Add GSM into list of supported audio codecs.
[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 Name @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 Name @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 Name @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 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 @tab encoding supported through external library libx264
246 @item HuffYUV @tab X @tab X
247 @item IBM Ultimotion @tab @tab X
248 @tab fourcc: ULTI
249 @item id Cinematic video @tab @tab X
250 @tab Used in Quake II.
251 @item id RoQ @tab X @tab X
252 @tab Used in Quake III, Jedi Knight 2, other computer games.
253 @item Intel Indeo 3 @tab @tab X
254 @item Interplay Video @tab @tab X
255 @tab Used in Interplay .MVE files.
256 @item JPEG-LS @tab X @tab X
257 @tab fourcc: MJLS, lossless and near-lossless is supported.
258 @item KMVC @tab @tab X
259 @tab Codec used in Worms games.
260 @item LOCO @tab @tab X
261 @item lossless MJPEG @tab X @tab X
262 @item Microsoft RLE @tab @tab X
263 @item Microsoft Video-1 @tab @tab X
264 @item Mimic @tab @tab X
265 @tab Used in MSN Messenger Webcam streams.
266 @item Miro VideoXL @tab @tab X
267 @tab fourcc: VIXL
268 @item MJPEG @tab X @tab X
269 @item Motion Pixels Video @tab @tab X
270 @item MPEG-1 @tab X @tab X
271 @item MPEG-2 @tab X @tab X
272 @item MPEG-4 @tab X @tab X
273 @item MSMPEG4 V1 @tab X @tab X
274 @item MSMPEG4 V2 @tab X @tab X
275 @item MSMPEG4 V3 @tab X @tab X
276 @item MSZH @tab @tab X
277 @tab Part of LCL
278 @item On2 VP3 @tab @tab X
279 @tab still experimental
280 @item On2 VP5 @tab @tab X
281 @tab fourcc: VP50
282 @item On2 VP6 @tab @tab X
283 @tab fourcc: VP60,VP61,VP62
284 @item planar RGB @tab @tab X
285 @tab fourcc: 8BPS
286 @item QPEG @tab @tab X
287 @tab fourccs: QPEG, Q1.0, Q1.1
288 @item RealVideo 1.0 @tab X @tab X
289 @item RealVideo 2.0 @tab X @tab X
290 @item Renderware TXD @tab @tab X
291 @tab Texture dictionaries used by the Renderware Engine.
292 @item RTjpeg @tab @tab X
293 @tab Video encoding used in NuppelVideo files.
294 @item Smacker video @tab @tab X
295 @tab Video encoding used in Smacker.
296 @item Snow @tab X @tab X
297 @tab experimental wavelet codec (fourcc: SNOW)
298 @item Sony PlayStation MDEC @tab @tab X
299 @item Sorenson Video 1 @tab X @tab X
300 @tab fourcc: SVQ1
301 @item Sorenson Video 3 @tab @tab X
302 @tab fourcc: SVQ3
303 @item Sunplus MJPEG @tab @tab X
304 @tab fourcc: SP5X
305 @item TechSmith Camtasia @tab @tab X
306 @tab fourcc: TSCC
307 @item Theora @tab X @tab X
308 @tab encoding supported through external library libtheora
309 @item THP @tab @tab X
310 @tab Used on the Nintendo GameCube.
311 @item Tiertex Seq video @tab @tab X
312 @tab Codec used in DOS CD-ROM FlashBack game.
313 @item VC-1 @tab @tab X
314 @item VMD Video @tab @tab X
315 @tab Used in Sierra VMD files.
316 @item VMware Video @tab @tab X
317 @tab Codec used in videos captured by VMware.
318 @item Westwood VQA @tab @tab X
319 @item Winnov WNV1 @tab @tab X
320 @item WMV7 @tab X @tab X
321 @item WMV8 @tab X @tab X
322 @item WMV9 @tab @tab X
323 @tab not completely working
324 @item Xan/WC3 @tab @tab X
325 @tab Used in Wing Commander III .MVE files.
326 @item ZLIB @tab X @tab X
327 @tab part of LCL, encoder experimental
328 @item ZMBV @tab X @tab X
329 @tab Encoder works only in PAL8.
