On Cygwin, libswscale is needed in VHOOK(SHFLAGS|LIBS) only when
[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 tolerance (in bit/s).
390 @item -minrate bitrate
391 Set min video bitrate tolerance (in bit/s).
392 @item -bufsize size
393 Set rate control 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
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 epzs
481 (default method)
482 @item full
483 exhaustive search (slow and marginally better than epzs)
484 @end table
486 @item -dct_algo algo
487 Set DCT algorithm to @var{algo}. Available values are:
488 @table @samp
489 @item 0
490 FF_DCT_AUTO (default)
491 @item 1
493 @item 2
495 @item 3
497 @item 4
499 @item 5
501 @end table
503 @item -idct_algo algo
504 Set IDCT algorithm to @var{algo}. Available values are:
505 @table @samp
506 @item 0
507 FF_IDCT_AUTO (default)
508 @item 1
510 @item 2
512 @item 3
514 @item 4
516 @item 5
518 @item 6
520 @item 7
522 @item 8
524 @item 9
526 @item 10
528 @end table
530 @item -er n
531 Set error resilience to @var{n}.
532 @table @samp
533 @item 1
534 FF_ER_CAREFUL (default)
535 @item 2
537 @item 3
539 @item 4
541 @end table
543 @item -ec bit_mask
544 Set error concealment to @var{bit_mask}. @var{bit_mask} is a bit mask of
545 the following values:
546 @table @samp
547 @item 1
548 FF_EC_GUESS_MVS (default = enabled)
549 @item 2
550 FF_EC_DEBLOCK (default = enabled)
551 @end table
553 @item -bf frames
554 Use 'frames' B-frames (supported for MPEG-1, MPEG-2 and MPEG-4).
555 @item -mbd mode
556 macroblock decision
557 @table @samp
558 @item 0
559 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot change it yet in FFmpeg).
560 @item 1
561 FF_MB_DECISION_BITS: Choose the one which needs the fewest bits.
562 @item 2
563 FF_MB_DECISION_RD: rate distortion
564 @end table
566 @item -4mv
567 Use four motion vector by macroblock (MPEG-4 only).
568 @item -part
569 Use data partitioning (MPEG-4 only).
570 @item -bug param
571 Work around encoder bugs that are not auto-detected.
572 @item -strict strictness
573 How strictly to follow the standards.
574 @item -aic
575 Enable Advanced intra coding (h263+).
576 @item -umv
577 Enable Unlimited Motion Vector (h263+)
579 @item -deinterlace
580 Deinterlace pictures.
581 @item -ilme
582 Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
583 Use this option if your input file is interlaced and you want
584 to keep the interlaced format for minimum losses.
585 The alternative is to deinterlace the input stream with
586 @option{-deinterlace}, but deinterlacing introduces losses.
587 @item -psnr
588 Calculate PSNR of compressed frames.
589 @item -vstats
590 Dump video coding statistics to @file{vstats_HHMMSS.log}.
591 @item -vstats_file file
592 Dump video coding statistics to @var{file}.
593 @item -vhook module
594 Insert video processing @var{module}. @var{module} contains the module
595 name and its parameters separated by spaces.
596 @item -top n
597 top=1/bottom=0/auto=-1 field first
598 @item -dc precision
599 Intra_dc_precision.
600 @item -vtag fourcc/tag
601 Force video tag/fourcc.
602 @item -qphist
603 Show QP histogram.
604 @item -vbsf bitstream filter
605 Bitstream filters available are "dump_extra", "remove_extra", "noise".
606 @end table
608 @section Audio Options
610 @table @option
611 @item -aframes number
612 Set the number of audio frames to record.
613 @item -ar freq
614 Set the audio sampling frequency (default = 44100 Hz).
615 @item -ab bitrate
616 Set the audio bitrate in bit/s (default = 64k).
617 @item -ac channels
618 Set the number of audio channels (default = 1).
619 @item -an
620 Disable audio recording.
621 @item -acodec codec
622 Force audio codec to @var{codec}. Use the @code{copy} special value to
623 specify that the raw codec data must be copied as is.
624 @item -newaudio
625 Add a new audio track to the output file. If you want to specify parameters,
626 do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
628 Mapping will be done automatically, if the number of output streams is equal to
629 the number of input streams, else it will pick the first one that matches. You
630 can override the mapping using @code{-map} as usual.
632 Example:
633 @example
634 ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
635 @end example
636 @item -alang code
637 Set the ISO 639 language code (3 letters) of the current audio stream.
638 @end table
640 @section Advanced Audio options:
642 @table @option
643 @item -atag fourcc/tag
644 Force audio tag/fourcc.
645 @item -absf bitstream filter
646 Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
647 @end table
649 @section Subtitle options:
651 @table @option
652 @item -scodec codec
653 Force subtitle codec ('copy' to copy stream).
654 @item -newsubtitle
655 Add a new subtitle stream to the current output stream.
656 @item -slang code
657 Set the ISO 639 language code (3 letters) of the current subtitle stream.
658 @end table
660 @section Audio/Video grab options
662 @table @option
663 @item -vc channel
664 Set video grab channel (DV1394 only).
665 @item -tvstd standard
666 Set television standard (NTSC, PAL (SECAM)).
667 @item -isync
668 Synchronize read on input.
669 @end table
671 @section Advanced options
673 @table @option
674 @item -map input stream id[:input stream id]
675 Set stream mapping from input streams to output streams.
676 Just enumerate the input streams in the order you want them in the output.
677 [input stream id] sets the (input) stream to sync against.
678 @item -map_meta_data outfile:infile
679 Set meta data information of outfile from infile.
680 @item -debug
681 Print specific debug info.
682 @item -benchmark
683 Add timings for benchmarking.
684 @item -dump
685 Dump each input packet.
686 @item -hex
687 When dumping packets, also dump the payload.
688 @item -bitexact
689 Only use bit exact algorithms (for codec testing).
690 @item -ps size
691 Set packet size in bits.
692 @item -re
693 Read input at native frame rate. Mainly used to simulate a grab device.
694 @item -loop_input
695 Loop over the input stream. Currently it works only for image
696 streams. This option is used for automatic FFserver testing.
697 @item -loop_output number_of_times
698 Repeatedly loop output for formats that support looping such as animated GIF
699 (0 will loop the output infinitely).
