Cygwin compilation and Cygwin/MinGW crosscompilation sections
[libav.git] / doc / ffmpeg-doc.texi
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
13 FFmpeg is a very fast video and audio converter. It can also grab from
14 a live audio/video source.
15
16 The command line interface is designed to be intuitive, in the sense
17 that FFmpeg tries to figure out all parameters that can possibly be
18 derived automatically. You usually only have to specify the target
19 bitrate you want.
20
21 FFmpeg can also convert from any sample rate to any other, and resize
22 video on the fly with a high quality polyphase filter.
23
24 @chapter Quick Start
25
26 @c man begin EXAMPLES
27 @section Video and Audio grabbing
28
29 FFmpeg can use a video4linux compatible video source and any Open Sound
30 System audio source:
31
32 @example
33 ffmpeg /tmp/out.mpg
34 @end example
35
36 Note that you must activate the right video source and channel before
37 launching FFmpeg with any TV viewer such as xawtv
38 (@url{http://bytesex.org/xawtv/}) by Gerd Knorr. You also
39 have to set the audio recording levels correctly with a
40 standard mixer.
41
42 @section Video and Audio file format conversion
43
44 * FFmpeg can use any supported file format and protocol as input:
45
46 Examples:
47
48 * You can use YUV files as input:
49
50 @example
51 ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
52 @end example
53
54 It will use the files:
55 @example
56 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
57 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
58 @end example
59
60 The Y files use twice the resolution of the U and V files. They are
61 raw files, without header. They can be generated by all decent video
62 decoders. You must specify the size of the image with the @option{-s} option
63 if FFmpeg cannot guess it.
64
65 * You can input from a raw YUV420P file:
66
67 @example
68 ffmpeg -i /tmp/test.yuv /tmp/out.avi
69 @end example
70
71 test.yuv is a file containing raw YUV planar data. Each frame is composed
72 of the Y plane followed by the U and V planes at half vertical and
73 horizontal resolution.
74
75 * You can output to a raw YUV420P file:
76
77 @example
78 ffmpeg -i mydivx.avi hugefile.yuv
79 @end example
80
81 * You can set several input files and output files:
82
83 @example
84 ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
85 @end example
86
87 Converts the audio file a.wav and the raw YUV video file a.yuv
88 to MPEG file a.mpg.
89
90 * You can also do audio and video conversions at the same time:
91
92 @example
93 ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
94 @end example
95
96 Converts a.wav to MPEG audio at 22050Hz sample rate.
97
98 * You can encode to several formats at the same time and define a
99 mapping from input stream to output streams:
100
101 @example
102 ffmpeg -i /tmp/a.wav -ab 64 /tmp/a.mp2 -ab 128 /tmp/b.mp2 -map 0:0 -map 0:0
103 @end example
104
105 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
106 file:index' specifies which input stream is used for each output
107 stream, in the order of the definition of output streams.
108
109 * You can transcode decrypted VOBs
110
111 @example
112 ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800 -g 300 -bf 2 -acodec mp3 -ab 128 snatch.avi
113 @end example
114
115 This is a typical DVD ripping example; the input is a VOB file, the
116 output an AVI file with MPEG-4 video and MP3 audio. Note that in this
117 command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
118 GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
119 input video. Furthermore, the audio stream is MP3-encoded so you need
120 to enable LAME support by passing @code{--enable-mp3lame} to configure.
121 The mapping is particularly useful for DVD transcoding
122 to get the desired audio language.
123
124 NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
125 @c man end
126
127 @chapter Invocation
128
129 @section Syntax
130
131 The generic syntax is:
132
133 @example
134 @c man begin SYNOPSIS
135 ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
136 @c man end
137 @end example
138 @c man begin DESCRIPTION
139 If no input file is given, audio/video grabbing is done.
140
141 As a general rule, options are applied to the next specified
142 file. For example, if you give the @option{-b 64} option, it sets the video
143 bitrate of the next file. The format option may be needed for raw input
144 files.
145
146 By default, FFmpeg tries to convert as losslessly as possible: It
147 uses the same audio and video parameters for the outputs as the one
148 specified for the inputs.
149 @c man end
150
151 @c man begin OPTIONS
152 @section Main options
153
154 @table @option
155 @item -L
156 Show license.
157
158 @item -h
159 Show help.
160
161 @item -formats
162 Show available formats, codecs, protocols, ...
163
164 @item -f fmt
165 Force format.
166
167 @item -i filename
168 input filename
169
170 @item -y
171 Overwrite output files.
172
173 @item -t duration
174 Set the recording time in seconds.
175 @code{hh:mm:ss[.xxx]} syntax is also supported.
176
177 @item -ss position
178 Seek to given time position in seconds.
179 @code{hh:mm:ss[.xxx]} syntax is also supported.
180
181 @item -title string
182 Set the title.
183
184 @item -author string
185 Set the author.
186
187 @item -copyright string
188 Set the copyright.
189
190 @item -comment string
191 Set the comment.
192
193 @item -target type
194 Specify target file type ("vcd", "svcd", "dvd", "dv", "pal-vcd",
195 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
196 buffer sizes) are then set automatically. You can just type:
197
198 @example
199 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
200 @end example
201
202 Nevertheless you can specify additional options as long as you know
203 they do not conflict with the standard, as in:
204
205 @example
206 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
207 @end example
208
209 @item -hq
210 Activate high quality settings.
211
212 @item -itsoffset offset
213 Set the input time offset in seconds.
214 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
215 This option affects all the input files that follow it.
216 The offset is added to the timestamps of the input files.
217 Specifying a positive offset means that the corresponding
218 streams are delayed by 'offset' seconds.