330 @end multitable
332 @code{X} means that encoding (resp. decoding) is supported.
334 @section Audio Codecs
336 @multitable @columnfractions .4 .1 .1 .1 .7
337 @item Name @tab Encoding @tab Decoding @tab Comments
338 @item 4X IMA ADPCM @tab @tab X
339 @item 8SVX audio @tab @tab X
340 @item AAC @tab X @tab X
341 @tab encoding supported through external library libfaac
342 @item AC-3 @tab IX @tab IX
343 @item AMR-NB @tab X @tab X
344 @tab supported through external library libamrnb
345 @item AMR-WB @tab X @tab X
346 @tab supported through external library libamrwb
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 FLAC lossless audio @tab IX @tab X
372 @item G.726 ADPCM @tab X @tab X
373 @item GSM @tab X @tab X
374 @tab supported through external library libgsm
375 @item GSM_MS @tab X @tab X
376 @tab supported through external library libgsm
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 supported through 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 X @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 IX @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 Sonic @tab X @tab X
414 @tab experimental codec
415 @item Sonic lossless @tab X @tab X
416 @tab experimental codec
417 @item Speex @tab @tab X
418 @tab supported through external library libspeex
419 @item THP ADPCM @tab @tab X
420 @tab Used on the Nintendo GameCube.
421 @item True Audio (TTA) @tab @tab X
422 @item Vorbis @tab X @tab X
423 @item WavPack @tab @tab X
424 @item Westwood Studios IMA ADPCM @tab @tab X
425 @tab Used in Westwood Studios games like Command and Conquer.
426 @item WMA v1/v2 @tab X @tab X
427 @item Xan DPCM @tab @tab X
428 @tab Used in Origin's Wing Commander IV AVI files.
429 @end multitable
431 @code{X} means that encoding (resp. decoding) is supported.
433 @code{I} means that an integer-only version is available, too (ensures high
434 performance on systems without hardware floating point support).
436 @chapter Platform Specific information
438 @section BSD
440 BSD make will not build FFmpeg, you need to install and use GNU Make
441 (@file{gmake}).
443 @section Windows
445 To get help and instructions for building FFmpeg under Windows, check out
446 the FFmpeg Windows Help Forum at
447 @url{}.
449 @subsection Native Windows compilation
451 FFmpeg can be built to run natively on Windows using the MinGW tools. Install
452 the latest versions of MSYS and MinGW from @url{}.
453 You can find detailed installation
454 instructions in the download section and the FAQ.
456 FFmpeg does not build out-of-the-box with the packages the automated MinGW
457 installer provides. It also requires coreutils to be installed and many other
458 packages updated to the latest version. The minimum version for some packages
459 are listed below:
461 @itemize
462 @item bash 3.1
463 @item msys-make 3.81-2 (note: not mingw32-make)
464 @item w32api 3.12
465 @item mingw-runtime 3.15
466 @end itemize
468 You will also need to pass @code{-fno-common} to the compiler to work around
469 a GCC bug (see @url{}).
471 Within the MSYS shell, configure and make with:
473 @example
474 ./configure --enable-memalign-hack --extra-cflags=-fno-common
475 make
476 make install
477 @end example
479 This will install @file{ffmpeg.exe} along with many other development files
480 to @file{/usr/local}. You may specify another install path using the
481 @code{--prefix} option in @file{configure}.
483 Notes:
485 @itemize
487 @item In order to compile vhooks, you must have a POSIX-compliant libdl in
488 your MinGW system. Get dlfcn-win32 from
489 @url{}.
491 @item In order to compile FFplay, you must have the MinGW development library
492 of SDL. Get it from @url{}.
493 Edit the @file{bin/sdl-config} script so that it points to the correct prefix
494 where SDL was installed. Verify that @file{sdl-config} can be launched from
495 the MSYS command line.
497 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
498 you can build libavutil, libavcodec and libavformat as DLLs.
500 @end itemize
502 @subsection Microsoft Visual C++ compatibility
504 As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
505 want to use the libav* libraries in your own applications, you can still
506 compile those applications using MSVC++. But the libav* libraries you link
507 to @emph{must} be built with MinGW. However, you will not be able to debug
508 inside the libav* libraries, since MSVC++ does not recognize the debug
509 symbols generated by GCC.
