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
44 @item MPEG audio @tab X @tab X
45 @item MPEG-1 systems @tab X @tab X
46 @tab muxed audio and video
47 @item MPEG-2 PS @tab X @tab X
48 @tab also known as @code{VOB} file
49 @item MPEG-2 TS @tab @tab X
50 @tab also known as DVB Transport Stream
51 @item ASF@tab X @tab X
52 @item AVI@tab X @tab X
53 @item WAV@tab X @tab X
54 @item Macromedia Flash@tab X @tab X
55 @tab Only embedded audio is decoded.
56 @item FLV @tab X @tab X
57 @tab Macromedia Flash video files
58 @item Real Audio and Video @tab X @tab X
59 @item Raw AC3 @tab X @tab X
60 @item Raw MJPEG @tab X @tab X
61 @item Raw MPEG video @tab X @tab X
62 @item Raw PCM8/16 bits, mulaw/Alaw@tab X @tab X
63 @item Raw CRI ADX audio @tab X @tab X
64 @item Raw Shorten audio @tab @tab X
65 @item SUN AU format @tab X @tab X
66 @item NUT @tab X @tab X @tab NUT Open Container Format
67 @item QuickTime @tab X @tab X
68 @item MPEG-4 @tab X @tab X
69 @tab MPEG-4 is a variant of QuickTime.
70 @item Raw MPEG4 video @tab X @tab X
71 @item DV @tab X @tab X
73 @tab 4X Technologies format, used in some games.
74 @item Playstation STR @tab @tab X
75 @item Id RoQ @tab X @tab X
76 @tab Used in Quake III, Jedi Knight 2, other computer games.
77 @item Interplay MVE @tab @tab X
78 @tab Format used in various Interplay computer games.
79 @item WC3 Movie @tab @tab X
80 @tab Multimedia format used in Origin's Wing Commander III computer game.
81 @item Sega FILM/CPK @tab @tab X
82 @tab Used in many Sega Saturn console games.
83 @item Westwood Studios VQA/AUD @tab @tab X
84 @tab Multimedia formats used in Westwood Studios games.
85 @item Id Cinematic (.cin) @tab @tab X
86 @tab Used in Quake II.
87 @item FLIC format @tab @tab X
89 @item Sierra VMD @tab @tab X
90 @tab Used in Sierra CD-ROM games.
91 @item Sierra Online @tab @tab X
92 @tab .sol files used in Sierra Online games.
93 @item Matroska @tab X @tab X
94 @item Electronic Arts Multimedia @tab @tab X
95 @tab Used in various EA games; files have extensions like WVE and UV2.
96 @item Nullsoft Video (NSV) format @tab @tab X
97 @item ADTS AAC audio @tab X @tab X
98 @item Creative VOC @tab X @tab X @tab Created for the Sound Blaster Pro.
99 @item American Laser Games MM @tab @tab X
100 @tab Multimedia format used in games like Mad Dog McCree
101 @item AVS @tab @tab X
102 @tab Multimedia format used by the Creature Shock game.
103 @item Smacker @tab @tab X
104 @tab Multimedia format used by many games.
105 @item GXF @tab X @tab X
106 @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley playout servers.
107 @item CIN @tab @tab X
108 @tab Multimedia format used by Delphine Software games.
109 @item MXF @tab @tab X
110 @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
111 @item SEQ @tab @tab X
112 @tab Tiertex .seq files used in the DOS CDROM version of the game Flashback.
113 @item DXA @tab @tab X
114 @tab This format is used in non-Windows version of Feeble Files game and
115 different game cutscenes repacked for use with ScummVM.
116 @item THP @tab @tab X
117 @tab Used on the Nintendo GameCube.
118 @item C93 @tab @tab X
119 @tab Used in the game Cyberia from Interplay.
120 @item Bethsoft VID @tab @tab X
121 @tab Used in some games from Bethesda Softworks.
122 @item CRYO APC @tab @tab X
123 @tab Audio format used in some games by CRYO Interactive Entertainment.
124 @item Monkey's Audio @tab @tab X
125 @item SIFF @tab @tab X
126 @tab Audio and video format used in some games by Beam Software
129 @code{X} means that encoding (resp. decoding) is supported.
