NuppelVideo/MythTVVideo support, including rtjpeg decoder
[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 @end multitable
708
709 @code{X} means that encoding (resp. decoding) is supported.
710
711 @section Image Formats
712
713 FFmpeg can read and write images for each frame of a video sequence. The
714 following image formats are supported:
715
716 @multitable @columnfractions .4 .1 .1 .4
717 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
718 @item PGM, PPM @tab X @tab X
719 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
720 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
721 @item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
722 @item .Y.U.V @tab X @tab X @tab one raw file per component
723 @item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
724 @item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
725 @item SGI @tab X @tab X @tab SGI RGB image format
726 @end multitable
727
728 @code{X} means that encoding (resp. decoding) is supported.
729
730 @section Video Codecs
731
732 @multitable @columnfractions .4 .1 .1 .4
733 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
734 @item MPEG-1 video @tab X @tab X
735 @item MPEG-2 video @tab X @tab X
736 @item MPEG-4 @tab X @tab X @tab also known as DivX4/5
737 @item MSMPEG4 V1 @tab X @tab X
738 @item MSMPEG4 V2 @tab X @tab X
739 @item MSMPEG4 V3 @tab X @tab X @tab also known as DivX3
740 @item WMV7 @tab X @tab X
741 @item WMV8 @tab X @tab X @tab not completely working
742 @item H.261 @tab X @tab X
743 @item H.263(+) @tab X @tab X @tab also known as RealVideo 1.0
744 @item H.264 @tab @tab X
745 @item RealVideo 1.0 @tab X @tab X
746 @item RealVideo 2.0 @tab X @tab X
747 @item MJPEG @tab X @tab X
748 @item lossless MJPEG @tab X @tab X
749 @item JPEG-LS @tab X @tab X @tab fourcc: MJLS, lossless and near-lossless is supported
750 @item Apple MJPEG-B @tab @tab X
751 @item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
752 @item DV @tab X @tab X
753 @item HuffYUV @tab X @tab X
754 @item FFmpeg Video 1 @tab X @tab X @tab experimental lossless codec (fourcc: FFV1)
755 @item FFmpeg Snow @tab X @tab X @tab experimental wavelet codec (fourcc: SNOW)
756 @item Asus v1 @tab X @tab X @tab fourcc: ASV1
757 @item Asus v2 @tab X @tab X @tab fourcc: ASV2
758 @item Creative YUV @tab @tab X @tab fourcc: CYUV
759 @item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
760 @item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
761 @item On2 VP3 @tab @tab X @tab still experimental
762 @item Theora @tab @tab X @tab still experimental
763 @item Intel Indeo 3 @tab @tab X
764 @item FLV @tab X @tab X @tab Sorenson H.263 used in Flash
765 @item ATI VCR1 @tab @tab X @tab fourcc: VCR1
766 @item ATI VCR2 @tab @tab X @tab fourcc: VCR2
767 @item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
768 @item 4X Video @tab @tab X @tab Used in certain computer games.
769 @item Sony Playstation MDEC @tab @tab X
770 @item Id RoQ @tab @tab X @tab Used in Quake III, Jedi Knight 2, other computer games.
771 @item Xan/WC3 @tab @tab X @tab Used in Wing Commander III .MVE files.
772 @item Interplay Video @tab @tab X @tab Used in Interplay .MVE files.
773 @item Apple Animation @tab @tab X @tab fourcc: 'rle '
774 @item Apple Graphics @tab @tab X @tab fourcc: 'smc '
775 @item Apple Video @tab @tab X @tab fourcc: rpza
776 @item Apple QuickDraw @tab @tab X @tab fourcc: qdrw
777 @item Cinepak @tab @tab X
778 @item Microsoft RLE @tab @tab X
779 @item Microsoft Video-1 @tab @tab X
780 @item Westwood VQA @tab @tab X
781 @item Id Cinematic Video @tab @tab X @tab Used in Quake II.
782 @item Planar RGB @tab @tab X @tab fourcc: 8BPS
783 @item FLIC video @tab @tab X
784 @item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK
785 @item Duck TrueMotion v2 @tab @tab X @tab fourcc: TM20
786 @item VMD Video @tab @tab X @tab Used in Sierra VMD files.
