Update info for Sonic, add Dirac to supported formats list.
[libav.git] / doc / general.texi
1 \input texinfo @c -*- texinfo -*-
2
3 @settitle General Documentation
4 @titlepage
5 @sp 7
6 @center @titlefont{General Documentation}
7 @sp 3
8 @end titlepage
9
10
11 @chapter external libraries
12
13 FFmpeg can be hooked up with a number of external libraries to add support
14 for more formats. None of them are used by default, their use has to be
15 explicitly requested by passing the appropriate flags to @file{./configure}.
16
17 @section AMR
18
19 AMR comes in two different flavors, wideband and narrowband. FFmpeg can make
20 use of the AMR wideband (floating-point mode) and the AMR narrowband
21 (floating-point mode) reference decoders and encoders.
22
23 Go to @url{http://www.penguin.cz/~utx/amr} and follow the instructions for
24 installing the libraries. Then pass @code{--enable-libamr-nb} and/or
25 @code{--enable-libamr-wb} to configure to enable the libraries.
26
27 Note that libamr is copyrighted without any sort of license grant. This means
28 that you can use it if you legally obtained it but you are not allowed to
29 redistribute it in any way. @strong{Any FFmpeg binaries with libamr support
30 you create are non-free and unredistributable!}
31
32
33 @chapter Supported File Formats and Codecs
34
35 You can use the @code{-formats} option to have an exhaustive list.
36
37 @section File Formats
38
39 FFmpeg supports the following file formats through the @code{libavformat}
40 library:
41
42 @multitable @columnfractions .4 .1 .1 .4
43 @item Supported File Format @tab Encoding @tab Decoding @tab Comments
44 @item 4xm @tab @tab X
45 @tab 4X Technologies format, used in some games.
46 @item ADTS AAC audio @tab X @tab X
47 @item American Laser Games MM @tab @tab X
48 @tab Multimedia format used in games like Mad Dog McCree.
49 @item ASF @tab X @tab X
50 @item AVI @tab X @tab X
51 @item AVM2 (Flash 9) @tab X @tab X
52 @tab Only embedded audio is decoded.
53 @item AVS @tab @tab X
54 @tab Multimedia format used by the Creature Shock game.
55 @item Bethsoft VID @tab @tab X
56 @tab Used in some games from Bethesda Softworks.
57 @item BFI @tab @tab X
58 @tab Brute Force & Ignorance, used in Flash Traffic: City of Angels.
59 @item C93 @tab @tab X
60 @tab Used in the game Cyberia from Interplay.
61 @item CIN @tab @tab X
62 @tab Multimedia format used by Delphine Software games.
63 @item Creative VOC @tab X @tab X
64 @tab Created for the Sound Blaster Pro.
65 @item CRYO APC @tab @tab X
66 @tab Audio format used in some games by CRYO Interactive Entertainment.
67 @item DV @tab X @tab X
68 @item DXA @tab @tab X
69 @tab This format is used in the non-Windows version of the Feeble Files
70 game and different game cutscenes repacked for use with ScummVM.
71 @item Electronic Arts Multimedia @tab @tab X
72 @tab Used in various EA games; files have extensions like WVE and UV2.
73 @item FLIC @tab @tab X
74 @tab .fli/.flc files
75 @item FLV @tab X @tab X
76 @tab Macromedia Flash video files
77 @item GXF @tab X @tab X
78 @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley
79 playout servers.
80 @item id Cinematic @tab @tab X
81 @tab Used in Quake II.
82 @item id RoQ @tab X @tab X
83 @tab Used in Quake III, Jedi Knight 2, other computer games.
84 @item IFF @tab @tab X
85 @tab Interchange File Format
86 @item Interplay MVE @tab @tab X
87 @tab Format used in various Interplay computer games.
88 @item LMLM4 @tab @tab X
89 @tab Used by Linux Media Labs MPEG-4 PCI boards
90 @item Matroska @tab X @tab X
91 @item MAXIS EA XA @tab @tab X
92 @tab Used in Sim City 3000; file extension .xa.
93 @item Monkey's Audio @tab @tab X
94 @item MOV/QuickTime @tab X @tab X
95 @item MPEG audio @tab X @tab X
96 @item MPEG-1 systems @tab X @tab X
97 @tab muxed audio and video
98 @item MPEG-2 PS @tab X @tab X
99 @tab also known as @code{VOB} file
100 @item MPEG-2 TS @tab @tab X
101 @tab also known as DVB Transport Stream
102 @item MPEG-4 @tab X @tab X
103 @tab MPEG-4 is a variant of QuickTime.
104 @item MSN TCP webcam @tab @tab X
105 @tab Used by MSN Messenger webcam streams.
106 @item MXF @tab @tab X
107 @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
108 @item Nullsoft Video @tab @tab X
109 @item NUT @tab X @tab X
110 @tab NUT Open Container Format
111 @item OMA @tab @tab X
112 @tab Audio format used in Sony Sonic Stage and Sony Vegas.
113 @item PlayStation STR @tab @tab X
114 @item PVA @tab @tab X
115 @tab Used by TechnoTrend DVB PCI boards.