131 @section Image Formats
133 FFmpeg can read and write images for each frame of a video sequence. The
134 following image formats are supported:
136 @multitable @columnfractions .4 .1 .1 .4
137 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
138 @item PGM, PPM @tab X @tab X
139 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
140 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
141 @item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
142 @item .Y.U.V @tab X @tab X @tab one raw file per component
143 @item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
144 @item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
145 @item Targa @tab @tab X @tab Targa (.TGA) image format.
146 @item TIFF @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
147 @item SGI @tab X @tab X @tab SGI RGB image format
148 @item PTX @tab @tab X @tab V.Flash PTX format
151 @code{X} means that encoding (resp. decoding) is supported.
153 @section Video Codecs
155 @multitable @columnfractions .4 .1 .1 .4
156 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
157 @item MPEG-1 video @tab X @tab X
158 @item MPEG-2 video @tab X @tab X
159 @item MPEG-4 @tab X @tab X
160 @item MSMPEG4 V1 @tab X @tab X
161 @item MSMPEG4 V2 @tab X @tab X
162 @item MSMPEG4 V3 @tab X @tab X
163 @item WMV7 @tab X @tab X
164 @item WMV8 @tab X @tab X @tab not completely working
165 @item WMV9 @tab @tab X @tab not completely working
166 @item VC1 @tab @tab X
167 @item H.261 @tab X @tab X
168 @item H.263(+) @tab X @tab X @tab also known as RealVideo 1.0
169 @item H.264 @tab @tab X
170 @item RealVideo 1.0 @tab X @tab X
171 @item RealVideo 2.0 @tab X @tab X
172 @item MJPEG @tab X @tab X
173 @item lossless MJPEG @tab X @tab X
174 @item JPEG-LS @tab X @tab X @tab fourcc: MJLS, lossless and near-lossless is supported
175 @item Apple MJPEG-B @tab @tab X
176 @item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
177 @item DV @tab X @tab X
178 @item HuffYUV @tab X @tab X
179 @item FFmpeg Video 1 @tab X @tab X @tab experimental lossless codec (fourcc: FFV1)
180 @item FFmpeg Snow @tab X @tab X @tab experimental wavelet codec (fourcc: SNOW)
181 @item Asus v1 @tab X @tab X @tab fourcc: ASV1
182 @item Asus v2 @tab X @tab X @tab fourcc: ASV2
183 @item Creative YUV @tab @tab X @tab fourcc: CYUV
184 @item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
185 @item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
186 @item On2 VP3 @tab @tab X @tab still experimental
187 @item On2 VP5 @tab @tab X @tab fourcc: VP50
188 @item On2 VP6 @tab @tab X @tab fourcc: VP60,VP61,VP62
189 @item Theora @tab X @tab X @tab still experimental
190 @item Intel Indeo 3 @tab @tab X
191 @item FLV @tab X @tab X @tab Sorenson H.263 used in Flash
192 @item Flash Screen Video @tab X @tab X @tab fourcc: FSV1
193 @item ATI VCR1 @tab @tab X @tab fourcc: VCR1
194 @item ATI VCR2 @tab @tab X @tab fourcc: VCR2
195 @item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
196 @item 4X Video @tab @tab X @tab Used in certain computer games.
197 @item Sony Playstation MDEC @tab @tab X
198 @item Id RoQ @tab X @tab X @tab Used in Quake III, Jedi Knight 2, other computer games.
199 @item Xan/WC3 @tab @tab X @tab Used in Wing Commander III .MVE files.
200 @item Interplay Video @tab @tab X @tab Used in Interplay .MVE files.
201 @item Apple Animation @tab X @tab X @tab fourcc: 'rle '
202 @item Apple Graphics @tab @tab X @tab fourcc: 'smc '
203 @item Apple Video @tab @tab X @tab fourcc: rpza
204 @item Apple QuickDraw @tab @tab X @tab fourcc: qdrw
205 @item Cinepak @tab @tab X
206 @item Microsoft RLE @tab @tab X
207 @item Microsoft Video-1 @tab @tab X
208 @item Westwood VQA @tab @tab X
209 @item Id Cinematic Video @tab @tab X @tab Used in Quake II.
