[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 grab video and audio from devices given that you specify the input
30 format and device.
32 @example
33 ffmpeg -f audio_device -i /dev/dsp -f video4linux2 -i /dev/video0 /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{http://bytesex.org/xawtv/}) 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 -s cif -i :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 -s cif -i :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 64k /tmp/a.mp2 -ab 128k /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 libmp3lame -ab 128k 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-libmp3lame} 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 As a general rule, options are applied to the next specified
158 file. Therefore, order is important, and you can have the same
159 option on the command line multiple times. Each occurrence is
160 then applied to the next input or output file.
162 * To set the video bitrate of the output file to 64kbit/s:
163 @example
164 ffmpeg -i input.avi -b 64k output.avi
165 @end example
167 * To force the frame rate of the input and output file to 24 fps:
168 @example
169 ffmpeg -r 24 -i input.avi output.avi
170 @end example
172 * To force the frame rate of the output file to 24 fps:
173 @example
174 ffmpeg -i input.avi -r 24 output.avi
175 @end example
177 * To force the frame rate of input file to 1 fps and the output file to 24 fps:
178 @example
179 ffmpeg -r 1 -i input.avi -r 24 output.avi
180 @end example
182 The format option may be needed for raw input files.
184 By default, FFmpeg tries to convert as losslessly as possible: It
185 uses the same audio and video parameters for the outputs as the one
186 specified for the inputs.
187 @c man end
189 @c man begin OPTIONS
190 @section Main options
192 @table @option
193 @item -L
194 Show license.
196 @item -h
197 Show help.
199 @item -version
200 Show version.
202 @item -formats
203 Show available formats, codecs, protocols, ...
205 @item -f fmt
206 Force format.
208 @item -i filename
209 input filename
211 @item -y
212 Overwrite output files.
214 @item -t duration
215 Set the recording time in seconds.
216 @code{hh:mm:ss[.xxx]} syntax is also supported.
218 @item -fs limit_size
219 Set the file size limit.
221 @item -ss position
222 Seek to given time position in seconds.
223 @code{hh:mm:ss[.xxx]} syntax is also supported.
225 @item -itsoffset offset
226 Set the input time offset in seconds.
227 @code{[-]hh:mm:ss[.xxx]} syntax is also supported.
228 This option affects all the input files that follow it.
229 The offset is added to the timestamps of the input files.
230 Specifying a positive offset means that the corresponding
231 streams are delayed by 'offset' seconds.
233 @item -title string
234 Set the title.
236 @item -timestamp time
237 Set the timestamp.
239 @item -author string
240 Set the author.
242 @item -copyright string
243 Set the copyright.
245 @item -comment string
246 Set the comment.
248 @item -album string
249 Set the album.
251 @item -track number
252 Set the track.
254 @item -year number
255 Set the year.
257 @item -v verbose
258 Control amount of logging.
260 @item -target type
261 Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
262 "ntsc-svcd", ... ). All the format options (bitrate, codecs,
263 buffer sizes) are then set automatically. You can just type:
265 @example
266 ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg
267 @end example
269 Nevertheless you can specify additional options as long as you know
270 they do not conflict with the standard, as in:
272 @example
273 ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
274 @end example
276 @item -dframes number
277 Set the number of data frames to record.
279 @item -scodec codec
280 Force subtitle codec ('copy' to copy stream).
282 @item -newsubtitle
283 Add a new subtitle stream to the current output stream.
285 @item -slang code
286 Set the ISO 639 language code (3 letters) of the current subtitle stream.
288 @end table
290 @section Video Options
292 @table @option
293 @item -b bitrate
294 Set the video bitrate in bit/s (default = 200 kb/s).
295 @item -vframes number
296 Set the number of video frames to record.
297 @item -r fps
298 Set frame rate (Hz value, fraction or abbreviation), (default = 25).
299 @item -s size
300 Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
301 The following abbreviations are recognized:
302 @table @samp
303 @item sqcif
304 128x96
305 @item qcif
306 176x144
307 @item cif
308 352x288
309 @item 4cif
310 704x576
311 @item qqvga
312 160x120
313 @item qvga
314 320x240
315 @item vga
316 640x480
317 @item svga
318 800x600
319 @item xga
320 1024x768
321 @item uxga
322 1600x1200
323 @item qxga
324 2048x1536
325 @item sxga
326 1280x1024
327 @item qsxga
328 2560x2048
329 @item hsxga
330 5120x4096
331 @item wvga
332 852x480
333 @item wxga
334 1366x768
335 @item wsxga
336 1600x1024
337 @item wuxga
338 1920x1200
339 @item woxga
340 2560x1600
341 @item wqsxga
342 3200x2048
343 @item wquxga
344 3840x2400
345 @item whsxga
346 6400x4096
347 @item whuxga
348 7680x4800
349 @item cga
350 320x200
351 @item ega
352 640x350
353 @item hd480
354 852x480
355 @item hd720
356 1280x720
357 @item hd1080
358 1920x1080
359 @end table
361 @item -aspect aspect
362 Set aspect ratio (4:3, 16:9 or 1.3333, 1.7777).
363 @item -croptop size
364 Set top crop band size (in pixels).
365 @item -cropbottom size
366 Set bottom crop band size (in pixels).
367 @item -cropleft size
368 Set left crop band size (in pixels).
369 @item -cropright size
370 Set right crop band size (in pixels).
371 @item -padtop size
372 Set top pad band size (in pixels).
373 @item -padbottom size
374 Set bottom pad band size (in pixels).
375 @item -padleft size
376 Set left pad band size (in pixels).
377 @item -padright size
378 Set right pad band size (in pixels).
379 @item -padcolor (hex color)
380 Set color of padded bands. The value for padcolor is expressed
381 as a six digit hexadecimal number where the first two digits
382 represent red, the middle two digits green and last two digits
383 blue (default = 000000 (black)).
384 @item -vn
385 Disable video recording.
386 @item -bt tolerance
387 Set video bitrate tolerance (in bit/s).
388 @item -maxrate bitrate
389 Set max video bitrate (in bit/s).
390 @item -minrate bitrate
391 Set min video bitrate (in bit/s).
392 @item -bufsize size
393 Set video buffer verifier buffer size (in bits).
394 @item -vcodec codec
395 Force video codec to @var{codec}. Use the @code{copy} special value to
396 tell that the raw codec data must be copied as is.
397 @item -sameq
398 Use same video quality as source (implies VBR).
400 @item -pass n
401 Select the pass number (1 or 2). It is useful to do two pass
402 encoding. The statistics of the video are recorded in the first
403 pass and the video is generated at the exact requested bitrate
404 in the second pass.
406 @item -passlogfile file
407 Set two pass logfile name to @var{file}.
409 @item -newvideo
410 Add a new video stream to the current output stream.
412 @end table
414 @section Advanced Video Options
416 @table @option
417 @item -pix_fmt format
418 Set pixel format. Use 'list' as parameter to show all the supported
419 pixel formats.
