Theora encoding via libtheora.
[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 X11 grabbing
44 FFmpeg can grab the X11 display.
46 @example
47 ffmpeg -f x11grab -vd x11:0.0 /tmp/out.mpg
48 @end example
50 0.0 is display.screen number of your X11 server, same as
51 the DISPLAY environment variable.
53 @example
54 ffmpeg -f x11grab -vd x11:0.0+10,20 /tmp/out.mpg
55 @end example
57 0.0 is display.screen number of your X11 server, same as the DISPLAY environment
58 variable. 10 is the x-offset and 20 the y-offset for the grabbing.
60 @section Video and Audio file format conversion
62 * FFmpeg can use any supported file format and protocol as input:
64 Examples:
66 * You can use YUV files as input:
68 @example
69 ffmpeg -i /tmp/test%d.Y /tmp/out.mpg
70 @end example
72 It will use the files:
73 @example
74 /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,
75 /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...
76 @end example
78 The Y files use twice the resolution of the U and V files. They are
79 raw files, without header. They can be generated by all decent video
80 decoders. You must specify the size of the image with the @option{-s} option
81 if FFmpeg cannot guess it.
83 * You can input from a raw YUV420P file:
85 @example
86 ffmpeg -i /tmp/test.yuv /tmp/out.avi
87 @end example
89 test.yuv is a file containing raw YUV planar data. Each frame is composed
90 of the Y plane followed by the U and V planes at half vertical and
91 horizontal resolution.
93 * You can output to a raw YUV420P file:
95 @example
96 ffmpeg -i mydivx.avi hugefile.yuv
97 @end example
99 * You can set several input files and output files:
101 @example
102 ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg
103 @end example
105 Converts the audio file a.wav and the raw YUV video file a.yuv
106 to MPEG file a.mpg.
108 * You can also do audio and video conversions at the same time:
110 @example
111 ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2
112 @end example
114 Converts a.wav to MPEG audio at 22050Hz sample rate.
116 * You can encode to several formats at the same time and define a
117 mapping from input stream to output streams:
119 @example
120 ffmpeg -i /tmp/a.wav -ab 64 /tmp/a.mp2 -ab 128 /tmp/b.mp2 -map 0:0 -map 0:0
121 @end example
123 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
124 file:index' specifies which input stream is used for each output
125 stream, in the order of the definition of output streams.
127 * You can transcode decrypted VOBs
129 @example
130 ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800k -g 300 -bf 2 -acodec mp3 -ab 128 snatch.avi
131 @end example
133 This is a typical DVD ripping example; the input is a VOB file, the
134 output an AVI file with MPEG-4 video and MP3 audio. Note that in this
135 command we use B-frames so the MPEG-4 stream is DivX5 compatible, and
136 GOP size is 300 which means one intra frame every 10 seconds for 29.97fps
137 input video. Furthermore, the audio stream is MP3-encoded so you need
138 to enable LAME support by passing @code{--enable-mp3lame} to configure.
139 The mapping is particularly useful for DVD transcoding
140 to get the desired audio language.
142 NOTE: To see the supported input formats, use @code{ffmpeg -formats}.
143 @c man end
145 @chapter Invocation
147 @section Syntax
149 The generic syntax is:
151 @example
152 @c man begin SYNOPSIS
153 ffmpeg [[infile options][@option{-i} @var{infile}]]... @{[outfile options] @var{outfile}@}...
154 @c man end
155 @end example
156 @c man begin DESCRIPTION
157 If no input file is given, audio/video grabbing is done.
159 As a general rule, options are applied to the next specified
160 file. Therefore, order is important, and you can have the same
161 option on the command line multiple times. Each occurrence is
162 then applied to the next input or output file.
164 * To set the video bitrate of the output file to 64kbit/s:
165 @example
166 ffmpeg -i input.avi -b 64k output.avi
167 @end example
169 * To force the frame rate of the input and output file to 24 fps:
170 @example
171 ffmpeg -r 24 -i input.avi output.avi
172 @end example
174 * To force the frame rate of the output file to 24 fps:
175 @example
176 ffmpeg -i input.avi -r 24 output.avi
177 @end example
179 * To force the frame rate of input file to 1 fps and the output file to 24 fps:
180 @example
181 ffmpeg -r 1 -i input.avi -r 24 output.avi
182 @end example
184 The format option may be needed for raw input files.
186 By default, FFmpeg tries to convert as losslessly as possible: It
187 uses the same audio and video parameters for the outputs as the one
188 specified for the inputs.
189 @c man end
191 @c man begin OPTIONS
192 @section Main options
194 @table @option
195 @item -L
196 Show license.
198 @item -h
199 Show help.
201 @item -version
202 Show version.
204 @item -formats
205 Show available formats, codecs, protocols, ...
207 @item -f fmt
208 Force format.
210 @item -i filename
211 input filename
213 @item -y
214 Overwrite output files.
216 @item -t duration
217 Set the recording time in seconds.
218 @code{hh:mm:ss[.xxx]} syntax is also supported.
220 @item -fs limit_size
221 Set the file size limit.
223 @item -ss position
224 Seek to given time position in seconds.
225 @code{hh:mm:ss[.xxx]} syntax is also supported.
227 @item -itsoffset offset
228 Set the input time offset in seconds.
229 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
230 This option affects all the input files that follow it.
231 The offset is added to the timestamps of the input files.
232 Specifying a positive offset means that the corresponding
233 streams are delayed by 'offset' seconds.
235 @item -title string
236 Set the title.
238 @item -timestamp time
239 Set the timestamp.
241 @item -author string
242 Set the author.
244 @item -copyright string
245 Set the copyright.
247 @item -comment string
248 Set the comment.
250 @item -album string
251 Set the album.
253 @item -track number
254 Set the track.
256 @item -year number
257 Set the year.
259 @item -v verbose
260 Control amount of logging.
262 @item -target type
263 Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
264 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
265 buffer sizes) are then set automatically. You can just type:
267 @example
268 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
269 @end example
271 Nevertheless you can specify additional options as long as you know
272 they do not conflict with the standard, as in:
274 @example
275 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
276 @end example
278 @item -dframes number
279 Set the number of data frames to record.
281 @item -scodec codec
282 Force subtitle codec ('copy' to copy stream).
284 @item -newsubtitle
285 Add a new subtitle stream to the current output stream.
287 @item -slang code
288 Set the ISO 639 language code (3 letters) of the current subtitle stream.
290 @end table
292 @section Video Options
294 @table @option
295 @item -b bitrate
296 Set the video bitrate in bit/s (default = 200 kb/s).
297 @item -vframes number
298 Set the number of video frames to record.
299 @item -r fps
300 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
301 @item -s size
302 Set frame size. The format is @samp{wxh} (default = 160x128).
303 The following abbreviations are recognized:
304 @table @samp
305 @item sqcif
306 128x96
307 @item qcif
308 176x144
309 @item cif
310 352x288
311 @item 4cif
312 704x576
313 @end table
315 @item -aspect aspect
316 Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
317 @item -croptop size
318 Set top crop band size (in pixels).
319 @item -cropbottom size
320 Set bottom crop band size (in pixels).
321 @item -cropleft size
322 Set left crop band size (in pixels).
323 @item -cropright size
324 Set right crop band size (in pixels).
325 @item -padtop size
326 Set top pad band size (in pixels).
327 @item -padbottom size
328 Set bottom pad band size (in pixels).
329 @item -padleft size
330 Set left pad band size (in pixels).
331 @item -padright size
332 Set right pad band size (in pixels).
333 @item -padcolor (hex color)
334 Set color of padded bands. The value for padcolor is expressed
335 as a six digit hexadecimal number where the first two digits
336 represent red, the middle two digits green and last two digits
337 blue (default = 000000 (black)).