210 @item Planar RGB @tab @tab X @tab fourcc: 8BPS
211 @item FLIC video @tab @tab X
212 @item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK
213 @item Duck TrueMotion v2 @tab @tab X @tab fourcc: TM20
214 @item VMD Video @tab @tab X @tab Used in Sierra VMD files.
215 @item MSZH @tab @tab X @tab Part of LCL
216 @item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental
217 @item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC
218 @item IBM Ultimotion @tab @tab X @tab fourcc: ULTI
219 @item Miro VideoXL @tab @tab X @tab fourcc: VIXL
220 @item QPEG @tab @tab X @tab fourccs: QPEG, Q1.0, Q1.1
221 @item LOCO @tab @tab X @tab
222 @item Winnov WNV1 @tab @tab X @tab
223 @item Autodesk Animator Studio Codec @tab @tab X @tab fourcc: AASC
224 @item Fraps FPS1 @tab @tab X @tab
225 @item CamStudio @tab @tab X @tab fourcc: CSCD
226 @item American Laser Games Video @tab @tab X @tab Used in games like Mad Dog McCree
227 @item ZMBV @tab X @tab X @tab Encoder works only on PAL8
228 @item AVS Video @tab @tab X @tab Video encoding used by the Creature Shock game.
229 @item Smacker Video @tab @tab X @tab Video encoding used in Smacker.
230 @item RTjpeg @tab @tab X @tab Video encoding used in NuppelVideo files.
231 @item KMVC @tab @tab X @tab Codec used in Worms games.
232 @item VMware Video @tab @tab X @tab Codec used in videos captured by VMware.
233 @item Cin Video @tab @tab X @tab Codec used in Delphine Software games.
234 @item Tiertex Seq Video @tab @tab X @tab Codec used in DOS CDROM FlashBack game.
235 @item DXA Video @tab @tab X @tab Codec originally used in Feeble Files game.
236 @item AVID DNxHD @tab X @tab X @tab aka SMPTE VC3
237 @item C93 Video @tab @tab X @tab Codec used in Cyberia game.
238 @item THP @tab @tab X @tab Used on the Nintendo GameCube.
239 @item Bethsoft VID @tab @tab X @tab Used in some games from Bethesda Softworks.
240 @item Renderware TXD @tab @tab X @tab Texture dictionaries used by the Renderware Engine.
241 @item AMV @tab @tab X @tab Used in Chinese MP3 players.
244 @code{X} means that encoding (resp. decoding) is supported.
246 @section Audio Codecs
248 @multitable @columnfractions .4 .1 .1 .1 .7
249 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
250 @item MPEG audio layer 2 @tab IX @tab IX
251 @item MPEG audio layer 1/3 @tab X @tab IX
252 @tab MP3 encoding is supported through the external library LAME.
253 @item AC3 @tab IX @tab IX
254 @tab liba52 is used internally for decoding.
255 @item Vorbis @tab X @tab X
256 @item WMA V1/V2 @tab X @tab X
257 @item AAC @tab X @tab X
258 @tab Supported through the external library libfaac/libfaad.
259 @item Microsoft ADPCM @tab X @tab X
260 @item AMV IMA ADPCM @tab @tab X
261 @tab Used in AMV files
262 @item MS IMA ADPCM @tab X @tab X
263 @item QT IMA ADPCM @tab @tab X
264 @item 4X IMA ADPCM @tab @tab X
265 @item G.726 ADPCM @tab X @tab X
266 @item Duck DK3 IMA ADPCM @tab @tab X
267 @tab Used in some Sega Saturn console games.
268 @item Duck DK4 IMA ADPCM @tab @tab X
269 @tab Used in some Sega Saturn console games.
270 @item Westwood Studios IMA ADPCM @tab @tab X
271 @tab Used in Westwood Studios games like Command and Conquer.
272 @item SMJPEG IMA ADPCM @tab @tab X
273 @tab Used in certain Loki game ports.
274 @item CD-ROM XA ADPCM @tab @tab X
275 @item CRI ADX ADPCM @tab X @tab X
276 @tab Used in Sega Dreamcast games.