420 @item -sws_flags flags
421 Set SwScaler flags (only available when compiled with SwScaler support).
422 @item -g gop_size
423 Set the group of pictures size.
424 @item -intra
425 Use only intra frames.
426 @item -vdt n
427 Discard threshold.
428 @item -qscale q
429 Use fixed video quantizer scale (VBR).
430 @item -qmin q
431 minimum video quantizer scale (VBR)
432 @item -qmax q
433 maximum video quantizer scale (VBR)
434 @item -qdiff q
435 maximum difference between the quantizer scales (VBR)
436 @item -qblur blur
437 video quantizer scale blur (VBR)
438 @item -qcomp compression
439 video quantizer scale compression (VBR)
441 @item -lmin lambda
442 minimum video lagrange factor (VBR)
443 @item -lmax lambda
444 max video lagrange factor (VBR)
445 @item -mblmin lambda
446 minimum macroblock quantizer scale (VBR)
447 @item -mblmax lambda
448 maximum macroblock quantizer scale (VBR)
450 These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
451 but you may use the QP2LAMBDA constant to easily convert from 'q' units:
452 @example
453 ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
454 @end example
456 @item -rc_init_cplx complexity
457 initial complexity for single pass encoding
458 @item -b_qfactor factor
459 qp factor between P- and B-frames
460 @item -i_qfactor factor
461 qp factor between P- and I-frames
462 @item -b_qoffset offset
463 qp offset between P- and B-frames
464 @item -i_qoffset offset
465 qp offset between P- and I-frames
466 @item -rc_eq equation
467 Set rate control equation (@pxref{FFmpeg formula
468 evaluator}) (default = @code{tex^qComp}).
469 @item -rc_override override
470 rate control override for specific intervals
471 @item -me_method method
472 Set motion estimation method to @var{method}.
473 Available methods are (from lowest to best quality):
474 @table @samp
475 @item zero
476 Try just the (0, 0) vector.
477 @item phods
478 @item log
479 @item x1
480 @item hex
481 @item umh
482 @item epzs
483 (default method)
484 @item full
485 exhaustive search (slow and marginally better than epzs)
486 @end table
488 @item -dct_algo algo
489 Set DCT algorithm to @var{algo}. Available values are:
490 @table @samp
491 @item 0
492 FF_DCT_AUTO (default)
493 @item 1
495 @item 2
497 @item 3
499 @item 4
501 @item 5
503 @end table
505 @item -idct_algo algo
506 Set IDCT algorithm to @var{algo}. Available values are:
507 @table @samp
508 @item 0
509 FF_IDCT_AUTO (default)
510 @item 1
512 @item 2
514 @item 3
516 @item 4
518 @item 5
520 @item 6
522 @item 7
524 @item 8
526 @item 9
528 @item 10
530 @end table
532 @item -er n
533 Set error resilience to @var{n}.
534 @table @samp
535 @item 1
536 FF_ER_CAREFUL (default)
537 @item 2
539 @item 3
541 @item 4
543 @end table
545 @item -ec bit_mask
546 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
547 the following values:
548 @table @samp
549 @item 1
550 FF_EC_GUESS_MVS (default = enabled)
551 @item 2
552 FF_EC_DEBLOCK (default = enabled)
553 @end table
555 @item -bf frames
556 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
557 @item -mbd mode
558 macroblock decision
559 @table @samp
560 @item 0
561 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
562 @item 1
563 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
564 @item 2
565 FF_MB_DECISION_RD: rate distortion
566 @end table
568 @item -4mv
569 Use four motion vector by macroblock (MPEG-4 only).
570 @item -part
571 Use data partitioning (MPEG-4 only).
572 @item -bug param
573 Work around encoder bugs that are not auto-detected.
574 @item -strict strictness
575 How strictly to follow the standards.
576 @item -aic
577 Enable Advanced intra coding (h263+).
578 @item -umv
579 Enable Unlimited Motion Vector (h263+)
581 @item -deinterlace
582 Deinterlace pictures.
583 @item -ilme
584 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
585 Use this option if your input file is interlaced and you want
586 to keep the interlaced format for minimum losses.
587 The alternative is to deinterlace the input stream with
588 @option{-deinterlace}, but deinterlacing introduces losses.
589 @item -psnr
590 Calculate PSNR of compressed frames.
591 @item -vstats
592 Dump video coding statistics to @file{vstats_HHMMSS.log}.
593 @item -vstats_file file
594 Dump video coding statistics to @var{file}.
595 @item -vhook module
596 Insert video processing @var{module}. @var{module} contains the module
597 name and its parameters separated by spaces.
598 @item -top n
599 top=1/bottom=0/auto=-1 field first
600 @item -dc precision
601 Intra_dc_precision.
602 @item -vtag fourcc/tag
603 Force video tag/fourcc.
604 @item -qphist
605 Show QP histogram.
606 @item -vbsf bitstream filter
607 Bitstream filters available are "dump_extra", "remove_extra", "noise".
608 @end table
610 @section Audio Options
612 @table @option
613 @item -aframes number
614 Set the number of audio frames to record.
615 @item -ar freq
616 Set the audio sampling frequency (default = 44100 Hz).
617 @item -ab bitrate
618 Set the audio bitrate in bit/s (default = 64k).
619 @item -ac channels
620 Set the number of audio channels (default = 1).
621 @item -an
622 Disable audio recording.
623 @item -acodec codec
624 Force audio codec to @var{codec}. Use the @code{copy} special value to
625 specify that the raw codec data must be copied as is.
626 @item -newaudio
627 Add a new audio track to the output file. If you want to specify parameters,
628 do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
630 Mapping will be done automatically, if the number of output streams is equal to
631 the number of input streams, else it will pick the first one that matches. You
632 can override the mapping using @code{-map} as usual.
634 Example:
635 @example
636 ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
637 @end example
638 @item -alang code
639 Set the ISO 639 language code (3 letters) of the current audio stream.
640 @end table
642 @section Advanced Audio options:
644 @table @option
645 @item -atag fourcc/tag
646 Force audio tag/fourcc.
647 @item -absf bitstream filter
648 Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
649 @end table
651 @section Subtitle options:
653 @table @option
654 @item -scodec codec
655 Force subtitle codec ('copy' to copy stream).
656 @item -newsubtitle
657 Add a new subtitle stream to the current output stream.
658 @item -slang code
659 Set the ISO 639 language code (3 letters) of the current subtitle stream.
660 @end table
662 @section Audio/Video grab options
664 @table @option
665 @item -vc channel
666 Set video grab channel (DV1394 only).
667 @item -tvstd standard
668 Set television standard (NTSC, PAL (SECAM)).
669 @item -isync
670 Synchronize read on input.
671 @end table
673 @section Advanced options
675 @table @option
676 @item -map input stream id[:input stream id]
677 Set stream mapping from input streams to output streams.
678 Just enumerate the input streams in the order you want them in the output.
679 [input stream id] sets the (input) stream to sync against.
680 @item -map_meta_data outfile:infile
681 Set meta data information of outfile from infile.
682 @item -debug
683 Print specific debug info.
684 @item -benchmark
685 Add timings for benchmarking.
686 @item -dump
687 Dump each input packet.
688 @item -hex
689 When dumping packets, also dump the payload.
690 @item -bitexact
691 Only use bit exact algorithms (for codec testing).
692 @item -ps size
693 Set packet size in bits.
694 @item -re
695 Read input at native frame rate. Mainly used to simulate a grab device.
696 @item -loop_input
697 Loop over the input stream. Currently it works only for image
698 streams. This option is used for automatic FFserver testing.
699 @item -loop_output number_of_times
700 Repeatedly loop output for formats that support looping such as animated GIF
701 (0 will loop the output infinitely).