700 @item -threads count
701 Thread count.
702 @item -vsync parameter
703 Video sync method. Video will be stretched/squeezed to match the timestamps,
704 it is done by duplicating and dropping frames. With -map you can select from
705 which stream the timestamps should be taken. You can leave either video or
706 audio unchanged and sync the remaining stream(s) to the unchanged one.
707 @item -async samples_per_second
708 Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
709 the parameter is the maximum samples per second by which the audio is changed.
710 -async 1 is a special case where only the start of the audio stream is corrected
711 without any later correction.
712 @item -copyts
713 Copy timestamps from input to output.
714 @item -shortest
715 Finish encoding when the shortest input stream ends.
716 @item -dts_delta_threshold
717 Timestamp discontinuity delta threshold.
718 @item -muxdelay seconds
719 Set the maximum demux-decode delay.
720 @item -muxpreload seconds
721 Set the initial demux-decode delay.
722 @end table
724 @node FFmpeg formula evaluator
725 @section FFmpeg formula evaluator
727 When evaluating a rate control string, FFmpeg uses an internal formula
728 evaluator.
730 The following binary operators are available: @code{+}, @code{-},
731 @code{*}, @code{/}, @code{^}.
733 The following unary operators are available: @code{+}, @code{-},
734 @code{(...)}.
736 The following functions are available:
737 @table @var
738 @item sinh(x)
739 @item cosh(x)
740 @item tanh(x)
741 @item sin(x)
742 @item cos(x)
743 @item tan(x)
744 @item exp(x)
745 @item log(x)
746 @item squish(x)
747 @item gauss(x)
748 @item abs(x)
749 @item max(x, y)
750 @item min(x, y)
751 @item gt(x, y)
752 @item lt(x, y)
753 @item eq(x, y)
754 @item bits2qp(bits)
755 @item qp2bits(qp)
756 @end table
758 The following constants are available:
759 @table @var
760 @item PI
761 @item E
762 @item iTex
763 @item pTex
764 @item tex
765 @item mv
766 @item fCode
767 @item iCount
768 @item mcVar
769 @item var
770 @item isI
771 @item isP
772 @item isB
773 @item avgQP
774 @item qComp
775 @item avgIITex
776 @item avgPITex
777 @item avgPPTex
778 @item avgBPTex
779 @item avgTex
780 @end table
782 @c man end
784 @ignore
786 @setfilename ffmpeg
787 @settitle FFmpeg video converter
789 @c man begin SEEALSO
790 ffserver(1), ffplay(1) and the HTML documentation of @file{ffmpeg}.
791 @c man end
793 @c man begin AUTHOR
794 Fabrice Bellard
795 @c man end
797 @end ignore
799 @section Protocols
801 The filename can be @file{-} to read from standard input or to write
802 to standard output.
804 FFmpeg also handles many protocols specified with an URL syntax.
806 Use 'ffmpeg -formats' to see a list of the supported protocols.
808 The protocol @code{http:} is currently used only to communicate with
809 FFserver (see the FFserver documentation). When FFmpeg will be a
810 video player it will also be used for streaming :-)
812 @chapter Tips
814 @itemize
815 @item For streaming at very low bitrate application, use a low frame rate
816 and a small GOP size. This is especially true for RealVideo where
817 the Linux player does not seem to be very fast, so it can miss
818 frames. An example is:
820 @example
821 ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
822 @end example
824 @item The parameter 'q' which is displayed while encoding is the current
825 quantizer. The value 1 indicates that a very good quality could
826 be achieved. The value 31 indicates the worst quality. If q=31 appears
827 too often, it means that the encoder cannot compress enough to meet
828 your bitrate. You must either increase the bitrate, decrease the
829 frame rate or decrease the frame size.
831 @item If your computer is not fast enough, you can speed up the
832 compression at the expense of the compression ratio. You can use
833 '-me zero' to speed up motion estimation, and '-intra' to disable
834 motion estimation completely (you have only I-frames, which means it
835 is about as good as JPEG compression).
837 @item To have very low audio bitrates, reduce the sampling frequency
838 (down to 22050 kHz for MPEG audio, 22050 or 11025 for AC3).
840 @item To have a constant quality (but a variable bitrate), use the option
841 '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst
842 quality).
844 @item When converting video files, you can use the '-sameq' option which
845 uses the same quality factor in the encoder as in the decoder.
846 It allows almost lossless encoding.
848 @end itemize
851 @chapter external libraries
853 FFmpeg can be hooked up with a number of external libraries to add support
854 for more formats. None of them are used by default, their use has to be
855 explicitly requested by passing the appropriate flags to @file{./configure}.
857 @section AMR
859 AMR comes in two different flavors, WB and NB. FFmpeg can make use of the
860 AMR WB (floating-point mode) and the AMR NB (floating-point mode) reference
861 decoders and encoders.
863 Go to @url{http://www.penguin.cz/~utx/amr} and follow the instructions for
864 installing the libraries. Then pass @code{--enable-libamr-nb} and/or
865 @code{--enable-libamr-wb} to configure to enable the libraries.
868 @chapter Supported File Formats and Codecs
870 You can use the @code{-formats} option to have an exhaustive list.
872 @section File Formats
874 FFmpeg supports the following file formats through the @code{libavformat}
875 library:
877 @multitable @columnfractions .4 .1 .1 .4
878 @item Supported File Format @tab Encoding @tab Decoding @tab Comments
879 @item MPEG audio @tab X @tab X
880 @item MPEG-1 systems @tab X @tab X
881 @tab muxed audio and video
882 @item MPEG-2 PS @tab X @tab X
883 @tab also known as @code{VOB} file
884 @item MPEG-2 TS @tab @tab X
885 @tab also known as DVB Transport Stream
886 @item ASF@tab X @tab X
887 @item AVI@tab X @tab X
888 @item WAV@tab X @tab X
889 @item Macromedia Flash@tab X @tab X
890 @tab Only embedded audio is decoded.