338 @item -vn
339 Disable video recording.
340 @item -bt tolerance
341 Set video bitrate tolerance (in bit/s).
342 @item -maxrate bitrate
343 Set max video bitrate tolerance (in bit/s).
344 @item -minrate bitrate
345 Set min video bitrate tolerance (in bit/s).
346 @item -bufsize size
347 Set rate control buffer size (in bits).
348 @item -vcodec codec
349 Force video codec to @var{codec}. Use the @code{copy} special value to
350 tell that the raw codec data must be copied as is.
351 @item -sameq
352 Use same video quality as source (implies VBR).
354 @item -pass n
355 Select the pass number (1 or 2). It is useful to do two pass
356 encoding. The statistics of the video are recorded in the first
357 pass and the video is generated at the exact requested bitrate
358 in the second pass.
360 @item -passlogfile file
361 Set two pass logfile name to @var{file}.
363 @item -newvideo
364 Add a new video stream to the current output stream.
366 @end table
368 @section Advanced Video Options
370 @table @option
371 @item -pix_fmt format
372 Set pixel format.
373 @item -g gop_size
374 Set the group of pictures size.
375 @item -intra
376 Use only intra frames.
377 @item -vdt n
378 Discard threshold.
379 @item -qscale q
380 Use fixed video quantizer scale (VBR).
381 @item -qmin q
382 minimum video quantizer scale (VBR)
383 @item -qmax q
384 maximum video quantizer scale (VBR)
385 @item -qdiff q
386 maximum difference between the quantizer scales (VBR)
387 @item -qblur blur
388 video quantizer scale blur (VBR)
389 @item -qcomp compression
390 video quantizer scale compression (VBR)
392 @item -lmin lambda
393 minimum video lagrange factor (VBR)
394 @item -lmax lambda
395 max video lagrange factor (VBR)
396 @item -mblmin lambda
397 minimum macroblock quantizer scale (VBR)
398 @item -mblmax lambda
399 maximum macroblock quantizer scale (VBR)
401 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
402 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
403 @example
404 ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
405 @end example
407 @item -rc_init_cplx complexity
408 initial complexity for single pass encoding
409 @item -b_qfactor factor
410 qp factor between P- and B-frames
411 @item -i_qfactor factor
412 qp factor between P- and I-frames
413 @item -b_qoffset offset
414 qp offset between P- and B-frames
415 @item -i_qoffset offset
416 qp offset between P- and I-frames
417 @item -rc_eq equation
418 Set rate control equation (@pxref{FFmpeg formula
419 evaluator}) (default = @code{tex^qComp}).
420 @item -rc_override override
421 rate control override for specific intervals
422 @item -me method
423 Set motion estimation method to @var{method}.
424 Available methods are (from lowest to best quality):
425 @table @samp
426 @item zero
427 Try just the (0, 0) vector.
428 @item phods
429 @item log
430 @item x1
431 @item epzs
432 (default method)
433 @item full
434 exhaustive search (slow and marginally better than epzs)
435 @end table
437 @item -dct_algo algo
438 Set DCT algorithm to @var{algo}. Available values are:
439 @table @samp
440 @item 0
441 FF_DCT_AUTO (default)
442 @item 1
444 @item 2
446 @item 3
448 @item 4
450 @item 5
452 @end table
454 @item -idct_algo algo
455 Set IDCT algorithm to @var{algo}. Available values are:
456 @table @samp
457 @item 0
458 FF_IDCT_AUTO (default)
459 @item 1
461 @item 2
463 @item 3
465 @item 4
467 @item 5
469 @item 6
471 @item 7
473 @item 8
475 @item 9
477 @item 10
479 @end table
481 @item -er n
482 Set error resilience to @var{n}.
483 @table @samp
484 @item 1
485 FF_ER_CAREFUL (default)
486 @item 2
488 @item 3
490 @item 4
492 @end table
494 @item -ec bit_mask
495 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
496 the following values:
497 @table @samp
498 @item 1
499 FF_EC_GUESS_MVS (default = enabled)
500 @item 2
501 FF_EC_DEBLOCK (default = enabled)
502 @end table
504 @item -bf frames
505 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
506 @item -mbd mode
507 macroblock decision
508 @table @samp
509 @item 0
510 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
511 @item 1
512 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
513 @item 2
514 FF_MB_DECISION_RD: rate distortion
515 @end table
517 @item -4mv
518 Use four motion vector by macroblock (MPEG-4 only).
519 @item -part
520 Use data partitioning (MPEG-4 only).
521 @item -bug param
522 Work around encoder bugs that are not auto-detected.
523 @item -strict strictness
524 How strictly to follow the standards.
525 @item -aic
526 Enable Advanced intra coding (h263+).
527 @item -umv
528 Enable Unlimited Motion Vector (h263+)
530 @item -deinterlace
531 Deinterlace pictures.
532 @item -ilme
533 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
534 Use this option if your input file is interlaced and you want
535 to keep the interlaced format for minimum losses.
536 The alternative is to deinterlace the input stream with
537 @option{-deinterlace}, but deinterlacing introduces losses.
538 @item -psnr
539 Calculate PSNR of compressed frames.
540 @item -vstats
541 Dump video coding statistics to @file{vstats_HHMMSS.log}.
542 @item -vhook module
543 Insert video processing @var{module}. @var{module} contains the module
544 name and its parameters separated by spaces.
545 @item -top n
546 top=1/bottom=0/auto=-1 field first
547 @item -dc precision
548 Intra_dc_precision.
549 @item -vtag fourcc/tag
550 Force video tag/fourcc.
551 @item -qphist
552 Show QP histogram.
553 @item -vbsf bitstream filter
554 Bitstream filters available are "dump_extra", "remove_extra", "noise".
555 @end table
557 @section Audio Options
559 @table @option
560 @item -aframes number
561 Set the number of audio frames to record.
562 @item -ar freq
563 Set the audio sampling frequency (default = 44100 Hz).
564 @item -ab bitrate
565 Set the audio bitrate in kbit/s (default = 64).
566 @item -ac channels
567 Set the number of audio channels (default = 1).
568 @item -an
569 Disable audio recording.
570 @item -acodec codec
571 Force audio codec to @var{codec}. Use the @code{copy} special value to
572 specify that the raw codec data must be copied as is.
