KMVC (used in Worms games) decoder. Works fine with samples from MPHQ
[libav.git] / doc / ffmpeg-doc.texi
1 \input texinfo @c -*- texinfo -*-
3 @settitle FFmpeg Documentation
4 @titlepage
5 @sp 7
6 @center @titlefont{FFmpeg Documentation}
7 @sp 3
8 @end titlepage
11 @chapter Introduction
13 FFmpeg is a very fast video and audio converter. It can also grab from
14 a live audio/video source.
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.
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.
24 @chapter Quick Start
26 @c man begin EXAMPLES
27 @section Video and Audio grabbing
29 FFmpeg can use a video4linux compatible video source and any Open Sound
30 System audio source:
32 @example
33 ffmpeg /tmp/out.mpg
34 @end example
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{}) by Gerd Knorr. You also
39 have to set the audio recording levels correctly with a
40 standard mixer.
42 @section Video and Audio file format conversion
44 * FFmpeg can use any supported file format and protocol as input:
46 Examples:
48 * You can use YUV files as input:
50 @example
51 ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
52 @end example
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
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.
65 * You can input from a raw YUV420P file:
67 @example
68 ffmpeg -i /tmp/test.yuv /tmp/out.avi
69 @end example
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.
75 * You can output to a raw YUV420P file:
77 @example
78 ffmpeg -i mydivx.avi hugefile.yuv
79 @end example
81 * You can set several input files and output files:
83 @example
84 ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
85 @end example
87 Converts the audio file a.wav and the raw YUV video file a.yuv
88 to MPEG file a.mpg.
90 * You can also do audio and video conversions at the same time:
92 @example
93 ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
94 @end example
96 Converts a.wav to MPEG audio at 22050Hz sample rate.
98 * You can encode to several formats at the same time and define a
99 mapping from input stream to output streams:
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
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.
109 * You can transcode decrypted VOBs
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
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.
124 NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
125 @c man end
127 @chapter Invocation
129 @section Syntax
131 The generic syntax is:
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.
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.
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
151 @c man begin OPTIONS
152 @section Main options
154 @table @option
155 @item -L
156 Show license.
158 @item -h
159 Show help.
161 @item -formats
162 Show available formats, codecs, protocols, ...
164 @item -f fmt
165 Force format.
167 @item -i filename
168 input filename
170 @item -y
171 Overwrite output files.
173 @item -t duration
174 Set the recording time in seconds.
175 @code{hh:mm:ss[.xxx]} syntax is also supported.
177 @item -ss position
178 Seek to given time position in seconds.
179 @code{hh:mm:ss[.xxx]} syntax is also supported.
181 @item -title string
182 Set the title.
184 @item -author string
185 Set the author.
187 @item -copyright string
188 Set the copyright.
190 @item -comment string
191 Set the comment.
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:
198 @example
199 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
200 @end example
202 Nevertheless you can specify additional options as long as you know
203 they do not conflict with the standard, as in:
205 @example
206 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
207 @end example
209 @item -hq
210 Activate high quality settings.
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.
220 @end table
222 @section Video Options
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
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).
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.
288 @item -passlogfile file
289 Set two pass logfile name to @var{file}.
291 @end table
293 @section Advanced Video Options
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)
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
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
350 @item 2
352 @item 3
354 @item 4
356 @item 5
358 @end table
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
367 @item 2
369 @item 3
371 @item 4
373 @item 5
375 @item 6
377 @item 7
379 @item 8
381 @item 9
383 @item 10
385 @end table
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
394 @item 3
396 @item 4
398 @end table
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
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
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+)
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
453 @section Audio Options
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
469 @section Audio/Video grab options
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
484 @section Advanced options
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
509 @node FFmpeg formula evaluator
510 @section FFmpeg formula evaluator
512 When evaluating a rate control string, FFmpeg uses an internal formula
513 evaluator.
515 The following binary operators are available: @code{+}, @code{-},
516 @code{*}, @code{/}, @code{^}.