891 @item FLV @tab X @tab X
892 @tab Macromedia Flash video files
893 @item Real Audio and Video @tab X @tab X
894 @item Raw AC3 @tab X @tab X
895 @item Raw MJPEG @tab X @tab X
896 @item Raw MPEG video @tab X @tab X
897 @item Raw PCM8/16 bits, mulaw/Alaw@tab X @tab X
898 @item Raw CRI ADX audio @tab X @tab X
899 @item Raw Shorten audio @tab @tab X
900 @item SUN AU format @tab X @tab X
901 @item NUT @tab X @tab X @tab NUT Open Container Format
902 @item QuickTime @tab X @tab X
903 @item MPEG-4 @tab X @tab X
904 @tab MPEG-4 is a variant of QuickTime.
905 @item Raw MPEG4 video @tab X @tab X
906 @item DV @tab X @tab X
907 @item 4xm @tab @tab X
908 @tab 4X Technologies format, used in some games.
909 @item Playstation STR @tab @tab X
910 @item Id RoQ @tab X @tab X
911 @tab Used in Quake III, Jedi Knight 2, other computer games.
912 @item Interplay MVE @tab @tab X
913 @tab Format used in various Interplay computer games.
914 @item WC3 Movie @tab @tab X
915 @tab Multimedia format used in Origin's Wing Commander III computer game.
916 @item Sega FILM/CPK @tab @tab X
917 @tab Used in many Sega Saturn console games.
918 @item Westwood Studios VQA/AUD @tab @tab X
919 @tab Multimedia formats used in Westwood Studios games.
920 @item Id Cinematic (.cin) @tab @tab X
921 @tab Used in Quake II.
922 @item FLIC format @tab @tab X
923 @tab .fli/.flc files
924 @item Sierra VMD @tab @tab X
925 @tab Used in Sierra CD-ROM games.
926 @item Sierra Online @tab @tab X
927 @tab .sol files used in Sierra Online games.
928 @item Matroska @tab @tab X
929 @item Electronic Arts Multimedia @tab @tab X
930 @tab Used in various EA games; files have extensions like WVE and UV2.
931 @item Nullsoft Video (NSV) format @tab @tab X
932 @item ADTS AAC audio @tab X @tab X
933 @item Creative VOC @tab X @tab X @tab Created for the Sound Blaster Pro.
934 @item American Laser Games MM @tab @tab X
935 @tab Multimedia format used in games like Mad Dog McCree
936 @item AVS @tab @tab X
937 @tab Multimedia format used by the Creature Shock game.
938 @item Smacker @tab @tab X
939 @tab Multimedia format used by many games.
940 @item GXF @tab X @tab X
941 @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley playout servers.
942 @item CIN @tab @tab X
943 @tab Multimedia format used by Delphine Software games.
944 @item MXF @tab @tab X
945 @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
946 @item SEQ @tab @tab X
947 @tab Tiertex .seq files used in the DOS CDROM version of the game Flashback.
948 @item DXA @tab @tab X
949 @tab This format is used in non-Windows version of Feeble Files game and
950 different game cutscenes repacked for use with ScummVM.
951 @item THP @tab @tab X
952 @tab Used on the Nintendo GameCube.
953 @item C93 @tab @tab X
954 @tab Used in the game Cyberia from Interplay.
955 @item Bethsoft VID @tab @tab X
956 @tab Used in some games from Bethesda Softworks.
957 @item CRYO APC @tab @tab X
958 @tab Audio format used in some games by CRYO Interactive Entertainment.
959 @end multitable
961 @code{X} means that encoding (resp. decoding) is supported.
963 @section Image Formats
965 FFmpeg can read and write images for each frame of a video sequence. The
966 following image formats are supported:
968 @multitable @columnfractions .4 .1 .1 .4
969 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
970 @item PGM, PPM @tab X @tab X
971 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
972 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
973 @item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
974 @item .Y.U.V @tab X @tab X @tab one raw file per component
975 @item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
976 @item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
977 @item Targa @tab @tab X @tab Targa (.TGA) image format.
978 @item TIFF @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
979 @item SGI @tab X @tab X @tab SGI RGB image format
980 @item PTX @tab @tab X @tab V.Flash PTX format
981 @end multitable
983 @code{X} means that encoding (resp. decoding) is supported.
985 @section Video Codecs
987 @multitable @columnfractions .4 .1 .1 .4
988 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
989 @item MPEG-1 video @tab X @tab X
990 @item MPEG-2 video @tab X @tab X
991 @item MPEG-4 @tab X @tab X
992 @item MSMPEG4 V1 @tab X @tab X
993 @item MSMPEG4 V2 @tab X @tab X
994 @item MSMPEG4 V3 @tab X @tab X
995 @item WMV7 @tab X @tab X
996 @item WMV8 @tab X @tab X @tab not completely working
997 @item WMV9 @tab @tab X @tab not completely working
998 @item VC1 @tab @tab X
999 @item H.261 @tab X @tab X
1000 @item H.263(+) @tab X @tab X @tab also known as RealVideo 1.0
1001 @item H.264 @tab @tab X
1002 @item RealVideo 1.0 @tab X @tab X
1003 @item RealVideo 2.0 @tab X @tab X
1004 @item MJPEG @tab X @tab X
1005 @item lossless MJPEG @tab X @tab X
1006 @item JPEG-LS @tab X @tab X @tab fourcc: MJLS, lossless and near-lossless is supported
1007 @item Apple MJPEG-B @tab @tab X
1008 @item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
1009 @item DV @tab X @tab X
1010 @item HuffYUV @tab X @tab X
1011 @item FFmpeg Video 1 @tab X @tab X @tab experimental lossless codec (fourcc: FFV1)
1012 @item FFmpeg Snow @tab X @tab X @tab experimental wavelet codec (fourcc: SNOW)
1013 @item Asus v1 @tab X @tab X @tab fourcc: ASV1
1014 @item Asus v2 @tab X @tab X @tab fourcc: ASV2
1015 @item Creative YUV @tab @tab X @tab fourcc: CYUV
1016 @item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
1017 @item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
1018 @item On2 VP3 @tab @tab X @tab still experimental
1019 @item On2 VP5 @tab @tab X @tab fourcc: VP50
1020 @item On2 VP6 @tab @tab X @tab fourcc: VP60,VP61,VP62
1021 @item Theora @tab X @tab X @tab still experimental
1022 @item Intel Indeo 3 @tab @tab X
1023 @item FLV @tab X @tab X @tab Sorenson H.263 used in Flash
1024 @item Flash Screen Video @tab X @tab X @tab fourcc: FSV1
1025 @item ATI VCR1 @tab @tab X @tab fourcc: VCR1
1026 @item ATI VCR2 @tab @tab X @tab fourcc: VCR2
1027 @item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
1028 @item 4X Video @tab @tab X @tab Used in certain computer games.