787 @item MSZH @tab @tab X @tab Part of LCL
788 @item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental
789 @item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC
790 @item IBM Ultimotion @tab @tab X @tab fourcc: ULTI
791 @item Miro VideoXL @tab @tab X @tab fourcc: VIXL
792 @item QPEG @tab @tab X @tab fourccs: QPEG, Q1.0, Q1.1
793 @item LOCO @tab @tab X @tab
794 @item Winnov WNV1 @tab @tab X @tab
795 @item Autodesk Animator Studio Codec @tab @tab X @tab fourcc: AASC
796 @item Fraps FPS1 @tab @tab X @tab
797 @item CamStudio @tab @tab X @tab fourcc: CSCD
798 @item American Laser Games Video @tab @tab X @tab Used in games like Mad Dog McCree
799 @item ZMBV @tab @tab X @tab
800 @item AVS Video @tab @tab X @tab Video encoding used by the Creature Shock game.
801 @item Smacker Video @tab @tab X @tab Video encoding used in Smacker.
802 @item RTjpeg @tab @tab X @tab Video encoding used in NuppelVideo files.
803 @end multitable
804
805 @code{X} means that encoding (resp. decoding) is supported.
806
807 See @url{http://mplayerhq.hu/~michael/codec-features.html} to
808 get a precise comparison of the FFmpeg MPEG-4 codec compared to
809 other implementations.
810
811 @section Audio Codecs
812
813 @multitable @columnfractions .4 .1 .1 .1 .7
814 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
815 @item MPEG audio layer 2 @tab IX @tab IX
816 @item MPEG audio layer 1/3 @tab IX @tab IX
817 @tab MP3 encoding is supported through the external library LAME.
818 @item AC3 @tab IX @tab IX
819 @tab liba52 is used internally for decoding.
820 @item Vorbis @tab X @tab X
821 @tab Supported through the external library libvorbis.
822 @item WMA V1/V2 @tab @tab X
823 @item AAC @tab X @tab X
824 @tab Supported through the external library libfaac/libfaad.
825 @item Microsoft ADPCM @tab X @tab X
826 @item MS IMA ADPCM @tab X @tab X
827 @item QT IMA ADPCM @tab @tab X
828 @item 4X IMA ADPCM @tab @tab X
829 @item G.726 ADPCM @tab X @tab X
830 @item Duck DK3 IMA ADPCM @tab @tab X
831 @tab Used in some Sega Saturn console games.
832 @item Duck DK4 IMA ADPCM @tab @tab X
833 @tab Used in some Sega Saturn console games.
834 @item Westwood Studios IMA ADPCM @tab @tab X
835 @tab Used in Westwood Studios games like Command and Conquer.
836 @item SMJPEG IMA ADPCM @tab @tab X
837 @tab Used in certain Loki game ports.
838 @item CD-ROM XA ADPCM @tab @tab X
839 @item CRI ADX ADPCM @tab X @tab X
840 @tab Used in Sega Dreamcast games.
841 @item Electronic Arts ADPCM @tab @tab X
842 @tab Used in various EA titles.
843 @item Creative ADPCM @tab @tab X
844 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
845 @item RA144 @tab @tab X
846 @tab Real 14400 bit/s codec
847 @item RA288 @tab @tab X
848 @tab Real 28800 bit/s codec
849 @item RADnet @tab X @tab IX
850 @tab Real low bitrate AC3 codec, liba52 is used for decoding.
851 @item AMR-NB @tab X @tab X
852 @tab Supported through an external library.
853 @item AMR-WB @tab X @tab X
854 @tab Supported through an external library.
855 @item DV audio @tab @tab X
856 @item Id RoQ DPCM @tab @tab X
857 @tab Used in Quake III, Jedi Knight 2, other computer games.
858 @item Interplay MVE DPCM @tab @tab X
859 @tab Used in various Interplay computer games.
860 @item Xan DPCM @tab @tab X
861 @tab Used in Origin's Wing Commander IV AVI files.
