add E-AC-3 to supported codec list
[libav.git] / doc / general.texi
1 \input texinfo @c -*- texinfo -*-
3 @settitle General Documentation
4 @titlepage
5 @sp 7
6 @center @titlefont{General Documentation}
7 @sp 3
8 @end titlepage
11 @chapter external libraries
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}.
17 @section AMR
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.
23 Go to @url{} 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.
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!}
33 @chapter Supported File Formats and Codecs
35 You can use the @code{-formats} option to have an exhaustive list.
37 @section File Formats
39 FFmpeg supports the following file formats through the @code{libavformat}
40 library:
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 Motion Pixels MVI @tab @tab X
95 @item MOV/QuickTime @tab X @tab X
96 @item MPEG audio @tab X @tab X
97 @item MPEG-1 systems @tab X @tab X
98 @tab muxed audio and video
99 @item MPEG-2 PS @tab X @tab X
100 @tab also known as @code{VOB} file
101 @item MPEG-2 TS @tab @tab X
102 @tab also known as DVB Transport Stream
103 @item MPEG-4 @tab X @tab X
104 @tab MPEG-4 is a variant of QuickTime.
105 @item MSN TCP webcam @tab @tab X
106 @tab Used by MSN Messenger webcam streams.
107 @item MXF @tab X @tab X
108 @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
109 @item Nullsoft Video @tab @tab X
110 @item NUT @tab X @tab X
111 @tab NUT Open Container Format
112 @item OMA @tab @tab X
113 @tab Audio format used in Sony Sonic Stage and Sony Vegas.
114 @item PlayStation STR @tab @tab X
115 @item PVA @tab @tab X
116 @tab Used by TechnoTrend DVB PCI boards.
117 @item raw AC-3 @tab X @tab X
118 @item raw CRI ADX audio @tab X @tab X
119 @item raw MJPEG @tab X @tab X
120 @item raw MPEG video @tab X @tab X
121 @item raw MPEG-4 video @tab X @tab X
122 @item raw PCM 8/16/32 bits, 32/64-bit floating point, mu-law/A-law @tab X @tab X
123 @item raw Shorten audio @tab @tab X
124 @item RealMedia @tab X @tab X
125 @item RL2 @tab @tab X
126 @tab Audio and video format used in some games by Entertainment Software Partners.
127 @item Sega FILM/CPK @tab @tab X
128 @tab Used in many Sega Saturn console games.
129 @item SEQ @tab @tab X
130 @tab Tiertex .seq files used in the DOS CD-ROM version of the game Flashback.
131 @item Sierra Online @tab @tab X
132 @tab .sol files used in Sierra Online games.
133 @item Sierra VMD @tab @tab X
134 @tab Used in Sierra CD-ROM games.
135 @item SIFF @tab @tab X
136 @tab Audio and video format used in some games by Beam Software.
137 @item Smacker @tab @tab X
138 @tab Multimedia format used by many games.
139 @item SUN AU format @tab X @tab X
140 @item THP @tab @tab X
141 @tab Used on the Nintendo GameCube.
142 @item WAV @tab X @tab X
143 @item WC3 Movie @tab @tab X
144 @tab Multimedia format used in Origin's Wing Commander III computer game.
145 @item Westwood Studios VQA/AUD @tab @tab X
146 @tab Multimedia formats used in Westwood Studios games.
147 @end multitable
149 @code{X} means that encoding (resp. decoding) is supported.
151 @section Image Formats
153 FFmpeg can read and write images for each frame of a video sequence. The
154 following image formats are supported:
156 @multitable @columnfractions .4 .1 .1 .4
157 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
158 @item .Y.U.V @tab X @tab X @tab one raw file per component
159 @item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
160 @item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
161 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
162 @item PCX @tab @tab X @tab PC Paintbrush
163 @item PGM, PPM @tab X @tab X
164 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
165 @item PNG @tab X @tab X @tab 2/4 bpp not supported yet
166 @item PTX @tab @tab X @tab V.Flash PTX format
167 @item RAS @tab @tab X @tab Sun Rasterfile
168 @item SGI @tab X @tab X @tab SGI RGB image format
169 @item Targa @tab @tab X @tab Targa (.TGA) image format
170 @item TIFF @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
171 @end multitable
173 @code{X} means that encoding (resp. decoding) is supported.
175 @section Video Codecs
177 @multitable @columnfractions .4 .1 .1 .4
178 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
179 @item 4X Video @tab @tab X
180 @tab Used in certain computer games.
181 @item American Laser Games Video @tab @tab X
182 @tab Used in games like Mad Dog McCree.
183 @item AMV @tab @tab X
184 @tab Used in Chinese MP3 players.