1029 @item Sony Playstation MDEC @tab @tab X
1030 @item Id RoQ @tab X @tab X @tab Used in Quake III, Jedi Knight 2, other computer games.
1031 @item Xan/WC3 @tab @tab X @tab Used in Wing Commander III .MVE files.
1032 @item Interplay Video @tab @tab X @tab Used in Interplay .MVE files.
1033 @item Apple Animation @tab X @tab X @tab fourcc: 'rle '
1034 @item Apple Graphics @tab @tab X @tab fourcc: 'smc '
1035 @item Apple Video @tab @tab X @tab fourcc: rpza
1036 @item Apple QuickDraw @tab @tab X @tab fourcc: qdrw
1037 @item Cinepak @tab @tab X
1038 @item Microsoft RLE @tab @tab X
1039 @item Microsoft Video-1 @tab @tab X
1040 @item Westwood VQA @tab @tab X
1041 @item Id Cinematic Video @tab @tab X @tab Used in Quake II.
1042 @item Planar RGB @tab @tab X @tab fourcc: 8BPS
1043 @item FLIC video @tab @tab X
1044 @item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK
1045 @item Duck TrueMotion v2 @tab @tab X @tab fourcc: TM20
1046 @item VMD Video @tab @tab X @tab Used in Sierra VMD files.
1047 @item MSZH @tab @tab X @tab Part of LCL
1048 @item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental
1049 @item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC
1050 @item IBM Ultimotion @tab @tab X @tab fourcc: ULTI
1051 @item Miro VideoXL @tab @tab X @tab fourcc: VIXL
1052 @item QPEG @tab @tab X @tab fourccs: QPEG, Q1.0, Q1.1
1053 @item LOCO @tab @tab X @tab
1054 @item Winnov WNV1 @tab @tab X @tab
1055 @item Autodesk Animator Studio Codec @tab @tab X @tab fourcc: AASC
1056 @item Fraps FPS1 @tab @tab X @tab
1057 @item CamStudio @tab @tab X @tab fourcc: CSCD
1058 @item American Laser Games Video @tab @tab X @tab Used in games like Mad Dog McCree
1059 @item ZMBV @tab X @tab X @tab Encoder works only on PAL8
1060 @item AVS Video @tab @tab X @tab Video encoding used by the Creature Shock game.
1061 @item Smacker Video @tab @tab X @tab Video encoding used in Smacker.
1062 @item RTjpeg @tab @tab X @tab Video encoding used in NuppelVideo files.
1063 @item KMVC @tab @tab X @tab Codec used in Worms games.
1064 @item VMware Video @tab @tab X @tab Codec used in videos captured by VMware.
1065 @item Cin Video @tab @tab X @tab Codec used in Delphine Software games.
1066 @item Tiertex Seq Video @tab @tab X @tab Codec used in DOS CDROM FlashBack game.
1067 @item DXA Video @tab @tab X @tab Codec originally used in Feeble Files game.
1068 @item AVID DNxHD @tab @tab X @tab aka SMPTE VC3
1069 @item C93 Video @tab @tab X @tab Codec used in Cyberia game.
1070 @item THP @tab @tab X @tab Used on the Nintendo GameCube.
1071 @item Bethsoft VID @tab @tab X @tab Used in some games from Bethesda Softworks.
1072 @item Renderware TXD @tab @tab X @tab Texture dictionaries used by the Renderware Engine.
1073 @end multitable
1075 @code{X} means that encoding (resp. decoding) is supported.
1077 @section Audio Codecs
1079 @multitable @columnfractions .4 .1 .1 .1 .7
1080 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
1081 @item MPEG audio layer 2 @tab IX @tab IX
1082 @item MPEG audio layer 1/3 @tab IX @tab IX
1083 @tab MP3 encoding is supported through the external library LAME.
1084 @item AC3 @tab IX @tab IX
1085 @tab liba52 is used internally for decoding.
1086 @item Vorbis @tab X @tab X
1087 @item WMA V1/V2 @tab X @tab X
1088 @item AAC @tab X @tab X
1089 @tab Supported through the external library libfaac/libfaad.
1090 @item Microsoft ADPCM @tab X @tab X
1091 @item MS IMA ADPCM @tab X @tab X
1092 @item QT IMA ADPCM @tab @tab X
1093 @item 4X IMA ADPCM @tab @tab X
1094 @item G.726 ADPCM @tab X @tab X
1095 @item Duck DK3 IMA ADPCM @tab @tab X
1096 @tab Used in some Sega Saturn console games.
1097 @item Duck DK4 IMA ADPCM @tab @tab X
1098 @tab Used in some Sega Saturn console games.
1099 @item Westwood Studios IMA ADPCM @tab @tab X
1100 @tab Used in Westwood Studios games like Command and Conquer.
1101 @item SMJPEG IMA ADPCM @tab @tab X
1102 @tab Used in certain Loki game ports.
1103 @item CD-ROM XA ADPCM @tab @tab X
1104 @item CRI ADX ADPCM @tab X @tab X
1105 @tab Used in Sega Dreamcast games.
1106 @item Electronic Arts ADPCM @tab @tab X
1107 @tab Used in various EA titles.
1108 @item Creative ADPCM @tab @tab X
1109 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
1110 @item THP ADPCM @tab @tab X
1111 @tab Used on the Nintendo GameCube.
1112 @item RA144 @tab @tab X
1113 @tab Real 14400 bit/s codec
1114 @item RA288 @tab @tab X
1115 @tab Real 28800 bit/s codec
1116 @item RADnet @tab X @tab IX
1117 @tab Real low bitrate AC3 codec, liba52 is used for decoding.
1118 @item AMR-NB @tab X @tab X
1119 @tab Supported through an external library.
1120 @item AMR-WB @tab X @tab X
1121 @tab Supported through an external library.
1122 @item DV audio @tab @tab X
1123 @item Id RoQ DPCM @tab X @tab X
1124 @tab Used in Quake III, Jedi Knight 2, other computer games.
1125 @item Interplay MVE DPCM @tab @tab X
1126 @tab Used in various Interplay computer games.