219
220 @end table
221
222 @section Video Options
223
224 @table @option
225 @item -b bitrate
226 Set the video bitrate in kbit/s (default = 200 kb/s).
227 @item -r fps
228 Set frame rate (default = 25).
229 @item -s size
230 Set frame size. The format is @samp{wxh} (default = 160x128).
231 The following abbreviations are recognized:
232 @table @samp
233 @item sqcif
234 128x96
235 @item qcif
236 176x144
237 @item cif
238 352x288
239 @item 4cif
240 704x576
241 @end table
242
243 @item -aspect aspect
244 Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
245 @item -croptop size
246 Set top crop band size (in pixels).
247 @item -cropbottom size
248 Set bottom crop band size (in pixels).
249 @item -cropleft size
250 Set left crop band size (in pixels).
251 @item -cropright size
252 Set right crop band size (in pixels).
253 @item -padtop size
254 Set top pad band size (in pixels).
255 @item -padbottom size
256 Set bottom pad band size (in pixels).
257 @item -padleft size
258 Set left pad band size (in pixels).
259 @item -padright size
260 Set right pad band size (in pixels).
261 @item -padcolor (hex color)
262 Set color of padded bands. The value for padcolor is expressed
263 as a six digit hexadecimal number where the first two digits
264 represent red, the middle two digits green and last two digits
265 blue (default = 000000 (black)).
266 @item -vn
267 Disable video recording.
268 @item -bt tolerance
269 Set video bitrate tolerance (in kbit/s).
270 @item -maxrate bitrate
271 Set max video bitrate tolerance (in kbit/s).
272 @item -minrate bitrate
273 Set min video bitrate tolerance (in kbit/s).
274 @item -bufsize size
275 Set rate control buffer size (in kbit).
276 @item -vcodec codec
277 Force video codec to @var{codec}. Use the @code{copy} special value to
278 tell that the raw codec data must be copied as is.
279 @item -sameq
280 Use same video quality as source (implies VBR).
281
282 @item -pass n
283 Select the pass number (1 or 2). It is useful to do two pass
284 encoding. The statistics of the video are recorded in the first
285 pass and the video is generated at the exact requested bitrate
286 in the second pass.
287
288 @item -passlogfile file
289 Set two pass logfile name to @var{file}.
290
291 @end table
292
293 @section Advanced Video Options
294
295 @table @option
296 @item -g gop_size
297 Set the group of pictures size.
298 @item -intra
299 Use only intra frames.
300 @item -qscale q
301 Use fixed video quantiser scale (VBR).
302 @item -qmin q
303 minimum video quantiser scale (VBR)
304 @item -qmax q
305 maximum video quantiser scale (VBR)
306 @item -qdiff q
307 maximum difference between the quantiser scales (VBR)
308 @item -qblur blur
309 video quantiser scale blur (VBR)
310 @item -qcomp compression
311 video quantiser scale compression (VBR)
312
313 @item -rc_init_cplx complexity
314 initial complexity for single pass encoding
315 @item -b_qfactor factor
316 qp factor between P- and B-frames
317 @item -i_qfactor factor
318 qp factor between P- and I-frames
319 @item -b_qoffset offset
320 qp offset between P- and B-frames
321 @item -i_qoffset offset
322 qp offset between P- and I-frames
323 @item -rc_eq equation
324 Set rate control equation (@pxref{FFmpeg formula
325 evaluator}) (default = @code{tex^qComp}).
326 @item -rc_override override
327 rate control override for specific intervals
328 @item -me method
329 Set motion estimation method to @var{method}.
330 Available methods are (from lowest to best quality):
331 @table @samp
332 @item zero
333 Try just the (0, 0) vector.
334 @item phods
335 @item log
336 @item x1
337 @item epzs
338 (default method)
339 @item full
340 exhaustive search (slow and marginally better than epzs)
341 @end table
342
343 @item -dct_algo algo
344 Set DCT algorithm to @var{algo}. Available values are:
345 @table @samp
346 @item 0
347 FF_DCT_AUTO (default)
348 @item 1
349 FF_DCT_FASTINT
350 @item 2
351 FF_DCT_INT
352 @item 3
353 FF_DCT_MMX
354 @item 4
355 FF_DCT_MLIB
356 @item 5
357 FF_DCT_ALTIVEC
358 @end table
359
360 @item -idct_algo algo
361 Set IDCT algorithm to @var{algo}. Available values are:
362 @table @samp
363 @item 0
364 FF_IDCT_AUTO (default)
365 @item 1
366 FF_IDCT_INT
367 @item 2
368 FF_IDCT_SIMPLE
369 @item 3
370 FF_IDCT_SIMPLEMMX
371 @item 4
372 FF_IDCT_LIBMPEG2MMX
373 @item 5
374 FF_IDCT_PS2
375 @item 6
376 FF_IDCT_MLIB
377 @item 7
378 FF_IDCT_ARM
379 @item 8
380 FF_IDCT_ALTIVEC
381 @item 9
382 FF_IDCT_SH4
383 @item 10
384 FF_IDCT_SIMPLEARM
385 @end table
386
387 @item -er n
388 Set error resilience to @var{n}.
389 @table @samp
390 @item 1
391 FF_ER_CAREFUL (default)
392 @item 2
393 FF_ER_COMPLIANT
394 @item 3
395 FF_ER_AGGRESSIVE
396 @item 4
397 FF_ER_VERY_AGGRESSIVE
398 @end table
399
400 @item -ec bit_mask
401 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
402 the following values:
403 @table @samp
404 @item 1
405 FF_EC_GUESS_MVS (default = enabled)
406 @item 2
407 FF_EC_DEBLOCK (default = enabled)
408 @end table
409
410 @item -bf frames
411 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
412 @item -mbd mode
413 macroblock decision
414 @table @samp
415 @item 0
416 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
417 @item 1
418 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
419 @item 2
420 FF_MB_DECISION_RD: rate distortion
421 @end table
422
423 @item -4mv
424 Use four motion vector by macroblock (MPEG-4 only).
425 @item -part
426 Use data partitioning (MPEG-4 only).
427 @item -bug param
428 Work around encoder bugs that are not auto-detected.
429 @item -strict strictness
430 How strictly to follow the standards.
431 @item -aic
432 Enable Advanced intra coding (h263+).
433 @item -umv
434 Enable Unlimited Motion Vector (h263+)
435
436 @item -deinterlace
437 Deinterlace pictures.
438 @item -interlace
439 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
440 Use this option if your input file is interlaced and you want
441 to keep the interlaced format for minimum losses.
442 The alternative is to deinterlace the input stream with
443 @option{-deinterlace}, but deinterlacing introduces losses.
