
1632 always check values read from some untrusted source before using them
1633 as array index or other risky things.
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1634@item
1635 Remember to check if you need to bump versions for the specific libav
f0efbde7 1636 parts (libavutil, libavcodec, libavformat) you are changing. You need
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1637 to change the version integer and the version string.
1638 Incrementing the first component means no backward compatibility to
a940b428 1639 previous versions (e.g. removal of a function from the public API).
76bec1d8 1640 Incrementing the second component means backward compatible change
a940b428 1641 (e.g. addition of a function to the public API).
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1642 Incrementing the third component means a noteworthy binary compatible
1643 change (e.g. encoder bug fix that matters for the decoder).
ebd32fd7 1644@item
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1645 If you add a new codec, remember to update the changelog, add it to
1646 the supported codecs table in the documentation and bump the second
1647 component of the @file{libavcodec} version number appropriately. If
1648 it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
1649 is only a decoder.
65d0bea8 1650@item
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1651 Do not change code to hide warnings without ensuring that the underlying
1652 logic is correct and thus the warning was inappropriate.
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1653@item
1654 If you add a new file, give it a proper license header. Do not copy and
1655 paste it from a random place, use an existing file as template.
114afa9c 1656@end enumerate
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1657
1658We think our rules are not too hard. If you have comments, contact us.
1659
1660Note, these rules are mostly borrowed from the MPlayer project.
1661
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1662@section Submitting patches
1663
ce10ff8e 1664First, (@pxref{Coding Rules}) above if you did not yet.
80d1c272 1665
6a6810b1 1666When you submit your patch, try to send a unified diff (diff '-up'
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1667option). I cannot read other diffs :-)
1668
6e5c1877 1669Also please do not submit patches which contain several unrelated changes.
115329f1 1670Split them into individual self-contained patches; this makes reviewing
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1671them much easier.
1672
9181577c 1673Run the regression tests before submitting a patch so that you can
6bf40f39 1674verify that there are no big problems.
9181577c 1675
9181577c 1676Patches should be posted as base64 encoded attachments (or any other
ce10ff8e 1677encoding which ensures that the patch will not be trashed during
115329f1 1678transmission) to the ffmpeg-devel mailing list, see
2b165e29 1679@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
9181577c 1680
54fcf429 1681It also helps quite a bit if you tell us what the patch does (for example
4c5f7207 1682'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
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1683and has no lrint()')
1684
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1685Also please if you send several patches, send each patch as separate mail,
1686do not attach several unrelated patches to the same mail.
a15bcf70 1687
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1688@section patch submission checklist
1689
1690@enumerate
1691@item
1692 Do the regression tests pass with the patch applied?
1693@item
1694 Is the patch a unified diff?
1695@item
4a7a0908 1696 Is the patch against latest FFmpeg SVN?
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1697@item
1698 Are you subscribed to ffmpeg-dev?
1699 (the list is subscribers only due to spam)
1700@item
1701 Have you checked that the changes are minimal, so that the same cannot be
442d1598 1702 achieved with a smaller patch and/or simpler final code?
dd597cd7 1703@item
4a7a0908 1704 If the change is to speed critical code, did you benchmark it?
dd597cd7 1705@item
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1706 If you did any benchmarks, did you provide them in the mail?
1707@item
442d1598 1708 Have you checked that the patch does not introduce buffer overflows or
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1709 other security issues?
1710@item
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1711 Is the patch created from the root of the source tree, so it can be
1712 applied with @code{patch -p0}?
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1713@item
1714 Does the patch not mix functional and cosmetic changes?
1715@item
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1716 Did you add tabs or trailing whitespace to the code? Both are forbidden.
1717@item
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1718 Is the patch attached to the email you send?
1719@item
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1720 Is the mime type of the patch correct? It should be text/x-diff or
1721 text/x-patch or at least text/plain and not application/octet-stream.
dd597cd7 1722@item
4a7a0908 1723 If the patch fixes a bug, did you provide a verbose analysis of the bug?
dd597cd7 1724@item
4a7a0908 1725 If the patch fixes a bug, did you provide enough information, including
dd597cd7 1726 a sample, so the bug can be reproduced and the fix can be verified?
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1727 Note please do not attach samples >100k to mails but rather provide a
1728 URL, you can upload to ftp://upload.mplayerhq.hu
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1729@item
1730 Did you provide a verbose summary about what the patch does change?
1731@item
1732 Did you provide a verbose explanation why it changes things like it does?
1733@item
442d1598 1734 Did you provide a verbose summary of the user visible advantages and
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1735 disadvantages if the patch is applied?
1736@item
1737 Did you provide an example so we can verify the new feature added by the
1738 patch easily?
1739@item
bbe94afb 1740 If you added a new file, did you insert a license header? It should be
6baa2943 1741 taken from FFmpeg, not randomly copied and pasted from somewhere else.
6e4bc6ee 1742@item
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1743 You should maintain alphabetical order in alphabetically ordered lists as
1744 long as doing so does not break API/ABI compatibility.
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1745@item
1746 Did you provide a suggestion for a clear commit log message?
dd597cd7
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1747@end enumerate
1748
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1749@section Patch review process
1750
1751All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1752clear note that the patch is not for SVN.
1753Reviews and comments will be posted as replies to the patch on the
ce10ff8e 1754mailing list. The patch submitter then has to take care of every comment,
442d1598 1755that can be by resubmitting a changed patch or by discussion. Resubmitted
ce10ff8e 1756patches will themselves be reviewed like any other patch. If at some point
f5f11d71 1757a patch passes review with no comments then it is approved, that can for
ce10ff8e 1758simple and small patches happen immediately while large patches will generally
f5f11d71 1759have to be changed and reviewed many times before they are approved.
ce10ff8e 1760After a patch is approved it will be committed to the repository.
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1761
1762We will review all submitted patches, but sometimes we are quite busy so
1763especially for large patches this can take several weeks.
1764
1765When resubmitting patches, please do not make any significant changes
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1766not related to the comments received during review. Such patches will
1767be rejected. Instead, submit significant changes or new features as
1768separate patches.
cf7f2b16 1769
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1770@section Regression tests
1771
1c1b5a40 1772Before submitting a patch (or committing to the repository), you should at least
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1773test that you did not break anything.
1774
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1775The regression tests build a synthetic video stream and a synthetic
1776audio stream. These are then encoded and decoded with all codecs or
9181577c 1777formats. The CRC (or MD5) of each generated file is recorded in a
4c5f7207 1778result file. A 'diff' is launched to compare the reference results and
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1779the result file.
1780
4c5f7207 1781The regression tests then go on to test the FFserver code with a
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1782limited set of streams. It is important that this step runs correctly
1783as well.
1784
36d9b4e8 1785Run 'make test' to test all the codecs and formats.
9181577c 1786
4c5f7207 1787Run 'make fulltest' to test all the codecs, formats and FFserver.
9181577c 1788
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1789[Of course, some patches may change the results of the regression tests. In
1790this case, the reference results of the regression tests shall be modified
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1791accordingly].
1792
1793@bye