702 @item -threads count
703 Thread count.
704 @item -vsync parameter
705 Video sync method. Video will be stretched/squeezed to match the timestamps,
706 it is done by duplicating and dropping frames. With -map you can select from
707 which stream the timestamps should be taken. You can leave either video or
708 audio unchanged and sync the remaining stream(s) to the unchanged one.
709 @item -async samples_per_second
710 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
711 the parameter is the maximum samples per second by which the audio is changed.
712 -async 1 is a special case where only the start of the audio stream is corrected
713 without any later correction.
714 @item -copyts
715 Copy timestamps from input to output.
716 @item -shortest
717 Finish encoding when the shortest input stream ends.
718 @item -dts_delta_threshold
719 Timestamp discontinuity delta threshold.
720 @item -muxdelay seconds
721 Set the maximum demux-decode delay.
722 @item -muxpreload seconds
723 Set the initial demux-decode delay.
724 @end table
726 @node FFmpeg formula evaluator
727 @section FFmpeg formula evaluator
729 When evaluating a rate control string, FFmpeg uses an internal formula
730 evaluator.
732 The following binary operators are available: @code{+}, @code{-},
733 @code{*}, @code{/}, @code{^}.
735 The following unary operators are available: @code{+}, @code{-},
736 @code{(...)}.
738 The following functions are available:
739 @table @var
740 @item sinh(x)
741 @item cosh(x)
742 @item tanh(x)
743 @item sin(x)
744 @item cos(x)
745 @item tan(x)
746 @item exp(x)
747 @item log(x)
748 @item squish(x)
749 @item gauss(x)
750 @item abs(x)
751 @item max(x, y)
752 @item min(x, y)
753 @item gt(x, y)
754 @item lt(x, y)
755 @item eq(x, y)
756 @item bits2qp(bits)
757 @item qp2bits(qp)
758 @end table
760 The following constants are available:
761 @table @var
762 @item PI
763 @item E
764 @item iTex
765 @item pTex
766 @item tex
767 @item mv
768 @item fCode
769 @item iCount
770 @item mcVar
771 @item var
772 @item isI
773 @item isP
774 @item isB
775 @item avgQP
776 @item qComp
777 @item avgIITex
778 @item avgPITex
779 @item avgPPTex
780 @item avgBPTex
781 @item avgTex
782 @end table
784 @c man end
786 @ignore
788 @setfilename ffmpeg
789 @settitle FFmpeg video converter
791 @c man begin SEEALSO
792 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
793 @c man end
795 @c man begin AUTHOR
796 Fabrice Bellard
797 @c man end
799 @end ignore
801 @section Protocols
803 The filename can be @file{-} to read from standard input or to write
804 to standard output.
806 FFmpeg also handles many protocols specified with an URL syntax.
808 Use 'ffmpeg -formats' to see a list of the supported protocols.
810 The protocol @code{http:} is currently used only to communicate with
811 FFserver (see the FFserver documentation). When FFmpeg will be a
812 video player it will also be used for streaming :-)
814 @chapter Tips
816 @itemize
817 @item For streaming at very low bitrate application, use a low frame rate
818 and a small GOP size. This is especially true for RealVideo where
819 the Linux player does not seem to be very fast, so it can miss
820 frames. An example is:
822 @example
823 ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
824 @end example
826 @item The parameter 'q' which is displayed while encoding is the current
827 quantizer. The value 1 indicates that a very good quality could
828 be achieved. The value 31 indicates the worst quality. If q=31 appears
829 too often, it means that the encoder cannot compress enough to meet
830 your bitrate. You must either increase the bitrate, decrease the
831 frame rate or decrease the frame size.
833 @item If your computer is not fast enough, you can speed up the
834 compression at the expense of the compression ratio. You can use
835 '-me zero' to speed up motion estimation, and '-intra' to disable
836 motion estimation completely (you have only I-frames, which means it
837 is about as good as JPEG compression).
839 @item To have very low audio bitrates, reduce the sampling frequency
840 (down to 22050 kHz for MPEG audio, 22050 or 11025 for AC3).
842 @item To have a constant quality (but a variable bitrate), use the option
843 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
844 quality).
846 @item When converting video files, you can use the '-sameq' option which
847 uses the same quality factor in the encoder as in the decoder.
848 It allows almost lossless encoding.
850 @end itemize
853 @chapter external libraries
855 FFmpeg can be hooked up with a number of external libraries to add support
856 for more formats. None of them are used by default, their use has to be
857 explicitly requested by passing the appropriate flags to @file{./configure}.
859 @section AMR
861 AMR comes in two different flavors, WB and NB. FFmpeg can make use of the
862 AMR WB (floating-point mode) and the AMR NB (floating-point mode) reference
863 decoders and encoders.
865 Go to @url{http://www.penguin.cz/~utx/amr} and follow the instructions for
866 installing the libraries. Then pass @code{--enable-libamr-nb} and/or
867 @code{--enable-libamr-wb} to configure to enable the libraries.
870 @chapter Supported File Formats and Codecs
872 You can use the @code{-formats} option to have an exhaustive list.
874 @section File Formats
876 FFmpeg supports the following file formats through the @code{libavformat}
877 library:
879 @multitable @columnfractions .4 .1 .1 .4
880 @item Supported File Format @tab Encoding @tab Decoding @tab Comments
881 @item MPEG audio @tab X @tab X
882 @item MPEG-1 systems @tab X @tab X
883 @tab muxed audio and video
884 @item MPEG-2 PS @tab X @tab X
885 @tab also known as @code{VOB} file
886 @item MPEG-2 TS @tab @tab X
887 @tab also known as DVB Transport Stream
888 @item ASF@tab X @tab X
889 @item AVI@tab X @tab X
890 @item WAV@tab X @tab X
891 @item Macromedia Flash@tab X @tab X
892 @tab Only embedded audio is decoded.
893 @item FLV @tab X @tab X
894 @tab Macromedia Flash video files
895 @item Real Audio and Video @tab X @tab X
896 @item Raw AC3 @tab X @tab X
897 @item Raw MJPEG @tab X @tab X
898 @item Raw MPEG video @tab X @tab X
899 @item Raw PCM8/16 bits, mulaw/Alaw@tab X @tab X
900 @item Raw CRI ADX audio @tab X @tab X
901 @item Raw Shorten audio @tab @tab X
902 @item SUN AU format @tab X @tab X
903 @item NUT @tab X @tab X @tab NUT Open Container Format
904 @item QuickTime @tab X @tab X
905 @item MPEG-4 @tab X @tab X
906 @tab MPEG-4 is a variant of QuickTime.
907 @item Raw MPEG4 video @tab X @tab X
908 @item DV @tab X @tab X
909 @item 4xm @tab @tab X
910 @tab 4X Technologies format, used in some games.
911 @item Playstation STR @tab @tab X
912 @item Id RoQ @tab X @tab X
913 @tab Used in Quake III, Jedi Knight 2, other computer games.
914 @item Interplay MVE @tab @tab X
915 @tab Format used in various Interplay computer games.
916 @item WC3 Movie @tab @tab X
917 @tab Multimedia format used in Origin's Wing Commander III computer game.
918 @item Sega FILM/CPK @tab @tab X
919 @tab Used in many Sega Saturn console games.
920 @item Westwood Studios VQA/AUD @tab @tab X
921 @tab Multimedia formats used in Westwood Studios games.
922 @item Id Cinematic (.cin) @tab @tab X
923 @tab Used in Quake II.