277 @item Electronic Arts ADPCM @tab @tab X
278 @tab Used in various EA titles.
279 @item Creative ADPCM @tab @tab X
280 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
281 @item THP ADPCM @tab @tab X
282 @tab Used on the Nintendo GameCube.
283 @item RA144 @tab @tab X
284 @tab Real 14400 bit/s codec
285 @item RA288 @tab @tab X
286 @tab Real 28800 bit/s codec
287 @item RADnet @tab X @tab IX
288 @tab Real low bitrate AC3 codec, liba52 is used for decoding.
289 @item AMR-NB @tab X @tab X
290 @tab Supported through an external library.
291 @item AMR-WB @tab X @tab X
292 @tab Supported through an external library.
293 @item DV audio @tab @tab X
294 @item Id RoQ DPCM @tab X @tab X
295 @tab Used in Quake III, Jedi Knight 2, other computer games.
296 @item Interplay MVE DPCM @tab @tab X
297 @tab Used in various Interplay computer games.
298 @item Xan DPCM @tab @tab X
299 @tab Used in Origin's Wing Commander IV AVI files.
300 @item Sierra Online DPCM @tab @tab X
301 @tab Used in Sierra Online game audio files.
302 @item Apple MACE 3 @tab @tab X
303 @item Apple MACE 6 @tab @tab X
304 @item FLAC lossless audio @tab X @tab X
305 @item Shorten lossless audio @tab @tab X
306 @item Apple lossless audio @tab @tab X
307 @tab QuickTime fourcc 'alac'
308 @item FFmpeg Sonic @tab X @tab X
309 @tab experimental lossy/lossless codec
310 @item Qdesign QDM2 @tab @tab X
311 @tab there are still some distortions
312 @item Real COOK @tab @tab X
313 @tab All versions except 5.1 are supported
314 @item DSP Group TrueSpeech @tab @tab X
315 @item True Audio (TTA) @tab @tab X
316 @item Smacker Audio @tab @tab X
317 @item WavPack Audio @tab @tab X
318 @item Cin Audio @tab @tab X
319 @tab Codec used in Delphine Software games.
320 @item Intel Music Coder @tab @tab X
321 @item Musepack @tab @tab X
322 @tab SV7 and SV8 are supported
323 @item DT$ Coherent Audio @tab @tab X
324 @item ATRAC 3 @tab @tab X
325 @item Monkey's Audio @tab @tab X @tab Only versions 3.97-3.99 are supported
326 @item Nellymoser ASAO @tab @tab X
329 @code{X} means that encoding (resp. decoding) is supported.
331 @code{I} means that an integer-only version is available, too (ensures high
332 performance on systems without hardware floating point support).
334 @chapter Platform Specific information
338 BSD make will not build FFmpeg, you need to install and use GNU Make
343 To get help and instructions for building FFmpeg under Windows, check out
344 the FFmpeg Windows Help Forum at
345 @url{http://arrozcru.no-ip.org/ffmpeg/}.
347 @subsection Native Windows compilation
349 FFmpeg can be built to run natively on Windows using the MinGW tools. Install
350 the current versions of MSYS and MinGW from @url{http://www.mingw.org/}. Also
351 install the coreutils package. You can find detailed installation
352 instructions in the download section and the FAQ.
354 Within the MSYS shell, configure and make with:
357 ./configure --enable-memalign-hack
362 This will install @file{ffmpeg.exe} along with many other development files
363 to @file{/usr/local}. You may specify another install path using the
364 @code{--prefix} option in @file{configure}.
370 @item Use at least bash 3.1. Older versions are known to be fail on the
373 @item In order to compile vhooks, you must have a POSIX-compliant libdl in
374 your MinGW system. Get dlfcn-win32 from
375 @url{http://code.google.com/p/dlfcn-win32}.
377 @item In order to compile FFplay, you must have the MinGW development library
378 of SDL. Get it from @url{http://www.libsdl.org}.
379 Edit the @file{bin/sdl-config} script so that it points to the correct prefix
380 where SDL was installed. Verify that @file{sdl-config} can be launched from
381 the MSYS command line.