862 @item Sierra Online DPCM @tab @tab X
863 @tab Used in Sierra Online game audio files.
864 @item Apple MACE 3 @tab @tab X
865 @item Apple MACE 6 @tab @tab X
866 @item FLAC lossless audio @tab @tab X
867 @item Shorten lossless audio @tab @tab X
868 @item Apple lossless audio @tab @tab X
869 @tab QuickTime fourcc 'alac'
870 @item FFmpeg Sonic @tab X @tab X
871 @tab experimental lossy/lossless codec
872 @item Qdesign QDM2 @tab @tab X
873 @tab there are still some distortions
874 @item Real COOK @tab @tab X
875 @tab All versions except 5.1 are supported
876 @item DSP Group TrueSpeech @tab @tab X
877 @item True Audio (TTA) @tab @tab X
878 @item Smacker Audio @tab @tab X
879 @end multitable
880
881 @code{X} means that encoding (resp. decoding) is supported.
882
883 @code{I} means that an integer-only version is available, too (ensures high
884 performance on systems without hardware floating point support).
885
886 @chapter Platform Specific information
887
888 @section Linux
889
890 FFmpeg should be compiled with at least GCC 2.95.3. GCC 3.2 is the
891 preferred compiler now for FFmpeg. All future optimizations will depend on
892 features only found in GCC 3.2.
893
894 @section BSD
895
896 BSD make will not build FFmpeg, you need to install and use GNU Make
897 (@file{gmake}).
898
899 @section Windows
900
901 @subsection Native Windows compilation
902
903 @itemize
904 @item Install the current versions of MSYS and MinGW from
905 @url{http://www.mingw.org/}. You can find detailed installation
906 instructions in the download section and the FAQ.
907
908 @item If you want to test the FFplay, also download
909 the MinGW development library of SDL 1.2.x
910 (@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
911 @url{http://www.libsdl.org}. Unpack it in a temporary directory, and
912 unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
913 directory. Edit the @file{sdl-config} script so that it gives the
914 correct SDL directory when invoked.
915
916 @item Extract the current version of FFmpeg.
917
918 @item Start the MSYS shell (file @file{msys.bat}).
919
920 @item Change to the FFmpeg directory and follow
921 the instructions of how to compile FFmpeg (file
922 @file{INSTALL}). Usually, launching @file{./configure} and @file{make}
923 suffices. If you have problems using SDL, verify that
924 @file{sdl-config} can be launched from the MSYS command line.
925
926 @item You can install FFmpeg in @file{Program Files/FFmpeg} by typing
927 @file{make install}. Don't forget to copy @file{SDL.dll} to the place
928 you launch @file{ffplay} from.
929
930 @end itemize
931
932 Notes:
933 @itemize
934
935 @item The target @file{make wininstaller} can be used to create a
936 Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
937 must be copied to the FFmpeg directory in order to build the
938 installer.
939
940 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
941 you can build @file{avcodec.dll} and @file{avformat.dll}. With
942 @code{make install} you install the FFmpeg DLLs and the associated
943 headers in @file{Program Files/FFmpeg}.
944
945 @item Visual C++ compatibility: If you used @code{./configure --enable-shared}
946 when configuring FFmpeg, FFmpeg tries to use the Microsoft Visual
947 C++ @code{lib} tool to build @code{avcodec.lib} and
948 @code{avformat.lib}. With these libraries you can link your Visual C++
949 code directly with the FFmpeg DLLs (see below).
950
951 @end itemize
952
953 @subsection Visual C++ compatibility
954
955 FFmpeg will not compile under Visual C++ -- and it has too many
956 dependencies on the GCC compiler to make a port viable. However,
957 if you want to use the FFmpeg libraries in your own applications,
958 you can still compile those applications using Visual C++. An
959 important restriction to this is that you have to use the
960 dynamically linked versions of the FFmpeg libraries (i.e. the
961 DLLs), and you have to make sure that Visual-C++-compatible
962 import libraries are created during the FFmpeg build process.