573 @item -newaudio
574 Add a new audio track to the output file. If you want to specify parameters,
575 do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
577 Mapping will be done automatically, if the number of output streams is equal to
578 the number of input streams, else it will pick the first one that matches. You
579 can override the mapping using @code{-map} as usual.
581 Example:
582 @example
583 ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384 test.mpg -acodec mp2 -ab 192 -newaudio
584 @end example
585 @item -alang code
586 Set the ISO 639 language code (3 letters) of the current audio stream.
587 @end table
589 @section Advanced Audio options:
591 @table @option
592 @item -atag fourcc/tag
593 Force audio tag/fourcc.
594 @item -absf bitstream filter
595 Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
596 @end table
598 @section Subtitle options:
600 @table @option
601 @item -scodec codec
602 Force subtitle codec ('copy' to copy stream).
603 @item -newsubtitle
604 Add a new subtitle stream to the current output stream.
605 @item -slang code
606 Set the ISO 639 language code (3 letters) of the current subtitle stream.
607 @end table
609 @section Audio/Video grab options
611 @table @option
612 @item -vd device
613 sEt video grab device (e.g. @file{/dev/video0}).
614 @item -vc channel
615 Set video grab channel (DV1394 only).
616 @item -tvstd standard
617 Set television standard (NTSC, PAL (SECAM)).
618 @item -dv1394
619 Set DV1394 grab.
620 @item -ad device
621 Set audio device (e.g. @file{/dev/dsp}).
622 @item -grab format
623 Request grabbing using.
624 @item -gd device
625 Set grab device.
626 @end table
628 @section Advanced options
630 @table @option
631 @item -map input stream id[:input stream id]
632 Set stream mapping from input streams to output streams.
633 Just enumerate the input streams in the order you want them in the output.
634 [input stream id] sets the (input) stream to sync against.
635 @item -map_meta_data outfile:infile
636 Set meta data information of outfile from infile.
637 @item -debug
638 Print specific debug info.
639 @item -benchmark
640 Add timings for benchmarking.
641 @item -dump
642 Dump each input packet.
643 @item -hex
644 When dumping packets, also dump the payload.
645 @item -bitexact
646 Only use bit exact algorithms (for codec testing).
647 @item -ps size
648 Set packet size in bits.
649 @item -re
650 Read input at native frame rate. Mainly used to simulate a grab device.
651 @item -loop_input
652 Loop over the input stream. Currently it works only for image
653 streams. This option is used for automatic FFserver testing.
654 @item -loop_output number_of_times
655 Repeatedly loop output for formats that support looping such as animated GIF
656 (0 will loop the output infinitely).
657 @item -threads count
658 Thread count.
659 @item -vsync parameter
660 Video sync method. Video will be stretched/squeezed to match the timestamps,
661 it is done by duplicating and dropping frames. With -map you can select from
662 which stream the timestamps should be taken. You can leave either video or
663 audio unchanged and sync the remaining stream(s) to the unchanged one.
664 @item -async samples_per_second
665 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
666 the parameter is the maximum samples per second by which the audio is changed.
667 -async 1 is a special case where only the start of the audio stream is corrected
668 without any later correction.
669 @end table
671 @node FFmpeg formula evaluator
672 @section FFmpeg formula evaluator
674 When evaluating a rate control string, FFmpeg uses an internal formula
675 evaluator.
677 The following binary operators are available: @code{+}, @code{-},
678 @code{*}, @code{/}, @code{^}.
680 The following unary operators are available: @code{+}, @code{-},
681 @code{(...)}.
683 The following functions are available:
684 @table @var
685 @item sinh(x)
686 @item cosh(x)
687 @item tanh(x)
688 @item sin(x)
689 @item cos(x)
690 @item tan(x)
691 @item exp(x)
692 @item log(x)
693 @item squish(x)
694 @item gauss(x)
695 @item abs(x)
696 @item max(x, y)
697 @item min(x, y)
698 @item gt(x, y)
699 @item lt(x, y)
700 @item eq(x, y)
701 @item bits2qp(bits)
702 @item qp2bits(qp)
703 @end table
705 The following constants are available:
706 @table @var
707 @item PI
708 @item E
709 @item iTex
710 @item pTex
711 @item tex
712 @item mv
713 @item fCode
714 @item iCount
715 @item mcVar
716 @item var
717 @item isI
718 @item isP
719 @item isB
720 @item avgQP
721 @item qComp
722 @item avgIITex
723 @item avgPITex
724 @item avgPPTex
725 @item avgBPTex
726 @item avgTex
727 @end table
729 @c man end
731 @ignore
733 @setfilename ffmpeg
734 @settitle FFmpeg video converter
736 @c man begin SEEALSO
737 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
738 @c man end
740 @c man begin AUTHOR
741 Fabrice Bellard
742 @c man end
744 @end ignore
746 @section Protocols
748 The filename can be @file{-} to read from standard input or to write
749 to standard output.
751 FFmpeg also handles many protocols specified with an URL syntax.
753 Use 'ffmpeg -formats' to see a list of the supported protocols.
755 The protocol @code{http:} is currently used only to communicate with
756 FFserver (see the FFserver documentation). When FFmpeg will be a
757 video player it will also be used for streaming :-)
759 @chapter Tips
761 @itemize
762 @item For streaming at very low bitrate application, use a low frame rate
763 and a small GOP size. This is especially true for RealVideo where
764 the Linux player does not seem to be very fast, so it can miss
765 frames. An example is:
767 @example
768 ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
769 @end example
771 @item The parameter 'q' which is displayed while encoding is the current
772 quantizer. The value 1 indicates that a very good quality could
773 be achieved. The value 31 indicates the worst quality. If q=31 appears
774 too often, it means that the encoder cannot compress enough to meet
775 your bitrate. You must either increase the bitrate, decrease the
776 frame rate or decrease the frame size.
778 @item If your computer is not fast enough, you can speed up the
779 compression at the expense of the compression ratio. You can use
780 '-me zero' to speed up motion estimation, and '-intra' to disable
781 motion estimation completely (you have only I-frames, which means it
782 is about as good as JPEG compression).
784 @item To have very low audio bitrates, reduce the sampling frequency
785 (down to 22050 kHz for MPEG audio, 22050 or 11025 for AC3).
787 @item To have a constant quality (but a variable bitrate), use the option
788 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
789 quality).
791 @item When converting video files, you can use the '-sameq' option which
792 uses the same quality factor in the encoder as in the decoder.
793 It allows almost lossless encoding.
795 @end itemize
798 @chapter external libraries
800 FFmpeg can be hooked up with a number of external libraries to add support
801 for more formats.