510 We strongly recommend you to move over from MSVC++ to MinGW tools.
512 This description of how to use the FFmpeg libraries with MSVC++ is based on
513 Microsoft Visual C++ 2005 Express Edition. If you have a different version,
514 you might have to modify the procedures slightly.
516 @subsubsection Using static libraries
518 Assuming you have just built and installed FFmpeg in @file{/usr/local}.
520 @enumerate
522 @item Create a new console application ("File / New / Project") and then
523 select "Win32 Console Application". On the appropriate page of the
524 Application Wizard, uncheck the "Precompiled headers" option.
526 @item Write the source code for your application, or, for testing, just
527 copy the code from an existing sample application into the source file
528 that MSVC++ has already created for you. For example, you can copy
529 @file{output_example.c} from the FFmpeg distribution.
531 @item Open the "Project / Properties" dialog box. In the "Configuration"
532 combo box, select "All Configurations" so that the changes you make will
533 affect both debug and release builds. In the tree view on the left hand
534 side, select "C/C++ / General", then edit the "Additional Include
535 Directories" setting to contain the path where the FFmpeg includes were
536 installed (i.e. @file{c:\msys\1.0\local\include}).
537 Do not add MinGW's include directory here, or the include files will
538 conflict with MSVC's.
540 @item Still in the "Project / Properties" dialog box, select
541 "Linker / General" from the tree view and edit the
542 "Additional Library Directories" setting to contain the @file{lib}
543 directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
544 the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
545 and the directory where MinGW's GCC libs are installed
546 (i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
547 "Linker / Input" from the tree view, and add the files @file{libavformat.a},
548 @file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
549 @file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
550 to the end of "Additional Dependencies".
552 @item Now, select "C/C++ / Code Generation" from the tree view. Select
553 "Debug" in the "Configuration" combo box. Make sure that "Runtime
554 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
555 the "Configuration" combo box and make sure that "Runtime Library" is
556 set to "Multi-threaded DLL".
558 @item Click "OK" to close the "Project / Properties" dialog box.
560 @item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
561 Get msinttypes from @url{}
562 and install it in MSVC++'s include directory
563 (i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
565 @item MSVC++ also does not understand the @code{inline} keyword used by
566 FFmpeg, so you must add this line before @code{#include}ing libav*:
567 @example
568 #define inline _inline
569 @end example
571 @item Build your application, everything should work.
573 @end enumerate
575 @subsubsection Using shared libraries
577 This is how to create DLL and LIB files that are compatible with MSVC++:
579 @enumerate
581 @item Add a call to @file{vcvars32.bat} (which sets up the environment
582 variables for the Visual C++ tools) as the first line of @file{msys.bat}.
583 The standard location for @file{vcvars32.bat} is
584 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
585 and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
586 If this corresponds to your setup, add the following line as the first line
587 of @file{msys.bat}:
589 @example
590 call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
591 @end example
593 Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
594 and run @file{c:\msys\1.0\msys.bat} from there.
596 @item Within the MSYS shell, run @code{lib.exe}. If you get a help message
597 from @file{Microsoft (R) Library Manager}, this means your environment
598 variables are set up correctly, the @file{Microsoft (R) Library Manager}
599 is on the path and will be used by FFmpeg to create
600 MSVC++-compatible import libraries.
602 @item Build FFmpeg with
604 @example
605 ./configure --enable-shared --enable-memalign-hack
606 make
607 make install
608 @end example
610 Your install path (@file{/usr/local/} by default) should now have the
611 necessary DLL and LIB files under the @file{bin} directory.
613 @end enumerate
615 To use those files with MSVC++, do the same as you would do with
616 the static libraries, as described above. But in Step 4,
617 you should only need to add the directory where the LIB files are installed
618 (i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
619 installed in the @file{bin} directory. And instead of adding @file{libxx.a}
620 files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
621 @file{avutil.lib}. There should be no need for @file{libmingwex.a},
622 @file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
623 statically linked into the DLLs. The @file{bin} directory contains a bunch
624 of DLL files, but the ones that are actually used to run your application
625 are the ones with a major version number in their filenames
626 (i.e. @file{avcodec-51.dll}).