963
964 This description of how to use the FFmpeg libraries with Visual C++ is
965 based on Visual C++ 2005 Express Edition Beta 2. If you have a different
966 version, you might have to modify the procedures slightly.
967
968 Here are the step-by-step instructions for building the FFmpeg libraries
969 so they can be used with Visual C++:
970
971 @enumerate
972
973 @item Install Visual C++ (if you haven't done so already).
974
975 @item Install MinGW and MSYS as described above.
976
977 @item Add a call to @file{vcvars32.bat} (which sets up the environment
978 variables for the Visual C++ tools) as the first line of
979 @file{msys.bat}. The standard location for @file{vcvars32.bat} is
980 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
981 and the standard location for @file{msys.bat} is
982 @file{C:\msys\1.0\msys.bat}. If this corresponds to your setup, add the
983 following line as the first line of @file{msys.bat}:
984
985 @code{call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"}
986
987 @item Start the MSYS shell (file @file{msys.bat}) and type @code{link.exe}.
988 If you get a help message with the command line options of @code{link.exe},
989 this means your environment variables are set up correctly, the
990 Microsoft linker is on the path and will be used by FFmpeg to
991 create Visual-C++-compatible import libraries.
992
993 @item Extract the current version of FFmpeg and change to the FFmpeg directory.
994
995 @item Type the command
996 @code{./configure --enable-shared --disable-static --enable-memalign-hack}
997 to configure and, if that didn't produce any errors,
998 type @code{make} to build FFmpeg.
999
1000 @item The subdirectories @file{libavformat}, @file{libavcodec}, and
1001 @file{libavutil} should now contain the files @file{avformat.dll},
1002 @file{avformat.lib}, @file{avcodec.dll}, @file{avcodec.lib},
1003 @file{avutil.dll}, and @file{avutil.lib}, respectively. Copy the three
1004 DLLs to your System32 directory (typically @file{C:\Windows\System32}).
1005
1006 @end enumerate
1007
1008 And here is how to use these libraries with Visual C++:
1009
1010 @enumerate
1011
1012 @item Create a new console application ("File / New / Project") and then
1013 select "Win32 Console Application". On the appropriate page of the
1014 Application Wizard, uncheck the "Precompiled headers" option.
1015
1016 @item Write the source code for your application, or, for testing, just
1017 copy the code from an existing sample application into the source file
1018 that Visual C++ has already created for you. (Note that your source
1019 filehas to have a @code{.cpp} extension; otherwise, Visual C++ won't
1020 compile the FFmpeg headers correctly because in C mode, it doesn't
1021 recognize the @code{inline} keyword.) For example, you can copy
1022 @file{output_example.c} from the FFmpeg distribution (but you will
1023 have to make minor modifications so the code will compile under
1024 C++, see below).
1025
1026 @item Open the "Project / Properties" dialog box. In the "Configuration"
1027 combo box, select "All Configurations" so that the changes you make will
1028 affect both debug and release builds. In the tree view on the left hand
1029 side, select "C/C++ / General", then edit the "Additional Include
1030 Directories" setting to contain the complete paths to the
1031 @file{libavformat}, @file{libavcodec}, and @file{libavutil}
1032 subdirectories of your FFmpeg directory. Note that the directories have
1033 to be separated using semicolons. Now select "Linker / General" from the
1034 tree view and edit the "Additional Library Directories" setting to
1035 contain the same three directories.
1036
1037 @item Still in the "Project / Properties" dialog box, select "Linker / Input"
1038 from the tree view, then add the files @file{avformat.lib},
1039 @file{avcodec.lib}, and @file{avutil.lib} to the end of the "Additional
1040 Dependencies". Note that the names of the libraries have to be separated
1041 using spaces.
1042
1043 @item Now, select "C/C++ / Code Generation" from the tree view. Select
1044 "Debug" in the "Configuration" combo box. Make sure that "Runtime
1045 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
1046 the "Configuration" combo box and make sure that "Runtime Library" is
1047 set to "Multi-threaded DLL".