383 @item The target @code{make wininstaller} can be used to create a
384 Nullsoft-based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
385 must be copied to the FFmpeg directory in order to build the
388 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
389 you can build libavutil, libavcodec and libavformat as DLLs.
393 @subsection Microsoft Visual C++ compatibility
395 As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
396 want to use the libav* libraries in your own applications, you can still
397 compile those applications using MSVC++. But the libav* libraries you link
398 to @emph{must} be built with MinGW. However, you will not be able to debug
399 inside the libav* libraries, since MSVC++ does not recognize the debug
400 symbols generated by GCC.
401 We strongly recommend you to move over from MSVC++ to MinGW tools.
403 This description of how to use the FFmpeg libraries with MSVC++ is based on
404 Microsoft Visual C++ 2005 Express Edition. If you have a different version,
405 you might have to modify the procedures slightly.
407 @subsubsection Using static libraries
409 Assuming you have just built and installed FFmpeg in @file{/usr/local}.
413 @item Create a new console application ("File / New / Project") and then
414 select "Win32 Console Application". On the appropriate page of the
415 Application Wizard, uncheck the "Precompiled headers" option.
417 @item Write the source code for your application, or, for testing, just
418 copy the code from an existing sample application into the source file
419 that MSVC++ has already created for you. For example, you can copy
420 @file{output_example.c} from the FFmpeg distribution.
422 @item Open the "Project / Properties" dialog box. In the "Configuration"
423 combo box, select "All Configurations" so that the changes you make will
424 affect both debug and release builds. In the tree view on the left hand
425 side, select "C/C++ / General", then edit the "Additional Include
426 Directories" setting to contain the path where the FFmpeg includes were
427 installed (i.e. @file{c:\msys\1.0\local\include}).
429 @item Still in the "Project / Properties" dialog box, select
430 "Linker / General" from the tree view and edit the
431 "Additional Library Directories" setting to contain the @file{lib}
432 directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
433 the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
434 and the directory where MinGW's GCC libs are installed
435 (i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
436 "Linker / Input" from the tree view, and add the files @file{libavformat.a},
437 @file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
438 @file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
439 to the end of "Additional Dependencies".
441 @item Now, select "C/C++ / Code Generation" from the tree view. Select
442 "Debug" in the "Configuration" combo box. Make sure that "Runtime
443 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
444 the "Configuration" combo box and make sure that "Runtime Library" is
445 set to "Multi-threaded DLL".
447 @item Click "OK" to close the "Project / Properties" dialog box.
449 @item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
450 Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
451 and install it in MSVC++'s include directory
452 (i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
454 @item MSVC++ also does not understand the @code{inline} keyword used by
455 FFmpeg, so you must add this line before @code{#include}ing libav*:
457 #define inline _inline
460 @item If you used @file{output_example.c} as your sample application,
461 you will have to edit the @code{#include}s to point to the files which
462 are under the @file{ffmpeg} directory (i.e. @code{<ffmpeg/avformat.h>}).
464 @item Build your application, everything should work.
468 @subsubsection Using shared libraries
470 This is how to create DLL and LIB files that are compatible with MSVC++:
474 @item Add a call to @file{vcvars32.bat} (which sets up the environment
475 variables for the Visual C++ tools) as the first line of @file{msys.bat}.
476 The standard location for @file{vcvars32.bat} is
477 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
478 and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
479 If this corresponds to your setup, add the following line as the first line
483 call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
486 Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
487 and run @file{c:\msys\1.0\msys.bat} from there.
489 @item Within the MSYS shell, run @code{lib.exe}. If you get a help message
490 from @file{Microsoft (R) Library Manager}, this means your environment
491 variables are set up correctly, the @file{Microsoft (R) Library Manager}
492 is on the path and will be used by FFmpeg to create
493 MSVC++-compatible import libraries.
495 @item Build FFmpeg with
498 ./configure --enable-shared --enable-memalign-hack
503 Your install path (@file{/usr/local/} by default) should now have the
504 necessary DLL and LIB files under the @file{bin} directory.