518 The following unary operators are available: @code{+}, @code{-},
519 @code{(...)}.
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
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
567 @c man end
569 @ignore
571 @setfilename ffmpeg
572 @settitle FFmpeg video converter
574 @c man begin SEEALSO
575 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
576 @c man end
578 @c man begin AUTHOR
579 Fabrice Bellard
580 @c man end
582 @end ignore
584 @section Protocols
586 The filename can be @file{-} to read from standard input or to write
587 to standard output.
589 FFmpeg also handles many protocols specified with an URL syntax.
591 Use 'ffmpeg -formats' to see a list of the supported protocols.
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 :-)
597 @chapter Tips
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:
605 @example
606 ffmpeg -g 3 -r 3 -t 10 -b 50 -s qcif -f rv10 /tmp/b.rm
607 @end example
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.
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).
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).
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).
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.
633 @end itemize
635 @chapter Supported File Formats and Codecs
637 You can use the @code{-formats} option to have an exhaustive list.
639 @section File Formats
641 FFmpeg supports the following file formats through the @code{libavformat}
642 library:
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
709 @code{X} means that encoding (resp. decoding) is supported.
711 @section Image Formats
713 FFmpeg can read and write images for each frame of a video sequence. The
714 following image formats are supported:
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
728 @code{X} means that encoding (resp. decoding) is supported.
730 @section Video Codecs
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 @item KMVC @tab @tab X @tab Codec used in Worms games.
804 @end multitable
806 @code{X} means that encoding (resp. decoding) is supported.
808 See @url{} to
809 get a precise comparison of the FFmpeg MPEG-4 codec compared to
810 other implementations.
812 @section Audio Codecs
814 @multitable @columnfractions .4 .1 .1 .1 .7
815 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
816 @item MPEG audio layer 2 @tab IX @tab IX
817 @item MPEG audio layer 1/3 @tab IX @tab IX
818 @tab MP3 encoding is supported through the external library LAME.
819 @item AC3 @tab IX @tab IX
820 @tab liba52 is used internally for decoding.
821 @item Vorbis @tab X @tab X
822 @tab Supported through the external library libvorbis.
823 @item WMA V1/V2 @tab @tab X
824 @item AAC @tab X @tab X
825 @tab Supported through the external library libfaac/libfaad.
826 @item Microsoft ADPCM @tab X @tab X
827 @item MS IMA ADPCM @tab X @tab X
828 @item QT IMA ADPCM @tab @tab X
829 @item 4X IMA ADPCM @tab @tab X
830 @item G.726 ADPCM @tab X @tab X
831 @item Duck DK3 IMA ADPCM @tab @tab X
832 @tab Used in some Sega Saturn console games.
833 @item Duck DK4 IMA ADPCM @tab @tab X
834 @tab Used in some Sega Saturn console games.
835 @item Westwood Studios IMA ADPCM @tab @tab X
836 @tab Used in Westwood Studios games like Command and Conquer.
837 @item SMJPEG IMA ADPCM @tab @tab X
838 @tab Used in certain Loki game ports.
839 @item CD-ROM XA ADPCM @tab @tab X
840 @item CRI ADX ADPCM @tab X @tab X
841 @tab Used in Sega Dreamcast games.
842 @item Electronic Arts ADPCM @tab @tab X
843 @tab Used in various EA titles.
844 @item Creative ADPCM @tab @tab X
845 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
846 @item RA144 @tab @tab X
847 @tab Real 14400 bit/s codec
848 @item RA288 @tab @tab X
849 @tab Real 28800 bit/s codec
850 @item RADnet @tab X @tab IX
851 @tab Real low bitrate AC3 codec, liba52 is used for decoding.
852 @item AMR-NB @tab X @tab X
853 @tab Supported through an external library.
854 @item AMR-WB @tab X @tab X
855 @tab Supported through an external library.
856 @item DV audio @tab @tab X
857 @item Id RoQ DPCM @tab @tab X
858 @tab Used in Quake III, Jedi Knight 2, other computer games.