185 @item Apple Animation @tab X @tab X
186 @tab fourcc: 'rle '
187 @item Apple Graphics @tab @tab X
188 @tab fourcc: 'smc '
189 @item Apple MJPEG-B @tab @tab X
190 @item Apple QuickDraw @tab @tab X
191 @tab fourcc: qdrw
192 @item Apple Video @tab @tab X
193 @tab fourcc: rpza
194 @item Asus v1 @tab X @tab X
195 @tab fourcc: ASV1
196 @item Asus v2 @tab X @tab X
197 @tab fourcc: ASV2
198 @item ATI VCR1 @tab @tab X
199 @tab fourcc: VCR1
200 @item ATI VCR2 @tab @tab X
201 @tab fourcc: VCR2
202 @item Autodesk RLE @tab @tab X
203 @tab fourcc: AASC
204 @item AVID DNxHD @tab X @tab X
205 @tab aka SMPTE VC3
206 @item AVS video @tab @tab X
207 @tab Video encoding used by the Creature Shock game.
208 @item Bethsoft VID @tab @tab X
209 @tab Used in some games from Bethesda Softworks.
210 @item C93 video @tab @tab X
211 @tab Codec used in Cyberia game.
212 @item CamStudio @tab @tab X
213 @tab fourcc: CSCD
214 @item Cin video @tab @tab X
215 @tab Codec used in Delphine Software games.
216 @item Cinepak @tab @tab X
217 @item Cirrus Logic AccuPak @tab @tab X
218 @tab fourcc: CLJR
219 @item Creative YUV @tab @tab X
220 @tab fourcc: CYUV
221 @item Dirac @tab X @tab X
222 @tab Supported through the external libdirac/libschroedinger libraries.
223 @item Duck TrueMotion v1 @tab @tab X
224 @tab fourcc: DUCK
225 @item Duck TrueMotion v2 @tab @tab X
226 @tab fourcc: TM20
227 @item DV @tab X @tab X
228 @item DXA Video @tab @tab X
229 @tab Codec originally used in Feeble Files game.
230 @item Electronic Arts CMV @tab @tab X
231 @tab Used in NHL 95 game.
232 @item Electronic Arts TGV @tab @tab X
233 @item FFmpeg Video 1 @tab X @tab X
234 @tab experimental lossless codec (fourcc: FFV1)
235 @item Flash Screen Video @tab X @tab X
236 @tab fourcc: FSV1
237 @item FLIC video @tab @tab X
238 @item FLV @tab X @tab X
239 @tab Sorenson H.263 used in Flash
240 @item Fraps FPS1 @tab @tab X
241 @item H.261 @tab X @tab X
242 @item H.263(+) @tab X @tab X
243 @tab also known as RealVideo 1.0
244 @item H.264 @tab @tab X
245 @item HuffYUV @tab X @tab X
246 @item IBM Ultimotion @tab @tab X
247 @tab fourcc: ULTI
248 @item id Cinematic video @tab @tab X
249 @tab Used in Quake II.
250 @item id RoQ @tab X @tab X
251 @tab Used in Quake III, Jedi Knight 2, other computer games.
252 @item Intel Indeo 3 @tab @tab X
253 @item Interplay Video @tab @tab X
254 @tab Used in Interplay .MVE files.
255 @item JPEG-LS @tab X @tab X
256 @tab fourcc: MJLS, lossless and near-lossless is supported.
257 @item KMVC @tab @tab X
258 @tab Codec used in Worms games.
259 @item LOCO @tab @tab X
260 @item lossless MJPEG @tab X @tab X
261 @item Microsoft RLE @tab @tab X
262 @item Microsoft Video-1 @tab @tab X
263 @item Mimic @tab @tab X
264 @tab Used in MSN Messenger Webcam streams.
265 @item Miro VideoXL @tab @tab X
266 @tab fourcc: VIXL
267 @item MJPEG @tab X @tab X
268 @item Motion Pixels Video @tab @tab X
269 @item MPEG-1 @tab X @tab X
270 @item MPEG-2 @tab X @tab X
271 @item MPEG-4 @tab X @tab X
272 @item MSMPEG4 V1 @tab X @tab X
273 @item MSMPEG4 V2 @tab X @tab X
274 @item MSMPEG4 V3 @tab X @tab X
275 @item MSZH @tab @tab X
276 @tab Part of LCL
277 @item On2 VP3 @tab @tab X
278 @tab still experimental
279 @item On2 VP5 @tab @tab X
280 @tab fourcc: VP50
281 @item On2 VP6 @tab @tab X
282 @tab fourcc: VP60,VP61,VP62
283 @item planar RGB @tab @tab X
284 @tab fourcc: 8BPS
285 @item QPEG @tab @tab X
286 @tab fourccs: QPEG, Q1.0, Q1.1
287 @item RealVideo 1.0 @tab X @tab X
288 @item RealVideo 2.0 @tab X @tab X
289 @item Renderware TXD @tab @tab X
290 @tab Texture dictionaries used by the Renderware Engine.
291 @item RTjpeg @tab @tab X
292 @tab Video encoding used in NuppelVideo files.