924 @item FLIC format @tab @tab X
925 @tab .fli/.flc files
926 @item Sierra VMD @tab @tab X
927 @tab Used in Sierra CD-ROM games.
928 @item Sierra Online @tab @tab X
929 @tab .sol files used in Sierra Online games.
930 @item Matroska @tab @tab X
931 @item Electronic Arts Multimedia @tab @tab X
932 @tab Used in various EA games; files have extensions like WVE and UV2.
933 @item Nullsoft Video (NSV) format @tab @tab X
934 @item ADTS AAC audio @tab X @tab X
935 @item Creative VOC @tab X @tab X @tab Created for the Sound Blaster Pro.
936 @item American Laser Games MM @tab @tab X
937 @tab Multimedia format used in games like Mad Dog McCree
938 @item AVS @tab @tab X
939 @tab Multimedia format used by the Creature Shock game.
940 @item Smacker @tab @tab X
941 @tab Multimedia format used by many games.
942 @item GXF @tab X @tab X
943 @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley playout servers.
944 @item CIN @tab @tab X
945 @tab Multimedia format used by Delphine Software games.
946 @item MXF @tab @tab X
947 @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
948 @item SEQ @tab @tab X
949 @tab Tiertex .seq files used in the DOS CDROM version of the game Flashback.
950 @item DXA @tab @tab X
951 @tab This format is used in non-Windows version of Feeble Files game and
952 different game cutscenes repacked for use with ScummVM.
953 @item THP @tab @tab X
954 @tab Used on the Nintendo GameCube.
955 @item C93 @tab @tab X
956 @tab Used in the game Cyberia from Interplay.
957 @item Bethsoft VID @tab @tab X
958 @tab Used in some games from Bethesda Softworks.
959 @item CRYO APC @tab @tab X
960 @tab Audio format used in some games by CRYO Interactive Entertainment.
961 @end multitable
963 @code{X} means that encoding (resp. decoding) is supported.
965 @section Image Formats
967 FFmpeg can read and write images for each frame of a video sequence. The
968 following image formats are supported:
970 @multitable @columnfractions .4 .1 .1 .4
971 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
972 @item PGM, PPM @tab X @tab X
973 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
974 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
975 @item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
976 @item .Y.U.V @tab X @tab X @tab one raw file per component
977 @item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
978 @item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
979 @item Targa @tab @tab X @tab Targa (.TGA) image format.
980 @item TIFF @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
981 @item SGI @tab X @tab X @tab SGI RGB image format
982 @item PTX @tab @tab X @tab V.Flash PTX format
983 @end multitable
985 @code{X} means that encoding (resp. decoding) is supported.
987 @section Video Codecs
989 @multitable @columnfractions .4 .1 .1 .4
990 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
991 @item MPEG-1 video @tab X @tab X
992 @item MPEG-2 video @tab X @tab X
993 @item MPEG-4 @tab X @tab X
994 @item MSMPEG4 V1 @tab X @tab X
995 @item MSMPEG4 V2 @tab X @tab X
996 @item MSMPEG4 V3 @tab X @tab X
997 @item WMV7 @tab X @tab X
998 @item WMV8 @tab X @tab X @tab not completely working
999 @item WMV9 @tab @tab X @tab not completely working
1000 @item VC1 @tab @tab X
1001 @item H.261 @tab X @tab X
1002 @item H.263(+) @tab X @tab X @tab also known as RealVideo 1.0
1003 @item H.264 @tab @tab X
1004 @item RealVideo 1.0 @tab X @tab X
1005 @item RealVideo 2.0 @tab X @tab X
1006 @item MJPEG @tab X @tab X
1007 @item lossless MJPEG @tab X @tab X
1008 @item JPEG-LS @tab X @tab X @tab fourcc: MJLS, lossless and near-lossless is supported
1009 @item Apple MJPEG-B @tab @tab X
1010 @item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
1011 @item DV @tab X @tab X
1012 @item HuffYUV @tab X @tab X
1013 @item FFmpeg Video 1 @tab X @tab X @tab experimental lossless codec (fourcc: FFV1)
1014 @item FFmpeg Snow @tab X @tab X @tab experimental wavelet codec (fourcc: SNOW)
1015 @item Asus v1 @tab X @tab X @tab fourcc: ASV1
1016 @item Asus v2 @tab X @tab X @tab fourcc: ASV2
1017 @item Creative YUV @tab @tab X @tab fourcc: CYUV
1018 @item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
1019 @item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
1020 @item On2 VP3 @tab @tab X @tab still experimental
1021 @item On2 VP5 @tab @tab X @tab fourcc: VP50
1022 @item On2 VP6 @tab @tab X @tab fourcc: VP60,VP61,VP62
1023 @item Theora @tab X @tab X @tab still experimental
1024 @item Intel Indeo 3 @tab @tab X
1025 @item FLV @tab X @tab X @tab Sorenson H.263 used in Flash
1026 @item Flash Screen Video @tab X @tab X @tab fourcc: FSV1
1027 @item ATI VCR1 @tab @tab X @tab fourcc: VCR1
1028 @item ATI VCR2 @tab @tab X @tab fourcc: VCR2
1029 @item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
1030 @item 4X Video @tab @tab X @tab Used in certain computer games.
1031 @item Sony Playstation MDEC @tab @tab X
1032 @item Id RoQ @tab X @tab X @tab Used in Quake III, Jedi Knight 2, other computer games.
1033 @item Xan/WC3 @tab @tab X @tab Used in Wing Commander III .MVE files.
1034 @item Interplay Video @tab @tab X @tab Used in Interplay .MVE files.
1035 @item Apple Animation @tab X @tab X @tab fourcc: 'rle '
1036 @item Apple Graphics @tab @tab X @tab fourcc: 'smc '
1037 @item Apple Video @tab @tab X @tab fourcc: rpza
1038 @item Apple QuickDraw @tab @tab X @tab fourcc: qdrw
1039 @item Cinepak @tab @tab X
1040 @item Microsoft RLE @tab @tab X
1041 @item Microsoft Video-1 @tab @tab X
1042 @item Westwood VQA @tab @tab X
1043 @item Id Cinematic Video @tab @tab X @tab Used in Quake II.
1044 @item Planar RGB @tab @tab X @tab fourcc: 8BPS
1045 @item FLIC video @tab @tab X
1046 @item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK
1047 @item Duck TrueMotion v2 @tab @tab X @tab fourcc: TM20
1048 @item VMD Video @tab @tab X @tab Used in Sierra VMD files.
1049 @item MSZH @tab @tab X @tab Part of LCL
1050 @item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental
1051 @item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC
1052 @item IBM Ultimotion @tab @tab X @tab fourcc: ULTI
1053 @item Miro VideoXL @tab @tab X @tab fourcc: VIXL
1054 @item QPEG @tab @tab X @tab fourccs: QPEG, Q1.0, Q1.1
1055 @item LOCO @tab @tab X @tab
1056 @item Winnov WNV1 @tab @tab X @tab
1057 @item Autodesk Animator Studio Codec @tab @tab X @tab fourcc: AASC
1058 @item Fraps FPS1 @tab @tab X @tab
1059 @item CamStudio @tab @tab X @tab fourcc: CSCD
1060 @item American Laser Games Video @tab @tab X @tab Used in games like Mad Dog McCree
1061 @item ZMBV @tab X @tab X @tab Encoder works only on PAL8
1062 @item AVS Video @tab @tab X @tab Video encoding used by the Creature Shock game.