859 @item Interplay MVE DPCM @tab @tab X
860 @tab Used in various Interplay computer games.
861 @item Xan DPCM @tab @tab X
862 @tab Used in Origin's Wing Commander IV AVI files.
863 @item Sierra Online DPCM @tab @tab X
864 @tab Used in Sierra Online game audio files.
865 @item Apple MACE 3 @tab @tab X
866 @item Apple MACE 6 @tab @tab X
867 @item FLAC lossless audio @tab @tab X
868 @item Shorten lossless audio @tab @tab X
869 @item Apple lossless audio @tab @tab X
870 @tab QuickTime fourcc 'alac'
871 @item FFmpeg Sonic @tab X @tab X
872 @tab experimental lossy/lossless codec
873 @item Qdesign QDM2 @tab @tab X
874 @tab there are still some distortions
875 @item Real COOK @tab @tab X
876 @tab All versions except 5.1 are supported
877 @item DSP Group TrueSpeech @tab @tab X
878 @item True Audio (TTA) @tab @tab X
879 @item Smacker Audio @tab @tab X
880 @end multitable
882 @code{X} means that encoding (resp. decoding) is supported.
884 @code{I} means that an integer-only version is available, too (ensures high
885 performance on systems without hardware floating point support).
887 @chapter Platform Specific information
889 @section Linux
891 FFmpeg should be compiled with at least GCC 2.95.3. GCC 3.2 is the
892 preferred compiler now for FFmpeg. All future optimizations will depend on
893 features only found in GCC 3.2.
895 @section BSD
897 BSD make will not build FFmpeg, you need to install and use GNU Make
898 (@file{gmake}).
900 @section Windows
902 @subsection Native Windows compilation
904 @itemize
905 @item Install the current versions of MSYS and MinGW from
906 @url{}. You can find detailed installation
907 instructions in the download section and the FAQ.
909 @item If you want to test the FFplay, also download
910 the MinGW development library of SDL 1.2.x
911 (@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
912 @url{}. Unpack it in a temporary directory, and
913 unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
914 directory. Edit the @file{sdl-config} script so that it gives the
915 correct SDL directory when invoked.
917 @item Extract the current version of FFmpeg.
919 @item Start the MSYS shell (file @file{msys.bat}).
921 @item Change to the FFmpeg directory and follow
922 the instructions of how to compile FFmpeg (file
923 @file{INSTALL}). Usually, launching @file{./configure} and @file{make}
924 suffices. If you have problems using SDL, verify that
925 @file{sdl-config} can be launched from the MSYS command line.
927 @item You can install FFmpeg in @file{Program Files/FFmpeg} by typing
928 @file{make install}. Don't forget to copy @file{SDL.dll} to the place
929 you launch @file{ffplay} from.
931 @end itemize
933 Notes:
934 @itemize
936 @item The target @file{make wininstaller} can be used to create a
937 Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
938 must be copied to the FFmpeg directory in order to build the
939 installer.
941 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
942 you can build @file{avcodec.dll} and @file{avformat.dll}. With
943 @code{make install} you install the FFmpeg DLLs and the associated
944 headers in @file{Program Files/FFmpeg}.
946 @item Visual C++ compatibility: If you used @code{./configure --enable-shared}
947 when configuring FFmpeg, FFmpeg tries to use the Microsoft Visual
948 C++ @code{lib} tool to build @code{avcodec.lib} and
949 @code{avformat.lib}. With these libraries you can link your Visual C++
950 code directly with the FFmpeg DLLs (see below).
952 @end itemize
954 @subsection Visual C++ compatibility
956 FFmpeg will not compile under Visual C++ -- and it has too many
957 dependencies on the GCC compiler to make a port viable. However,
958 if you want to use the FFmpeg libraries in your own applications,
959 you can still compile those applications using Visual C++. An
960 important restriction to this is that you have to use the
961 dynamically linked versions of the FFmpeg libraries (i.e. the
962 DLLs), and you have to make sure that Visual-C++-compatible
963 import libraries are created during the FFmpeg build process.