116 @item raw AC-3 @tab X @tab X
117 @item raw CRI ADX audio @tab X @tab X
118 @item raw MJPEG @tab X @tab X
119 @item raw MPEG video @tab X @tab X
120 @item raw MPEG-4 video @tab X @tab X
121 @item raw PCM 8/16 bits, mu-law/A-law @tab X @tab X
122 @item raw Shorten audio @tab @tab X
123 @item RealMedia @tab X @tab X
124 @item RL2 @tab @tab X
125 @tab Audio and video format used in some games by Entertainment Software Partners.
126 @item Sega FILM/CPK @tab @tab X
127 @tab Used in many Sega Saturn console games.
128 @item SEQ @tab @tab X
129 @tab Tiertex .seq files used in the DOS CD-ROM version of the game Flashback.
130 @item Sierra Online @tab @tab X
131 @tab .sol files used in Sierra Online games.
132 @item Sierra VMD @tab @tab X
133 @tab Used in Sierra CD-ROM games.
134 @item SIFF @tab @tab X
135 @tab Audio and video format used in some games by Beam Software.
136 @item Smacker @tab @tab X
137 @tab Multimedia format used by many games.
138 @item SUN AU format @tab X @tab X
139 @item THP @tab @tab X
140 @tab Used on the Nintendo GameCube.
141 @item WAV @tab X @tab X
142 @item WC3 Movie @tab @tab X
143 @tab Multimedia format used in Origin's Wing Commander III computer game.
144 @item Westwood Studios VQA/AUD @tab @tab X
145 @tab Multimedia formats used in Westwood Studios games.
146 @end multitable
147
148 @code{X} means that encoding (resp. decoding) is supported.
149
150 @section Image Formats
151
152 FFmpeg can read and write images for each frame of a video sequence. The
153 following image formats are supported:
154
155 @multitable @columnfractions .4 .1 .1 .4
156 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
157 @item .Y.U.V @tab X @tab X @tab one raw file per component
158 @item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
159 @item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
160 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
161 @item PCX @tab @tab X @tab PC Paintbrush
162 @item PGM, PPM @tab X @tab X
163 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
164 @item PNG @tab X @tab X @tab 2/4 bpp not supported yet
165 @item PTX @tab @tab X @tab V.Flash PTX format
166 @item RAS @tab @tab X @tab Sun Rasterfile
167 @item SGI @tab X @tab X @tab SGI RGB image format
168 @item Targa @tab @tab X @tab Targa (.TGA) image format
169 @item TIFF @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
170 @end multitable
171
172 @code{X} means that encoding (resp. decoding) is supported.
173
174 @section Video Codecs
175
176 @multitable @columnfractions .4 .1 .1 .4
177 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
178 @item 4X Video @tab @tab X
179 @tab Used in certain computer games.
180 @item American Laser Games Video @tab @tab X
181 @tab Used in games like Mad Dog McCree.
182 @item AMV @tab @tab X
183 @tab Used in Chinese MP3 players.
184 @item Apple Animation @tab X @tab X
185 @tab fourcc: 'rle '
186 @item Apple Graphics @tab @tab X
187 @tab fourcc: 'smc '
188 @item Apple MJPEG-B @tab @tab X
189 @item Apple QuickDraw @tab @tab X
190 @tab fourcc: qdrw
191 @item Apple Video @tab @tab X
192 @tab fourcc: rpza
193 @item Asus v1 @tab X @tab X
194 @tab fourcc: ASV1
195 @item Asus v2 @tab X @tab X
196 @tab fourcc: ASV2
197 @item ATI VCR1 @tab @tab X
198 @tab fourcc: VCR1
199 @item ATI VCR2 @tab @tab X
200 @tab fourcc: VCR2
201 @item Autodesk RLE @tab @tab X
202 @tab fourcc: AASC
203 @item AVID DNxHD @tab X @tab X
204 @tab aka SMPTE VC3
205 @item AVS video @tab @tab X
206 @tab Video encoding used by the Creature Shock game.
207 @item Bethsoft VID @tab @tab X
208 @tab Used in some games from Bethesda Softworks.
209 @item C93 video @tab @tab X
210 @tab Codec used in Cyberia game.
211 @item CamStudio @tab @tab X
212 @tab fourcc: CSCD
213 @item Cin video @tab @tab X
214 @tab Codec used in Delphine Software games.
215 @item Cinepak @tab @tab X
216 @item Cirrus Logic AccuPak @tab @tab X
217 @tab fourcc: CLJR
218 @item Creative YUV @tab @tab X
219 @tab fourcc: CYUV
220 @item Dirac @tab X @tab X
221 @tab Supported through the external libdirac/libschroedinger libraries.
222 @item Duck TrueMotion v1 @tab @tab X
223 @tab fourcc: DUCK
224 @item Duck TrueMotion v2 @tab @tab X
225 @tab fourcc: TM20
226 @item DV @tab X @tab X
227 @item DXA Video @tab @tab X
228 @tab Codec originally used in Feeble Files game.
229 @item Electronic Arts CMV @tab @tab X
230 @tab Used in NHL 95 game.