628 @subsection Cross compilation for Windows with Linux
630 You must use the MinGW cross compilation tools available at
631 @url{}.
633 Then configure FFmpeg with the following options:
634 @example
635 ./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
636 @end example
637 (you can change the cross-prefix according to the prefix chosen for the
638 MinGW tools).
640 Then you can easily test FFmpeg with Wine
641 (@url{}).
643 @subsection Compilation under Cygwin
645 The main issue with Cygwin is that newlib, its C library, does not
646 contain llrint(). However, it is possible to leverage the
647 implementation in MinGW.
649 Just install your Cygwin with all the "Base" packages, plus the
650 following "Devel" ones:
651 @example
652 binutils, gcc-core, make, subversion, mingw-runtime
653 @end example
655 Do not install binutils-20060709-1 (they are buggy on shared builds);
656 use binutils-20050610-1 instead.
658 Then create a small library that just contains llrint():
660 @example
661 ar x /usr/lib/mingw/libmingwex.a llrint.o
662 ar cq /usr/local/lib/libllrint.a llrint.o
663 @end example
665 Then run
667 @example
668 ./configure --enable-static --disable-shared --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
669 @end example
671 to make a static build or
673 @example
674 ./configure --enable-shared --disable-static --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
675 @end example
677 to build shared libraries.
679 If you want to build FFmpeg with additional libraries, download Cygwin
680 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository
681 and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
682 (@url{}).
684 @subsection Crosscompilation for Windows under Cygwin
686 With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
688 Just install your Cygwin as explained before, plus these additional
689 "Devel" packages:
690 @example
691 gcc-mingw-core, mingw-runtime, mingw-zlib
692 @end example
694 and add some special flags to your configure invocation.
696 For a static build run
697 @example
698 ./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
699 @end example
701 and for a build with shared libraries
702 @example
703 ./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
704 @end example
706 @section BeOS
708 BeOS support is broken in mysterious ways.
710 @section OS/2
712 For information about compiling FFmpeg on OS/2 see
713 @url{}.
715 @chapter Developers Guide
717 @section API
718 @itemize @bullet
719 @item libavcodec is the library containing the codecs (both encoding and
720 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
722 @item libavformat is the library containing the file format handling (mux and
723 demux code for several formats). Look at @file{ffplay.c} to use it in a
724 player. See @file{output_example.c} to use it to generate audio or video
725 streams.
727 @end itemize
729 @section Integrating libavcodec or libavformat in your program
731 You can integrate all the source code of the libraries to link them
732 statically to avoid any version problem. All you need is to provide a
733 'config.mak' and a 'config.h' in the parent directory. See the defines
734 generated by ./configure to understand what is needed.
736 You can use libavcodec or libavformat in your commercial program, but
737 @emph{any patch you make must be published}. The best way to proceed is
738 to send your patches to the FFmpeg mailing list.
740 @node Coding Rules
741 @section Coding Rules
743 FFmpeg is programmed in the ISO C90 language with a few additional
744 features from ISO C99, namely:
745 @itemize @bullet
746 @item
747 the @samp{inline} keyword;
748 @item
749 @samp{//} comments;
750 @item
751 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
752 @item
753 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
754 @end itemize
756 These features are supported by all compilers we care about, so we will not
757 accept patches to remove their use unless they absolutely do not impair
758 clarity and performance.
760 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
761 compiles with several other compilers, such as the Compaq ccc compiler
762 or Sun Studio 9, and we would like to keep it that way unless it would
763 be exceedingly involved. To ensure compatibility, please do not use any
764 additional C99 features or GCC extensions. Especially watch out for:
765 @itemize @bullet
766 @item
767 mixing statements and declarations;
768 @item
769 @samp{long long} (use @samp{int64_t} instead);
770 @item
771 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
772 @item
773 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
774 @end itemize
776 Indent size is 4.
777 The presentation is the one specified by 'indent -i4 -kr -nut'.
778 The TAB character is forbidden outside of Makefiles as is any
779 form of trailing whitespace. Commits containing either will be
780 rejected by the Subversion repository.
782 The main priority in FFmpeg is simplicity and small code size in order to
783 minimize the bug count.
785 Comments: Use the JavaDoc/Doxygen
786 format (see examples below) so that code documentation
787 can be generated automatically. All nontrivial functions should have a comment
788 above them explaining what the function does, even if it is just one sentence.