965 This description of how to use the FFmpeg libraries with Visual C++ is
966 based on Visual C++ 2005 Express Edition Beta 2. If you have a different
967 version, you might have to modify the procedures slightly.
969 Here are the step-by-step instructions for building the FFmpeg libraries
970 so they can be used with Visual C++:
972 @enumerate
974 @item Install Visual C++ (if you haven't done so already).
976 @item Install MinGW and MSYS as described above.
978 @item Add a call to @file{vcvars32.bat} (which sets up the environment
979 variables for the Visual C++ tools) as the first line of
980 @file{msys.bat}. The standard location for @file{vcvars32.bat} is
981 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
982 and the standard location for @file{msys.bat} is
983 @file{C:\msys\1.0\msys.bat}. If this corresponds to your setup, add the
984 following line as the first line of @file{msys.bat}:
986 @code{call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"}
988 @item Start the MSYS shell (file @file{msys.bat}) and type @code{link.exe}.
989 If you get a help message with the command line options of @code{link.exe},
990 this means your environment variables are set up correctly, the
991 Microsoft linker is on the path and will be used by FFmpeg to
992 create Visual-C++-compatible import libraries.
994 @item Extract the current version of FFmpeg and change to the FFmpeg directory.
996 @item Type the command
997 @code{./configure --enable-shared --disable-static --enable-memalign-hack}
998 to configure and, if that didn't produce any errors,
999 type @code{make} to build FFmpeg.
1001 @item The subdirectories @file{libavformat}, @file{libavcodec}, and
1002 @file{libavutil} should now contain the files @file{avformat.dll},
1003 @file{avformat.lib}, @file{avcodec.dll}, @file{avcodec.lib},
1004 @file{avutil.dll}, and @file{avutil.lib}, respectively. Copy the three
1005 DLLs to your System32 directory (typically @file{C:\Windows\System32}).
1007 @end enumerate
1009 And here is how to use these libraries with Visual C++:
1011 @enumerate
1013 @item Create a new console application ("File / New / Project") and then
1014 select "Win32 Console Application". On the appropriate page of the
1015 Application Wizard, uncheck the "Precompiled headers" option.
1017 @item Write the source code for your application, or, for testing, just
1018 copy the code from an existing sample application into the source file
1019 that Visual C++ has already created for you. (Note that your source
1020 filehas to have a @code{.cpp} extension; otherwise, Visual C++ won't
1021 compile the FFmpeg headers correctly because in C mode, it doesn't
1022 recognize the @code{inline} keyword.) For example, you can copy
1023 @file{output_example.c} from the FFmpeg distribution (but you will
1024 have to make minor modifications so the code will compile under
1025 C++, see below).
1027 @item Open the "Project / Properties" dialog box. In the "Configuration"
1028 combo box, select "All Configurations" so that the changes you make will
1029 affect both debug and release builds. In the tree view on the left hand
1030 side, select "C/C++ / General", then edit the "Additional Include
1031 Directories" setting to contain the complete paths to the
1032 @file{libavformat}, @file{libavcodec}, and @file{libavutil}
1033 subdirectories of your FFmpeg directory. Note that the directories have
1034 to be separated using semicolons. Now select "Linker / General" from the
1035 tree view and edit the "Additional Library Directories" setting to
1036 contain the same three directories.
1038 @item Still in the "Project / Properties" dialog box, select "Linker / Input"
1039 from the tree view, then add the files @file{avformat.lib},
1040 @file{avcodec.lib}, and @file{avutil.lib} to the end of the "Additional
1041 Dependencies". Note that the names of the libraries have to be separated
1042 using spaces.
1044 @item Now, select "C/C++ / Code Generation" from the tree view. Select
1045 "Debug" in the "Configuration" combo box. Make sure that "Runtime
1046 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
1047 the "Configuration" combo box and make sure that "Runtime Library" is
1048 set to "Multi-threaded DLL".