1048
1049 @item Click "OK" to close the "Project / Properties" dialog box and build
1050 the application. Hopefully, it should compile and run cleanly. If you
1051 used @file{output_example.c} as your sample application, you will get a
1052 few compiler errors, but they are easy to fix. The first type of error
1053 occurs because Visual C++ doesn't allow an @code{int} to be converted to
1054 an @code{enum} without a cast. To solve the problem, insert the required
1055 casts (this error occurs once for a @code{CodecID} and once for a
1056 @code{CodecType}). The second type of error occurs because C++ requires
1057 the return value of @code{malloc} to be cast to the exact type of the
1058 pointer it is being assigned to. Visual C++ will complain that, for
1059 example, @code{(void *)} is being assigned to @code{(uint8_t *)} without
1060 an explicit cast. So insert an explicit cast in these places to silence
1061 the compiler. The third type of error occurs because the @code{snprintf}
1062 library function is called @code{_snprintf} under Visual C++. So just
1063 add an underscore to fix the problem. With these changes,
1064 @file{output_example.c} should compile under Visual C++, and the
1065 resulting executable should produce valid video files.
1066
1067 @end enumerate
1068
1069 @subsection Cross compilation for Windows with Linux
1070
1071 You must use the MinGW cross compilation tools available at
1072 @url{http://www.mingw.org/}.
1073
1074 Then configure FFmpeg with the following options:
1075 @example
1076 ./configure --enable-mingw32 --cross-prefix=i386-mingw32msvc-
1077 @end example
1078 (you can change the cross-prefix according to the prefix chosen for the
1079 MinGW tools).
1080
1081 Then you can easily test FFmpeg with Wine
1082 (@url{http://www.winehq.com/}).
1083
1084 @section Mac OS X
1085
1086 @section BeOS
1087
1088 The configure script should guess the configuration itself.
1089 Networking support is currently not finished.
1090 errno issues fixed by Andrew Bachmann.
1091
1092 Old stuff:
1093
1094 Fran├žois Revol - revol at free dot fr - April 2002
1095
1096 The configure script should guess the configuration itself,
1097 however I still didn't test building on the net_server version of BeOS.
1098
1099 FFserver is broken (needs poll() implementation).
1100
1101 There are still issues with errno codes, which are negative in BeOS, and
1102 that FFmpeg negates when returning. This ends up turning errors into
1103 valid results, then crashes.
1104 (To be fixed)
1105
1106 @chapter Developers Guide
1107
1108 @section API
1109 @itemize
1110 @item libavcodec is the library containing the codecs (both encoding and
1111 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
1112
1113 @item libavformat is the library containing the file format handling (mux and
1114 demux code for several formats). Look at @file{ffplay.c} to use it in a
1115 player. See @file{output_example.c} to use it to generate audio or video
1116 streams.
1117
1118 @end itemize
1119
1120 @section Integrating libavcodec or libavformat in your program
1121
1122 You can integrate all the source code of the libraries to link them
1123 statically to avoid any version problem. All you need is to provide a
1124 'config.mak' and a 'config.h' in the parent directory. See the defines
1125 generated by ./configure to understand what is needed.
1126
1127 You can use libavcodec or libavformat in your commercial program, but
1128 @emph{any patch you make must be published}. The best way to proceed is
1129 to send your patches to the FFmpeg mailing list.
1130
1131 @node Coding Rules
1132 @section Coding Rules
1133
1134 FFmpeg is programmed in the ISO C90 language with a few additional
1135 features from ISO C99, namely:
1136 @itemize @bullet
1137 @item
1138 the @samp{inline} keyword;
1139 @item
1140 @samp{//} comments;
1141 @item
1142 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
1143 @item
1144 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
1145 @end itemize
1146
1147 These features are supported by all compilers we care about, so we won't
1148 accept patches to remove their use unless they absolutely don't impair
1149 clarity and performance.