1127 @item Xan DPCM @tab @tab X
1128 @tab Used in Origin's Wing Commander IV AVI files.
1129 @item Sierra Online DPCM @tab @tab X
1130 @tab Used in Sierra Online game audio files.
1131 @item Apple MACE 3 @tab @tab X
1132 @item Apple MACE 6 @tab @tab X
1133 @item FLAC lossless audio @tab X @tab X
1134 @item Shorten lossless audio @tab @tab X
1135 @item Apple lossless audio @tab @tab X
1136 @tab QuickTime fourcc 'alac'
1137 @item FFmpeg Sonic @tab X @tab X
1138 @tab experimental lossy/lossless codec
1139 @item Qdesign QDM2 @tab @tab X
1140 @tab there are still some distortions
1141 @item Real COOK @tab @tab X
1142 @tab All versions except 5.1 are supported
1143 @item DSP Group TrueSpeech @tab @tab X
1144 @item True Audio (TTA) @tab @tab X
1145 @item Smacker Audio @tab @tab X
1146 @item WavPack Audio @tab @tab X
1147 @item Cin Audio @tab @tab X
1148 @tab Codec used in Delphine Software games.
1149 @item Intel Music Coder @tab @tab X
1150 @item Musepack @tab @tab X
1151 @tab Only SV7 is supported
1152 @item DT$ Coherent Audio @tab @tab X
1153 @item ATRAC 3 @tab @tab X
1154 @end multitable
1156 @code{X} means that encoding (resp. decoding) is supported.
1158 @code{I} means that an integer-only version is available, too (ensures high
1159 performance on systems without hardware floating point support).
1161 @chapter Platform Specific information
1163 @section BSD
1165 BSD make will not build FFmpeg, you need to install and use GNU Make
1166 (@file{gmake}).
1168 @section Windows
1170 To get help and instructions for using FFmpeg under Windows, check out
1171 the FFmpeg Windows Help Forum at
1172 @url{http://arrozcru.no-ip.org/ffmpeg/}.
1174 @subsection Native Windows compilation
1176 @itemize
1177 @item Install the current versions of MSYS and MinGW from
1178 @url{http://www.mingw.org/}. You can find detailed installation
1179 instructions in the download section and the FAQ.
1181 NOTE: Use at least bash 3.1. Older versions are known to be failing on the
1182 configure script.
1184 @item If you want to test the FFplay, also download
1185 the MinGW development library of SDL 1.2.x
1186 (@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
1187 @url{http://www.libsdl.org}. Unpack it in a temporary directory, and
1188 unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
1189 directory. Edit the @file{sdl-config} script so that it gives the
1190 correct SDL directory when invoked.
1192 @item Extract the current version of FFmpeg.
1194 @item Start the MSYS shell (file @file{msys.bat}).
1196 @item Change to the FFmpeg directory and follow
1197 the instructions of how to compile FFmpeg (file
1198 @file{INSTALL}). Usually, launching @file{./configure} and @file{make}
1199 suffices. If you have problems using SDL, verify that
1200 @file{sdl-config} can be launched from the MSYS command line.
1202 @item You can install FFmpeg in @file{Program Files/FFmpeg} by typing
1203 @file{make install}. Do not forget to copy @file{SDL.dll} to the place
1204 you launch @file{ffplay} from.
1206 @end itemize
1208 Notes:
1209 @itemize
1211 @item The target @file{make wininstaller} can be used to create a
1212 Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
1213 must be copied to the FFmpeg directory in order to build the
1214 installer.
1216 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
1217 you can build @file{avcodec.dll} and @file{avformat.dll}. With
1218 @code{make install} you install the FFmpeg DLLs and the associated
1219 headers in @file{Program Files/FFmpeg}.
1221 @item Visual C++ compatibility: If you used @code{./configure --enable-shared}
1222 when configuring FFmpeg, FFmpeg tries to use the Microsoft Visual
1223 C++ @code{lib} tool to build @code{avcodec.lib} and
1224 @code{avformat.lib}. With these libraries you can link your Visual C++
1225 code directly with the FFmpeg DLLs (see below).
1227 @end itemize
1229 @subsection Visual C++ compatibility
1231 FFmpeg will not compile under Visual C++ -- and it has too many
1232 dependencies on the GCC compiler to make a port viable. However,
1233 if you want to use the FFmpeg libraries in your own applications,
1234 you can still compile those applications using Visual C++. An
1235 important restriction to this is that you have to use the
1236 dynamically linked versions of the FFmpeg libraries (i.e. the
1237 DLLs), and you have to make sure that Visual-C++-compatible
1238 import libraries are created during the FFmpeg build process.
1240 This description of how to use the FFmpeg libraries with Visual C++ is
1241 based on Visual C++ 2005 Express Edition Beta 2. If you have a different
1242 version, you might have to modify the procedures slightly.
1244 Here are the step-by-step instructions for building the FFmpeg libraries
1245 so they can be used with Visual C++:
1247 @enumerate
1249 @item Install Visual C++ (if you have not done so already).
1251 @item Install MinGW and MSYS as described above.
1253 @item Add a call to @file{vcvars32.bat} (which sets up the environment
1254 variables for the Visual C++ tools) as the first line of
1255 @file{msys.bat}. The standard location for @file{vcvars32.bat} is
1256 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
1257 and the standard location for @file{msys.bat} is
1258 @file{C:\msys\1.0\msys.bat}. If this corresponds to your setup, add the
1259 following line as the first line of @file{msys.bat}:
1261 @code{call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"}
1263 @item Start the MSYS shell (file @file{msys.bat}) and type @code{link.exe}.
1264 If you get a help message with the command line options of @code{link.exe},
1265 this means your environment variables are set up correctly, the
1266 Microsoft linker is on the path and will be used by FFmpeg to
1267 create Visual-C++-compatible import libraries.
1269 @item Extract the current version of FFmpeg and change to the FFmpeg directory.
1271 @item Type the command
1272 @code{./configure --enable-shared --disable-static --enable-memalign-hack}
1273 to configure and, if that did not produce any errors,
1274 type @code{make} to build FFmpeg.