1050 @item Click "OK" to close the "Project / Properties" dialog box and build
1051 the application. Hopefully, it should compile and run cleanly. If you
1052 used @file{output_example.c} as your sample application, you will get a
1053 few compiler errors, but they are easy to fix. The first type of error
1054 occurs because Visual C++ doesn't allow an @code{int} to be converted to
1055 an @code{enum} without a cast. To solve the problem, insert the required
1056 casts (this error occurs once for a @code{CodecID} and once for a
1057 @code{CodecType}). The second type of error occurs because C++ requires
1058 the return value of @code{malloc} to be cast to the exact type of the
1059 pointer it is being assigned to. Visual C++ will complain that, for
1060 example, @code{(void *)} is being assigned to @code{(uint8_t *)} without
1061 an explicit cast. So insert an explicit cast in these places to silence
1062 the compiler. The third type of error occurs because the @code{snprintf}
1063 library function is called @code{_snprintf} under Visual C++. So just
1064 add an underscore to fix the problem. With these changes,
1065 @file{output_example.c} should compile under Visual C++, and the
1066 resulting executable should produce valid video files.
1068 @end enumerate
1070 @subsection Cross compilation for Windows with Linux
1072 You must use the MinGW cross compilation tools available at
1073 @url{}.
1075 Then configure FFmpeg with the following options:
1076 @example
1077 ./configure --enable-mingw32 --cross-prefix=i386-mingw32msvc-
1078 @end example
1079 (you can change the cross-prefix according to the prefix chosen for the
1080 MinGW tools).
1082 Then you can easily test FFmpeg with Wine
1083 (@url{}).
1085 @section Mac OS X
1087 @section BeOS
1089 The configure script should guess the configuration itself.
1090 Networking support is currently not finished.
1091 errno issues fixed by Andrew Bachmann.
1093 Old stuff:
1095 Fran├žois Revol - revol at free dot fr - April 2002
1097 The configure script should guess the configuration itself,
1098 however I still didn't test building on the net_server version of BeOS.
1100 FFserver is broken (needs poll() implementation).
1102 There are still issues with errno codes, which are negative in BeOS, and
1103 that FFmpeg negates when returning. This ends up turning errors into
1104 valid results, then crashes.
1105 (To be fixed)
1107 @chapter Developers Guide
1109 @section API
1110 @itemize
1111 @item libavcodec is the library containing the codecs (both encoding and
1112 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
1114 @item libavformat is the library containing the file format handling (mux and
1115 demux code for several formats). Look at @file{ffplay.c} to use it in a
1116 player. See @file{output_example.c} to use it to generate audio or video
1117 streams.
1119 @end itemize
1121 @section Integrating libavcodec or libavformat in your program
1123 You can integrate all the source code of the libraries to link them
1124 statically to avoid any version problem. All you need is to provide a
1125 'config.mak' and a 'config.h' in the parent directory. See the defines
1126 generated by ./configure to understand what is needed.
1128 You can use libavcodec or libavformat in your commercial program, but
1129 @emph{any patch you make must be published}. The best way to proceed is
1130 to send your patches to the FFmpeg mailing list.
1132 @node Coding Rules
1133 @section Coding Rules
1135 FFmpeg is programmed in the ISO C90 language with a few additional
1136 features from ISO C99, namely:
1137 @itemize @bullet
1138 @item
1139 the @samp{inline} keyword;
1140 @item
1141 @samp{//} comments;
1142 @item
1143 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
1144 @item
1145 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
1146 @end itemize
1148 These features are supported by all compilers we care about, so we won't
1149 accept patches to remove their use unless they absolutely don't impair
1150 clarity and performance.