803 @section AMR
805 AMR comes in two different flavors, WB and NB. FFmpeg can make use of the
806 AMR WB (floating-point mode) and the AMR NB (both floating-point and
807 fixed-point mode) reference decoders and encoders.
809 @itemize
811 @item For AMR WB floating-point download TS26.204 V5.1.0 from
812 @url{}
813 and extract the source to @file{libavcodec/amrwb_float/}.
815 @item For AMR NB floating-point download TS26.104 REL-5 V5.1.0 from
816 @url{}
817 and extract the source to @file{libavcodec/amr_float/}.
818 If you try this on Alpha, you may need to change @code{Word32} to
819 @code{int} in @file{amr/typedef.h}.
821 @item For AMR NB fixed-point download TS26.073 REL-5 V5.1.0 from
822 @url{}
823 and extract the source to @file{libavcodec/amr}.
824 You must also add @code{-DMMS_IO} and remove @code{-pedantic-errors}
825 to/from @code{CFLAGS} in @file{libavcodec/amr/makefile}, i.e.
826 ``@code{CFLAGS = -Wall -I. \$(CFLAGS_\$(MODE)) -D\$(VAD) -DMMS_IO}''.
828 @end itemize
831 @chapter Supported File Formats and Codecs
833 You can use the @code{-formats} option to have an exhaustive list.
835 @section File Formats
837 FFmpeg supports the following file formats through the @code{libavformat}
838 library:
840 @multitable @columnfractions .4 .1 .1 .4
841 @item Supported File Format @tab Encoding @tab Decoding @tab Comments
842 @item MPEG audio @tab X @tab X
843 @item MPEG-1 systems @tab X @tab X
844 @tab muxed audio and video
845 @item MPEG-2 PS @tab X @tab X
846 @tab also known as @code{VOB} file
847 @item MPEG-2 TS @tab @tab X
848 @tab also known as DVB Transport Stream
849 @item ASF@tab X @tab X
850 @item AVI@tab X @tab X
851 @item WAV@tab X @tab X
852 @item Macromedia Flash@tab X @tab X
853 @tab Only embedded audio is decoded.
854 @item FLV @tab X @tab X
855 @tab Macromedia Flash video files
856 @item Real Audio and Video @tab X @tab X
857 @item Raw AC3 @tab X @tab X
858 @item Raw MJPEG @tab X @tab X
859 @item Raw MPEG video @tab X @tab X
860 @item Raw PCM8/16 bits, mulaw/Alaw@tab X @tab X
861 @item Raw CRI ADX audio @tab X @tab X
862 @item Raw Shorten audio @tab @tab X
863 @item SUN AU format @tab X @tab X
864 @item NUT @tab X @tab X @tab NUT Open Container Format
865 @item QuickTime @tab X @tab X
866 @item MPEG-4 @tab X @tab X
867 @tab MPEG-4 is a variant of QuickTime.
868 @item Raw MPEG4 video @tab X @tab X
869 @item DV @tab X @tab X
870 @item 4xm @tab @tab X
871 @tab 4X Technologies format, used in some games.
872 @item Playstation STR @tab @tab X
873 @item Id RoQ @tab @tab X
874 @tab Used in Quake III, Jedi Knight 2, other computer games.
875 @item Interplay MVE @tab @tab X
876 @tab Format used in various Interplay computer games.
877 @item WC3 Movie @tab @tab X
878 @tab Multimedia format used in Origin's Wing Commander III computer game.
879 @item Sega FILM/CPK @tab @tab X
880 @tab Used in many Sega Saturn console games.
881 @item Westwood Studios VQA/AUD @tab @tab X
882 @tab Multimedia formats used in Westwood Studios games.
883 @item Id Cinematic (.cin) @tab @tab X
884 @tab Used in Quake II.
885 @item FLIC format @tab @tab X
886 @tab .fli/.flc files
887 @item Sierra VMD @tab @tab X
888 @tab Used in Sierra CD-ROM games.
889 @item Sierra Online @tab @tab X
890 @tab .sol files used in Sierra Online games.
891 @item Matroska @tab @tab X
892 @item Electronic Arts Multimedia @tab @tab X
893 @tab Used in various EA games; files have extensions like WVE and UV2.
894 @item Nullsoft Video (NSV) format @tab @tab X
895 @item ADTS AAC audio @tab X @tab X
896 @item Creative VOC @tab X @tab X @tab Created for the Sound Blaster Pro.
897 @item American Laser Games MM @tab @tab X
898 @tab Multimedia format used in games like Mad Dog McCree
899 @item AVS @tab @tab X
900 @tab Multimedia format used by the Creature Shock game.
901 @item Smacker @tab @tab X
902 @tab Multimedia format used by many games.
903 @item GXF @tab X @tab X
904 @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley playout servers.
905 @item CIN @tab @tab X
906 @tab Multimedia format used by Delphine Software games.
907 @item MXF @tab @tab X
908 @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
909 @item SEQ @tab @tab X
910 @tab Tiertex .seq files used in the DOS CDROM version of the game Flashback.
911 @end multitable
913 @code{X} means that encoding (resp. decoding) is supported.
915 @section Image Formats
917 FFmpeg can read and write images for each frame of a video sequence. The
918 following image formats are supported:
920 @multitable @columnfractions .4 .1 .1 .4
921 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
922 @item PGM, PPM @tab X @tab X
923 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
924 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
925 @item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
926 @item .Y.U.V @tab X @tab X @tab one raw file per component
927 @item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
928 @item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
929 @item Targa @tab @tab X @tab Targa (.TGA) image format.
930 @item TIFF @tab @tab X @tab Only 24 bit/pixel images are supported.
931 @item SGI @tab X @tab X @tab SGI RGB image format
932 @end multitable
934 @code{X} means that encoding (resp. decoding) is supported.