1150
1151 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
1152 compiles with several other compilers, such as the Compaq ccc compiler
1153 or Sun Studio 9, and we would like to keep it that way unless it would
1154 be exceedingly involved. To ensure compatibility, please don't use any
1155 additional C99 features or GCC extensions. Especially watch out for:
1156 @itemize @bullet
1157 @item
1158 mixing statements and declarations;
1159 @item
1160 @samp{long long} (use @samp{int64_t} instead);
1161 @item
1162 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
1163 @item
1164 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
1165 @end itemize
1166
1167 Indent size is 4.
1168 The presentation is the one specified by 'indent -i4 -kr -nut'.
1169 The TAB character is forbidden outside of Makefiles as is any
1170 form of trailing whitespace. Commits containing either will be
1171 rejected by the CVS repository.
1172
1173 Main priority in FFmpeg is simplicity and small code size (=less
1174 bugs).
1175
1176 Comments: Use the JavaDoc/Doxygen
1177 format (see examples below) so that code documentation
1178 can be generated automatically. All nontrivial functions should have a comment
1179 above them explaining what the function does, even if it's just one sentence.
1180 All structures and their member variables should be documented, too.
1181 @example
1182 /**
1183 * @@file mpeg.c
1184 * MPEG codec.
1185 * @@author ...
1186 */
1187
1188 /**
1189 * Summary sentence.
1190 * more text ...
1191 * ...
1192 */
1193 typedef struct Foobar@{
1194 int var1; /**< var1 description */
1195 int var2; ///< var2 description
1196 /** var3 description */
1197 int var3;
1198 @} Foobar;
1199
1200 /**
1201 * Summary sentence.
1202 * more text ...
1203 * ...
1204 * @@param my_parameter description of my_parameter
1205 * @@return return value description
1206 */
1207 int myfunc(int my_parameter)
1208 ...
1209 @end example
1210
1211 fprintf and printf are forbidden in libavformat and libavcodec,
1212 please use av_log() instead.
1213
1214 @node CVS Policy
1215 @section CVS Policy
1216
1217 @enumerate
1218 @item
1219 You must not commit code which breaks FFmpeg! (Meaning unfinished but
1220 enabled code which breaks compilation or compiles but does not work or
1221 breaks the regression tests)
1222 You can commit unfinished stuff (for testing etc), but it must be disabled
1223 (#ifdef etc) by default so it does not interfere with other developers'
1224 work.
1225 @item
1226 You don't have to over-test things. If it works for you, and you think it
1227 should work for others, then commit. If your code has problems
1228 (portability, triggers compiler bugs, unusual environment etc) they will be
1229 reported and eventually fixed.
1230 @item
1231 Do not commit unrelated changes together, split them into self-contained
1232 pieces.
1233 @item
1234 Do not change behavior of the program (renaming options etc) without
1235 first discussing it on the ffmpeg-devel mailing list. Do not remove
1236 functionality from the code. Just improve!
1237
1238 Note: Redundant code can be removed.
1239 @item
1240 Do not commit changes to the build system (Makefiles, configure script)
1241 which change behavior, defaults etc, without asking first. The same
1242 applies to compiler warning fixes, trivial looking fixes and to code
1243 maintained by other developers. We usually have a reason for doing things
1244 the way we do. Send your changes as patches to the ffmpeg-devel mailing
1245 list, and if the code maintainers say OK, you may commit. This does not
1246 apply to files you wrote and/or maintain.
1247 @item
1248 We refuse source indentation and other cosmetic changes if they are mixed
1249 with functional changes, such commits will be rejected and removed. Every
1250 developer has his own indentation style, you should not change it. Of course
1251 if you (re)write something, you can use your own style, even though we would
1252 prefer if the indentation throughout FFmpeg was consistent (Many projects
1253 force a given indentation style - we don't.). If you really need to make
1254 indentation changes (try to avoid this), separate them strictly from real
1255 changes.
1256
1257 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
1258 then either do NOT change the indentation of the inner part within (don't
1259 move it to the right)! or do so in a separate commit
1260 @item
1261 Always fill out the commit log message. Describe in a few lines what you
1262 changed and why. You can refer to mailing list postings if you fix a
1263 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1264 @item
1265 If you apply a patch by someone else, include the name and email address in
1266 the CVS log message. Since the ffmpeg-cvslog mailing list is publicly
1267 archived you should add some SPAM protection to the email address. Send an
1268 answer to ffmpeg-devel (or wherever you got the patch from) saying that
1269 you applied the patch.