444 @item -psnr
445 Calculate PSNR of compressed frames.
446 @item -vstats
447 Dump video coding statistics to @file{vstats_HHMMSS.log}.
448 @item -vhook module
449 Insert video processing @var{module}. @var{module} contains the module
450 name and its parameters separated by spaces.
451 @end table
452
453 @section Audio Options
454
455 @table @option
456 @item -ar freq
457 Set the audio sampling frequency (default = 44100 Hz).
458 @item -ab bitrate
459 Set the audio bitrate in kbit/s (default = 64).
460 @item -ac channels
461 Set the number of audio channels (default = 1).
462 @item -an
463 Disable audio recording.
464 @item -acodec codec
465 Force audio codec to @var{codec}. Use the @code{copy} special value to
466 specify that the raw codec data must be copied as is.
467 @end table
468
469 @section Audio/Video grab options
470
471 @table @option
472 @item -vd device
473 sEt video grab device (e.g. @file{/dev/video0}).
474 @item -vc channel
475 Set video grab channel (DV1394 only).
476 @item -tvstd standard
477 Set television standard (NTSC, PAL (SECAM)).
478 @item -dv1394
479 Set DV1394 grab.
480 @item -ad device
481 Set audio device (e.g. @file{/dev/dsp}).
482 @end table
483
484 @section Advanced options
485
486 @table @option
487 @item -map file:stream
488 Set input stream mapping.
489 @item -debug
490 Print specific debug info.
491 @item -benchmark
492 Add timings for benchmarking.
493 @item -hex
494 Dump each input packet.
495 @item -bitexact
496 Only use bit exact algorithms (for codec testing).
497 @item -ps size
498 Set packet size in bits.
499 @item -re
500 Read input at native frame rate. Mainly used to simulate a grab device.
501 @item -loop
502 Loop over the input stream. Currently it works only for image
503 streams. This option is used for automatic FFserver testing.
504 @item -loop_output number_of_times
505 Repeatedly loop output for formats that support looping such as animated GIF
506 (0 will loop the output infinitely).
507 @end table
508
509 @node FFmpeg formula evaluator
510 @section FFmpeg formula evaluator
511
512 When evaluating a rate control string, FFmpeg uses an internal formula
513 evaluator.
514
515 The following binary operators are available: @code{+}, @code{-},
516 @code{*}, @code{/}, @code{^}.
517
518 The following unary operators are available: @code{+}, @code{-},
519 @code{(...)}.
520
521 The 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
543 The 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
567 @c man end
568
569 @ignore
570
571 @setfilename ffmpeg
572 @settitle FFmpeg video converter
573
574 @c man begin SEEALSO
575 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
576 @c man end
577
578 @c man begin AUTHOR
579 Fabrice Bellard
580 @c man end
581
582 @end ignore
583
584 @section Protocols
585
586 The filename can be @file{-} to read from standard input or to write
587 to standard output.
588
589 FFmpeg also handles many protocols specified with an URL syntax.
590
591 Use 'ffmpeg -formats' to see a list of the supported protocols.
592
593 The protocol @code{http:} is currently used only to communicate with
594 FFserver (see the FFserver documentation). When FFmpeg will be a
595 video player it will also be used for streaming :-)
596
597 @chapter Tips
598
599 @itemize
600 @item For streaming at very low bitrate application, use a low frame rate
601 and a small GOP size. This is especially true for RealVideo where
602 the Linux player does not seem to be very fast, so it can miss
603 frames. An example is:
604
605 @example
606 ffmpeg -g 3 -r 3 -t 10 -b 50 -s qcif -f rv10 /tmp/b.rm
607 @end example
608
609 @item The parameter 'q' which is displayed while encoding is the current
610 quantizer. The value 1 indicates that a very good quality could
611 be achieved. The value 31 indicates the worst quality. If q=31 appears
612 too often, it means that the encoder cannot compress enough to meet
613 your bitrate. You must either increase the bitrate, decrease the
614 frame rate or decrease the frame size.
615
616 @item If your computer is not fast enough, you can speed up the
617 compression at the expense of the compression ratio. You can use
618 '-me zero' to speed up motion estimation, and '-intra' to disable
619 motion estimation completely (you have only I-frames, which means it
620 is about as good as JPEG compression).
621
622 @item To have very low audio bitrates, reduce the sampling frequency
623 (down to 22050 kHz for MPEG audio, 22050 or 11025 for AC3).
624
625 @item To have a constant quality (but a variable bitrate), use the option
626 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
627 quality).
628
629 @item When converting video files, you can use the '-sameq' option which
630 uses the same quality factor in the encoder as in the decoder.
631 It allows almost lossless encoding.
632
633 @end itemize
634
635 @chapter Supported File Formats and Codecs
636
637 You can use the @code{-formats} option to have an exhaustive list.
638
639 @section File Formats
640
641 FFmpeg supports the following file formats through the @code{libavformat}
642 library:
643
644 @multitable @columnfractions .4 .1 .1 .4
645 @item Supported File Format @tab Encoding @tab Decoding @tab Comments
646 @item MPEG audio @tab X @tab X
647 @item MPEG-1 systems @tab X @tab X
648 @tab muxed audio and video
649 @item MPEG-2 PS @tab X @tab X
650 @tab also known as @code{VOB} file
651 @item MPEG-2 TS @tab @tab X
652 @tab also known as DVB Transport Stream
653 @item ASF@tab X @tab X
654 @item AVI@tab X @tab X
655 @item WAV@tab X @tab X
656 @item Macromedia Flash@tab X @tab X
657 @tab Only embedded audio is decoded.
658 @item FLV @tab X @tab X
659 @tab Macromedia Flash video files
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
668 @item NUT @tab X @tab X @tab NUT Open Container Format
669 @item QuickTime @tab X @tab X
670 @item MPEG-4 @tab X @tab X
671 @tab MPEG-4 is a variant of QuickTime.
672 @item Raw MPEG4 video @tab X @tab X
673 @item DV @tab X @tab X
674 @item 4xm @tab @tab X
675 @tab 4X Technologies format, used in some games.
676 @item Playstation STR @tab @tab X
677 @item Id RoQ @tab @tab X
678 @tab Used in Quake III, Jedi Knight 2, other computer games.