293 @item Smacker video @tab @tab X
294 @tab Video encoding used in Smacker.
295 @item Snow @tab X @tab X
296 @tab experimental wavelet codec (fourcc: SNOW)
297 @item Sony PlayStation MDEC @tab @tab X
298 @item Sorenson Video 1 @tab X @tab X
299 @tab fourcc: SVQ1
300 @item Sorenson Video 3 @tab @tab X
301 @tab fourcc: SVQ3
302 @item Sunplus MJPEG @tab @tab X
303 @tab fourcc: SP5X
304 @item TechSmith Camtasia @tab @tab X
305 @tab fourcc: TSCC
306 @item Theora @tab X @tab X
307 @tab still experimental
308 @item THP @tab @tab X
309 @tab Used on the Nintendo GameCube.
310 @item Tiertex Seq video @tab @tab X
311 @tab Codec used in DOS CD-ROM FlashBack game.
312 @item VC-1 @tab @tab X
313 @item VMD Video @tab @tab X
314 @tab Used in Sierra VMD files.
315 @item VMware Video @tab @tab X
316 @tab Codec used in videos captured by VMware.
317 @item Westwood VQA @tab @tab X
318 @item Winnov WNV1 @tab @tab X
319 @item WMV7 @tab X @tab X
320 @item WMV8 @tab X @tab X
321 @item WMV9 @tab @tab X
322 @tab not completely working
323 @item Xan/WC3 @tab @tab X
324 @tab Used in Wing Commander III .MVE files.
325 @item ZLIB @tab X @tab X
326 @tab part of LCL, encoder experimental
327 @item ZMBV @tab X @tab X
328 @tab Encoder works only in PAL8.
329 @end multitable
331 @code{X} means that encoding (resp. decoding) is supported.
333 @section Audio Codecs
335 @multitable @columnfractions .4 .1 .1 .1 .7
336 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
337 @item 4X IMA ADPCM @tab @tab X
338 @item 8SVX audio @tab @tab X
339 @item AAC @tab X @tab X
340 @tab Encoding is supported through the external library libfaac.
341 @item AC-3 @tab IX @tab IX
342 @tab liba52 can be used alternatively for decoding.
343 @item AMR-NB @tab X @tab X
344 @tab Supported through an external library.
345 @item AMR-WB @tab X @tab X
346 @tab Supported through an external library.
347 @item AMV IMA ADPCM @tab @tab X
348 @tab Used in AMV files
349 @item Apple lossless audio @tab X @tab X
350 @tab QuickTime fourcc 'alac'
351 @item Apple MACE 3 @tab @tab X
352 @item Apple MACE 6 @tab @tab X
353 @item ATRAC 3 @tab @tab X
354 @item CD-ROM XA ADPCM @tab @tab X
355 @item Cin audio @tab @tab X
356 @tab Codec used in Delphine Software International games.
357 @item Creative ADPCM @tab @tab X
358 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
359 @item CRI ADX ADPCM @tab X @tab X
360 @tab Used in Sega Dreamcast games.
361 @item DSP Group TrueSpeech @tab @tab X
362 @item DTS Coherent Audio @tab @tab X
363 @item Duck DK3 IMA ADPCM @tab @tab X
364 @tab Used in some Sega Saturn console games.
365 @item Duck DK4 IMA ADPCM @tab @tab X
366 @tab Used in some Sega Saturn console games.
367 @item DV audio @tab @tab X
368 @item Electronic Arts ADPCM @tab @tab X
369 @tab Used in various EA titles.
370 @item Enhanced AC-3 @tab @tab X
371 @item Sonic @tab X @tab X
372 @tab experimental codec
373 @item Sonic lossless @tab X @tab X
374 @tab experimental codec
375 @item FLAC lossless audio @tab X @tab X
376 @item G.726 ADPCM @tab X @tab X
377 @item id RoQ DPCM @tab X @tab X
378 @tab Used in Quake III, Jedi Knight 2, other computer games.
379 @item Intel Music Coder @tab @tab X
380 @item Interplay MVE DPCM @tab @tab X
381 @tab Used in various Interplay computer games.
382 @item MAXIS EA ADPCM @tab @tab X
383 @tab Used in Sim City 3000.
384 @item Microsoft ADPCM @tab X @tab X
385 @item MLP/TrueHD @tab @tab X
386 @tab Used in DVD-Audio and Blu-Ray discs.
387 @item Monkey's Audio @tab @tab X
388 @tab Only versions 3.97-3.99 are supported.
389 @item MPEG audio layer 1/3 @tab X @tab IX
390 @tab MP3 encoding is supported through the external library LAME.
391 @item MPEG audio layer 2 @tab IX @tab IX
392 @item MS IMA ADPCM @tab X @tab X
393 @item Musepack @tab @tab X
394 @tab SV7 and SV8 are supported.
395 @item Nellymoser ASAO @tab @tab X
396 @item Qdesign QDM2 @tab @tab X
397 @tab There are still some distortions.