1270 @item
1271 Do NOT commit to code actively maintained by others without permission. Send
1272 a patch to ffmpeg-devel instead.
1273 @item
1274 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all CVS commits
1275 are sent there and reviewed by all the other developers. Bugs and possible
1276 improvements or general questions regarding commits are discussed there. We
1277 expect you to react if problems with your code are uncovered.
1278 @item
1279 Update the documentation if you change behavior or add features. If you are
1280 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
1281 maintainer(s) will review and commit your stuff.
1282 @item
1283 Revert a commit ONLY in case of a big blunder like committing something not
1284 intended to be committed or committing a wrong file, the wrong version of a
1285 patch, CVS policy violation or broken code and you are going to recommit the
1286 right thing immediately.
1287
1288 Never revert changes made a long time ago or buggy code. Fix it in the
1289 normal way instead.
1290 @item
1291 Never write to unallocated memory, never write over the end of arrays,
1292 always check values read from some untrusted source before using them
1293 as array index or other risky things.
1294 @item
1295 Remember to check if you need to bump versions for the specific libav
1296 parts (libavutil, libavcodec, libavformat) you are changing. You need
1297 to change the version integer and the version string.
1298 Incrementing the first component means no backward compatibility to
1299 previous versions (e.g. removal of a function).
1300 Incrementing the second component means backward compatible change
1301 (e.g. addition of a function).
1302 Incrementing the third component means a noteworthy binary compatible
1303 change (e.g. encoder bug fix that matters for the decoder).
1304 @item
1305 If you add a new codec, remember to update the changelog, add it to
1306 the supported codecs table in the documentation and bump the second
1307 component of the @file{libavcodec} version number appropriately. If
1308 it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
1309 is only a decoder.
1310 @end enumerate
1311
1312 We think our rules are not too hard. If you have comments, contact us.
1313
1314 Note, these rules are mostly borrowed from the MPlayer project.
1315
1316 @subsection Renaming/moving files or content of files
1317 You CANNOT do that. Post a request for such a change to the mailing list
1318 Do NOT remove & readd a file - it will kill the changelog!!!!
1319
1320 @section Submitting patches
1321
1322 First, (@pxref{Coding Rules}) above if you didn't yet.
1323
1324 When you submit your patch, try to send a unified diff (diff '-up'
1325 option). I cannot read other diffs :-)
1326
1327 Also please do not submit patches which contain several unrelated changes.
1328 Split them into individual self-contained patches; this makes reviewing
1329 them much easier.
1330
1331 Run the regression tests before submitting a patch so that you can
1332 verify that there are no big problems.
1333
1334 Patches should be posted as base64 encoded attachments (or any other
1335 encoding which ensures that the patch won't be trashed during
1336 transmission) to the ffmpeg-devel mailing list, see
1337 @url{http://www1.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
1338
1339 It also helps quite a bit if you tell us what the patch does (for example
1340 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
1341 and has no lrint()')
1342
1343 We reply to all submitted patches and either apply or reject with some
1344 explanation why, but sometimes we are quite busy so it can take a week or two.
1345
1346 @section Regression tests
1347
1348 Before submitting a patch (or committing to CVS), you should at least
1349 test that you did not break anything.
1350
1351 The regression tests build a synthetic video stream and a synthetic
1352 audio stream. These are then encoded and decoded with all codecs or
1353 formats. The CRC (or MD5) of each generated file is recorded in a
1354 result file. A 'diff' is launched to compare the reference results and
1355 the result file.
1356
1357 The regression tests then go on to test the FFserver code with a
1358 limited set of streams. It is important that this step runs correctly
1359 as well.
1360
1361 Run 'make test' to test all the codecs and formats.
1362
1363 Run 'make fulltest' to test all the codecs, formats and FFserver.
1364
1365 [Of course, some patches may change the results of the regression tests. In
1366 this case, the reference results of the regression tests shall be modified
1367 accordingly].
1368
1369 @bye