936 @section Video Codecs
938 @multitable @columnfractions .4 .1 .1 .4
939 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
940 @item MPEG-1 video @tab X @tab X
941 @item MPEG-2 video @tab X @tab X
942 @item MPEG-4 @tab X @tab X
943 @item MSMPEG4 V1 @tab X @tab X
944 @item MSMPEG4 V2 @tab X @tab X
945 @item MSMPEG4 V3 @tab X @tab X
946 @item WMV7 @tab X @tab X
947 @item WMV8 @tab X @tab X @tab not completely working
948 @item WMV9 @tab @tab X @tab not completely working
949 @item VC1 @tab @tab X
950 @item H.261 @tab X @tab X
951 @item H.263(+) @tab X @tab X @tab also known as RealVideo 1.0
952 @item H.264 @tab @tab X
953 @item RealVideo 1.0 @tab X @tab X
954 @item RealVideo 2.0 @tab X @tab X
955 @item MJPEG @tab X @tab X
956 @item lossless MJPEG @tab X @tab X
957 @item JPEG-LS @tab X @tab X @tab fourcc: MJLS, lossless and near-lossless is supported
958 @item Apple MJPEG-B @tab @tab X
959 @item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
960 @item DV @tab X @tab X
961 @item HuffYUV @tab X @tab X
962 @item FFmpeg Video 1 @tab X @tab X @tab experimental lossless codec (fourcc: FFV1)
963 @item FFmpeg Snow @tab X @tab X @tab experimental wavelet codec (fourcc: SNOW)
964 @item Asus v1 @tab X @tab X @tab fourcc: ASV1
965 @item Asus v2 @tab X @tab X @tab fourcc: ASV2
966 @item Creative YUV @tab @tab X @tab fourcc: CYUV
967 @item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
968 @item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
969 @item On2 VP3 @tab @tab X @tab still experimental
970 @item On2 VP5 @tab @tab X @tab fourcc: VP50
971 @item On2 VP6 @tab @tab X @tab fourcc: VP60,VP61,VP62
972 @item Theora @tab X @tab X @tab still experimental
973 @item Intel Indeo 3 @tab @tab X
974 @item FLV @tab X @tab X @tab Sorenson H.263 used in Flash
975 @item Flash Screen Video @tab @tab X @tab fourcc: FSV1
976 @item ATI VCR1 @tab @tab X @tab fourcc: VCR1
977 @item ATI VCR2 @tab @tab X @tab fourcc: VCR2
978 @item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
979 @item 4X Video @tab @tab X @tab Used in certain computer games.
980 @item Sony Playstation MDEC @tab @tab X
981 @item Id RoQ @tab @tab X @tab Used in Quake III, Jedi Knight 2, other computer games.
982 @item Xan/WC3 @tab @tab X @tab Used in Wing Commander III .MVE files.
983 @item Interplay Video @tab @tab X @tab Used in Interplay .MVE files.
984 @item Apple Animation @tab @tab X @tab fourcc: 'rle '
985 @item Apple Graphics @tab @tab X @tab fourcc: 'smc '
986 @item Apple Video @tab @tab X @tab fourcc: rpza
987 @item Apple QuickDraw @tab @tab X @tab fourcc: qdrw
988 @item Cinepak @tab @tab X
989 @item Microsoft RLE @tab @tab X
990 @item Microsoft Video-1 @tab @tab X
991 @item Westwood VQA @tab @tab X
992 @item Id Cinematic Video @tab @tab X @tab Used in Quake II.
993 @item Planar RGB @tab @tab X @tab fourcc: 8BPS
994 @item FLIC video @tab @tab X
995 @item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK
996 @item Duck TrueMotion v2 @tab @tab X @tab fourcc: TM20
997 @item VMD Video @tab @tab X @tab Used in Sierra VMD files.
998 @item MSZH @tab @tab X @tab Part of LCL
999 @item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental
1000 @item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC
1001 @item IBM Ultimotion @tab @tab X @tab fourcc: ULTI
1002 @item Miro VideoXL @tab @tab X @tab fourcc: VIXL
1003 @item QPEG @tab @tab X @tab fourccs: QPEG, Q1.0, Q1.1
1004 @item LOCO @tab @tab X @tab
1005 @item Winnov WNV1 @tab @tab X @tab
1006 @item Autodesk Animator Studio Codec @tab @tab X @tab fourcc: AASC
1007 @item Fraps FPS1 @tab @tab X @tab
1008 @item CamStudio @tab @tab X @tab fourcc: CSCD
1009 @item American Laser Games Video @tab @tab X @tab Used in games like Mad Dog McCree
1010 @item ZMBV @tab X @tab X @tab Encoder works only on PAL8
1011 @item AVS Video @tab @tab X @tab Video encoding used by the Creature Shock game.
1012 @item Smacker Video @tab @tab X @tab Video encoding used in Smacker.
1013 @item RTjpeg @tab @tab X @tab Video encoding used in NuppelVideo files.
1014 @item KMVC @tab @tab X @tab Codec used in Worms games.
1015 @item VMware Video @tab @tab X @tab Codec used in videos captured by VMware.
1016 @item Cin Video @tab @tab X @tab Codec used in Delphine Software games.
1017 @item Tiertex Seq Video @tab @tab X @tab Codec used in DOS CDROM FlashBack game.
1018 @end multitable
1020 @code{X} means that encoding (resp. decoding) is supported.
1022 @section Audio Codecs
1024 @multitable @columnfractions .4 .1 .1 .1 .7
1025 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
1026 @item MPEG audio layer 2 @tab IX @tab IX
1027 @item MPEG audio layer 1/3 @tab IX @tab IX
1028 @tab MP3 encoding is supported through the external library LAME.
1029 @item AC3 @tab IX @tab IX
1030 @tab liba52 is used internally for decoding.
1031 @item Vorbis @tab X @tab X
1032 @item WMA V1/V2 @tab @tab X
1033 @item AAC @tab X @tab X
1034 @tab Supported through the external library libfaac/libfaad.
1035 @item Microsoft ADPCM @tab X @tab X
1036 @item MS IMA ADPCM @tab X @tab X
1037 @item QT IMA ADPCM @tab @tab X
1038 @item 4X IMA ADPCM @tab @tab X
1039 @item G.726 ADPCM @tab X @tab X
1040 @item Duck DK3 IMA ADPCM @tab @tab X
1041 @tab Used in some Sega Saturn console games.
1042 @item Duck DK4 IMA ADPCM @tab @tab X
1043 @tab Used in some Sega Saturn console games.
1044 @item Westwood Studios IMA ADPCM @tab @tab X
1045 @tab Used in Westwood Studios games like Command and Conquer.
1046 @item SMJPEG IMA ADPCM @tab @tab X
1047 @tab Used in certain Loki game ports.
1048 @item CD-ROM XA ADPCM @tab @tab X
1049 @item CRI ADX ADPCM @tab X @tab X
1050 @tab Used in Sega Dreamcast games.
1051 @item Electronic Arts ADPCM @tab @tab X
1052 @tab Used in various EA titles.
1053 @item Creative ADPCM @tab @tab X
1054 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
1055 @item RA144 @tab @tab X
1056 @tab Real 14400 bit/s codec
1057 @item RA288 @tab @tab X
1058 @tab Real 28800 bit/s codec
1059 @item RADnet @tab X @tab IX
1060 @tab Real low bitrate AC3 codec, liba52 is used for decoding.
1061 @item AMR-NB @tab X @tab X
1062 @tab Supported through an external library.
1063 @item AMR-WB @tab X @tab X
1064 @tab Supported through an external library.
1065 @item DV audio @tab @tab X
1066 @item Id RoQ DPCM @tab @tab X
1067 @tab Used in Quake III, Jedi Knight 2, other computer games.
1068 @item Interplay MVE DPCM @tab @tab X
1069 @tab Used in various Interplay computer games.
1070 @item Xan DPCM @tab @tab X
1071 @tab Used in Origin's Wing Commander IV AVI files.