231 @item FFmpeg Video 1 @tab X @tab X
232 @tab experimental lossless codec (fourcc: FFV1)
233 @item Flash Screen Video @tab X @tab X
234 @tab fourcc: FSV1
235 @item FLIC video @tab @tab X
236 @item FLV @tab X @tab X
237 @tab Sorenson H.263 used in Flash
238 @item Fraps FPS1 @tab @tab X
239 @item H.261 @tab X @tab X
240 @item H.263(+) @tab X @tab X
241 @tab also known as RealVideo 1.0
242 @item H.264 @tab @tab X
243 @item HuffYUV @tab X @tab X
244 @item IBM Ultimotion @tab @tab X
245 @tab fourcc: ULTI
246 @item id Cinematic video @tab @tab X
247 @tab Used in Quake II.
248 @item id RoQ @tab X @tab X
249 @tab Used in Quake III, Jedi Knight 2, other computer games.
250 @item Intel Indeo 3 @tab @tab X
251 @item Interplay Video @tab @tab X
252 @tab Used in Interplay .MVE files.
253 @item JPEG-LS @tab X @tab X
254 @tab fourcc: MJLS, lossless and near-lossless is supported.
255 @item KMVC @tab @tab X
256 @tab Codec used in Worms games.
257 @item LOCO @tab @tab X
258 @item lossless MJPEG @tab X @tab X
259 @item Microsoft RLE @tab @tab X
260 @item Microsoft Video-1 @tab @tab X
261 @item Mimic @tab @tab X
262 @tab Used in MSN Messenger Webcam streams.
263 @item Miro VideoXL @tab @tab X
264 @tab fourcc: VIXL
265 @item MJPEG @tab X @tab X
266 @item MPEG-1 @tab X @tab X
267 @item MPEG-2 @tab X @tab X
268 @item MPEG-4 @tab X @tab X
269 @item MSMPEG4 V1 @tab X @tab X
270 @item MSMPEG4 V2 @tab X @tab X
271 @item MSMPEG4 V3 @tab X @tab X
272 @item MSZH @tab @tab X
273 @tab Part of LCL
274 @item On2 VP3 @tab @tab X
275 @tab still experimental
276 @item On2 VP5 @tab @tab X
277 @tab fourcc: VP50
278 @item On2 VP6 @tab @tab X
279 @tab fourcc: VP60,VP61,VP62
280 @item planar RGB @tab @tab X
281 @tab fourcc: 8BPS
282 @item QPEG @tab @tab X
283 @tab fourccs: QPEG, Q1.0, Q1.1
284 @item RealVideo 1.0 @tab X @tab X
285 @item RealVideo 2.0 @tab X @tab X
286 @item Renderware TXD @tab @tab X
287 @tab Texture dictionaries used by the Renderware Engine.
288 @item RTjpeg @tab @tab X
289 @tab Video encoding used in NuppelVideo files.
290 @item Smacker video @tab @tab X
291 @tab Video encoding used in Smacker.
292 @item Snow @tab X @tab X
293 @tab experimental wavelet codec (fourcc: SNOW)
294 @item Sony PlayStation MDEC @tab @tab X
295 @item Sorenson Video 1 @tab X @tab X
296 @tab fourcc: SVQ1
297 @item Sorenson Video 3 @tab @tab X
298 @tab fourcc: SVQ3
299 @item Sunplus MJPEG @tab @tab X
300 @tab fourcc: SP5X
301 @item TechSmith Camtasia @tab @tab X
302 @tab fourcc: TSCC
303 @item Theora @tab X @tab X
304 @tab still experimental
305 @item THP @tab @tab X
306 @tab Used on the Nintendo GameCube.
307 @item Tiertex Seq video @tab @tab X
308 @tab Codec used in DOS CD-ROM FlashBack game.
309 @item VC-1 @tab @tab X
310 @item VMD Video @tab @tab X
311 @tab Used in Sierra VMD files.
312 @item VMware Video @tab @tab X
313 @tab Codec used in videos captured by VMware.
314 @item Westwood VQA @tab @tab X
315 @item Winnov WNV1 @tab @tab X
316 @item WMV7 @tab X @tab X
317 @item WMV8 @tab X @tab X
318 @item WMV9 @tab @tab X
319 @tab not completely working
320 @item Xan/WC3 @tab @tab X
321 @tab Used in Wing Commander III .MVE files.
322 @item ZLIB @tab X @tab X
323 @tab part of LCL, encoder experimental
324 @item ZMBV @tab X @tab X
325 @tab Encoder works only in PAL8.
326 @end multitable
327
328 @code{X} means that encoding (resp. decoding) is supported.
329
330 @section Audio Codecs
331
332 @multitable @columnfractions .4 .1 .1 .1 .7
333 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
334 @item 4X IMA ADPCM @tab @tab X
335 @item 8SVX audio @tab @tab X
336 @item AAC @tab X @tab X
337 @tab Supported through the external library libfaac/libfaad.
338 @item AC-3 @tab IX @tab IX
339 @tab liba52 can be used alternatively for decoding.
340 @item AMR-NB @tab X @tab X
341 @tab Supported through an external library.
342 @item AMR-WB @tab X @tab X
343 @tab Supported through an external library.
344 @item AMV IMA ADPCM @tab @tab X
345 @tab Used in AMV files
346 @item Apple lossless audio @tab @tab X
347 @tab QuickTime fourcc 'alac'
348 @item Apple MACE 3 @tab @tab X
349 @item Apple MACE 6 @tab @tab X
350 @item ATRAC 3 @tab @tab X
351 @item CD-ROM XA ADPCM @tab @tab X
352 @item Cin audio @tab @tab X
353 @tab Codec used in Delphine Software International games.