398 @item QT IMA ADPCM @tab X @tab X
399 @item RA144 @tab @tab X
400 @tab Real 14400 bit/s codec
401 @item RA288 @tab @tab X
402 @tab Real 28800 bit/s codec
403 @item RADnet @tab X @tab IX
404 @tab real low bitrate AC-3 codec
405 @item Real COOK @tab @tab X
406 @tab All versions except 5.1 are supported.
407 @item Shorten @tab @tab X
408 @item Sierra Online DPCM @tab @tab X
409 @tab Used in Sierra Online game audio files.
410 @item Smacker audio @tab @tab X
411 @item SMJPEG IMA ADPCM @tab @tab X
412 @tab Used in certain Loki game ports.
413 @item THP ADPCM @tab @tab X
414 @tab Used on the Nintendo GameCube.
415 @item True Audio (TTA) @tab @tab X
416 @item Vorbis @tab X @tab X
417 @item WavPack @tab @tab X
418 @item Westwood Studios IMA ADPCM @tab @tab X
419 @tab Used in Westwood Studios games like Command and Conquer.
420 @item WMA v1/v2 @tab X @tab X
421 @item Xan DPCM @tab @tab X
422 @tab Used in Origin's Wing Commander IV AVI files.
423 @end multitable
425 @code{X} means that encoding (resp. decoding) is supported.
427 @code{I} means that an integer-only version is available, too (ensures high
428 performance on systems without hardware floating point support).
430 @chapter Platform Specific information
432 @section BSD
434 BSD make will not build FFmpeg, you need to install and use GNU Make
435 (@file{gmake}).
437 @section Windows
439 To get help and instructions for building FFmpeg under Windows, check out
440 the FFmpeg Windows Help Forum at
441 @url{}.
443 @subsection Native Windows compilation
445 FFmpeg can be built to run natively on Windows using the MinGW tools. Install
446 the current versions of MSYS and MinGW from @url{}. Also
447 install the coreutils package, and update to the latest MSYS make (note: not
448 mingw32-make). You can find detailed installation
449 instructions in the download section and the FAQ.
451 Within the MSYS shell, configure and make with:
453 @example
454 ./configure --enable-memalign-hack
455 make
456 make install
457 @end example
459 This will install @file{ffmpeg.exe} along with many other development files
460 to @file{/usr/local}. You may specify another install path using the
461 @code{--prefix} option in @file{configure}.
463 Notes:
465 @itemize
467 @item Use at least bash 3.1. Older versions are known to fail on the
468 configure script.
470 @item In order to compile vhooks, you must have a POSIX-compliant libdl in
471 your MinGW system. Get dlfcn-win32 from
472 @url{}.
474 @item In order to compile FFplay, you must have the MinGW development library
475 of SDL. Get it from @url{}.
476 Edit the @file{bin/sdl-config} script so that it points to the correct prefix
477 where SDL was installed. Verify that @file{sdl-config} can be launched from
478 the MSYS command line.
480 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
481 you can build libavutil, libavcodec and libavformat as DLLs.
483 @end itemize
485 @subsection Microsoft Visual C++ compatibility
487 As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
488 want to use the libav* libraries in your own applications, you can still
489 compile those applications using MSVC++. But the libav* libraries you link
490 to @emph{must} be built with MinGW. However, you will not be able to debug
491 inside the libav* libraries, since MSVC++ does not recognize the debug
492 symbols generated by GCC.
493 We strongly recommend you to move over from MSVC++ to MinGW tools.
495 This description of how to use the FFmpeg libraries with MSVC++ is based on
496 Microsoft Visual C++ 2005 Express Edition. If you have a different version,
497 you might have to modify the procedures slightly.
499 @subsubsection Using static libraries
501 Assuming you have just built and installed FFmpeg in @file{/usr/local}.
503 @enumerate
505 @item Create a new console application ("File / New / Project") and then
506 select "Win32 Console Application". On the appropriate page of the
507 Application Wizard, uncheck the "Precompiled headers" option.
509 @item Write the source code for your application, or, for testing, just
510 copy the code from an existing sample application into the source file
511 that MSVC++ has already created for you. For example, you can copy
512 @file{output_example.c} from the FFmpeg distribution.
514 @item Open the "Project / Properties" dialog box. In the "Configuration"
515 combo box, select "All Configurations" so that the changes you make will
516 affect both debug and release builds. In the tree view on the left hand
517 side, select "C/C++ / General", then edit the "Additional Include
518 Directories" setting to contain the path where the FFmpeg includes were
519 installed (i.e. @file{c:\msys\1.0\local\include}).
520 Do not add MinGW's include directory here, or the include files will
521 conflict with MSVC's.