789 All structures and their member variables should be documented, too.
790 @example
791 /**
792 * @@file mpeg.c
793 * MPEG codec.
794 * @@author ...
795 */
797 /**
798 * Summary sentence.
799 * more text ...
800 * ...
801 */
802 typedef struct Foobar@{
803 int var1; /**< var1 description */
804 int var2; ///< var2 description
805 /** var3 description */
806 int var3;
807 @} Foobar;
809 /**
810 * Summary sentence.
811 * more text ...
812 * ...
813 * @@param my_parameter description of my_parameter
814 * @@return return value description
815 */
816 int myfunc(int my_parameter)
817 ...
818 @end example
820 fprintf and printf are forbidden in libavformat and libavcodec,
821 please use av_log() instead.
823 Casts should be used only when necessary. Unneeded parentheses
824 should also be avoided if they don't make the code easier to understand.
826 @section Development Policy
828 @enumerate
829 @item
830 Contributions should be licensed under the LGPL 2.1, including an
831 "or any later version" clause, or the MIT license. GPL 2 including
832 an "or any later version" clause is also acceptable, but LGPL is
833 preferred.
834 @item
835 You must not commit code which breaks FFmpeg! (Meaning unfinished but
836 enabled code which breaks compilation or compiles but does not work or
837 breaks the regression tests)
838 You can commit unfinished stuff (for testing etc), but it must be disabled
839 (#ifdef etc) by default so it does not interfere with other developers'
840 work.
841 @item
842 You do not have to over-test things. If it works for you, and you think it
843 should work for others, then commit. If your code has problems
844 (portability, triggers compiler bugs, unusual environment etc) they will be
845 reported and eventually fixed.
846 @item
847 Do not commit unrelated changes together, split them into self-contained
848 pieces. Also do not forget that if part B depends on part A, but A does not
849 depend on B, then A can and should be committed first and separate from B.
850 Keeping changes well split into self-contained parts makes reviewing and
851 understanding them on the commit log mailing list easier. This also helps
852 in case of debugging later on.
853 Also if you have doubts about splitting or not splitting, do not hesitate to
854 ask/discuss it on the developer mailing list.
855 @item
856 Do not change behavior of the program (renaming options etc) without
857 first discussing it on the ffmpeg-devel mailing list. Do not remove
858 functionality from the code. Just improve!
860 Note: Redundant code can be removed.
861 @item
862 Do not commit changes to the build system (Makefiles, configure script)
863 which change behavior, defaults etc, without asking first. The same
864 applies to compiler warning fixes, trivial looking fixes and to code
865 maintained by other developers. We usually have a reason for doing things
866 the way we do. Send your changes as patches to the ffmpeg-devel mailing
867 list, and if the code maintainers say OK, you may commit. This does not
868 apply to files you wrote and/or maintain.
869 @item
870 We refuse source indentation and other cosmetic changes if they are mixed
871 with functional changes, such commits will be rejected and removed. Every
872 developer has his own indentation style, you should not change it. Of course
873 if you (re)write something, you can use your own style, even though we would
874 prefer if the indentation throughout FFmpeg was consistent (Many projects
875 force a given indentation style - we do not.). If you really need to make
876 indentation changes (try to avoid this), separate them strictly from real
877 changes.
879 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
880 then either do NOT change the indentation of the inner part within (do not
881 move it to the right)! or do so in a separate commit
882 @item
883 Always fill out the commit log message. Describe in a few lines what you
884 changed and why. You can refer to mailing list postings if you fix a
885 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
886 @item
887 If you apply a patch by someone else, include the name and email address in
888 the log message. Since the ffmpeg-cvslog mailing list is publicly
889 archived you should add some SPAM protection to the email address. Send an
890 answer to ffmpeg-devel (or wherever you got the patch from) saying that
891 you applied the patch.
892 @item
893 When applying patches that have been discussed (at length) on the mailing
894 list, reference the thread in the log message.
895 @item
896 Do NOT commit to code actively maintained by others without permission.
897 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
898 timeframe (12h for build failures and security fixes, 3 days small changes,
899 1 week for big patches) then commit your patch if you think it is OK.