679 @item Interplay MVE @tab @tab X
680 @tab Format used in various Interplay computer games.
681 @item WC3 Movie @tab @tab X
682 @tab Multimedia format used in Origin's Wing Commander III computer game.
683 @item Sega FILM/CPK @tab @tab X
684 @tab Used in many Sega Saturn console games.
685 @item Westwood Studios VQA/AUD @tab @tab X
686 @tab Multimedia formats used in Westwood Studios games.
687 @item Id Cinematic (.cin) @tab @tab X
688 @tab Used in Quake II.
689 @item FLIC format @tab @tab X
690 @tab .fli/.flc files
691 @item Sierra VMD @tab @tab X
692 @tab Used in Sierra CD-ROM games.
693 @item Sierra Online @tab @tab X
694 @tab .sol files used in Sierra Online games.
695 @item Matroska @tab @tab X
696 @item Electronic Arts Multimedia @tab @tab X
697 @tab Used in various EA games; files have extensions like WVE and UV2.
698 @item Nullsoft Video (NSV) format @tab @tab X
699 @item ADTS AAC audio @tab X @tab X
700 @item Creative VOC @tab X @tab X @tab Created for the Sound Blaster Pro.
701 @item American Laser Games MM @tab @tab X
702 @tab Multimedia format used in games like Mad Dog McCree
703 @item AVS @tab @tab X
704 @tab Multimedia format used by the Creature Shock game.
705 @item Smacker @tab @tab X
706 @tab Multimedia format used by many games.
707 @item GXF @tab @tab X
708 @end multitable
709
710 @code{X} means that encoding (resp. decoding) is supported.
711
712 @section Image Formats
713
714 FFmpeg can read and write images for each frame of a video sequence. The
715 following image formats are supported:
716
717 @multitable @columnfractions .4 .1 .1 .4
718 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
719 @item PGM, PPM @tab X @tab X
720 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
721 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
722 @item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
723 @item .Y.U.V @tab X @tab X @tab one raw file per component
724 @item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
725 @item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
726 @item SGI @tab X @tab X @tab SGI RGB image format
727 @end multitable
728
729 @code{X} means that encoding (resp. decoding) is supported.
730
731 @section Video Codecs
732
733 @multitable @columnfractions .4 .1 .1 .4
734 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
735 @item MPEG-1 video @tab X @tab X
736 @item MPEG-2 video @tab X @tab X
737 @item MPEG-4 @tab X @tab X @tab also known as DivX4/5
738 @item MSMPEG4 V1 @tab X @tab X
739 @item MSMPEG4 V2 @tab X @tab X
740 @item MSMPEG4 V3 @tab X @tab X @tab also known as DivX3
741 @item WMV7 @tab X @tab X
742 @item WMV8 @tab X @tab X @tab not completely working
743 @item H.261 @tab X @tab X
744 @item H.263(+) @tab X @tab X @tab also known as RealVideo 1.0
745 @item H.264 @tab @tab X
746 @item RealVideo 1.0 @tab X @tab X
747 @item RealVideo 2.0 @tab X @tab X
748 @item MJPEG @tab X @tab X
749 @item lossless MJPEG @tab X @tab X
750 @item JPEG-LS @tab X @tab X @tab fourcc: MJLS, lossless and near-lossless is supported
751 @item Apple MJPEG-B @tab @tab X
752 @item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
753 @item DV @tab X @tab X
754 @item HuffYUV @tab X @tab X
755 @item FFmpeg Video 1 @tab X @tab X @tab experimental lossless codec (fourcc: FFV1)
756 @item FFmpeg Snow @tab X @tab X @tab experimental wavelet codec (fourcc: SNOW)
757 @item Asus v1 @tab X @tab X @tab fourcc: ASV1
758 @item Asus v2 @tab X @tab X @tab fourcc: ASV2
759 @item Creative YUV @tab @tab X @tab fourcc: CYUV
760 @item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
761 @item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
762 @item On2 VP3 @tab @tab X @tab still experimental
763 @item Theora @tab @tab X @tab still experimental
764 @item Intel Indeo 3 @tab @tab X
765 @item FLV @tab X @tab X @tab Sorenson H.263 used in Flash
766 @item Flash Screen Video @tab @tab X @tab fourcc: FSV1
767 @item ATI VCR1 @tab @tab X @tab fourcc: VCR1
768 @item ATI VCR2 @tab @tab X @tab fourcc: VCR2
769 @item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
770 @item 4X Video @tab @tab X @tab Used in certain computer games.
771 @item Sony Playstation MDEC @tab @tab X
772 @item Id RoQ @tab @tab X @tab Used in Quake III, Jedi Knight 2, other computer games.
773 @item Xan/WC3 @tab @tab X @tab Used in Wing Commander III .MVE files.
774 @item Interplay Video @tab @tab X @tab Used in Interplay .MVE files.
775 @item Apple Animation @tab @tab X @tab fourcc: 'rle '
776 @item Apple Graphics @tab @tab X @tab fourcc: 'smc '
777 @item Apple Video @tab @tab X @tab fourcc: rpza
778 @item Apple QuickDraw @tab @tab X @tab fourcc: qdrw
779 @item Cinepak @tab @tab X
780 @item Microsoft RLE @tab @tab X
781 @item Microsoft Video-1 @tab @tab X
782 @item Westwood VQA @tab @tab X
783 @item Id Cinematic Video @tab @tab X @tab Used in Quake II.
784 @item Planar RGB @tab @tab X @tab fourcc: 8BPS
785 @item FLIC video @tab @tab X
786 @item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK
787 @item Duck TrueMotion v2 @tab @tab X @tab fourcc: TM20
788 @item VMD Video @tab @tab X @tab Used in Sierra VMD files.
789 @item MSZH @tab @tab X @tab Part of LCL
790 @item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental
791 @item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC
792 @item IBM Ultimotion @tab @tab X @tab fourcc: ULTI
793 @item Miro VideoXL @tab @tab X @tab fourcc: VIXL
794 @item QPEG @tab @tab X @tab fourccs: QPEG, Q1.0, Q1.1
795 @item LOCO @tab @tab X @tab
796 @item Winnov WNV1 @tab @tab X @tab
797 @item Autodesk Animator Studio Codec @tab @tab X @tab fourcc: AASC
798 @item Fraps FPS1 @tab @tab X @tab
799 @item CamStudio @tab @tab X @tab fourcc: CSCD
800 @item American Laser Games Video @tab @tab X @tab Used in games like Mad Dog McCree
801 @item ZMBV @tab @tab X @tab
802 @item AVS Video @tab @tab X @tab Video encoding used by the Creature Shock game.