523 @item Still in the "Project / Properties" dialog box, select
524 "Linker / General" from the tree view and edit the
525 "Additional Library Directories" setting to contain the @file{lib}
526 directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
527 the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
528 and the directory where MinGW's GCC libs are installed
529 (i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
530 "Linker / Input" from the tree view, and add the files @file{libavformat.a},
531 @file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
532 @file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
533 to the end of "Additional Dependencies".
535 @item Now, select "C/C++ / Code Generation" from the tree view. Select
536 "Debug" in the "Configuration" combo box. Make sure that "Runtime
537 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
538 the "Configuration" combo box and make sure that "Runtime Library" is
539 set to "Multi-threaded DLL".
541 @item Click "OK" to close the "Project / Properties" dialog box.
543 @item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
544 Get msinttypes from @url{}
545 and install it in MSVC++'s include directory
546 (i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
548 @item MSVC++ also does not understand the @code{inline} keyword used by
549 FFmpeg, so you must add this line before @code{#include}ing libav*:
550 @example
551 #define inline _inline
552 @end example
554 @item Build your application, everything should work.
556 @end enumerate
558 @subsubsection Using shared libraries
560 This is how to create DLL and LIB files that are compatible with MSVC++:
562 @enumerate
564 @item Add a call to @file{vcvars32.bat} (which sets up the environment
565 variables for the Visual C++ tools) as the first line of @file{msys.bat}.
566 The standard location for @file{vcvars32.bat} is
567 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
568 and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
569 If this corresponds to your setup, add the following line as the first line
570 of @file{msys.bat}:
572 @example
573 call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
574 @end example
576 Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
577 and run @file{c:\msys\1.0\msys.bat} from there.
579 @item Within the MSYS shell, run @code{lib.exe}. If you get a help message
580 from @file{Microsoft (R) Library Manager}, this means your environment
581 variables are set up correctly, the @file{Microsoft (R) Library Manager}
582 is on the path and will be used by FFmpeg to create
583 MSVC++-compatible import libraries.
585 @item Build FFmpeg with
587 @example
588 ./configure --enable-shared --enable-memalign-hack
589 make
590 make install
591 @end example
593 Your install path (@file{/usr/local/} by default) should now have the
594 necessary DLL and LIB files under the @file{bin} directory.
596 @end enumerate
598 To use those files with MSVC++, do the same as you would do with
599 the static libraries, as described above. But in Step 4,
600 you should only need to add the directory where the LIB files are installed
601 (i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
602 installed in the @file{bin} directory. And instead of adding @file{libxx.a}
603 files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
604 @file{avutil.lib}. There should be no need for @file{libmingwex.a},
605 @file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
606 statically linked into the DLLs. The @file{bin} directory contains a bunch
607 of DLL files, but the ones that are actually used to run your application
608 are the ones with a major version number in their filenames
609 (i.e. @file{avcodec-51.dll}).
611 @subsection Cross compilation for Windows with Linux
613 You must use the MinGW cross compilation tools available at
614 @url{}.
616 Then configure FFmpeg with the following options:
617 @example
618 ./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
619 @end example
620 (you can change the cross-prefix according to the prefix chosen for the
621 MinGW tools).
623 Then you can easily test FFmpeg with Wine
624 (@url{}).
626 @subsection Compilation under Cygwin
628 The main issue with Cygwin is that newlib, its C library, does not
629 contain llrint(). However, it is possible to leverage the
630 implementation in MinGW.
632 Just install your Cygwin with all the "Base" packages, plus the
633 following "Devel" ones:
634 @example
635 binutils, gcc-core, make, subversion, mingw-runtime
636 @end example
638 Do not install binutils-20060709-1 (they are buggy on shared builds);
639 use binutils-20050610-1 instead.
641 Then create a small library that just contains llrint():
643 @example
644 ar x /usr/lib/mingw/libmingwex.a llrint.o
645 ar cq /usr/local/lib/libllrint.a llrint.o
646 @end example
648 Then run
650 @example
651 ./configure --enable-static --disable-shared --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
652 @end example
654 to make a static build or
656 @example
657 ./configure --enable-shared --disable-static --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
658 @end example
660 to build shared libraries.
662 If you want to build FFmpeg with additional libraries, download Cygwin
663 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository
664 and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
665 (@url{}).
667 @subsection Crosscompilation for Windows under Cygwin
669 With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
671 Just install your Cygwin as explained before, plus these additional
672 "Devel" packages:
673 @example
674 gcc-mingw-core, mingw-runtime, mingw-zlib
675 @end example
677 and add some special flags to your configure invocation.
679 For a static build run
680 @example
681 ./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
682 @end example
684 and for a build with shared libraries
685 @example
686 ./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
687 @end example
689 @section BeOS
691 BeOS support is broken in mysterious ways.
693 @section OS/2
695 For information about compiling FFmpeg on OS/2 see
696 @url{}.