1063 @item Smacker Video @tab @tab X @tab Video encoding used in Smacker.
1064 @item RTjpeg @tab @tab X @tab Video encoding used in NuppelVideo files.
1065 @item KMVC @tab @tab X @tab Codec used in Worms games.
1066 @item VMware Video @tab @tab X @tab Codec used in videos captured by VMware.
1067 @item Cin Video @tab @tab X @tab Codec used in Delphine Software games.
1068 @item Tiertex Seq Video @tab @tab X @tab Codec used in DOS CDROM FlashBack game.
1069 @item DXA Video @tab @tab X @tab Codec originally used in Feeble Files game.
1070 @item AVID DNxHD @tab @tab X @tab aka SMPTE VC3
1071 @item C93 Video @tab @tab X @tab Codec used in Cyberia game.
1072 @item THP @tab @tab X @tab Used on the Nintendo GameCube.
1073 @item Bethsoft VID @tab @tab X @tab Used in some games from Bethesda Softworks.
1074 @item Renderware TXD @tab @tab X @tab Texture dictionaries used by the Renderware Engine.
1075 @end multitable
1077 @code{X} means that encoding (resp. decoding) is supported.
1079 @section Audio Codecs
1081 @multitable @columnfractions .4 .1 .1 .1 .7
1082 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
1083 @item MPEG audio layer 2 @tab IX @tab IX
1084 @item MPEG audio layer 1/3 @tab IX @tab IX
1085 @tab MP3 encoding is supported through the external library LAME.
1086 @item AC3 @tab IX @tab IX
1087 @tab liba52 is used internally for decoding.
1088 @item Vorbis @tab X @tab X
1089 @item WMA V1/V2 @tab X @tab X
1090 @item AAC @tab X @tab X
1091 @tab Supported through the external library libfaac/libfaad.
1092 @item Microsoft ADPCM @tab X @tab X
1093 @item MS IMA ADPCM @tab X @tab X
1094 @item QT IMA ADPCM @tab @tab X
1095 @item 4X IMA ADPCM @tab @tab X
1096 @item G.726 ADPCM @tab X @tab X
1097 @item Duck DK3 IMA ADPCM @tab @tab X
1098 @tab Used in some Sega Saturn console games.
1099 @item Duck DK4 IMA ADPCM @tab @tab X
1100 @tab Used in some Sega Saturn console games.
1101 @item Westwood Studios IMA ADPCM @tab @tab X
1102 @tab Used in Westwood Studios games like Command and Conquer.
1103 @item SMJPEG IMA ADPCM @tab @tab X
1104 @tab Used in certain Loki game ports.
1105 @item CD-ROM XA ADPCM @tab @tab X
1106 @item CRI ADX ADPCM @tab X @tab X
1107 @tab Used in Sega Dreamcast games.
1108 @item Electronic Arts ADPCM @tab @tab X
1109 @tab Used in various EA titles.
1110 @item Creative ADPCM @tab @tab X
1111 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
1112 @item THP ADPCM @tab @tab X
1113 @tab Used on the Nintendo GameCube.
1114 @item RA144 @tab @tab X
1115 @tab Real 14400 bit/s codec
1116 @item RA288 @tab @tab X
1117 @tab Real 28800 bit/s codec
1118 @item RADnet @tab X @tab IX
1119 @tab Real low bitrate AC3 codec, liba52 is used for decoding.
1120 @item AMR-NB @tab X @tab X
1121 @tab Supported through an external library.
1122 @item AMR-WB @tab X @tab X
1123 @tab Supported through an external library.
1124 @item DV audio @tab @tab X
1125 @item Id RoQ DPCM @tab X @tab X
1126 @tab Used in Quake III, Jedi Knight 2, other computer games.
1127 @item Interplay MVE DPCM @tab @tab X
1128 @tab Used in various Interplay computer games.
1129 @item Xan DPCM @tab @tab X
1130 @tab Used in Origin's Wing Commander IV AVI files.
1131 @item Sierra Online DPCM @tab @tab X
1132 @tab Used in Sierra Online game audio files.
1133 @item Apple MACE 3 @tab @tab X
1134 @item Apple MACE 6 @tab @tab X
1135 @item FLAC lossless audio @tab X @tab X
1136 @item Shorten lossless audio @tab @tab X
1137 @item Apple lossless audio @tab @tab X
1138 @tab QuickTime fourcc 'alac'
1139 @item FFmpeg Sonic @tab X @tab X
1140 @tab experimental lossy/lossless codec
1141 @item Qdesign QDM2 @tab @tab X
1142 @tab there are still some distortions
1143 @item Real COOK @tab @tab X
1144 @tab All versions except 5.1 are supported
1145 @item DSP Group TrueSpeech @tab @tab X
1146 @item True Audio (TTA) @tab @tab X
1147 @item Smacker Audio @tab @tab X
1148 @item WavPack Audio @tab @tab X
1149 @item Cin Audio @tab @tab X
1150 @tab Codec used in Delphine Software games.
1151 @item Intel Music Coder @tab @tab X
1152 @item Musepack @tab @tab X
1153 @tab Only SV7 is supported
1154 @item DT$ Coherent Audio @tab @tab X
1155 @item ATRAC 3 @tab @tab X
1156 @end multitable
1158 @code{X} means that encoding (resp. decoding) is supported.
1160 @code{I} means that an integer-only version is available, too (ensures high
1161 performance on systems without hardware floating point support).
1163 @chapter Platform Specific information
1165 @section BSD
1167 BSD make will not build FFmpeg, you need to install and use GNU Make
1168 (@file{gmake}).
1170 @section Windows
1172 To get help and instructions for using FFmpeg under Windows, check out
1173 the FFmpeg Windows Help Forum at
1174 @url{http://arrozcru.no-ip.org/ffmpeg/}.
1176 @subsection Native Windows compilation
1178 @itemize
1179 @item Install the current versions of MSYS and MinGW from
1180 @url{http://www.mingw.org/}. You can find detailed installation
1181 instructions in the download section and the FAQ.
1183 NOTE: Use at least bash 3.1. Older versions are known to be failing on the
1184 configure script.
1186 @item If you want to test the FFplay, also download
1187 the MinGW development library of SDL 1.2.x
1188 (@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
1189 @url{http://www.libsdl.org}. Unpack it in a temporary directory, and
1190 unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
1191 directory. Edit the @file{sdl-config} script so that it gives the
1192 correct SDL directory when invoked.
1194 @item If you want to use vhooks, you must have a POSIX compliant libdl in your
1195 MinGW system. Get dlfcn-win32 from @url{http://code.google.com/p/dlfcn-win32}.
1197 @item Extract the current version of FFmpeg.
1199 @item Start the MSYS shell (file @file{msys.bat}).
1201 @item Change to the FFmpeg directory and follow
1202 the instructions of how to compile FFmpeg (file
1203 @file{INSTALL}). Usually, launching @file{./configure} and @file{make}
1204 suffices. If you have problems using SDL, verify that
1205 @file{sdl-config} can be launched from the MSYS command line.
1207 @item You can install FFmpeg in @file{Program Files/FFmpeg} by typing
1208 @file{make install}. Do not forget to copy @file{SDL.dll} to the place
1209 you launch @file{ffplay} from.