803 @item Smacker Video @tab @tab X @tab Video encoding used in Smacker.
804 @item RTjpeg @tab @tab X @tab Video encoding used in NuppelVideo files.
805 @item KMVC @tab @tab X @tab Codec used in Worms games.
806 @end multitable
807
808 @code{X} means that encoding (resp. decoding) is supported.
809
810 See @url{http://mplayerhq.hu/~michael/codec-features.html} to
811 get a precise comparison of the FFmpeg MPEG-4 codec compared to
812 other implementations.
813
814 @section Audio Codecs
815
816 @multitable @columnfractions .4 .1 .1 .1 .7
817 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
818 @item MPEG audio layer 2 @tab IX @tab IX
819 @item MPEG audio layer 1/3 @tab IX @tab IX
820 @tab MP3 encoding is supported through the external library LAME.
821 @item AC3 @tab IX @tab IX
822 @tab liba52 is used internally for decoding.
823 @item Vorbis @tab X @tab X
824 @tab Supported through the external library libvorbis.
825 @item WMA V1/V2 @tab @tab X
826 @item AAC @tab X @tab X
827 @tab Supported through the external library libfaac/libfaad.
828 @item Microsoft ADPCM @tab X @tab X
829 @item MS IMA ADPCM @tab X @tab X
830 @item QT IMA ADPCM @tab @tab X
831 @item 4X IMA ADPCM @tab @tab X
832 @item G.726 ADPCM @tab X @tab X
833 @item Duck DK3 IMA ADPCM @tab @tab X
834 @tab Used in some Sega Saturn console games.
835 @item Duck DK4 IMA ADPCM @tab @tab X
836 @tab Used in some Sega Saturn console games.
837 @item Westwood Studios IMA ADPCM @tab @tab X
838 @tab Used in Westwood Studios games like Command and Conquer.
839 @item SMJPEG IMA ADPCM @tab @tab X
840 @tab Used in certain Loki game ports.
841 @item CD-ROM XA ADPCM @tab @tab X
842 @item CRI ADX ADPCM @tab X @tab X
843 @tab Used in Sega Dreamcast games.
844 @item Electronic Arts ADPCM @tab @tab X
845 @tab Used in various EA titles.
846 @item Creative ADPCM @tab @tab X
847 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
848 @item RA144 @tab @tab X
849 @tab Real 14400 bit/s codec
850 @item RA288 @tab @tab X
851 @tab Real 28800 bit/s codec
852 @item RADnet @tab X @tab IX
853 @tab Real low bitrate AC3 codec, liba52 is used for decoding.
854 @item AMR-NB @tab X @tab X
855 @tab Supported through an external library.
856 @item AMR-WB @tab X @tab X
857 @tab Supported through an external library.
858 @item DV audio @tab @tab X
859 @item Id RoQ DPCM @tab @tab X
860 @tab Used in Quake III, Jedi Knight 2, other computer games.
861 @item Interplay MVE DPCM @tab @tab X
862 @tab Used in various Interplay computer games.
863 @item Xan DPCM @tab @tab X
864 @tab Used in Origin's Wing Commander IV AVI files.
865 @item Sierra Online DPCM @tab @tab X
866 @tab Used in Sierra Online game audio files.
867 @item Apple MACE 3 @tab @tab X
868 @item Apple MACE 6 @tab @tab X
869 @item FLAC lossless audio @tab @tab X
870 @item Shorten lossless audio @tab @tab X
871 @item Apple lossless audio @tab @tab X
872 @tab QuickTime fourcc 'alac'
873 @item FFmpeg Sonic @tab X @tab X
874 @tab experimental lossy/lossless codec
875 @item Qdesign QDM2 @tab @tab X
876 @tab there are still some distortions
877 @item Real COOK @tab @tab X
878 @tab All versions except 5.1 are supported
879 @item DSP Group TrueSpeech @tab @tab X
880 @item True Audio (TTA) @tab @tab X
881 @item Smacker Audio @tab @tab X
882 @end multitable
883
884 @code{X} means that encoding (resp. decoding) is supported.
885
886 @code{I} means that an integer-only version is available, too (ensures high
887 performance on systems without hardware floating point support).
888
889 @chapter Platform Specific information
890
891 @section Linux
892
893 FFmpeg should be compiled with at least GCC 2.95.3. GCC 3.2 is the
894 preferred compiler now for FFmpeg. All future optimizations will depend on
895 features only found in GCC 3.2.
896
897 @section BSD
898
899 BSD make will not build FFmpeg, you need to install and use GNU Make
900 (@file{gmake}).
901
902 @section Windows
903
904 @subsection Native Windows compilation
905
906 @itemize
907 @item Install the current versions of MSYS and MinGW from
908 @url{http://www.mingw.org/}. You can find detailed installation
909 instructions in the download section and the FAQ.
910
911 @item If you want to test the FFplay, also download
912 the MinGW development library of SDL 1.2.x
913 (@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
914 @url{http://www.libsdl.org}. Unpack it in a temporary directory, and
915 unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
916 directory. Edit the @file{sdl-config} script so that it gives the
917 correct SDL directory when invoked.
918
919 @item Extract the current version of FFmpeg.
920
921 @item Start the MSYS shell (file @file{msys.bat}).
922
923 @item Change to the FFmpeg directory and follow
924 the instructions of how to compile FFmpeg (file
925 @file{INSTALL}). Usually, launching @file{./configure} and @file{make}
926 suffices. If you have problems using SDL, verify that
927 @file{sdl-config} can be launched from the MSYS command line.
928
929 @item You can install FFmpeg in @file{Program Files/FFmpeg} by typing
930 @file{make install}. Don't forget to copy @file{SDL.dll} to the place
931 you launch @file{ffplay} from.