354 @item Creative ADPCM @tab @tab X
355 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
356 @item CRI ADX ADPCM @tab X @tab X
357 @tab Used in Sega Dreamcast games.
358 @item DSP Group TrueSpeech @tab @tab X
359 @item DTS Coherent Audio @tab @tab X
360 @item Duck DK3 IMA ADPCM @tab @tab X
361 @tab Used in some Sega Saturn console games.
362 @item Duck DK4 IMA ADPCM @tab @tab X
363 @tab Used in some Sega Saturn console games.
364 @item DV audio @tab @tab X
365 @item Electronic Arts ADPCM @tab @tab X
366 @tab Used in various EA titles.
367 @item Sonic @tab X @tab X
368 @tab experimental codec
369 @item Sonic lossless @tab X @tab X
370 @tab experimental codec
371 @item FLAC lossless audio @tab X @tab X
372 @item G.726 ADPCM @tab X @tab X
373 @item id RoQ DPCM @tab X @tab X
374 @tab Used in Quake III, Jedi Knight 2, other computer games.
375 @item Intel Music Coder @tab @tab X
376 @item Interplay MVE DPCM @tab @tab X
377 @tab Used in various Interplay computer games.
378 @item MAXIS EA ADPCM @tab @tab X
379 @tab Used in Sim City 3000.
380 @item Microsoft ADPCM @tab X @tab X
381 @item MLP/TrueHD @tab @tab X
382 @tab Used in DVD-Audio and Blu-Ray discs.
383 @item Monkey's Audio @tab @tab X
384 @tab Only versions 3.97-3.99 are supported.
385 @item MPEG audio layer 1/3 @tab X @tab IX
386 @tab MP3 encoding is supported through the external library LAME.
387 @item MPEG audio layer 2 @tab IX @tab IX
388 @item MS IMA ADPCM @tab X @tab X
389 @item Musepack @tab @tab X
390 @tab SV7 and SV8 are supported.
391 @item Nellymoser ASAO @tab @tab X
392 @item Qdesign QDM2 @tab @tab X
393 @tab There are still some distortions.
394 @item QT IMA ADPCM @tab X @tab X
395 @item RA144 @tab @tab X
396 @tab Real 14400 bit/s codec
397 @item RA288 @tab @tab X
398 @tab Real 28800 bit/s codec
399 @item RADnet @tab X @tab IX
400 @tab real low bitrate AC-3 codec
401 @item Real COOK @tab @tab X
402 @tab All versions except 5.1 are supported.
403 @item Shorten @tab @tab X
404 @item Sierra Online DPCM @tab @tab X
405 @tab Used in Sierra Online game audio files.
406 @item Smacker audio @tab @tab X
407 @item SMJPEG IMA ADPCM @tab @tab X
408 @tab Used in certain Loki game ports.
409 @item THP ADPCM @tab @tab X
410 @tab Used on the Nintendo GameCube.
411 @item True Audio (TTA) @tab @tab X
412 @item Vorbis @tab X @tab X
413 @item WavPack @tab @tab X
414 @item Westwood Studios IMA ADPCM @tab @tab X
415 @tab Used in Westwood Studios games like Command and Conquer.
416 @item WMA v1/v2 @tab X @tab X
417 @item Xan DPCM @tab @tab X
418 @tab Used in Origin's Wing Commander IV AVI files.
419 @end multitable
420
421 @code{X} means that encoding (resp. decoding) is supported.
422
423 @code{I} means that an integer-only version is available, too (ensures high
424 performance on systems without hardware floating point support).
425
426 @chapter Platform Specific information
427
428 @section BSD
429
430 BSD make will not build FFmpeg, you need to install and use GNU Make
431 (@file{gmake}).
432
433 @section Windows
434
435 To get help and instructions for building FFmpeg under Windows, check out
436 the FFmpeg Windows Help Forum at
437 @url{http://arrozcru.no-ip.org/ffmpeg/}.
438
439 @subsection Native Windows compilation
440
441 FFmpeg can be built to run natively on Windows using the MinGW tools. Install
442 the current versions of MSYS and MinGW from @url{http://www.mingw.org/}. Also
443 install the coreutils package, and update to the latest MSYS make (note: not
444 mingw32-make). You can find detailed installation
445 instructions in the download section and the FAQ.
446
447 Within the MSYS shell, configure and make with:
448
449 @example
450 ./configure --enable-memalign-hack
451 make
452 make install
453 @end example
454
455 This will install @file{ffmpeg.exe} along with many other development files
456 to @file{/usr/local}. You may specify another install path using the
457 @code{--prefix} option in @file{configure}.
458
459 Notes:
460
461 @itemize
462
463 @item Use at least bash 3.1. Older versions are known to fail on the
464 configure script.
465
466 @item In order to compile vhooks, you must have a POSIX-compliant libdl in
467 your MinGW system. Get dlfcn-win32 from
468 @url{http://code.google.com/p/dlfcn-win32}.
469
470 @item In order to compile FFplay, you must have the MinGW development library
471 of SDL. Get it from @url{http://www.libsdl.org}.
472 Edit the @file{bin/sdl-config} script so that it points to the correct prefix
473 where SDL was installed. Verify that @file{sdl-config} can be launched from
474 the MSYS command line.