1276 @item The subdirectories @file{libavformat}, @file{libavcodec}, and
1277 @file{libavutil} should now contain the files @file{avformat.dll},
1278 @file{avformat.lib}, @file{avcodec.dll}, @file{avcodec.lib},
1279 @file{avutil.dll}, and @file{avutil.lib}, respectively. Copy the three
1280 DLLs to your System32 directory (typically @file{C:\Windows\System32}).
1282 @end enumerate
1284 And here is how to use these libraries with Visual C++:
1286 @enumerate
1288 @item Create a new console application ("File / New / Project") and then
1289 select "Win32 Console Application". On the appropriate page of the
1290 Application Wizard, uncheck the "Precompiled headers" option.
1292 @item Write the source code for your application, or, for testing, just
1293 copy the code from an existing sample application into the source file
1294 that Visual C++ has already created for you. (Note that your source
1295 filehas to have a @code{.cpp} extension; otherwise, Visual C++ will not
1296 compile the FFmpeg headers correctly because in C mode, it does not
1297 recognize the @code{inline} keyword.) For example, you can copy
1298 @file{output_example.c} from the FFmpeg distribution (but you will
1299 have to make minor modifications so the code will compile under
1300 C++, see below).
1302 @item Open the "Project / Properties" dialog box. In the "Configuration"
1303 combo box, select "All Configurations" so that the changes you make will
1304 affect both debug and release builds. In the tree view on the left hand
1305 side, select "C/C++ / General", then edit the "Additional Include
1306 Directories" setting to contain the complete paths to the
1307 @file{libavformat}, @file{libavcodec}, and @file{libavutil}
1308 subdirectories of your FFmpeg directory. Note that the directories have
1309 to be separated using semicolons. Now select "Linker / General" from the
1310 tree view and edit the "Additional Library Directories" setting to
1311 contain the same three directories.
1313 @item Still in the "Project / Properties" dialog box, select "Linker / Input"
1314 from the tree view, then add the files @file{avformat.lib},
1315 @file{avcodec.lib}, and @file{avutil.lib} to the end of the "Additional
1316 Dependencies". Note that the names of the libraries have to be separated
1317 using spaces.
1319 @item Now, select "C/C++ / Code Generation" from the tree view. Select
1320 "Debug" in the "Configuration" combo box. Make sure that "Runtime
1321 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
1322 the "Configuration" combo box and make sure that "Runtime Library" is
1323 set to "Multi-threaded DLL".
1325 @item Click "OK" to close the "Project / Properties" dialog box and build
1326 the application. Hopefully, it should compile and run cleanly. If you
1327 used @file{output_example.c} as your sample application, you will get a
1328 few compiler errors, but they are easy to fix. The first type of error
1329 occurs because Visual C++ does not allow an @code{int} to be converted to
1330 an @code{enum} without a cast. To solve the problem, insert the required
1331 casts (this error occurs once for a @code{CodecID} and once for a
1332 @code{CodecType}). The second type of error occurs because C++ requires
1333 the return value of @code{malloc} to be cast to the exact type of the
1334 pointer it is being assigned to. Visual C++ will complain that, for
1335 example, @code{(void *)} is being assigned to @code{(uint8_t *)} without
1336 an explicit cast. So insert an explicit cast in these places to silence
1337 the compiler. The third type of error occurs because the @code{snprintf}
1338 library function is called @code{_snprintf} under Visual C++. So just
1339 add an underscore to fix the problem. With these changes,
1340 @file{output_example.c} should compile under Visual C++, and the
1341 resulting executable should produce valid video files.
1343 @end enumerate
1345 @subsection Cross compilation for Windows with Linux
1347 You must use the MinGW cross compilation tools available at
1348 @url{http://www.mingw.org/}.
1350 Then configure FFmpeg with the following options:
1351 @example
1352 ./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
1353 @end example
1354 (you can change the cross-prefix according to the prefix chosen for the
1355 MinGW tools).
1357 Then you can easily test FFmpeg with Wine
1358 (@url{http://www.winehq.com/}).
1360 @subsection Compilation under Cygwin
1362 Cygwin works very much like Unix.
1364 Just install your Cygwin with all the "Base" packages, plus the
1365 following "Devel" ones:
1366 @example
1367 binutils, gcc-core, make, subversion
1368 @end example
1370 Do not install binutils-20060709-1 (they are buggy on shared builds);
1371 use binutils-20050610-1 instead.
1373 Then run
1375 @example
1376 ./configure --enable-static --disable-shared
1377 @end example
1379 to make a static build or
1381 @example
1382 ./configure --enable-shared --disable-static
1383 @end example
1385 to build shared libraries.
1387 If you want to build FFmpeg with additional libraries, download Cygwin
1388 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository
1389 and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
1390 (@url{http://cygwinports.dotsrc.org/}).
1392 @subsection Crosscompilation for Windows under Cygwin
1394 With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
1396 Just install your Cygwin as explained before, plus these additional
1397 "Devel" packages:
1398 @example
1399 gcc-mingw-core, mingw-runtime, mingw-zlib
1400 @end example
1402 and add some special flags to your configure invocation.
1404 For a static build run
1405 @example
1406 ./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
1407 @end example
1409 and for a build with shared libraries
1410 @example
1411 ./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
1412 @end example
1414 @section BeOS
1416 The configure script should guess the configuration itself.
1417 Networking support is currently not finished.
1418 errno issues fixed by Andrew Bachmann.
1420 Old stuff:
1422 Fran├žois Revol - revol at free dot fr - April 2002
1424 The configure script should guess the configuration itself,
1425 however I still did not test building on the net_server version of BeOS.
1427 FFserver is broken (needs poll() implementation).
1429 There are still issues with errno codes, which are negative in BeOS, and
1430 that FFmpeg negates when returning. This ends up turning errors into
1431 valid results, then crashes.
1432 (To be fixed)
1434 @chapter Developers Guide
1436 @section API
1437 @itemize @bullet
1438 @item libavcodec is the library containing the codecs (both encoding and
1439 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
1441 @item libavformat is the library containing the file format handling (mux and
1442 demux code for several formats). Look at @file{ffplay.c} to use it in a
1443 player. See @file{output_example.c} to use it to generate audio or video
1444 streams.
1446 @end itemize
1448 @section Integrating libavcodec or libavformat in your program
1450 You can integrate all the source code of the libraries to link them
1451 statically to avoid any version problem. All you need is to provide a
1452 'config.mak' and a 'config.h' in the parent directory. See the defines
1453 generated by ./configure to understand what is needed.