932
933 @end itemize
934
935 Notes:
936 @itemize
937
938 @item The target @file{make wininstaller} can be used to create a
939 Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
940 must be copied to the FFmpeg directory in order to build the
941 installer.
942
943 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
944 you can build @file{avcodec.dll} and @file{avformat.dll}. With
945 @code{make install} you install the FFmpeg DLLs and the associated
946 headers in @file{Program Files/FFmpeg}.
947
948 @item Visual C++ compatibility: If you used @code{./configure --enable-shared}
949 when configuring FFmpeg, FFmpeg tries to use the Microsoft Visual
950 C++ @code{lib} tool to build @code{avcodec.lib} and
951 @code{avformat.lib}. With these libraries you can link your Visual C++
952 code directly with the FFmpeg DLLs (see below).
953
954 @end itemize
955
956 @subsection Visual C++ compatibility
957
958 FFmpeg will not compile under Visual C++ -- and it has too many
959 dependencies on the GCC compiler to make a port viable. However,
960 if you want to use the FFmpeg libraries in your own applications,
961 you can still compile those applications using Visual C++. An
962 important restriction to this is that you have to use the
963 dynamically linked versions of the FFmpeg libraries (i.e. the
964 DLLs), and you have to make sure that Visual-C++-compatible
965 import libraries are created during the FFmpeg build process.
966
967 This description of how to use the FFmpeg libraries with Visual C++ is
968 based on Visual C++ 2005 Express Edition Beta 2. If you have a different
969 version, you might have to modify the procedures slightly.
970
971 Here are the step-by-step instructions for building the FFmpeg libraries
972 so they can be used with Visual C++:
973
974 @enumerate
975
976 @item Install Visual C++ (if you haven't done so already).
977
978 @item Install MinGW and MSYS as described above.
979
980 @item Add a call to @file{vcvars32.bat} (which sets up the environment
981 variables for the Visual C++ tools) as the first line of
982 @file{msys.bat}. The standard location for @file{vcvars32.bat} is
983 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
984 and the standard location for @file{msys.bat} is
985 @file{C:\msys\1.0\msys.bat}. If this corresponds to your setup, add the
986 following line as the first line of @file{msys.bat}:
987
988 @code{call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"}
989
990 @item Start the MSYS shell (file @file{msys.bat}) and type @code{link.exe}.
991 If you get a help message with the command line options of @code{link.exe},
992 this means your environment variables are set up correctly, the
993 Microsoft linker is on the path and will be used by FFmpeg to
994 create Visual-C++-compatible import libraries.
995
996 @item Extract the current version of FFmpeg and change to the FFmpeg directory.
997
998 @item Type the command
999 @code{./configure --enable-shared --disable-static --enable-memalign-hack}
1000 to configure and, if that didn't produce any errors,
1001 type @code{make} to build FFmpeg.
1002
1003 @item The subdirectories @file{libavformat}, @file{libavcodec}, and
1004 @file{libavutil} should now contain the files @file{avformat.dll},
1005 @file{avformat.lib}, @file{avcodec.dll}, @file{avcodec.lib},
1006 @file{avutil.dll}, and @file{avutil.lib}, respectively. Copy the three
1007 DLLs to your System32 directory (typically @file{C:\Windows\System32}).
1008
1009 @end enumerate
1010
1011 And here is how to use these libraries with Visual C++:
1012
1013 @enumerate
1014
1015 @item Create a new console application ("File / New / Project") and then
1016 select "Win32 Console Application". On the appropriate page of the
1017 Application Wizard, uncheck the "Precompiled headers" option.
1018
1019 @item Write the source code for your application, or, for testing, just
1020 copy the code from an existing sample application into the source file
1021 that Visual C++ has already created for you. (Note that your source
1022 filehas to have a @code{.cpp} extension; otherwise, Visual C++ won't
1023 compile the FFmpeg headers correctly because in C mode, it doesn't
1024 recognize the @code{inline} keyword.) For example, you can copy
1025 @file{output_example.c} from the FFmpeg distribution (but you will
1026 have to make minor modifications so the code will compile under
1027 C++, see below).
1028
1029 @item Open the "Project / Properties" dialog box. In the "Configuration"
1030 combo box, select "All Configurations" so that the changes you make will
1031 affect both debug and release builds. In the tree view on the left hand
1032 side, select "C/C++ / General", then edit the "Additional Include
1033 Directories" setting to contain the complete paths to the
1034 @file{libavformat}, @file{libavcodec}, and @file{libavutil}
1035 subdirectories of your FFmpeg directory. Note that the directories have
1036 to be separated using semicolons. Now select "Linker / General" from the
1037 tree view and edit the "Additional Library Directories" setting to
1038 contain the same three directories.
1039
1040 @item Still in the "Project / Properties" dialog box, select "Linker / Input"
1041 from the tree view, then add the files @file{avformat.lib},
1042 @file{avcodec.lib}, and @file{avutil.lib} to the end of the "Additional
1043 Dependencies". Note that the names of the libraries have to be separated
1044 using spaces.
1045
1046 @item Now, select "C/C++ / Code Generation" from the tree view. Select
1047 "Debug" in the "Configuration" combo box. Make sure that "Runtime
1048 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
1049 the "Configuration" combo box and make sure that "Runtime Library" is
1050 set to "Multi-threaded DLL".
1051
1052 @item Click "OK" to close the "Project / Properties" dialog box and build
1053 the application. Hopefully, it should compile and run cleanly. If you
1054 used @file{output_example.c} as your sample application, you will get a
1055 few compiler errors, but they are easy to fix. The first type of error
1056 occurs because Visual C++ doesn't allow an @code{int} to be converted to
1057 an @code{enum} without a cast. To solve the problem, insert the required
1058 casts (this error occurs once for a @code{CodecID} and once for a
1059 @code{CodecType}). The second type of error occurs because C++ requires
1060 the return value of @code{malloc} to be cast to the exact type of the
1061 pointer it is being assigned to. Visual C++ will complain that, for
1062 example, @code{(void *)} is being assigned to @code{(uint8_t *)} without
1063 an explicit cast. So insert an explicit cast in these places to silence
1064 the compiler. The third type of error occurs because the @code{snprintf}
1065 library function is called @code{_snprintf} under Visual C++. So just
1066 add an underscore to fix the problem. With these changes,
1067 @file{output_example.c} should compile under Visual C++, and the
1068 resulting executable should produce valid video files.