1152 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
1153 compiles with several other compilers, such as the Compaq ccc compiler
1154 or Sun Studio 9, and we would like to keep it that way unless it would
1155 be exceedingly involved. To ensure compatibility, please don't use any
1156 additional C99 features or GCC extensions. Especially watch out for:
1157 @itemize @bullet
1158 @item
1159 mixing statements and declarations;
1160 @item
1161 @samp{long long} (use @samp{int64_t} instead);
1162 @item
1163 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
1164 @item
1165 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
1166 @end itemize
1168 Indent size is 4.
1169 The presentation is the one specified by 'indent -i4 -kr -nut'.
1170 The TAB character is forbidden outside of Makefiles as is any
1171 form of trailing whitespace. Commits containing either will be
1172 rejected by the CVS repository.
1174 Main priority in FFmpeg is simplicity and small code size (=less
1175 bugs).
1177 Comments: Use the JavaDoc/Doxygen
1178 format (see examples below) so that code documentation
1179 can be generated automatically. All nontrivial functions should have a comment
1180 above them explaining what the function does, even if it's just one sentence.
1181 All structures and their member variables should be documented, too.
1182 @example
1183 /**
1184 * @@file mpeg.c
1185 * MPEG codec.
1186 * @@author ...
1187 */
1189 /**
1190 * Summary sentence.
1191 * more text ...
1192 * ...
1193 */
1194 typedef struct Foobar@{
1195 int var1; /**< var1 description */
1196 int var2; ///< var2 description
1197 /** var3 description */
1198 int var3;
1199 @} Foobar;
1201 /**
1202 * Summary sentence.
1203 * more text ...
1204 * ...
1205 * @@param my_parameter description of my_parameter
1206 * @@return return value description
1207 */
1208 int myfunc(int my_parameter)
1209 ...
1210 @end example
1212 fprintf and printf are forbidden in libavformat and libavcodec,
1213 please use av_log() instead.
1215 @node CVS Policy
1216 @section CVS Policy
1218 @enumerate
1219 @item
1220 You must not commit code which breaks FFmpeg! (Meaning unfinished but
1221 enabled code which breaks compilation or compiles but does not work or
1222 breaks the regression tests)
1223 You can commit unfinished stuff (for testing etc), but it must be disabled
1224 (#ifdef etc) by default so it does not interfere with other developers'
1225 work.
1226 @item
1227 You don't have to over-test things. If it works for you, and you think it
1228 should work for others, then commit. If your code has problems
1229 (portability, triggers compiler bugs, unusual environment etc) they will be
1230 reported and eventually fixed.
1231 @item
1232 Do not commit unrelated changes together, split them into self-contained
1233 pieces.
1234 @item
1235 Do not change behavior of the program (renaming options etc) without
1236 first discussing it on the ffmpeg-devel mailing list. Do not remove
1237 functionality from the code. Just improve!
1239 Note: Redundant code can be removed.
1240 @item
1241 Do not commit changes to the build system (Makefiles, configure script)
1242 which change behavior, defaults etc, without asking first. The same
1243 applies to compiler warning fixes, trivial looking fixes and to code
1244 maintained by other developers. We usually have a reason for doing things
1245 the way we do. Send your changes as patches to the ffmpeg-devel mailing
1246 list, and if the code maintainers say OK, you may commit. This does not
1247 apply to files you wrote and/or maintain.
1248 @item
1249 We refuse source indentation and other cosmetic changes if they are mixed
1250 with functional changes, such commits will be rejected and removed. Every
1251 developer has his own indentation style, you should not change it. Of course
1252 if you (re)write something, you can use your own style, even though we would
1253 prefer if the indentation throughout FFmpeg was consistent (Many projects
1254 force a given indentation style - we don't.). If you really need to make
1255 indentation changes (try to avoid this), separate them strictly from real
1256 changes.
1258 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
1259 then either do NOT change the indentation of the inner part within (don't
1260 move it to the right)! or do so in a separate commit
1261 @item
1262 Always fill out the commit log message. Describe in a few lines what you
1263 changed and why. You can refer to mailing list postings if you fix a
1264 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1265 @item
1266 If you apply a patch by someone else, include the name and email address in
1267 the CVS log message. Since the ffmpeg-cvslog mailing list is publicly
1268 archived you should add some SPAM protection to the email address. Send an
1269 answer to ffmpeg-devel (or wherever you got the patch from) saying that
1270 you applied the patch.