1455 You can use libavcodec or libavformat in your commercial program, but
1456 @emph{any patch you make must be published}. The best way to proceed is
1457 to send your patches to the FFmpeg mailing list.
1459 @node Coding Rules
1460 @section Coding Rules
1462 FFmpeg is programmed in the ISO C90 language with a few additional
1463 features from ISO C99, namely:
1464 @itemize @bullet
1465 @item
1466 the @samp{inline} keyword;
1467 @item
1468 @samp{//} comments;
1469 @item
1470 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
1471 @item
1472 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
1473 @end itemize
1475 These features are supported by all compilers we care about, so we will not
1476 accept patches to remove their use unless they absolutely do not impair
1477 clarity and performance.
1479 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
1480 compiles with several other compilers, such as the Compaq ccc compiler
1481 or Sun Studio 9, and we would like to keep it that way unless it would
1482 be exceedingly involved. To ensure compatibility, please do not use any
1483 additional C99 features or GCC extensions. Especially watch out for:
1484 @itemize @bullet
1485 @item
1486 mixing statements and declarations;
1487 @item
1488 @samp{long long} (use @samp{int64_t} instead);
1489 @item
1490 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
1491 @item
1492 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
1493 @end itemize
1495 Indent size is 4.
1496 The presentation is the one specified by 'indent -i4 -kr -nut'.
1497 The TAB character is forbidden outside of Makefiles as is any
1498 form of trailing whitespace. Commits containing either will be
1499 rejected by the Subversion repository.
1501 Main priority in FFmpeg is simplicity and small code size (=less
1502 bugs).
1504 Comments: Use the JavaDoc/Doxygen
1505 format (see examples below) so that code documentation
1506 can be generated automatically. All nontrivial functions should have a comment
1507 above them explaining what the function does, even if it is just one sentence.
1508 All structures and their member variables should be documented, too.
1509 @example
1510 /**
1511 * @@file mpeg.c
1512 * MPEG codec.
1513 * @@author ...
1514 */
1516 /**
1517 * Summary sentence.
1518 * more text ...
1519 * ...
1520 */
1521 typedef struct Foobar@{
1522 int var1; /**< var1 description */
1523 int var2; ///< var2 description
1524 /** var3 description */
1525 int var3;
1526 @} Foobar;
1528 /**
1529 * Summary sentence.
1530 * more text ...
1531 * ...
1532 * @@param my_parameter description of my_parameter
1533 * @@return return value description
1534 */
1535 int myfunc(int my_parameter)
1536 ...
1537 @end example
1539 fprintf and printf are forbidden in libavformat and libavcodec,
1540 please use av_log() instead.
1542 Casts should be used only when necessary. Unneeded parentheses
1543 should also be avoided if they don't make the code easier to understand.
1545 @section Development Policy
1547 @enumerate
1548 @item
1549 You must not commit code which breaks FFmpeg! (Meaning unfinished but
1550 enabled code which breaks compilation or compiles but does not work or
1551 breaks the regression tests)
1552 You can commit unfinished stuff (for testing etc), but it must be disabled
1553 (#ifdef etc) by default so it does not interfere with other developers'
1554 work.
1555 @item
1556 You do not have to over-test things. If it works for you, and you think it
1557 should work for others, then commit. If your code has problems
1558 (portability, triggers compiler bugs, unusual environment etc) they will be
1559 reported and eventually fixed.
1560 @item
1561 Do not commit unrelated changes together, split them into self-contained
1562 pieces. Also do not forget that if part B depends on part A, but A does not
1563 depend on B, then A can and should be committed first and separate from B.
1564 Keeping changes well split into self-contained parts makes reviewing and
1565 understanding them on the commit log mailing list easier. This also helps
1566 in case of debugging later on.
1567 Also if you have doubts about splitting or not splitting, do not hesitate to
1568 ask/discuss it on the developer mailing list.
1569 @item
1570 Do not change behavior of the program (renaming options etc) without
1571 first discussing it on the ffmpeg-devel mailing list. Do not remove
1572 functionality from the code. Just improve!
1574 Note: Redundant code can be removed.
1575 @item
1576 Do not commit changes to the build system (Makefiles, configure script)
1577 which change behavior, defaults etc, without asking first. The same
1578 applies to compiler warning fixes, trivial looking fixes and to code
1579 maintained by other developers. We usually have a reason for doing things
1580 the way we do. Send your changes as patches to the ffmpeg-devel mailing
1581 list, and if the code maintainers say OK, you may commit. This does not
1582 apply to files you wrote and/or maintain.
1583 @item
1584 We refuse source indentation and other cosmetic changes if they are mixed
1585 with functional changes, such commits will be rejected and removed. Every
1586 developer has his own indentation style, you should not change it. Of course
1587 if you (re)write something, you can use your own style, even though we would
1588 prefer if the indentation throughout FFmpeg was consistent (Many projects
1589 force a given indentation style - we do not.). If you really need to make
1590 indentation changes (try to avoid this), separate them strictly from real
1591 changes.
1593 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
1594 then either do NOT change the indentation of the inner part within (do not
1595 move it to the right)! or do so in a separate commit
1596 @item
1597 Always fill out the commit log message. Describe in a few lines what you
1598 changed and why. You can refer to mailing list postings if you fix a
1599 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1600 @item
1601 If you apply a patch by someone else, include the name and email address in
1602 the log message. Since the ffmpeg-cvslog mailing list is publicly
1603 archived you should add some SPAM protection to the email address. Send an
1604 answer to ffmpeg-devel (or wherever you got the patch from) saying that
1605 you applied the patch.
1606 @item
1607 When applying patches that have been discussed (at length) on the mailing
1608 list, reference the thread in the log message.
1609 @item
1610 Do NOT commit to code actively maintained by others without permission.
1611 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
1612 timeframe (12h for build failures and security fixes, 3 days small changes,
1613 1 week for big patches) then commit your patch if you think it is OK.
1614 Also note, the maintainer can simply ask for more time to review!
1615 @item
1616 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
1617 are sent there and reviewed by all the other developers. Bugs and possible
1618 improvements or general questions regarding commits are discussed there. We
1619 expect you to react if problems with your code are uncovered.
1620 @item
1621 Update the documentation if you change behavior or add features. If you are
1622 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
1623 maintainer(s) will review and commit your stuff.