1069
1070 @end enumerate
1071
1072 @subsection Cross compilation for Windows with Linux
1073
1074 You must use the MinGW cross compilation tools available at
1075 @url{http://www.mingw.org/}.
1076
1077 Then configure FFmpeg with the following options:
1078 @example
1079 ./configure --enable-mingw32 --cross-prefix=i386-mingw32msvc-
1080 @end example
1081 (you can change the cross-prefix according to the prefix chosen for the
1082 MinGW tools).
1083
1084 Then you can easily test FFmpeg with Wine
1085 (@url{http://www.winehq.com/}).
1086
1087 @subsection Compilation under Cygwin
1088
1089 Cygwin works very much like Unix.
1090
1091 Just install your Cygwin with all the "Base" packages, plus the
1092 following "Devel" ones:
1093 @example
1094 binutils, gcc-core, make, subversion
1095 @end example
1096
1097 Do not install binutils-20060709-1 (they are buggy on shared builds);
1098 use binutils-20050610-1 instead.
1099
1100 Then run
1101
1102 @example
1103 ./configure --enable-static --disable-shared
1104 @end example
1105
1106 to make a static build or
1107
1108 @example
1109 ./configure --enable-shared --disable-static
1110 @end example
1111
1112 to build shared libraries.
1113
1114 If you want to build FFmpeg with additional libraries, download Cygwin
1115 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository
1116 and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
1117 (@url{http://cygwinports.dotsrc.org/}).
1118
1119 @subsection Crosscompilation for Windows under Cygwin
1120
1121 With Cygwin you can create Windows binaries that don't need the cygwin1.dll.
1122
1123 Just install your Cygwin as explained before, plus these additional
1124 "Devel" packages:
1125 @example
1126 gcc-mingw-core, mingw-runtime, mingw-zlib
1127 @end example
1128
1129 and add some special flags to your configure invocation.
1130
1131 For a static build run
1132 @example
1133 ./configure --enable-mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
1134 @end example
1135
1136 and for a build with shared libraries
1137 @example
1138 ./configure --enable-mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
1139 @end example
1140
1141 @section Mac OS X
1142
1143 @section BeOS
1144
1145 The configure script should guess the configuration itself.
1146 Networking support is currently not finished.
1147 errno issues fixed by Andrew Bachmann.
1148
1149 Old stuff:
1150
1151 Fran├žois Revol - revol at free dot fr - April 2002
1152
1153 The configure script should guess the configuration itself,
1154 however I still didn't test building on the net_server version of BeOS.
1155
1156 FFserver is broken (needs poll() implementation).
1157
1158 There are still issues with errno codes, which are negative in BeOS, and
1159 that FFmpeg negates when returning. This ends up turning errors into
1160 valid results, then crashes.
1161 (To be fixed)
1162
1163 @chapter Developers Guide
1164
1165 @section API
1166 @itemize @bullet
1167 @item libavcodec is the library containing the codecs (both encoding and
1168 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
1169
1170 @item libavformat is the library containing the file format handling (mux and
1171 demux code for several formats). Look at @file{ffplay.c} to use it in a
1172 player. See @file{output_example.c} to use it to generate audio or video
1173 streams.
1174
1175 @end itemize
1176
1177 @section Integrating libavcodec or libavformat in your program
1178
1179 You can integrate all the source code of the libraries to link them
1180 statically to avoid any version problem. All you need is to provide a
1181 'config.mak' and a 'config.h' in the parent directory. See the defines
1182 generated by ./configure to understand what is needed.
1183
1184 You can use libavcodec or libavformat in your commercial program, but
1185 @emph{any patch you make must be published}. The best way to proceed is
1186 to send your patches to the FFmpeg mailing list.
1187
1188 @node Coding Rules
1189 @section Coding Rules
1190
1191 FFmpeg is programmed in the ISO C90 language with a few additional
1192 features from ISO C99, namely:
1193 @itemize @bullet
1194 @item
1195 the @samp{inline} keyword;
1196 @item
1197 @samp{//} comments;
1198 @item
1199 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
1200 @item
1201 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
1202 @end itemize
1203
1204 These features are supported by all compilers we care about, so we won't
1205 accept patches to remove their use unless they absolutely don't impair
1206 clarity and performance.
1207
1208 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
1209 compiles with several other compilers, such as the Compaq ccc compiler
1210 or Sun Studio 9, and we would like to keep it that way unless it would
1211 be exceedingly involved. To ensure compatibility, please don't use any
1212 additional C99 features or GCC extensions. Especially watch out for:
1213 @itemize @bullet
1214 @item
1215 mixing statements and declarations;
1216 @item
1217 @samp{long long} (use @samp{int64_t} instead);
1218 @item
1219 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
1220 @item
1221 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
1222 @end itemize
1223
1224 Indent size is 4.
1225 The presentation is the one specified by 'indent -i4 -kr -nut'.
1226 The TAB character is forbidden outside of Makefiles as is any
1227 form of trailing whitespace. Commits containing either will be
1228 rejected by the Subversion repository.
1229
1230 Main priority in FFmpeg is simplicity and small code size (=less
1231 bugs).
1232
1233 Comments: Use the JavaDoc/Doxygen
1234 format (see examples below) so that code documentation
1235 can be generated automatically. All nontrivial functions should have a comment
1236 above them explaining what the function does, even if it's just one sentence.
1237 All structures and their member variables should be documented, too.
1238 @example
1239 /**
1240 * @@file mpeg.c
1241 * MPEG codec.
1242 * @@author ...
1243 */
1244
1245 /**
1246 * Summary sentence.
1247 * more text ...
1248 * ...
1249 */
1250 typedef struct Foobar@{
1251 int var1; /**< var1 description */
1252 int var2; ///< var2 description
1253 /** var3 description */
1254 int var3;
1255 @} Foobar;
1256
1257 /**
1258 * Summary sentence.
1259 * more text ...
1260 * ...
1261 * @@param my_parameter description of my_parameter
1262 * @@return return value description
1263 */
1264 int myfunc(int my_parameter)
1265 ...
