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