475
476 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
477 you can build libavutil, libavcodec and libavformat as DLLs.
478
479 @end itemize
480
481 @subsection Microsoft Visual C++ compatibility
482
483 As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
484 want to use the libav* libraries in your own applications, you can still
485 compile those applications using MSVC++. But the libav* libraries you link
486 to @emph{must} be built with MinGW. However, you will not be able to debug
487 inside the libav* libraries, since MSVC++ does not recognize the debug
488 symbols generated by GCC.
489 We strongly recommend you to move over from MSVC++ to MinGW tools.
490
491 This description of how to use the FFmpeg libraries with MSVC++ is based on
492 Microsoft Visual C++ 2005 Express Edition. If you have a different version,
493 you might have to modify the procedures slightly.
494
495 @subsubsection Using static libraries
496
497 Assuming you have just built and installed FFmpeg in @file{/usr/local}.
498
499 @enumerate
500
501 @item Create a new console application ("File / New / Project") and then
502 select "Win32 Console Application". On the appropriate page of the
503 Application Wizard, uncheck the "Precompiled headers" option.
504
505 @item Write the source code for your application, or, for testing, just
506 copy the code from an existing sample application into the source file
507 that MSVC++ has already created for you. For example, you can copy
508 @file{output_example.c} from the FFmpeg distribution.
509
510 @item Open the "Project / Properties" dialog box. In the "Configuration"
511 combo box, select "All Configurations" so that the changes you make will
512 affect both debug and release builds. In the tree view on the left hand
513 side, select "C/C++ / General", then edit the "Additional Include
514 Directories" setting to contain the path where the FFmpeg includes were
515 installed (i.e. @file{c:\msys\1.0\local\include}).
516 Do not add MinGW's include directory here, or the include files will
517 conflict with MSVC's.
518
519 @item Still in the "Project / Properties" dialog box, select
520 "Linker / General" from the tree view and edit the
521 "Additional Library Directories" setting to contain the @file{lib}
522 directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
523 the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
524 and the directory where MinGW's GCC libs are installed
525 (i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
526 "Linker / Input" from the tree view, and add the files @file{libavformat.a},
527 @file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
528 @file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
529 to the end of "Additional Dependencies".
530
531 @item Now, select "C/C++ / Code Generation" from the tree view. Select
532 "Debug" in the "Configuration" combo box. Make sure that "Runtime
533 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
534 the "Configuration" combo box and make sure that "Runtime Library" is
535 set to "Multi-threaded DLL".
536
537 @item Click "OK" to close the "Project / Properties" dialog box.
538
539 @item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
540 Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
541 and install it in MSVC++'s include directory
542 (i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
543
544 @item MSVC++ also does not understand the @code{inline} keyword used by
545 FFmpeg, so you must add this line before @code{#include}ing libav*:
546 @example
547 #define inline _inline
548 @end example
549
550 @item Build your application, everything should work.
551
552 @end enumerate
553
554 @subsubsection Using shared libraries
555
556 This is how to create DLL and LIB files that are compatible with MSVC++:
557
558 @enumerate
559
560 @item Add a call to @file{vcvars32.bat} (which sets up the environment
561 variables for the Visual C++ tools) as the first line of @file{msys.bat}.
562 The standard location for @file{vcvars32.bat} is
563 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
564 and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
565 If this corresponds to your setup, add the following line as the first line
566 of @file{msys.bat}:
567
568 @example
569 call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
570 @end example
571
572 Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
573 and run @file{c:\msys\1.0\msys.bat} from there.
574
575 @item Within the MSYS shell, run @code{lib.exe}. If you get a help message
576 from @file{Microsoft (R) Library Manager}, this means your environment
577 variables are set up correctly, the @file{Microsoft (R) Library Manager}
578 is on the path and will be used by FFmpeg to create
579 MSVC++-compatible import libraries.
580
581 @item Build FFmpeg with
582
583 @example
584 ./configure --enable-shared --enable-memalign-hack
585 make
586 make install
587 @end example
588
589 Your install path (@file{/usr/local/} by default) should now have the
590 necessary DLL and LIB files under the @file{bin} directory.
591
592 @end enumerate
593
594 To use those files with MSVC++, do the same as you would do with
595 the static libraries, as described above. But in Step 4,
596 you should only need to add the directory where the LIB files are installed
597 (i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
598 installed in the @file{bin} directory. And instead of adding @file{libxx.a}
599 files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
600 @file{avutil.lib}. There should be no need for @file{libmingwex.a},
601 @file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
602 statically linked into the DLLs. The @file{bin} directory contains a bunch
603 of DLL files, but the ones that are actually used to run your application
604 are the ones with a major version number in their filenames
605 (i.e. @file{avcodec-51.dll}).
606
607 @subsection Cross compilation for Windows with Linux
608
609 You must use the MinGW cross compilation tools available at
610 @url{http://www.mingw.org/}.
611
612 Then configure FFmpeg with the following options:
613 @example
614 ./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
615 @end example
616 (you can change the cross-prefix according to the prefix chosen for the
617 MinGW tools).
618
619 Then you can easily test FFmpeg with Wine
620 (@url{http://www.winehq.com/}).
621
622 @subsection Compilation under Cygwin
623
624 The main issue with Cygwin is that newlib, its C library, does not
625 contain llrint(). However, it is possible to leverage the
626 implementation in MinGW.