900 Also note, the maintainer can simply ask for more time to review!
901 @item
902 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
903 are sent there and reviewed by all the other developers. Bugs and possible
904 improvements or general questions regarding commits are discussed there. We
905 expect you to react if problems with your code are uncovered.
906 @item
907 Update the documentation if you change behavior or add features. If you are
908 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
909 maintainer(s) will review and commit your stuff.
910 @item
911 Try to keep important discussions and requests (also) on the public
912 developer mailing list, so that all developers can benefit from them.
913 @item
914 Never write to unallocated memory, never write over the end of arrays,
915 always check values read from some untrusted source before using them
916 as array index or other risky things.
917 @item
918 Remember to check if you need to bump versions for the specific libav
919 parts (libavutil, libavcodec, libavformat) you are changing. You need
920 to change the version integer.
921 Incrementing the first component means no backward compatibility to
922 previous versions (e.g. removal of a function from the public API).
923 Incrementing the second component means backward compatible change
924 (e.g. addition of a function to the public API or extension of an
925 existing data structure).
926 Incrementing the third component means a noteworthy binary compatible
927 change (e.g. encoder bug fix that matters for the decoder).
928 @item
929 Compiler warnings indicate potential bugs or code with bad style. If a type of
930 warning always points to correct and clean code, that warning should
931 be disabled, not the code changed.
932 Thus the remaining warnings can either be bugs or correct code.
933 If it is a bug, the bug has to be fixed. If it is not, the code should
934 be changed to not generate a warning unless that causes a slowdown
935 or obfuscates the code.
936 @item
937 If you add a new file, give it a proper license header. Do not copy and
938 paste it from a random place, use an existing file as template.
939 @end enumerate
941 We think our rules are not too hard. If you have comments, contact us.
943 Note, these rules are mostly borrowed from the MPlayer project.
945 @section Submitting patches
947 First, (@pxref{Coding Rules}) above if you did not yet.
949 When you submit your patch, try to send a unified diff (diff '-up'
950 option). We cannot read other diffs :-)
952 Also please do not submit a patch which contains several unrelated changes.
953 Split it into separate, self-contained pieces. This does not mean splitting
954 file by file. Instead, make the patch as small as possible while still
955 keeping it as a logical unit that contains an individual change, even
956 if it spans multiple files. This makes reviewing your patches much easier
957 for us and greatly increases your chances of getting your patch applied.
959 Run the regression tests before submitting a patch so that you can
960 verify that there are no big problems.
962 Patches should be posted as base64 encoded attachments (or any other
963 encoding which ensures that the patch will not be trashed during
964 transmission) to the ffmpeg-devel mailing list, see
965 @url{}
967 It also helps quite a bit if you tell us what the patch does (for example
968 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
969 and has no lrint()')
971 Also please if you send several patches, send each patch as a separate mail,
972 do not attach several unrelated patches to the same mail.
974 @section New codecs or formats checklist
976 @enumerate
977 @item
978 Did you use av_cold for codec initialization and close functions?
979 @item
980 Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
981 AVInputFormat/AVOutputFormat struct?
982 @item
983 Did you bump the minor version number in @file{avcodec.h} or
984 @file{avformat.h}?
985 @item
986 Did you register it in @file{allcodecs.c} or @file{allformats.c}?
987 @item
988 Did you add the CodecID to @file{avcodec.h}?
989 @item
990 If it has a fourcc, did you add it to @file{libavformat/riff.c},
991 even if it is only a decoder?
992 @item
993 Did you add a rule to compile the appropriate files in the Makefile?
994 Remember to do this even if you're just adding a format to a file that is
995 already being compiled by some other rule, like a raw demuxer.
996 @item
997 Did you add an entry to the table of supported formats or codecs in the
998 documentation?
999 @item
1000 Did you add an entry in the Changelog?
1001 @item
1002 If it depends on a parser or a library, did you add that dependency in
1003 configure?
1004 @item
1005 Did you "svn add" the appropriate files before commiting?
1006 @end enumerate
1008 @section patch submission checklist
1010 @enumerate
1011 @item
1012 Do the regression tests pass with the patch applied?
1013 @item
1014 Is the patch a unified diff?
1015 @item
1016 Is the patch against latest FFmpeg SVN?
1017 @item
1018 Are you subscribed to ffmpeg-dev?
1019 (the list is subscribers only due to spam)
1020 @item
1021 Have you checked that the changes are minimal, so that the same cannot be
1022 achieved with a smaller patch and/or simpler final code?