1072 @item Sierra Online DPCM @tab @tab X
1073 @tab Used in Sierra Online game audio files.
1074 @item Apple MACE 3 @tab @tab X
1075 @item Apple MACE 6 @tab @tab X
1076 @item FLAC lossless audio @tab @tab X
1077 @item Shorten lossless audio @tab @tab X
1078 @item Apple lossless audio @tab @tab X
1079 @tab QuickTime fourcc 'alac'
1080 @item FFmpeg Sonic @tab X @tab X
1081 @tab experimental lossy/lossless codec
1082 @item Qdesign QDM2 @tab @tab X
1083 @tab there are still some distortions
1084 @item Real COOK @tab @tab X
1085 @tab All versions except 5.1 are supported
1086 @item DSP Group TrueSpeech @tab @tab X
1087 @item True Audio (TTA) @tab @tab X
1088 @item Smacker Audio @tab @tab X
1089 @item WavPack Audio @tab @tab X
1090 @item Cin Audio @tab @tab X
1091 @tab Codec used in Delphine Software games.
1092 @item Intel Music Coder @tab @tab X
1093 @item Musepack @tab @tab X
1094 @tab Only SV7 is supported
1095 @end multitable
1097 @code{X} means that encoding (resp. decoding) is supported.
1099 @code{I} means that an integer-only version is available, too (ensures high
1100 performance on systems without hardware floating point support).
1102 @chapter Platform Specific information
1104 @section BSD
1106 BSD make will not build FFmpeg, you need to install and use GNU Make
1107 (@file{gmake}).
1109 @section Windows
1111 @subsection Native Windows compilation
1113 @itemize
1114 @item Install the current versions of MSYS and MinGW from
1115 @url{}. You can find detailed installation
1116 instructions in the download section and the FAQ.
1118 @item If you want to test the FFplay, also download
1119 the MinGW development library of SDL 1.2.x
1120 (@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
1121 @url{}. Unpack it in a temporary directory, and
1122 unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
1123 directory. Edit the @file{sdl-config} script so that it gives the
1124 correct SDL directory when invoked.
1126 @item Extract the current version of FFmpeg.
1128 @item Start the MSYS shell (file @file{msys.bat}).
1130 @item Change to the FFmpeg directory and follow
1131 the instructions of how to compile FFmpeg (file
1132 @file{INSTALL}). Usually, launching @file{./configure} and @file{make}
1133 suffices. If you have problems using SDL, verify that
1134 @file{sdl-config} can be launched from the MSYS command line.
1136 @item You can install FFmpeg in @file{Program Files/FFmpeg} by typing
1137 @file{make install}. Don't forget to copy @file{SDL.dll} to the place
1138 you launch @file{ffplay} from.
1140 @end itemize
1142 Notes:
1143 @itemize
1145 @item The target @file{make wininstaller} can be used to create a
1146 Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
1147 must be copied to the FFmpeg directory in order to build the
1148 installer.
1150 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
1151 you can build @file{avcodec.dll} and @file{avformat.dll}. With
1152 @code{make install} you install the FFmpeg DLLs and the associated
1153 headers in @file{Program Files/FFmpeg}.
1155 @item Visual C++ compatibility: If you used @code{./configure --enable-shared}
1156 when configuring FFmpeg, FFmpeg tries to use the Microsoft Visual
1157 C++ @code{lib} tool to build @code{avcodec.lib} and
1158 @code{avformat.lib}. With these libraries you can link your Visual C++
1159 code directly with the FFmpeg DLLs (see below).
1161 @end itemize
1163 @subsection Visual C++ compatibility
1165 FFmpeg will not compile under Visual C++ -- and it has too many
1166 dependencies on the GCC compiler to make a port viable. However,
1167 if you want to use the FFmpeg libraries in your own applications,
1168 you can still compile those applications using Visual C++. An
1169 important restriction to this is that you have to use the
1170 dynamically linked versions of the FFmpeg libraries (i.e. the
1171 DLLs), and you have to make sure that Visual-C++-compatible
1172 import libraries are created during the FFmpeg build process.
1174 This description of how to use the FFmpeg libraries with Visual C++ is
1175 based on Visual C++ 2005 Express Edition Beta 2. If you have a different
1176 version, you might have to modify the procedures slightly.
1178 Here are the step-by-step instructions for building the FFmpeg libraries
1179 so they can be used with Visual C++:
1181 @enumerate
1183 @item Install Visual C++ (if you haven't done so already).
1185 @item Install MinGW and MSYS as described above.
1187 @item Add a call to @file{vcvars32.bat} (which sets up the environment
1188 variables for the Visual C++ tools) as the first line of
1189 @file{msys.bat}. The standard location for @file{vcvars32.bat} is
1190 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
1191 and the standard location for @file{msys.bat} is
1192 @file{C:\msys\1.0\msys.bat}. If this corresponds to your setup, add the
1193 following line as the first line of @file{msys.bat}:
1195 @code{call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"}
1197 @item Start the MSYS shell (file @file{msys.bat}) and type @code{link.exe}.
1198 If you get a help message with the command line options of @code{link.exe},
1199 this means your environment variables are set up correctly, the
1200 Microsoft linker is on the path and will be used by FFmpeg to
1201 create Visual-C++-compatible import libraries.
1203 @item Extract the current version of FFmpeg and change to the FFmpeg directory.
1205 @item Type the command
1206 @code{./configure --enable-shared --disable-static --enable-memalign-hack}
1207 to configure and, if that didn't produce any errors,
1208 type @code{make} to build FFmpeg.
1210 @item The subdirectories @file{libavformat}, @file{libavcodec}, and
1211 @file{libavutil} should now contain the files @file{avformat.dll},
1212 @file{avformat.lib}, @file{avcodec.dll}, @file{avcodec.lib},
1213 @file{avutil.dll}, and @file{avutil.lib}, respectively. Copy the three
1214 DLLs to your System32 directory (typically @file{C:\Windows\System32}).
1216 @end enumerate
1218 And here is how to use these libraries with Visual C++:
1220 @enumerate
1222 @item Create a new console application ("File / New / Project") and then
1223 select "Win32 Console Application". On the appropriate page of the
1224 Application Wizard, uncheck the "Precompiled headers" option.
1226 @item Write the source code for your application, or, for testing, just
1227 copy the code from an existing sample application into the source file
1228 that Visual C++ has already created for you. (Note that your source
1229 filehas to have a @code{.cpp} extension; otherwise, Visual C++ won't
1230 compile the FFmpeg headers correctly because in C mode, it doesn't
1231 recognize the @code{inline} keyword.) For example, you can copy
1232 @file{output_example.c} from the FFmpeg distribution (but you will
1233 have to make minor modifications so the code will compile under
1234 C++, see below).
1236 @item Open the "Project / Properties" dialog box. In the "Configuration"
1237 combo box, select "All Configurations" so that the changes you make will
1238 affect both debug and release builds. In the tree view on the left hand
1239 side, select "C/C++ / General", then edit the "Additional Include
1240 Directories" setting to contain the complete paths to the
1241 @file{libavformat}, @file{libavcodec}, and @file{libavutil}
1242 subdirectories of your FFmpeg directory. Note that the directories have
1243 to be separated using semicolons. Now select "Linker / General" from the
1244 tree view and edit the "Additional Library Directories" setting to
1245 contain the same three directories.