1211 @end itemize
1213 Notes:
1214 @itemize
1216 @item The target @file{make wininstaller} can be used to create a
1217 Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
1218 must be copied to the FFmpeg directory in order to build the
1219 installer.
1221 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
1222 you can build @file{avcodec.dll} and @file{avformat.dll}. With
1223 @code{make install} you install the FFmpeg DLLs and the associated
1224 headers in @file{Program Files/FFmpeg}.
1226 @item Visual C++ compatibility: If you used @code{./configure --enable-shared}
1227 when configuring FFmpeg, FFmpeg tries to use the Microsoft Visual
1228 C++ @code{lib} tool to build @code{avcodec.lib} and
1229 @code{avformat.lib}. With these libraries you can link your Visual C++
1230 code directly with the FFmpeg DLLs (see below).
1232 @end itemize
1234 @subsection Visual C++ compatibility
1236 FFmpeg will not compile under Visual C++ -- and it has too many
1237 dependencies on the GCC compiler to make a port viable. However,
1238 if you want to use the FFmpeg libraries in your own applications,
1239 you can still compile those applications using Visual C++. An
1240 important restriction to this is that you have to use the
1241 dynamically linked versions of the FFmpeg libraries (i.e. the
1242 DLLs), and you have to make sure that Visual-C++-compatible
1243 import libraries are created during the FFmpeg build process.
1245 This description of how to use the FFmpeg libraries with Visual C++ is
1246 based on Visual C++ 2005 Express Edition Beta 2. If you have a different
1247 version, you might have to modify the procedures slightly.
1249 Here are the step-by-step instructions for building the FFmpeg libraries
1250 so they can be used with Visual C++:
1252 @enumerate
1254 @item Install Visual C++ (if you have not done so already).
1256 @item Install MinGW and MSYS as described above.
1258 @item Add a call to @file{vcvars32.bat} (which sets up the environment
1259 variables for the Visual C++ tools) as the first line of
1260 @file{msys.bat}. The standard location for @file{vcvars32.bat} is
1261 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
1262 and the standard location for @file{msys.bat} is
1263 @file{C:\msys\1.0\msys.bat}. If this corresponds to your setup, add the
1264 following line as the first line of @file{msys.bat}:
1266 @code{call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"}
1268 @item Start the MSYS shell (file @file{msys.bat}) and type @code{link.exe}.
1269 If you get a help message with the command line options of @code{link.exe},
1270 this means your environment variables are set up correctly, the
1271 Microsoft linker is on the path and will be used by FFmpeg to
1272 create Visual-C++-compatible import libraries.
1274 @item Extract the current version of FFmpeg and change to the FFmpeg directory.
1276 @item Type the command
1277 @code{./configure --enable-shared --disable-static --enable-memalign-hack}
1278 to configure and, if that did not produce any errors,
1279 type @code{make} to build FFmpeg.
1281 @item The subdirectories @file{libavformat}, @file{libavcodec}, and
1282 @file{libavutil} should now contain the files @file{avformat.dll},
1283 @file{avformat.lib}, @file{avcodec.dll}, @file{avcodec.lib},
1284 @file{avutil.dll}, and @file{avutil.lib}, respectively. Copy the three
1285 DLLs to your System32 directory (typically @file{C:\Windows\System32}).
1287 @end enumerate
1289 And here is how to use these libraries with Visual C++:
1291 @enumerate
1293 @item Create a new console application ("File / New / Project") and then
1294 select "Win32 Console Application". On the appropriate page of the
1295 Application Wizard, uncheck the "Precompiled headers" option.
1297 @item Write the source code for your application, or, for testing, just
1298 copy the code from an existing sample application into the source file
1299 that Visual C++ has already created for you. (Note that your source
1300 filehas to have a @code{.cpp} extension; otherwise, Visual C++ will not
1301 compile the FFmpeg headers correctly because in C mode, it does not
1302 recognize the @code{inline} keyword.) For example, you can copy
1303 @file{output_example.c} from the FFmpeg distribution (but you will
1304 have to make minor modifications so the code will compile under
1305 C++, see below).
1307 @item Open the "Project / Properties" dialog box. In the "Configuration"
1308 combo box, select "All Configurations" so that the changes you make will
1309 affect both debug and release builds. In the tree view on the left hand
1310 side, select "C/C++ / General", then edit the "Additional Include
1311 Directories" setting to contain the complete paths to the
1312 @file{libavformat}, @file{libavcodec}, and @file{libavutil}
1313 subdirectories of your FFmpeg directory. Note that the directories have
1314 to be separated using semicolons. Now select "Linker / General" from the
1315 tree view and edit the "Additional Library Directories" setting to
1316 contain the same three directories.
1318 @item Still in the "Project / Properties" dialog box, select "Linker / Input"
1319 from the tree view, then add the files @file{avformat.lib},
1320 @file{avcodec.lib}, and @file{avutil.lib} to the end of the "Additional
1321 Dependencies". Note that the names of the libraries have to be separated
1322 using spaces.
1324 @item Now, select "C/C++ / Code Generation" from the tree view. Select
1325 "Debug" in the "Configuration" combo box. Make sure that "Runtime
1326 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
1327 the "Configuration" combo box and make sure that "Runtime Library" is
1328 set to "Multi-threaded DLL".
1330 @item Click "OK" to close the "Project / Properties" dialog box and build
1331 the application. Hopefully, it should compile and run cleanly. If you
1332 used @file{output_example.c} as your sample application, you will get a
1333 few compiler errors, but they are easy to fix. The first type of error
1334 occurs because Visual C++ does not allow an @code{int} to be converted to
1335 an @code{enum} without a cast. To solve the problem, insert the required
1336 casts (this error occurs once for a @code{CodecID} and once for a
1337 @code{CodecType}). The second type of error occurs because C++ requires
1338 the return value of @code{malloc} to be cast to the exact type of the
1339 pointer it is being assigned to. Visual C++ will complain that, for
1340 example, @code{(void *)} is being assigned to @code{(uint8_t *)} without
1341 an explicit cast. So insert an explicit cast in these places to silence
1342 the compiler. The third type of error occurs because the @code{snprintf}
1343 library function is called @code{_snprintf} under Visual C++. So just
1344 add an underscore to fix the problem. With these changes,
1345 @file{output_example.c} should compile under Visual C++, and the
1346 resulting executable should produce valid video files.
1348 @end enumerate
1350 @subsection Cross compilation for Windows with Linux
1352 You must use the MinGW cross compilation tools available at
1353 @url{http://www.mingw.org/}.
1355 Then configure FFmpeg with the following options:
1356 @example
1357 ./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
1358 @end example
1359 (you can change the cross-prefix according to the prefix chosen for the
1360 MinGW tools).
1362 Then you can easily test FFmpeg with Wine
1363 (@url{http://www.winehq.com/}).
1365 @subsection Compilation under Cygwin
1367 Cygwin works very much like Unix.
1369 Just install your Cygwin with all the "Base" packages, plus the
1370 following "Devel" ones:
1371 @example
1372 binutils, gcc-core, make, subversion
1373 @end example
1375 Do not install binutils-20060709-1 (they are buggy on shared builds);
1376 use binutils-20050610-1 instead.
1378 Then run
1380 @example
1381 ./configure --enable-static --disable-shared
1382 @end example
1384 to make a static build or
1386 @example
1387 ./configure --enable-shared --disable-static
1388 @end example
1390 to build shared libraries.