627
628 Just install your Cygwin with all the "Base" packages, plus the
629 following "Devel" ones:
630 @example
631 binutils, gcc-core, make, subversion, mingw-runtime
632 @end example
633
634 Do not install binutils-20060709-1 (they are buggy on shared builds);
635 use binutils-20050610-1 instead.
636
637 Then create a small library that just contains llrint():
638
639 @example
640 ar x /usr/lib/mingw/libmingwex.a llrint.o
641 ar cq /usr/local/lib/libllrint.a llrint.o
642 @end example
643
644 Then run
645
646 @example
647 ./configure --enable-static --disable-shared --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
648 @end example
649
650 to make a static build or
651
652 @example
653 ./configure --enable-shared --disable-static --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
654 @end example
655
656 to build shared libraries.
657
658 If you want to build FFmpeg with additional libraries, download Cygwin
659 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository
660 and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
661 (@url{http://cygwinports.dotsrc.org/}).
662
663 @subsection Crosscompilation for Windows under Cygwin
664
665 With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
666
667 Just install your Cygwin as explained before, plus these additional
668 "Devel" packages:
669 @example
670 gcc-mingw-core, mingw-runtime, mingw-zlib
671 @end example
672
673 and add some special flags to your configure invocation.
674
675 For a static build run
676 @example
677 ./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
678 @end example
679
680 and for a build with shared libraries
681 @example
682 ./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
683 @end example
684
685 @section BeOS
686
687 BeOS support is broken in mysterious ways.
688
689 @section OS/2
690
691 For information about compiling FFmpeg on OS/2 see
692 @url{http://www.edm2.com/index.php/FFmpeg}.
693
694 @chapter Developers Guide
695
696 @section API
697 @itemize @bullet
698 @item libavcodec is the library containing the codecs (both encoding and
699 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
700
701 @item libavformat is the library containing the file format handling (mux and
702 demux code for several formats). Look at @file{ffplay.c} to use it in a
703 player. See @file{output_example.c} to use it to generate audio or video
704 streams.
705
706 @end itemize
707
708 @section Integrating libavcodec or libavformat in your program
709
710 You can integrate all the source code of the libraries to link them
711 statically to avoid any version problem. All you need is to provide a
712 'config.mak' and a 'config.h' in the parent directory. See the defines
713 generated by ./configure to understand what is needed.
714
715 You can use libavcodec or libavformat in your commercial program, but
716 @emph{any patch you make must be published}. The best way to proceed is
717 to send your patches to the FFmpeg mailing list.
718
719 @node Coding Rules
720 @section Coding Rules
721
722 FFmpeg is programmed in the ISO C90 language with a few additional
723 features from ISO C99, namely:
724 @itemize @bullet
725 @item
726 the @samp{inline} keyword;
727 @item
728 @samp{//} comments;
729 @item
730 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
731 @item
732 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
733 @end itemize
734
735 These features are supported by all compilers we care about, so we will not
736 accept patches to remove their use unless they absolutely do not impair
737 clarity and performance.
738
739 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
740 compiles with several other compilers, such as the Compaq ccc compiler
741 or Sun Studio 9, and we would like to keep it that way unless it would
742 be exceedingly involved. To ensure compatibility, please do not use any
743 additional C99 features or GCC extensions. Especially watch out for:
744 @itemize @bullet
745 @item
746 mixing statements and declarations;
747 @item
748 @samp{long long} (use @samp{int64_t} instead);
749 @item
750 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
751 @item
752 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
753 @end itemize
754
755 Indent size is 4.
756 The presentation is the one specified by 'indent -i4 -kr -nut'.
757 The TAB character is forbidden outside of Makefiles as is any
758 form of trailing whitespace. Commits containing either will be
759 rejected by the Subversion repository.
760
761 The main priority in FFmpeg is simplicity and small code size in order to
762 minimize the bug count.
763
764 Comments: Use the JavaDoc/Doxygen
765 format (see examples below) so that code documentation
766 can be generated automatically. All nontrivial functions should have a comment
767 above them explaining what the function does, even if it is just one sentence.
768 All structures and their member variables should be documented, too.
769 @example
770 /**
771 * @@file mpeg.c
772 * MPEG codec.
773 * @@author ...
774 */
775
776 /**
777 * Summary sentence.
778 * more text ...
779 * ...
780 */
781 typedef struct Foobar@{
782 int var1; /**< var1 description */
783 int var2; ///< var2 description
784 /** var3 description */
785 int var3;
786 @} Foobar;
787
788 /**
789 * Summary sentence.
790 * more text ...
791 * ...
792 * @@param my_parameter description of my_parameter
793 * @@return return value description
794 */
795 int myfunc(int my_parameter)
796 ...
797 @end example
798
799 fprintf and printf are forbidden in libavformat and libavcodec,
800 please use av_log() instead.
801
802 Casts should be used only when necessary. Unneeded parentheses
803 should also be avoided if they don't make the code easier to understand.
804
805 @section Development Policy
806
807 @enumerate
808 @item
809 Contributions should be licensed under the LGPL 2.1, including an
810 "or any later version" clause, or the MIT license. GPL 2 including
811 an "or any later version" clause is also acceptable, but LGPL is
812 preferred.