698 @chapter Developers Guide
700 @section API
701 @itemize @bullet
702 @item libavcodec is the library containing the codecs (both encoding and
703 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
705 @item libavformat is the library containing the file format handling (mux and
706 demux code for several formats). Look at @file{ffplay.c} to use it in a
707 player. See @file{output_example.c} to use it to generate audio or video
708 streams.
710 @end itemize
712 @section Integrating libavcodec or libavformat in your program
714 You can integrate all the source code of the libraries to link them
715 statically to avoid any version problem. All you need is to provide a
716 'config.mak' and a 'config.h' in the parent directory. See the defines
717 generated by ./configure to understand what is needed.
719 You can use libavcodec or libavformat in your commercial program, but
720 @emph{any patch you make must be published}. The best way to proceed is
721 to send your patches to the FFmpeg mailing list.
723 @node Coding Rules
724 @section Coding Rules
726 FFmpeg is programmed in the ISO C90 language with a few additional
727 features from ISO C99, namely:
728 @itemize @bullet
729 @item
730 the @samp{inline} keyword;
731 @item
732 @samp{//} comments;
733 @item
734 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
735 @item
736 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
737 @end itemize
739 These features are supported by all compilers we care about, so we will not
740 accept patches to remove their use unless they absolutely do not impair
741 clarity and performance.
743 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
744 compiles with several other compilers, such as the Compaq ccc compiler
745 or Sun Studio 9, and we would like to keep it that way unless it would
746 be exceedingly involved. To ensure compatibility, please do not use any
747 additional C99 features or GCC extensions. Especially watch out for:
748 @itemize @bullet
749 @item
750 mixing statements and declarations;
751 @item
752 @samp{long long} (use @samp{int64_t} instead);
753 @item
754 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
755 @item
756 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
757 @end itemize
759 Indent size is 4.
760 The presentation is the one specified by 'indent -i4 -kr -nut'.
761 The TAB character is forbidden outside of Makefiles as is any
762 form of trailing whitespace. Commits containing either will be
763 rejected by the Subversion repository.
765 The main priority in FFmpeg is simplicity and small code size in order to
766 minimize the bug count.
768 Comments: Use the JavaDoc/Doxygen
769 format (see examples below) so that code documentation
770 can be generated automatically. All nontrivial functions should have a comment
771 above them explaining what the function does, even if it is just one sentence.
772 All structures and their member variables should be documented, too.
773 @example
774 /**
775 * @@file mpeg.c
776 * MPEG codec.
777 * @@author ...
778 */
780 /**
781 * Summary sentence.
782 * more text ...
783 * ...
784 */
785 typedef struct Foobar@{
786 int var1; /**< var1 description */
787 int var2; ///< var2 description
788 /** var3 description */
789 int var3;
790 @} Foobar;
792 /**
793 * Summary sentence.
794 * more text ...
795 * ...
796 * @@param my_parameter description of my_parameter
797 * @@return return value description
798 */
799 int myfunc(int my_parameter)
800 ...
801 @end example
803 fprintf and printf are forbidden in libavformat and libavcodec,
804 please use av_log() instead.
806 Casts should be used only when necessary. Unneeded parentheses
807 should also be avoided if they don't make the code easier to understand.
809 @section Development Policy
811 @enumerate
812 @item
813 Contributions should be licensed under the LGPL 2.1, including an
814 "or any later version" clause, or the MIT license. GPL 2 including
815 an "or any later version" clause is also acceptable, but LGPL is
816 preferred.
817 @item
818 You must not commit code which breaks FFmpeg! (Meaning unfinished but
819 enabled code which breaks compilation or compiles but does not work or
820 breaks the regression tests)
821 You can commit unfinished stuff (for testing etc), but it must be disabled
822 (#ifdef etc) by default so it does not interfere with other developers'
823 work.
824 @item
825 You do not have to over-test things. If it works for you, and you think it
826 should work for others, then commit. If your code has problems
827 (portability, triggers compiler bugs, unusual environment etc) they will be
828 reported and eventually fixed.
829 @item
830 Do not commit unrelated changes together, split them into self-contained
831 pieces. Also do not forget that if part B depends on part A, but A does not
832 depend on B, then A can and should be committed first and separate from B.
833 Keeping changes well split into self-contained parts makes reviewing and
834 understanding them on the commit log mailing list easier. This also helps
835 in case of debugging later on.
836 Also if you have doubts about splitting or not splitting, do not hesitate to
837 ask/discuss it on the developer mailing list.
838 @item
839 Do not change behavior of the program (renaming options etc) without
840 first discussing it on the ffmpeg-devel mailing list. Do not remove
841 functionality from the code. Just improve!
843 Note: Redundant code can be removed.
844 @item
845 Do not commit changes to the build system (Makefiles, configure script)
846 which change behavior, defaults etc, without asking first. The same
847 applies to compiler warning fixes, trivial looking fixes and to code
848 maintained by other developers. We usually have a reason for doing things
849 the way we do. Send your changes as patches to the ffmpeg-devel mailing
850 list, and if the code maintainers say OK, you may commit. This does not
851 apply to files you wrote and/or maintain.