1266 @end example
1267
1268 fprintf and printf are forbidden in libavformat and libavcodec,
1269 please use av_log() instead.
1270
1271 @section Development Policy
1272
1273 @enumerate
1274 @item
1275 You must not commit code which breaks FFmpeg! (Meaning unfinished but
1276 enabled code which breaks compilation or compiles but does not work or
1277 breaks the regression tests)
1278 You can commit unfinished stuff (for testing etc), but it must be disabled
1279 (#ifdef etc) by default so it does not interfere with other developers'
1280 work.
1281 @item
1282 You don't have to over-test things. If it works for you, and you think it
1283 should work for others, then commit. If your code has problems
1284 (portability, triggers compiler bugs, unusual environment etc) they will be
1285 reported and eventually fixed.
1286 @item
1287 Do not commit unrelated changes together, split them into self-contained
1288 pieces.
1289 @item
1290 Do not change behavior of the program (renaming options etc) without
1291 first discussing it on the ffmpeg-devel mailing list. Do not remove
1292 functionality from the code. Just improve!
1293
1294 Note: Redundant code can be removed.
1295 @item
1296 Do not commit changes to the build system (Makefiles, configure script)
1297 which change behavior, defaults etc, without asking first. The same
1298 applies to compiler warning fixes, trivial looking fixes and to code
1299 maintained by other developers. We usually have a reason for doing things
1300 the way we do. Send your changes as patches to the ffmpeg-devel mailing
1301 list, and if the code maintainers say OK, you may commit. This does not
1302 apply to files you wrote and/or maintain.
1303 @item
1304 We refuse source indentation and other cosmetic changes if they are mixed
1305 with functional changes, such commits will be rejected and removed. Every
1306 developer has his own indentation style, you should not change it. Of course
1307 if you (re)write something, you can use your own style, even though we would
1308 prefer if the indentation throughout FFmpeg was consistent (Many projects
1309 force a given indentation style - we don't.). If you really need to make
1310 indentation changes (try to avoid this), separate them strictly from real
1311 changes.
1312
1313 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
1314 then either do NOT change the indentation of the inner part within (don't
1315 move it to the right)! or do so in a separate commit
1316 @item
1317 Always fill out the commit log message. Describe in a few lines what you
1318 changed and why. You can refer to mailing list postings if you fix a
1319 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1320 @item
1321 If you apply a patch by someone else, include the name and email address in
1322 the log message. Since the ffmpeg-cvslog mailing list is publicly
1323 archived you should add some SPAM protection to the email address. Send an
1324 answer to ffmpeg-devel (or wherever you got the patch from) saying that
1325 you applied the patch.
1326 @item
1327 Do NOT commit to code actively maintained by others without permission.
1328 Send a patch to ffmpeg-devel instead. If noone answers within a reasonable
1329 timeframe (12h for build failures and security fixes, 3 days small changes,
1330 1 week for big patches) then commit your patch if you think it's OK.
1331 Also note, the maintainer can simply ask for more time to review!
1332 @item
1333 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
1334 are sent there and reviewed by all the other developers. Bugs and possible
1335 improvements or general questions regarding commits are discussed there. We
1336 expect you to react if problems with your code are uncovered.
1337 @item
1338 Update the documentation if you change behavior or add features. If you are
1339 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
1340 maintainer(s) will review and commit your stuff.
1341 @item
1342 Never write to unallocated memory, never write over the end of arrays,
1343 always check values read from some untrusted source before using them
1344 as array index or other risky things.
1345 @item
1346 Remember to check if you need to bump versions for the specific libav
1347 parts (libavutil, libavcodec, libavformat) you are changing. You need
1348 to change the version integer and the version string.
1349 Incrementing the first component means no backward compatibility to
1350 previous versions (e.g. removal of a function).
1351 Incrementing the second component means backward compatible change
1352 (e.g. addition of a function).
1353 Incrementing the third component means a noteworthy binary compatible
1354 change (e.g. encoder bug fix that matters for the decoder).
1355 @item
1356 If you add a new codec, remember to update the changelog, add it to
1357 the supported codecs table in the documentation and bump the second
1358 component of the @file{libavcodec} version number appropriately. If
1359 it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
1360 is only a decoder.
1361 @end enumerate
1362
1363 We think our rules are not too hard. If you have comments, contact us.
1364
1365 Note, these rules are mostly borrowed from the MPlayer project.
1366
1367 @section Submitting patches
1368
1369 First, (@pxref{Coding Rules}) above if you didn't yet.
1370
1371 When you submit your patch, try to send a unified diff (diff '-up'
1372 option). I cannot read other diffs :-)
1373
1374 Also please do not submit patches which contain several unrelated changes.
1375 Split them into individual self-contained patches; this makes reviewing
1376 them much easier.
1377
1378 Run the regression tests before submitting a patch so that you can
1379 verify that there are no big problems.
1380
1381 Patches should be posted as base64 encoded attachments (or any other
1382 encoding which ensures that the patch won't be trashed during
1383 transmission) to the ffmpeg-devel mailing list, see
1384 @url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
1385
1386 It also helps quite a bit if you tell us what the patch does (for example
1387 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
1388 and has no lrint()')
1389
1390 We reply to all submitted patches and either apply or reject with some
1391 explanation why, but sometimes we are quite busy so it can take a week or two.
1392
1393 @section Regression tests
1394
1395 Before submitting a patch (or committing to the repository), you should at least
1396 test that you did not break anything.
1397
1398 The regression tests build a synthetic video stream and a synthetic
1399 audio stream. These are then encoded and decoded with all codecs or
1400 formats. The CRC (or MD5) of each generated file is recorded in a
1401 result file. A 'diff' is launched to compare the reference results and
1402 the result file.
1403
1404 The regression tests then go on to test the FFserver code with a
1405 limited set of streams. It is important that this step runs correctly
1406 as well.
1407
1408 Run 'make test' to test all the codecs and formats.
1409
1410 Run 'make fulltest' to test all the codecs, formats and FFserver.
1411
1412 [Of course, some patches may change the results of the regression tests. In
1413 this case, the reference results of the regression tests shall be modified
1414 accordingly].
1415
1416 @bye