1392 If you want to build FFmpeg with additional libraries, download Cygwin
1393 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository
1394 and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
1395 (@url{http://cygwinports.dotsrc.org/}).
1397 @subsection Crosscompilation for Windows under Cygwin
1399 With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
1401 Just install your Cygwin as explained before, plus these additional
1402 "Devel" packages:
1403 @example
1404 gcc-mingw-core, mingw-runtime, mingw-zlib
1405 @end example
1407 and add some special flags to your configure invocation.
1409 For a static build run
1410 @example
1411 ./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
1412 @end example
1414 and for a build with shared libraries
1415 @example
1416 ./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
1417 @end example
1419 @section BeOS
1421 The configure script should guess the configuration itself.
1422 Networking support is currently not finished.
1423 errno issues fixed by Andrew Bachmann.
1425 Old stuff:
1427 Fran├žois Revol - revol at free dot fr - April 2002
1429 The configure script should guess the configuration itself,
1430 however I still did not test building on the net_server version of BeOS.
1432 FFserver is broken (needs poll() implementation).
1434 There are still issues with errno codes, which are negative in BeOS, and
1435 that FFmpeg negates when returning. This ends up turning errors into
1436 valid results, then crashes.
1437 (To be fixed)
1439 @chapter Developers Guide
1441 @section API
1442 @itemize @bullet
1443 @item libavcodec is the library containing the codecs (both encoding and
1444 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
1446 @item libavformat is the library containing the file format handling (mux and
1447 demux code for several formats). Look at @file{ffplay.c} to use it in a
1448 player. See @file{output_example.c} to use it to generate audio or video
1449 streams.
1451 @end itemize
1453 @section Integrating libavcodec or libavformat in your program
1455 You can integrate all the source code of the libraries to link them
1456 statically to avoid any version problem. All you need is to provide a
1457 'config.mak' and a 'config.h' in the parent directory. See the defines
1458 generated by ./configure to understand what is needed.
1460 You can use libavcodec or libavformat in your commercial program, but
1461 @emph{any patch you make must be published}. The best way to proceed is
1462 to send your patches to the FFmpeg mailing list.
1464 @node Coding Rules
1465 @section Coding Rules
1467 FFmpeg is programmed in the ISO C90 language with a few additional
1468 features from ISO C99, namely:
1469 @itemize @bullet
1470 @item
1471 the @samp{inline} keyword;
1472 @item
1473 @samp{//} comments;
1474 @item
1475 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
1476 @item
1477 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
1478 @end itemize
1480 These features are supported by all compilers we care about, so we will not
1481 accept patches to remove their use unless they absolutely do not impair
1482 clarity and performance.
1484 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
1485 compiles with several other compilers, such as the Compaq ccc compiler
1486 or Sun Studio 9, and we would like to keep it that way unless it would
1487 be exceedingly involved. To ensure compatibility, please do not use any
1488 additional C99 features or GCC extensions. Especially watch out for:
1489 @itemize @bullet
1490 @item
1491 mixing statements and declarations;
1492 @item
1493 @samp{long long} (use @samp{int64_t} instead);
1494 @item
1495 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
1496 @item
1497 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
1498 @end itemize
1500 Indent size is 4.
1501 The presentation is the one specified by 'indent -i4 -kr -nut'.
1502 The TAB character is forbidden outside of Makefiles as is any
1503 form of trailing whitespace. Commits containing either will be
1504 rejected by the Subversion repository.
1506 The main priority in FFmpeg is simplicity and small code size in order to
1507 minimize the bug count.
1509 Comments: Use the JavaDoc/Doxygen
1510 format (see examples below) so that code documentation
1511 can be generated automatically. All nontrivial functions should have a comment
1512 above them explaining what the function does, even if it is just one sentence.
1513 All structures and their member variables should be documented, too.
1514 @example
1515 /**
1516 * @@file mpeg.c
1517 * MPEG codec.
1518 * @@author ...
1519 */
1521 /**
1522 * Summary sentence.
1523 * more text ...
1524 * ...
1525 */
1526 typedef struct Foobar@{
1527 int var1; /**< var1 description */
1528 int var2; ///< var2 description
1529 /** var3 description */
1530 int var3;
1531 @} Foobar;
1533 /**
1534 * Summary sentence.
1535 * more text ...
1536 * ...
1537 * @@param my_parameter description of my_parameter
1538 * @@return return value description
1539 */
1540 int myfunc(int my_parameter)
1541 ...
1542 @end example
1544 fprintf and printf are forbidden in libavformat and libavcodec,
1545 please use av_log() instead.
1547 Casts should be used only when necessary. Unneeded parentheses
1548 should also be avoided if they don't make the code easier to understand.
1550 @section Development Policy
1552 @enumerate
1553 @item
1554 Contributions should be licensed under the LGPL 2.1, including an
1555 "or any later version" clause, or the MIT license. GPL 2 including
1556 an "or any later version" clause is also acceptable, but LGPL is
1557 preferred.
1558 @item
1559 You must not commit code which breaks FFmpeg! (Meaning unfinished but
1560 enabled code which breaks compilation or compiles but does not work or
1561 breaks the regression tests)
1562 You can commit unfinished stuff (for testing etc), but it must be disabled
1563 (#ifdef etc) by default so it does not interfere with other developers'
1564 work.
1565 @item
1566 You do not have to over-test things. If it works for you, and you think it
1567 should work for others, then commit. If your code has problems
1568 (portability, triggers compiler bugs, unusual environment etc) they will be
1569 reported and eventually fixed.
1570 @item
1571 Do not commit unrelated changes together, split them into self-contained
1572 pieces. Also do not forget that if part B depends on part A, but A does not
1573 depend on B, then A can and should be committed first and separate from B.
1574 Keeping changes well split into self-contained parts makes reviewing and
1575 understanding them on the commit log mailing list easier. This also helps
1576 in case of debugging later on.
1577 Also if you have doubts about splitting or not splitting, do not hesitate to
1578 ask/discuss it on the developer mailing list.
1579 @item
1580 Do not change behavior of the program (renaming options etc) without
1581 first discussing it on the ffmpeg-devel mailing list. Do not remove
1582 functionality from the code. Just improve!
1584 Note: Redundant code can be removed.
1585 @item
1586 Do not commit changes to the build system (Makefiles, configure script)
1587 which change behavior, defaults etc, without asking first. The same
1588 applies to compiler warning fixes, trivial looking fixes and to code
1589 maintained by other developers. We usually have a reason for doing things
1590 the way we do. Send your changes as patches to the ffmpeg-devel mailing
1591 list, and if the code maintainers say OK, you may commit. This does not
1592 apply to files you wrote and/or maintain.
1593 @item
1594 We refuse source indentation and other cosmetic changes if they are mixed
1595 with functional changes, such commits will be rejected and removed. Every
1596 developer has his own indentation style, you should not change it. Of course
1597 if you (re)write something, you can use your own style, even though we would
1598 prefer if the indentation throughout FFmpeg was consistent (Many projects
1599 force a given indentation style - we do not.). If you really need to make
1600 indentation changes (try to avoid this), separate them strictly from real
1601 changes.
1603 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
1604 then either do NOT change the indentation of the inner part within (do not
1605 move it to the right)! or do so in a separate commit
1606 @item
1607 Always fill out the commit log message. Describe in a few lines what you
1608 changed and why. You can refer to mailing list postings if you fix a
1609 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1610 @item
1611 If you apply a patch by someone else, include the name and email address in
1612 the log message. Since the ffmpeg-cvslog mailing list is publicly
1613 archived you should add some SPAM protection to the email address. Send an
1614 answer to ffmpeg-devel (or wherever you got the patch from) saying that
1615 you applied the patch.