1023 @item
1024 If the change is to speed critical code, did you benchmark it?
1025 @item
1026 If you did any benchmarks, did you provide them in the mail?
1027 @item
1028 Have you checked that the patch does not introduce buffer overflows or
1029 other security issues?
1030 @item
1031 If you add a new demuxer or decoder, have you checked that it does not
1032 crash with damaged input (see tools/trasher)?
1033 @item
1034 Is the patch created from the root of the source tree, so it can be
1035 applied with @code{patch -p0}?
1036 @item
1037 Does the patch not mix functional and cosmetic changes?
1038 @item
1039 Did you add tabs or trailing whitespace to the code? Both are forbidden.
1040 @item
1041 Is the patch attached to the email you send?
1042 @item
1043 Is the mime type of the patch correct? It should be text/x-diff or
1044 text/x-patch or at least text/plain and not application/octet-stream.
1045 @item
1046 If the patch fixes a bug, did you provide a verbose analysis of the bug?
1047 @item
1048 If the patch fixes a bug, did you provide enough information, including
1049 a sample, so the bug can be reproduced and the fix can be verified?
1050 Note please do not attach samples >100k to mails but rather provide a
1051 URL, you can upload to
1052 @item
1053 Did you provide a verbose summary about what the patch does change?
1054 @item
1055 Did you provide a verbose explanation why it changes things like it does?
1056 @item
1057 Did you provide a verbose summary of the user visible advantages and
1058 disadvantages if the patch is applied?
1059 @item
1060 Did you provide an example so we can verify the new feature added by the
1061 patch easily?
1062 @item
1063 If you added a new file, did you insert a license header? It should be
1064 taken from FFmpeg, not randomly copied and pasted from somewhere else.
1065 @item
1066 You should maintain alphabetical order in alphabetically ordered lists as
1067 long as doing so does not break API/ABI compatibility.
1068 @item
1069 Lines with similar content should be aligned vertically when doing so
1070 improves readability.
1071 @item
1072 Did you provide a suggestion for a clear commit log message?
1073 @item
1074 Did you test your decoder or demuxer against damaged data? If no, see
1075 tools/trasher and the noise bitstream filter. Your decoder or demuxer
1076 should not crash or end in a (near) infinite loop when fed damaged data.
1077 @end enumerate
1079 @section Patch review process
1081 All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1082 clear note that the patch is not for SVN.
1083 Reviews and comments will be posted as replies to the patch on the
1084 mailing list. The patch submitter then has to take care of every comment,
1085 that can be by resubmitting a changed patch or by discussion. Resubmitted
1086 patches will themselves be reviewed like any other patch. If at some point
1087 a patch passes review with no comments then it is approved, that can for
1088 simple and small patches happen immediately while large patches will generally
1089 have to be changed and reviewed many times before they are approved.
1090 After a patch is approved it will be committed to the repository.
1092 We will review all submitted patches, but sometimes we are quite busy so
1093 especially for large patches this can take several weeks.
1095 When resubmitting patches, please do not make any significant changes
1096 not related to the comments received during review. Such patches will
1097 be rejected. Instead, submit significant changes or new features as
1098 separate patches.
1100 @section Regression tests
1102 Before submitting a patch (or committing to the repository), you should at least
1103 test that you did not break anything.
1105 The regression tests build a synthetic video stream and a synthetic
1106 audio stream. These are then encoded and decoded with all codecs or
1107 formats. The CRC (or MD5) of each generated file is recorded in a
1108 result file. A 'diff' is launched to compare the reference results and
1109 the result file.
1111 The regression tests then go on to test the FFserver code with a
1112 limited set of streams. It is important that this step runs correctly
1113 as well.
1115 Run 'make test' to test all the codecs and formats.
1117 Run 'make fulltest' to test all the codecs, formats and FFserver.
1119 [Of course, some patches may change the results of the regression tests. In
1120 this case, the reference results of the regression tests shall be modified
1121 accordingly].
1123 @bye