813 @item
814 You must not commit code which breaks FFmpeg! (Meaning unfinished but
815 enabled code which breaks compilation or compiles but does not work or
816 breaks the regression tests)
817 You can commit unfinished stuff (for testing etc), but it must be disabled
818 (#ifdef etc) by default so it does not interfere with other developers'
819 work.
820 @item
821 You do not have to over-test things. If it works for you, and you think it
822 should work for others, then commit. If your code has problems
823 (portability, triggers compiler bugs, unusual environment etc) they will be
824 reported and eventually fixed.
825 @item
826 Do not commit unrelated changes together, split them into self-contained
827 pieces. Also do not forget that if part B depends on part A, but A does not
828 depend on B, then A can and should be committed first and separate from B.
829 Keeping changes well split into self-contained parts makes reviewing and
830 understanding them on the commit log mailing list easier. This also helps
831 in case of debugging later on.
832 Also if you have doubts about splitting or not splitting, do not hesitate to
833 ask/discuss it on the developer mailing list.
834 @item
835 Do not change behavior of the program (renaming options etc) without
836 first discussing it on the ffmpeg-devel mailing list. Do not remove
837 functionality from the code. Just improve!
838
839 Note: Redundant code can be removed.
840 @item
841 Do not commit changes to the build system (Makefiles, configure script)
842 which change behavior, defaults etc, without asking first. The same
843 applies to compiler warning fixes, trivial looking fixes and to code
844 maintained by other developers. We usually have a reason for doing things
845 the way we do. Send your changes as patches to the ffmpeg-devel mailing
846 list, and if the code maintainers say OK, you may commit. This does not
847 apply to files you wrote and/or maintain.
848 @item
849 We refuse source indentation and other cosmetic changes if they are mixed
850 with functional changes, such commits will be rejected and removed. Every
851 developer has his own indentation style, you should not change it. Of course
852 if you (re)write something, you can use your own style, even though we would
853 prefer if the indentation throughout FFmpeg was consistent (Many projects
854 force a given indentation style - we do not.). If you really need to make
855 indentation changes (try to avoid this), separate them strictly from real
856 changes.
857
858 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
859 then either do NOT change the indentation of the inner part within (do not
860 move it to the right)! or do so in a separate commit
861 @item
862 Always fill out the commit log message. Describe in a few lines what you
863 changed and why. You can refer to mailing list postings if you fix a
864 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
865 @item
866 If you apply a patch by someone else, include the name and email address in
867 the log message. Since the ffmpeg-cvslog mailing list is publicly
868 archived you should add some SPAM protection to the email address. Send an
869 answer to ffmpeg-devel (or wherever you got the patch from) saying that
870 you applied the patch.
871 @item
872 When applying patches that have been discussed (at length) on the mailing
873 list, reference the thread in the log message.
874 @item
875 Do NOT commit to code actively maintained by others without permission.
876 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
877 timeframe (12h for build failures and security fixes, 3 days small changes,
878 1 week for big patches) then commit your patch if you think it is OK.
879 Also note, the maintainer can simply ask for more time to review!
880 @item
881 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
882 are sent there and reviewed by all the other developers. Bugs and possible
883 improvements or general questions regarding commits are discussed there. We
884 expect you to react if problems with your code are uncovered.
885 @item
886 Update the documentation if you change behavior or add features. If you are
887 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
888 maintainer(s) will review and commit your stuff.
889 @item
890 Try to keep important discussions and requests (also) on the public
891 developer mailing list, so that all developers can benefit from them.
892 @item
893 Never write to unallocated memory, never write over the end of arrays,
894 always check values read from some untrusted source before using them
895 as array index or other risky things.
896 @item
897 Remember to check if you need to bump versions for the specific libav
898 parts (libavutil, libavcodec, libavformat) you are changing. You need
899 to change the version integer and the version string.
900 Incrementing the first component means no backward compatibility to
901 previous versions (e.g. removal of a function from the public API).
902 Incrementing the second component means backward compatible change
903 (e.g. addition of a function to the public API).
904 Incrementing the third component means a noteworthy binary compatible
905 change (e.g. encoder bug fix that matters for the decoder).
906 @item
907 If you add a new codec, remember to update the changelog, add it to
908 the supported codecs table in the documentation and bump the second
909 component of the @file{libavcodec} version number appropriately. If
910 it has a fourcc, add it to @file{libavformat/riff.c}, even if it
911 is only a decoder.
912 @item
913 Compiler warnings indicate potential bugs or code with bad style. If a type of
914 warning always points to correct and clean code, that warning should
915 be disabled, not the code changed.
916 Thus the remaining warnings can either be bugs or correct code.
917 If it is a bug, the bug has to be fixed. If it is not, the code should
918 be changed to not generate a warning unless that causes a slowdown
919 or obfuscates the code.
920 @item
921 If you add a new file, give it a proper license header. Do not copy and
922 paste it from a random place, use an existing file as template.
923 @end enumerate
924
925 We think our rules are not too hard. If you have comments, contact us.
926
927 Note, these rules are mostly borrowed from the MPlayer project.
928
929 @section Submitting patches
930
931 First, (@pxref{Coding Rules}) above if you did not yet.
932
933 When you submit your patch, try to send a unified diff (diff '-up'
934 option). We cannot read other diffs :-)
935
936 Also please do not submit a patch which contains several unrelated changes.
937 Split it into separate, self-contained pieces. This does not mean splitting
938 file by file. Instead, make the patch as small as possible while still
939 keeping it as a logical unit that contains an individual change, even
940 if it spans multiple files. This makes reviewing your patches much easier
941 for us and greatly increases your chances of getting your patch applied.