852 @item
853 We refuse source indentation and other cosmetic changes if they are mixed
854 with functional changes, such commits will be rejected and removed. Every
855 developer has his own indentation style, you should not change it. Of course
856 if you (re)write something, you can use your own style, even though we would
857 prefer if the indentation throughout FFmpeg was consistent (Many projects
858 force a given indentation style - we do not.). If you really need to make
859 indentation changes (try to avoid this), separate them strictly from real
860 changes.
862 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
863 then either do NOT change the indentation of the inner part within (do not
864 move it to the right)! or do so in a separate commit
865 @item
866 Always fill out the commit log message. Describe in a few lines what you
867 changed and why. You can refer to mailing list postings if you fix a
868 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
869 @item
870 If you apply a patch by someone else, include the name and email address in
871 the log message. Since the ffmpeg-cvslog mailing list is publicly
872 archived you should add some SPAM protection to the email address. Send an
873 answer to ffmpeg-devel (or wherever you got the patch from) saying that
874 you applied the patch.
875 @item
876 When applying patches that have been discussed (at length) on the mailing
877 list, reference the thread in the log message.
878 @item
879 Do NOT commit to code actively maintained by others without permission.
880 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
881 timeframe (12h for build failures and security fixes, 3 days small changes,
882 1 week for big patches) then commit your patch if you think it is OK.
883 Also note, the maintainer can simply ask for more time to review!
884 @item
885 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
886 are sent there and reviewed by all the other developers. Bugs and possible
887 improvements or general questions regarding commits are discussed there. We
888 expect you to react if problems with your code are uncovered.
889 @item
890 Update the documentation if you change behavior or add features. If you are
891 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
892 maintainer(s) will review and commit your stuff.
893 @item
894 Try to keep important discussions and requests (also) on the public
895 developer mailing list, so that all developers can benefit from them.
896 @item
897 Never write to unallocated memory, never write over the end of arrays,
898 always check values read from some untrusted source before using them
899 as array index or other risky things.
900 @item
901 Remember to check if you need to bump versions for the specific libav
902 parts (libavutil, libavcodec, libavformat) you are changing. You need
903 to change the version integer.
904 Incrementing the first component means no backward compatibility to
905 previous versions (e.g. removal of a function from the public API).
906 Incrementing the second component means backward compatible change
907 (e.g. addition of a function to the public API or extension of an
908 existing data structure).
909 Incrementing the third component means a noteworthy binary compatible
910 change (e.g. encoder bug fix that matters for the decoder).
911 @item
912 Compiler warnings indicate potential bugs or code with bad style. If a type of
913 warning always points to correct and clean code, that warning should
914 be disabled, not the code changed.
915 Thus the remaining warnings can either be bugs or correct code.
916 If it is a bug, the bug has to be fixed. If it is not, the code should
917 be changed to not generate a warning unless that causes a slowdown
918 or obfuscates the code.
919 @item
920 If you add a new file, give it a proper license header. Do not copy and
921 paste it from a random place, use an existing file as template.
922 @end enumerate
924 We think our rules are not too hard. If you have comments, contact us.
926 Note, these rules are mostly borrowed from the MPlayer project.
928 @section Submitting patches
930 First, (@pxref{Coding Rules}) above if you did not yet.
932 When you submit your patch, try to send a unified diff (diff '-up'
933 option). We cannot read other diffs :-)
935 Also please do not submit a patch which contains several unrelated changes.
936 Split it into separate, self-contained pieces. This does not mean splitting
937 file by file. Instead, make the patch as small as possible while still
938 keeping it as a logical unit that contains an individual change, even
939 if it spans multiple files. This makes reviewing your patches much easier
940 for us and greatly increases your chances of getting your patch applied.
942 Run the regression tests before submitting a patch so that you can
943 verify that there are no big problems.
945 Patches should be posted as base64 encoded attachments (or any other
946 encoding which ensures that the patch will not be trashed during
947 transmission) to the ffmpeg-devel mailing list, see
948 @url{}
950 It also helps quite a bit if you tell us what the patch does (for example
951 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
952 and has no lrint()')
954 Also please if you send several patches, send each patch as a separate mail,
955 do not attach several unrelated patches to the same mail.
957 @section New codecs or formats checklist
959 @enumerate
960 @item
961 Did you use av_cold for codec initialization and close functions?
962 @item
963 Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
964 AVInputFormat/AVOutputFormat struct?
965 @item
966 Did you bump the minor version number in @file{avcodec.h} or
967 @file{avformat.h}?
968 @item
969 Did you register it in @file{allcodecs.c} or @file{allformats.c}?
970 @item
971 Did you add the CodecID to @file{avcodec.h}?
972 @item
973 If it has a fourcc, did you add it to @file{libavformat/riff.c},
974 even if it is only a decoder?