1616 @item
1617 When applying patches that have been discussed (at length) on the mailing
1618 list, reference the thread in the log message.
1619 @item
1620 Do NOT commit to code actively maintained by others without permission.
1621 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
1622 timeframe (12h for build failures and security fixes, 3 days small changes,
1623 1 week for big patches) then commit your patch if you think it is OK.
1624 Also note, the maintainer can simply ask for more time to review!
1625 @item
1626 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
1627 are sent there and reviewed by all the other developers. Bugs and possible
1628 improvements or general questions regarding commits are discussed there. We
1629 expect you to react if problems with your code are uncovered.
1630 @item
1631 Update the documentation if you change behavior or add features. If you are
1632 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
1633 maintainer(s) will review and commit your stuff.
1634 @item
1635 Try to keep important discussions and requests (also) on the public
1636 developer mailing list, so that all developers can benefit from them.
1637 @item
1638 Never write to unallocated memory, never write over the end of arrays,
1639 always check values read from some untrusted source before using them
1640 as array index or other risky things.
1641 @item
1642 Remember to check if you need to bump versions for the specific libav
1643 parts (libavutil, libavcodec, libavformat) you are changing. You need
1644 to change the version integer and the version string.
1645 Incrementing the first component means no backward compatibility to
1646 previous versions (e.g. removal of a function from the public API).
1647 Incrementing the second component means backward compatible change
1648 (e.g. addition of a function to the public API).
1649 Incrementing the third component means a noteworthy binary compatible
1650 change (e.g. encoder bug fix that matters for the decoder).
1651 @item
1652 If you add a new codec, remember to update the changelog, add it to
1653 the supported codecs table in the documentation and bump the second
1654 component of the @file{libavcodec} version number appropriately. If
1655 it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
1656 is only a decoder.
1657 @item
1658 Do not change code to hide warnings without ensuring that the underlying
1659 logic is correct and thus the warning was inappropriate.
1660 @item
1661 If you add a new file, give it a proper license header. Do not copy and
1662 paste it from a random place, use an existing file as template.
1663 @end enumerate
1665 We think our rules are not too hard. If you have comments, contact us.
1667 Note, these rules are mostly borrowed from the MPlayer project.
1669 @section Submitting patches
1671 First, (@pxref{Coding Rules}) above if you did not yet.
1673 When you submit your patch, try to send a unified diff (diff '-up'
1674 option). We cannot read other diffs :-)
1676 Also please do not submit patches which contain several unrelated changes.
1677 Split them into individual self-contained patches; this makes reviewing
1678 them much easier.
1680 Run the regression tests before submitting a patch so that you can
1681 verify that there are no big problems.
1683 Patches should be posted as base64 encoded attachments (or any other
1684 encoding which ensures that the patch will not be trashed during
1685 transmission) to the ffmpeg-devel mailing list, see
1686 @url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
1688 It also helps quite a bit if you tell us what the patch does (for example
1689 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
1690 and has no lrint()')
1692 Also please if you send several patches, send each patch as a separate mail,
1693 do not attach several unrelated patches to the same mail.
1695 @section patch submission checklist
1697 @enumerate
1698 @item
1699 Do the regression tests pass with the patch applied?
1700 @item
1701 Is the patch a unified diff?
1702 @item
1703 Is the patch against latest FFmpeg SVN?
1704 @item
1705 Are you subscribed to ffmpeg-dev?
1706 (the list is subscribers only due to spam)
1707 @item
1708 Have you checked that the changes are minimal, so that the same cannot be
1709 achieved with a smaller patch and/or simpler final code?
1710 @item
1711 If the change is to speed critical code, did you benchmark it?
1712 @item
1713 If you did any benchmarks, did you provide them in the mail?
1714 @item
1715 Have you checked that the patch does not introduce buffer overflows or
1716 other security issues?
1717 @item
1718 Is the patch created from the root of the source tree, so it can be
1719 applied with @code{patch -p0}?
1720 @item
1721 Does the patch not mix functional and cosmetic changes?
1722 @item
1723 Did you add tabs or trailing whitespace to the code? Both are forbidden.
1724 @item
1725 Is the patch attached to the email you send?
1726 @item
1727 Is the mime type of the patch correct? It should be text/x-diff or
1728 text/x-patch or at least text/plain and not application/octet-stream.
1729 @item
1730 If the patch fixes a bug, did you provide a verbose analysis of the bug?
1731 @item
1732 If the patch fixes a bug, did you provide enough information, including
1733 a sample, so the bug can be reproduced and the fix can be verified?
1734 Note please do not attach samples >100k to mails but rather provide a
1735 URL, you can upload to ftp://upload.mplayerhq.hu
1736 @item
1737 Did you provide a verbose summary about what the patch does change?
1738 @item
1739 Did you provide a verbose explanation why it changes things like it does?
1740 @item
1741 Did you provide a verbose summary of the user visible advantages and
1742 disadvantages if the patch is applied?
1743 @item
1744 Did you provide an example so we can verify the new feature added by the
1745 patch easily?
1746 @item
1747 If you added a new file, did you insert a license header? It should be
1748 taken from FFmpeg, not randomly copied and pasted from somewhere else.
1749 @item
1750 You should maintain alphabetical order in alphabetically ordered lists as
1751 long as doing so does not break API/ABI compatibility.
1752 @item
1753 Lines with similar content should be aligned vertically when doing so
1754 improves readability.
1755 @item
1756 Did you provide a suggestion for a clear commit log message?
1757 @end enumerate
1759 @section Patch review process
1761 All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1762 clear note that the patch is not for SVN.
1763 Reviews and comments will be posted as replies to the patch on the
1764 mailing list. The patch submitter then has to take care of every comment,
1765 that can be by resubmitting a changed patch or by discussion. Resubmitted
1766 patches will themselves be reviewed like any other patch. If at some point
1767 a patch passes review with no comments then it is approved, that can for
1768 simple and small patches happen immediately while large patches will generally
1769 have to be changed and reviewed many times before they are approved.
1770 After a patch is approved it will be committed to the repository.
1772 We will review all submitted patches, but sometimes we are quite busy so
1773 especially for large patches this can take several weeks.
1775 When resubmitting patches, please do not make any significant changes
1776 not related to the comments received during review. Such patches will
1777 be rejected. Instead, submit significant changes or new features as
1778 separate patches.
1780 @section Regression tests
1782 Before submitting a patch (or committing to the repository), you should at least
1783 test that you did not break anything.
1785 The regression tests build a synthetic video stream and a synthetic
1786 audio stream. These are then encoded and decoded with all codecs or
1787 formats. The CRC (or MD5) of each generated file is recorded in a
1788 result file. A 'diff' is launched to compare the reference results and
1789 the result file.
1791 The regression tests then go on to test the FFserver code with a
1792 limited set of streams. It is important that this step runs correctly
1793 as well.
1795 Run 'make test' to test all the codecs and formats.
1797 Run 'make fulltest' to test all the codecs, formats and FFserver.
1799 [Of course, some patches may change the results of the regression tests. In
1800 this case, the reference results of the regression tests shall be modified
1801 accordingly].
1803 @bye