942
943 Run the regression tests before submitting a patch so that you can
944 verify that there are no big problems.
945
946 Patches should be posted as base64 encoded attachments (or any other
947 encoding which ensures that the patch will not be trashed during
948 transmission) to the ffmpeg-devel mailing list, see
949 @url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
950
951 It also helps quite a bit if you tell us what the patch does (for example
952 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
953 and has no lrint()')
954
955 Also please if you send several patches, send each patch as a separate mail,
956 do not attach several unrelated patches to the same mail.
957
958 @section patch submission checklist
959
960 @enumerate
961 @item
962 Do the regression tests pass with the patch applied?
963 @item
964 Is the patch a unified diff?
965 @item
966 Is the patch against latest FFmpeg SVN?
967 @item
968 Are you subscribed to ffmpeg-dev?
969 (the list is subscribers only due to spam)
970 @item
971 Have you checked that the changes are minimal, so that the same cannot be
972 achieved with a smaller patch and/or simpler final code?
973 @item
974 If the change is to speed critical code, did you benchmark it?
975 @item
976 If you did any benchmarks, did you provide them in the mail?
977 @item
978 Have you checked that the patch does not introduce buffer overflows or
979 other security issues?
980 @item
981 If you add a new demuxer or decoder, have you checked that it does not
982 crash with damaged input (see tools/trasher)?
983 @item
984 Is the patch created from the root of the source tree, so it can be
985 applied with @code{patch -p0}?
986 @item
987 Does the patch not mix functional and cosmetic changes?
988 @item
989 Did you add tabs or trailing whitespace to the code? Both are forbidden.
990 @item
991 Is the patch attached to the email you send?
992 @item
993 Is the mime type of the patch correct? It should be text/x-diff or
994 text/x-patch or at least text/plain and not application/octet-stream.
995 @item
996 If the patch fixes a bug, did you provide a verbose analysis of the bug?
997 @item
998 If the patch fixes a bug, did you provide enough information, including
999 a sample, so the bug can be reproduced and the fix can be verified?
1000 Note please do not attach samples >100k to mails but rather provide a
1001 URL, you can upload to ftp://upload.mplayerhq.hu
1002 @item
1003 Did you provide a verbose summary about what the patch does change?
1004 @item
1005 Did you provide a verbose explanation why it changes things like it does?
1006 @item
1007 Did you provide a verbose summary of the user visible advantages and
1008 disadvantages if the patch is applied?
1009 @item
1010 Did you provide an example so we can verify the new feature added by the
1011 patch easily?
1012 @item
1013 If you added a new file, did you insert a license header? It should be
1014 taken from FFmpeg, not randomly copied and pasted from somewhere else.
1015 @item
1016 You should maintain alphabetical order in alphabetically ordered lists as
1017 long as doing so does not break API/ABI compatibility.
1018 @item
1019 Lines with similar content should be aligned vertically when doing so
1020 improves readability.
1021 @item
1022 Did you provide a suggestion for a clear commit log message?
1023 @item
1024 Did you test your decoder or demuxer against damaged data? If no, see
1025 tools/trasher and the noise bitstream filter. Your decoder or demuxer
1026 should not crash or end in a (near) infinite loop when fed damaged data.
1027 @end enumerate
1028
1029 @section Patch review process
1030
1031 All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1032 clear note that the patch is not for SVN.
1033 Reviews and comments will be posted as replies to the patch on the
1034 mailing list. The patch submitter then has to take care of every comment,
1035 that can be by resubmitting a changed patch or by discussion. Resubmitted
1036 patches will themselves be reviewed like any other patch. If at some point
1037 a patch passes review with no comments then it is approved, that can for
1038 simple and small patches happen immediately while large patches will generally
1039 have to be changed and reviewed many times before they are approved.
1040 After a patch is approved it will be committed to the repository.
1041
1042 We will review all submitted patches, but sometimes we are quite busy so
1043 especially for large patches this can take several weeks.
1044
1045 When resubmitting patches, please do not make any significant changes
1046 not related to the comments received during review. Such patches will
1047 be rejected. Instead, submit significant changes or new features as
1048 separate patches.
1049
1050 @section Regression tests
1051
1052 Before submitting a patch (or committing to the repository), you should at least
1053 test that you did not break anything.
1054
1055 The regression tests build a synthetic video stream and a synthetic
1056 audio stream. These are then encoded and decoded with all codecs or
1057 formats. The CRC (or MD5) of each generated file is recorded in a
1058 result file. A 'diff' is launched to compare the reference results and
1059 the result file.
1060
1061 The regression tests then go on to test the FFserver code with a
1062 limited set of streams. It is important that this step runs correctly
1063 as well.
1064
1065 Run 'make test' to test all the codecs and formats.
1066
1067 Run 'make fulltest' to test all the codecs, formats and FFserver.
1068
1069 [Of course, some patches may change the results of the regression tests. In
1070 this case, the reference results of the regression tests shall be modified
1071 accordingly].
1072
1073 @bye