1247 @item Still in the "Project / Properties" dialog box, select "Linker / Input"
1248 from the tree view, then add the files @file{avformat.lib},
1249 @file{avcodec.lib}, and @file{avutil.lib} to the end of the "Additional
1250 Dependencies". Note that the names of the libraries have to be separated
1251 using spaces.
1253 @item Now, select "C/C++ / Code Generation" from the tree view. Select
1254 "Debug" in the "Configuration" combo box. Make sure that "Runtime
1255 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
1256 the "Configuration" combo box and make sure that "Runtime Library" is
1257 set to "Multi-threaded DLL".
1259 @item Click "OK" to close the "Project / Properties" dialog box and build
1260 the application. Hopefully, it should compile and run cleanly. If you
1261 used @file{output_example.c} as your sample application, you will get a
1262 few compiler errors, but they are easy to fix. The first type of error
1263 occurs because Visual C++ doesn't allow an @code{int} to be converted to
1264 an @code{enum} without a cast. To solve the problem, insert the required
1265 casts (this error occurs once for a @code{CodecID} and once for a
1266 @code{CodecType}). The second type of error occurs because C++ requires
1267 the return value of @code{malloc} to be cast to the exact type of the
1268 pointer it is being assigned to. Visual C++ will complain that, for
1269 example, @code{(void *)} is being assigned to @code{(uint8_t *)} without
1270 an explicit cast. So insert an explicit cast in these places to silence
1271 the compiler. The third type of error occurs because the @code{snprintf}
1272 library function is called @code{_snprintf} under Visual C++. So just
1273 add an underscore to fix the problem. With these changes,
1274 @file{output_example.c} should compile under Visual C++, and the
1275 resulting executable should produce valid video files.
1277 @end enumerate
1279 @subsection Cross compilation for Windows with Linux
1281 You must use the MinGW cross compilation tools available at
1282 @url{}.
1284 Then configure FFmpeg with the following options:
1285 @example
1286 ./configure --enable-mingw32 --cross-prefix=i386-mingw32msvc-
1287 @end example
1288 (you can change the cross-prefix according to the prefix chosen for the
1289 MinGW tools).
1291 Then you can easily test FFmpeg with Wine
1292 (@url{}).
1294 @subsection Compilation under Cygwin
1296 Cygwin works very much like Unix.
1298 Just install your Cygwin with all the "Base" packages, plus the
1299 following "Devel" ones:
1300 @example
1301 binutils, gcc-core, make, subversion
1302 @end example
1304 Do not install binutils-20060709-1 (they are buggy on shared builds);
1305 use binutils-20050610-1 instead.
1307 Then run
1309 @example
1310 ./configure --enable-static --disable-shared
1311 @end example
1313 to make a static build or
1315 @example
1316 ./configure --enable-shared --disable-static
1317 @end example
1319 to build shared libraries.
1321 If you want to build FFmpeg with additional libraries, download Cygwin
1322 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository
1323 and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
1324 (@url{}).
1326 @subsection Crosscompilation for Windows under Cygwin
1328 With Cygwin you can create Windows binaries that don't need the cygwin1.dll.
1330 Just install your Cygwin as explained before, plus these additional
1331 "Devel" packages:
1332 @example
1333 gcc-mingw-core, mingw-runtime, mingw-zlib
1334 @end example
1336 and add some special flags to your configure invocation.
1338 For a static build run
1339 @example
1340 ./configure --enable-mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
1341 @end example
1343 and for a build with shared libraries
1344 @example
1345 ./configure --enable-mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
1346 @end example
1348 @section BeOS
1350 The configure script should guess the configuration itself.
1351 Networking support is currently not finished.
1352 errno issues fixed by Andrew Bachmann.
1354 Old stuff:
1356 Fran├žois Revol - revol at free dot fr - April 2002
1358 The configure script should guess the configuration itself,
1359 however I still didn't test building on the net_server version of BeOS.
1361 FFserver is broken (needs poll() implementation).
1363 There are still issues with errno codes, which are negative in BeOS, and
1364 that FFmpeg negates when returning. This ends up turning errors into
1365 valid results, then crashes.
1366 (To be fixed)
1368 @chapter Developers Guide
1370 @section API
1371 @itemize @bullet
1372 @item libavcodec is the library containing the codecs (both encoding and
1373 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
1375 @item libavformat is the library containing the file format handling (mux and
1376 demux code for several formats). Look at @file{ffplay.c} to use it in a
1377 player. See @file{output_example.c} to use it to generate audio or video
1378 streams.
1380 @end itemize
1382 @section Integrating libavcodec or libavformat in your program
1384 You can integrate all the source code of the libraries to link them
1385 statically to avoid any version problem. All you need is to provide a
1386 'config.mak' and a 'config.h' in the parent directory. See the defines
1387 generated by ./configure to understand what is needed.
1389 You can use libavcodec or libavformat in your commercial program, but
1390 @emph{any patch you make must be published}. The best way to proceed is
1391 to send your patches to the FFmpeg mailing list.
1393 @node Coding Rules
1394 @section Coding Rules
1396 FFmpeg is programmed in the ISO C90 language with a few additional
1397 features from ISO C99, namely:
1398 @itemize @bullet
1399 @item
1400 the @samp{inline} keyword;
1401 @item
1402 @samp{//} comments;
1403 @item
1404 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
1405 @item
1406 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
1407 @end itemize
1409 These features are supported by all compilers we care about, so we won't
1410 accept patches to remove their use unless they absolutely don't impair
1411 clarity and performance.
1413 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
1414 compiles with several other compilers, such as the Compaq ccc compiler
1415 or Sun Studio 9, and we would like to keep it that way unless it would
1416 be exceedingly involved. To ensure compatibility, please don't use any
1417 additional C99 features or GCC extensions. Especially watch out for:
1418 @itemize @bullet
1419 @item
1420 mixing statements and declarations;
1421 @item
1422 @samp{long long} (use @samp{int64_t} instead);
1423 @item
1424 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
1425 @item
1426 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
1427 @end itemize
1429 Indent size is 4.
1430 The presentation is the one specified by 'indent -i4 -kr -nut'.
1431 The TAB character is forbidden outside of Makefiles as is any
1432 form of trailing whitespace. Commits containing either will be
1433 rejected by the Subversion repository.
1435 Main priority in FFmpeg is simplicity and small code size (=less
1436 bugs).