1271 @item
1272 Do NOT commit to code actively maintained by others without permission. Send
1273 a patch to ffmpeg-devel instead.
1274 @item
1275 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all CVS commits
1276 are sent there and reviewed by all the other developers. Bugs and possible
1277 improvements or general questions regarding commits are discussed there. We
1278 expect you to react if problems with your code are uncovered.
1279 @item
1280 Update the documentation if you change behavior or add features. If you are
1281 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
1282 maintainer(s) will review and commit your stuff.
1283 @item
1284 Revert a commit ONLY in case of a big blunder like committing something not
1285 intended to be committed or committing a wrong file, the wrong version of a
1286 patch, CVS policy violation or broken code and you are going to recommit the
1287 right thing immediately.
1289 Never revert changes made a long time ago or buggy code. Fix it in the
1290 normal way instead.
1291 @item
1292 Never write to unallocated memory, never write over the end of arrays,
1293 always check values read from some untrusted source before using them
1294 as array index or other risky things.
1295 @item
1296 Remember to check if you need to bump versions for the specific libav
1297 parts (libavutil, libavcodec, libavformat) you are changing. You need
1298 to change the version integer and the version string.
1299 Incrementing the first component means no backward compatibility to
1300 previous versions (e.g. removal of a function).
1301 Incrementing the second component means backward compatible change
1302 (e.g. addition of a function).
1303 Incrementing the third component means a noteworthy binary compatible
1304 change (e.g. encoder bug fix that matters for the decoder).
1305 @item
1306 If you add a new codec, remember to update the changelog, add it to
1307 the supported codecs table in the documentation and bump the second
1308 component of the @file{libavcodec} version number appropriately. If
1309 it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
1310 is only a decoder.
1311 @end enumerate
1313 We think our rules are not too hard. If you have comments, contact us.
1315 Note, these rules are mostly borrowed from the MPlayer project.
1317 @subsection Renaming/moving files or content of files
1318 You CANNOT do that. Post a request for such a change to the mailing list
1319 Do NOT remove & readd a file - it will kill the changelog!!!!
1321 @section Submitting patches
1323 First, (@pxref{Coding Rules}) above if you didn't yet.
1325 When you submit your patch, try to send a unified diff (diff '-up'
1326 option). I cannot read other diffs :-)
1328 Also please do not submit patches which contain several unrelated changes.
1329 Split them into individual self-contained patches; this makes reviewing
1330 them much easier.
1332 Run the regression tests before submitting a patch so that you can
1333 verify that there are no big problems.
1335 Patches should be posted as base64 encoded attachments (or any other
1336 encoding which ensures that the patch won't be trashed during
1337 transmission) to the ffmpeg-devel mailing list, see
1338 @url{}
1340 It also helps quite a bit if you tell us what the patch does (for example
1341 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
1342 and has no lrint()')
1344 We reply to all submitted patches and either apply or reject with some
1345 explanation why, but sometimes we are quite busy so it can take a week or two.
1347 @section Regression tests
1349 Before submitting a patch (or committing to CVS), you should at least
1350 test that you did not break anything.
1352 The regression tests build a synthetic video stream and a synthetic
1353 audio stream. These are then encoded and decoded with all codecs or
1354 formats. The CRC (or MD5) of each generated file is recorded in a
1355 result file. A 'diff' is launched to compare the reference results and
1356 the result file.
1358 The regression tests then go on to test the FFserver code with a
1359 limited set of streams. It is important that this step runs correctly
1360 as well.
1362 Run 'make test' to test all the codecs and formats.
1364 Run 'make fulltest' to test all the codecs, formats and FFserver.
1366 [Of course, some patches may change the results of the regression tests. In
1367 this case, the reference results of the regression tests shall be modified
1368 accordingly].
1370 @bye