1624 @item
1625 Try to keep important discussions and requests (also) on the public
1626 developer mailing list, so that all developers can benefit from them.
1627 @item
1628 Never write to unallocated memory, never write over the end of arrays,
1629 always check values read from some untrusted source before using them
1630 as array index or other risky things.
1631 @item
1632 Remember to check if you need to bump versions for the specific libav
1633 parts (libavutil, libavcodec, libavformat) you are changing. You need
1634 to change the version integer and the version string.
1635 Incrementing the first component means no backward compatibility to
1636 previous versions (e.g. removal of a function from the public API).
1637 Incrementing the second component means backward compatible change
1638 (e.g. addition of a function to the public API).
1639 Incrementing the third component means a noteworthy binary compatible
1640 change (e.g. encoder bug fix that matters for the decoder).
1641 @item
1642 If you add a new codec, remember to update the changelog, add it to
1643 the supported codecs table in the documentation and bump the second
1644 component of the @file{libavcodec} version number appropriately. If
1645 it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
1646 is only a decoder.
1647 @item
1648 Do not change code to hide warnings without ensuring that the underlying
1649 logic is correct and thus the warning was inappropriate.
1650 @item
1651 If you add a new file, give it a proper license header. Do not copy and
1652 paste it from a random place, use an existing file as template.
1653 @end enumerate
1655 We think our rules are not too hard. If you have comments, contact us.
1657 Note, these rules are mostly borrowed from the MPlayer project.
1659 @section Submitting patches
1661 First, (@pxref{Coding Rules}) above if you did not yet.
1663 When you submit your patch, try to send a unified diff (diff '-up'
1664 option). I cannot read other diffs :-)
1666 Also please do not submit patches which contain several unrelated changes.
1667 Split them into individual self-contained patches; this makes reviewing
1668 them much easier.
1670 Run the regression tests before submitting a patch so that you can
1671 verify that there are no big problems.
1673 Patches should be posted as base64 encoded attachments (or any other
1674 encoding which ensures that the patch will not be trashed during
1675 transmission) to the ffmpeg-devel mailing list, see
1676 @url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
1678 It also helps quite a bit if you tell us what the patch does (for example
1679 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
1680 and has no lrint()')
1682 Also please if you send several patches, send each patch as separate mail,
1683 do not attach several unrelated patches to the same mail.
1685 @section patch submission checklist
1687 @enumerate
1688 @item
1689 Do the regression tests pass with the patch applied?
1690 @item
1691 Is the patch a unified diff?
1692 @item
1693 Is the patch against latest FFmpeg SVN?
1694 @item
1695 Are you subscribed to ffmpeg-dev?
1696 (the list is subscribers only due to spam)
1697 @item
1698 Have you checked that the changes are minimal, so that the same cannot be
1699 achieved with a smaller patch and/or simpler final code?
1700 @item
1701 If the change is to speed critical code, did you benchmark it?
1702 @item
1703 If you did any benchmarks, did you provide them in the mail?
1704 @item
1705 Have you checked that the patch does not introduce buffer overflows or
1706 other security issues?
1707 @item
1708 Is the patch created from the root of the source tree, so it can be
1709 applied with @code{patch -p0}?
1710 @item
1711 Does the patch not mix functional and cosmetic changes?
1712 @item
1713 Did you add tabs or trailing whitespace to the code? Both are forbidden.
1714 @item
1715 Is the patch attached to the email you send?
1716 @item
1717 Is the mime type of the patch correct? It should be text/x-diff or
1718 text/x-patch or at least text/plain and not application/octet-stream.
1719 @item
1720 If the patch fixes a bug, did you provide a verbose analysis of the bug?
1721 @item
1722 If the patch fixes a bug, did you provide enough information, including
1723 a sample, so the bug can be reproduced and the fix can be verified?
1724 Note please do not attach samples >100k to mails but rather provide a
1725 URL, you can upload to ftp://upload.mplayerhq.hu
1726 @item
1727 Did you provide a verbose summary about what the patch does change?
1728 @item
1729 Did you provide a verbose explanation why it changes things like it does?
1730 @item
1731 Did you provide a verbose summary of the user visible advantages and
1732 disadvantages if the patch is applied?
1733 @item
1734 Did you provide an example so we can verify the new feature added by the
1735 patch easily?
1736 @item
1737 If you added a new file, did you insert a license header? It should be
1738 taken from FFmpeg, not randomly copied and pasted from somewhere else.
1739 @item
1740 You should maintain alphabetical order in alphabetically ordered lists as
1741 long as doing so does not break API/ABI compatibility.
1742 @item
1743 Did you provide a suggestion for a clear commit log message?
1744 @end enumerate
1746 @section Patch review process
1748 All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1749 clear note that the patch is not for SVN.
1750 Reviews and comments will be posted as replies to the patch on the
1751 mailing list. The patch submitter then has to take care of every comment,
1752 that can be by resubmitting a changed patch or by discussion. Resubmitted
1753 patches will themselves be reviewed like any other patch. If at some point
1754 a patch passes review with no comments then it is approved, that can for
1755 simple and small patches happen immediately while large patches will generally
1756 have to be changed and reviewed many times before they are approved.
1757 After a patch is approved it will be committed to the repository.
1759 We will review all submitted patches, but sometimes we are quite busy so
1760 especially for large patches this can take several weeks.
1762 When resubmitting patches, please do not make any significant changes
1763 not related to the comments received during review. Such patches will
1764 be rejected. Instead, submit significant changes or new features as
1765 separate patches.
1767 @section Regression tests
1769 Before submitting a patch (or committing to the repository), you should at least
1770 test that you did not break anything.
1772 The regression tests build a synthetic video stream and a synthetic
1773 audio stream. These are then encoded and decoded with all codecs or
1774 formats. The CRC (or MD5) of each generated file is recorded in a
1775 result file. A 'diff' is launched to compare the reference results and
1776 the result file.
1778 The regression tests then go on to test the FFserver code with a
1779 limited set of streams. It is important that this step runs correctly
1780 as well.
1782 Run 'make test' to test all the codecs and formats.
1784 Run 'make fulltest' to test all the codecs, formats and FFserver.
1786 [Of course, some patches may change the results of the regression tests. In
1787 this case, the reference results of the regression tests shall be modified
1788 accordingly].
1790 @bye