1438 Comments: Use the JavaDoc/Doxygen
1439 format (see examples below) so that code documentation
1440 can be generated automatically. All nontrivial functions should have a comment
1441 above them explaining what the function does, even if it's just one sentence.
1442 All structures and their member variables should be documented, too.
1443 @example
1444 /**
1445 * @@file mpeg.c
1446 * MPEG codec.
1447 * @@author ...
1448 */
1450 /**
1451 * Summary sentence.
1452 * more text ...
1453 * ...
1454 */
1455 typedef struct Foobar@{
1456 int var1; /**< var1 description */
1457 int var2; ///< var2 description
1458 /** var3 description */
1459 int var3;
1460 @} Foobar;
1462 /**
1463 * Summary sentence.
1464 * more text ...
1465 * ...
1466 * @@param my_parameter description of my_parameter
1467 * @@return return value description
1468 */
1469 int myfunc(int my_parameter)
1470 ...
1471 @end example
1473 fprintf and printf are forbidden in libavformat and libavcodec,
1474 please use av_log() instead.
1476 @section Development Policy
1478 @enumerate
1479 @item
1480 You must not commit code which breaks FFmpeg! (Meaning unfinished but
1481 enabled code which breaks compilation or compiles but does not work or
1482 breaks the regression tests)
1483 You can commit unfinished stuff (for testing etc), but it must be disabled
1484 (#ifdef etc) by default so it does not interfere with other developers'
1485 work.
1486 @item
1487 You don't have to over-test things. If it works for you, and you think it
1488 should work for others, then commit. If your code has problems
1489 (portability, triggers compiler bugs, unusual environment etc) they will be
1490 reported and eventually fixed.
1491 @item
1492 Do not commit unrelated changes together, split them into self-contained
1493 pieces.
1494 @item
1495 Do not change behavior of the program (renaming options etc) without
1496 first discussing it on the ffmpeg-devel mailing list. Do not remove
1497 functionality from the code. Just improve!
1499 Note: Redundant code can be removed.
1500 @item
1501 Do not commit changes to the build system (Makefiles, configure script)
1502 which change behavior, defaults etc, without asking first. The same
1503 applies to compiler warning fixes, trivial looking fixes and to code
1504 maintained by other developers. We usually have a reason for doing things
1505 the way we do. Send your changes as patches to the ffmpeg-devel mailing
1506 list, and if the code maintainers say OK, you may commit. This does not
1507 apply to files you wrote and/or maintain.
1508 @item
1509 We refuse source indentation and other cosmetic changes if they are mixed
1510 with functional changes, such commits will be rejected and removed. Every
1511 developer has his own indentation style, you should not change it. Of course
1512 if you (re)write something, you can use your own style, even though we would
1513 prefer if the indentation throughout FFmpeg was consistent (Many projects
1514 force a given indentation style - we don't.). If you really need to make
1515 indentation changes (try to avoid this), separate them strictly from real
1516 changes.
1518 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
1519 then either do NOT change the indentation of the inner part within (don't
1520 move it to the right)! or do so in a separate commit
1521 @item
1522 Always fill out the commit log message. Describe in a few lines what you
1523 changed and why. You can refer to mailing list postings if you fix a
1524 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1525 @item
1526 If you apply a patch by someone else, include the name and email address in
1527 the log message. Since the ffmpeg-cvslog mailing list is publicly
1528 archived you should add some SPAM protection to the email address. Send an
1529 answer to ffmpeg-devel (or wherever you got the patch from) saying that
1530 you applied the patch.
1531 @item
1532 Do NOT commit to code actively maintained by others without permission.
1533 Send a patch to ffmpeg-devel instead. If noone answers within a reasonable
1534 timeframe (12h for build failures and security fixes, 3 days small changes,
1535 1 week for big patches) then commit your patch if you think it's OK.
1536 Also note, the maintainer can simply ask for more time to review!
1537 @item
1538 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
1539 are sent there and reviewed by all the other developers. Bugs and possible
1540 improvements or general questions regarding commits are discussed there. We
1541 expect you to react if problems with your code are uncovered.
1542 @item
1543 Update the documentation if you change behavior or add features. If you are
1544 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
1545 maintainer(s) will review and commit your stuff.
1546 @item
1547 Never write to unallocated memory, never write over the end of arrays,
1548 always check values read from some untrusted source before using them
1549 as array index or other risky things.
1550 @item
1551 Remember to check if you need to bump versions for the specific libav
1552 parts (libavutil, libavcodec, libavformat) you are changing. You need
1553 to change the version integer and the version string.
1554 Incrementing the first component means no backward compatibility to
1555 previous versions (e.g. removal of a function from the public API).
1556 Incrementing the second component means backward compatible change
1557 (e.g. addition of a function to the public API).
1558 Incrementing the third component means a noteworthy binary compatible
1559 change (e.g. encoder bug fix that matters for the decoder).
1560 @item
1561 If you add a new codec, remember to update the changelog, add it to
1562 the supported codecs table in the documentation and bump the second
1563 component of the @file{libavcodec} version number appropriately. If
1564 it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
1565 is only a decoder.
1566 @end enumerate
1568 We think our rules are not too hard. If you have comments, contact us.
1570 Note, these rules are mostly borrowed from the MPlayer project.
1572 @section Submitting patches
1574 First, (@pxref{Coding Rules}) above if you didn't yet.
1576 When you submit your patch, try to send a unified diff (diff '-up'
1577 option). I cannot read other diffs :-)
1579 Also please do not submit patches which contain several unrelated changes.
1580 Split them into individual self-contained patches; this makes reviewing
1581 them much easier.
1583 Run the regression tests before submitting a patch so that you can
1584 verify that there are no big problems.
1586 Patches should be posted as base64 encoded attachments (or any other
1587 encoding which ensures that the patch won't be trashed during
1588 transmission) to the ffmpeg-devel mailing list, see
1589 @url{}
1591 It also helps quite a bit if you tell us what the patch does (for example
1592 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
1593 and has no lrint()')
1595 We reply to all submitted patches and either apply or reject with some
1596 explanation why, but sometimes we are quite busy so it can take a week or two.
1598 @section Regression tests
1600 Before submitting a patch (or committing to the repository), you should at least
1601 test that you did not break anything.
1603 The regression tests build a synthetic video stream and a synthetic
1604 audio stream. These are then encoded and decoded with all codecs or
1605 formats. The CRC (or MD5) of each generated file is recorded in a
1606 result file. A 'diff' is launched to compare the reference results and
1607 the result file.
1609 The regression tests then go on to test the FFserver code with a
1610 limited set of streams. It is important that this step runs correctly
1611 as well.
1613 Run 'make test' to test all the codecs and formats.
1615 Run 'make fulltest' to test all the codecs, formats and FFserver.
1617 [Of course, some patches may change the results of the regression tests. In
1618 this case, the reference results of the regression tests shall be modified
1619 accordingly].
1621 @bye