975 @item
976 Did you add a rule to compile the appropriate files in the Makefile?
977 Remember to do this even if you're just adding a format to a file that is
978 already being compiled by some other rule, like a raw demuxer.
979 @item
980 Did you add an entry to the table of supported formats or codecs in the
981 documentation?
982 @item
983 Did you add an entry in the Changelog?
984 @item
985 If it depends on a parser or a library, did you add that dependency in
986 configure?
987 @item
988 Did you "svn add" the appropriate files before commiting?
989 @end enumerate
991 @section patch submission checklist
993 @enumerate
994 @item
995 Do the regression tests pass with the patch applied?
996 @item
997 Is the patch a unified diff?
998 @item
999 Is the patch against latest FFmpeg SVN?
1000 @item
1001 Are you subscribed to ffmpeg-dev?
1002 (the list is subscribers only due to spam)
1003 @item
1004 Have you checked that the changes are minimal, so that the same cannot be
1005 achieved with a smaller patch and/or simpler final code?
1006 @item
1007 If the change is to speed critical code, did you benchmark it?
1008 @item
1009 If you did any benchmarks, did you provide them in the mail?
1010 @item
1011 Have you checked that the patch does not introduce buffer overflows or
1012 other security issues?
1013 @item
1014 If you add a new demuxer or decoder, have you checked that it does not
1015 crash with damaged input (see tools/trasher)?
1016 @item
1017 Is the patch created from the root of the source tree, so it can be
1018 applied with @code{patch -p0}?
1019 @item
1020 Does the patch not mix functional and cosmetic changes?
1021 @item
1022 Did you add tabs or trailing whitespace to the code? Both are forbidden.
1023 @item
1024 Is the patch attached to the email you send?
1025 @item
1026 Is the mime type of the patch correct? It should be text/x-diff or
1027 text/x-patch or at least text/plain and not application/octet-stream.
1028 @item
1029 If the patch fixes a bug, did you provide a verbose analysis of the bug?
1030 @item
1031 If the patch fixes a bug, did you provide enough information, including
1032 a sample, so the bug can be reproduced and the fix can be verified?
1033 Note please do not attach samples >100k to mails but rather provide a
1034 URL, you can upload to
1035 @item
1036 Did you provide a verbose summary about what the patch does change?
1037 @item
1038 Did you provide a verbose explanation why it changes things like it does?
1039 @item
1040 Did you provide a verbose summary of the user visible advantages and
1041 disadvantages if the patch is applied?
1042 @item
1043 Did you provide an example so we can verify the new feature added by the
1044 patch easily?
1045 @item
1046 If you added a new file, did you insert a license header? It should be
1047 taken from FFmpeg, not randomly copied and pasted from somewhere else.
1048 @item
1049 You should maintain alphabetical order in alphabetically ordered lists as
1050 long as doing so does not break API/ABI compatibility.
1051 @item
1052 Lines with similar content should be aligned vertically when doing so
1053 improves readability.
1054 @item
1055 Did you provide a suggestion for a clear commit log message?
1056 @item
1057 Did you test your decoder or demuxer against damaged data? If no, see
1058 tools/trasher and the noise bitstream filter. Your decoder or demuxer
1059 should not crash or end in a (near) infinite loop when fed damaged data.
1060 @end enumerate
1062 @section Patch review process
1064 All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1065 clear note that the patch is not for SVN.
1066 Reviews and comments will be posted as replies to the patch on the
1067 mailing list. The patch submitter then has to take care of every comment,
1068 that can be by resubmitting a changed patch or by discussion. Resubmitted
1069 patches will themselves be reviewed like any other patch. If at some point
1070 a patch passes review with no comments then it is approved, that can for
1071 simple and small patches happen immediately while large patches will generally
1072 have to be changed and reviewed many times before they are approved.
1073 After a patch is approved it will be committed to the repository.
1075 We will review all submitted patches, but sometimes we are quite busy so
1076 especially for large patches this can take several weeks.
1078 When resubmitting patches, please do not make any significant changes
1079 not related to the comments received during review. Such patches will
1080 be rejected. Instead, submit significant changes or new features as
1081 separate patches.
1083 @section Regression tests
1085 Before submitting a patch (or committing to the repository), you should at least
1086 test that you did not break anything.
1088 The regression tests build a synthetic video stream and a synthetic
1089 audio stream. These are then encoded and decoded with all codecs or
1090 formats. The CRC (or MD5) of each generated file is recorded in a
1091 result file. A 'diff' is launched to compare the reference results and
1092 the result file.
1094 The regression tests then go on to test the FFserver code with a
1095 limited set of streams. It is important that this step runs correctly
1096 as well.
1098 Run 'make test' to test all the codecs and formats.
1100 Run 'make fulltest' to test all the codecs, formats and FFserver.
1102 [Of course, some patches may change the results of the regression tests. In
1103 this case, the reference results of the regression tests shall be modified
1104 accordingly].
1106 @bye