508 To use those files with MSVC++, do the same as you would do with
509 the static libraries, as described above. But in Step 4,
510 you should only need to add the directory where the LIB files are installed
511 (i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
512 installed in the @file{bin} directory. And instead of adding @file{libxx.a}
513 files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
514 @file{avutil.lib}. There should be no need for @file{libmingwex.a},
515 @file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
516 statically linked into the DLLs. The @file{bin} directory contains a bunch
517 of DLL files, but the ones that are actually used to run your application
518 are the ones with a major version number in their filenames
519 (i.e. @file{avcodec-51.dll}).
521 @subsection Cross compilation for Windows with Linux
523 You must use the MinGW cross compilation tools available at
524 @url{http://www.mingw.org/}.
526 Then configure FFmpeg with the following options:
528 ./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
530 (you can change the cross-prefix according to the prefix chosen for the
533 Then you can easily test FFmpeg with Wine
534 (@url{http://www.winehq.com/}).
536 @subsection Compilation under Cygwin
538 The main issue with Cygwin is that newlib, its C library, does not
539 contain llrint(). However, it is possible to leverage the
540 implementation in MinGW.
542 Just install your Cygwin with all the "Base" packages, plus the
543 following "Devel" ones:
545 binutils, gcc-core, make, subversion, mingw-runtime
548 Do not install binutils-20060709-1 (they are buggy on shared builds);
549 use binutils-20050610-1 instead.
551 Then create a small library that just contains llrint():
554 ar x /usr/lib/mingw/libmingwex.a llrint.o
555 ar cq /usr/local/lib/libllrint.a llrint.o
561 ./configure --enable-static --disable-shared --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
564 to make a static build or
567 ./configure --enable-shared --disable-static --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
570 to build shared libraries.
572 If you want to build FFmpeg with additional libraries, download Cygwin
573 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository
574 and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
575 (@url{http://cygwinports.dotsrc.org/}).
577 @subsection Crosscompilation for Windows under Cygwin
579 With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
581 Just install your Cygwin as explained before, plus these additional
584 gcc-mingw-core, mingw-runtime, mingw-zlib
587 and add some special flags to your configure invocation.
589 For a static build run
591 ./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
594 and for a build with shared libraries
596 ./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
601 BeOS support is broken in mysterious ways.
605 For information about compiling FFmpeg on OS/2 see
606 @url{http://www.edm2.com/index.php/FFmpeg}.
608 @chapter Developers Guide
612 @item libavcodec is the library containing the codecs (both encoding and
613 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
615 @item libavformat is the library containing the file format handling (mux and
616 demux code for several formats). Look at @file{ffplay.c} to use it in a
617 player. See @file{output_example.c} to use it to generate audio or video
622 @section Integrating libavcodec or libavformat in your program
624 You can integrate all the source code of the libraries to link them
625 statically to avoid any version problem. All you need is to provide a
626 'config.mak' and a 'config.h' in the parent directory. See the defines
627 generated by ./configure to understand what is needed.
629 You can use libavcodec or libavformat in your commercial program, but
630 @emph{any patch you make must be published}. The best way to proceed is
631 to send your patches to the FFmpeg mailing list.
634 @section Coding Rules
636 FFmpeg is programmed in the ISO C90 language with a few additional
637 features from ISO C99, namely:
640 the @samp{inline} keyword;
644 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
646 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
649 These features are supported by all compilers we care about, so we will not
650 accept patches to remove their use unless they absolutely do not impair
651 clarity and performance.
653 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
654 compiles with several other compilers, such as the Compaq ccc compiler
655 or Sun Studio 9, and we would like to keep it that way unless it would
656 be exceedingly involved. To ensure compatibility, please do not use any
657 additional C99 features or GCC extensions. Especially watch out for:
660 mixing statements and declarations;
662 @samp{long long} (use @samp{int64_t} instead);
664 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
666 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
670 The presentation is the one specified by 'indent -i4 -kr -nut'.
671 The TAB character is forbidden outside of Makefiles as is any
672 form of trailing whitespace. Commits containing either will be
673 rejected by the Subversion repository.
675 The main priority in FFmpeg is simplicity and small code size in order to
676 minimize the bug count.
678 Comments: Use the JavaDoc/Doxygen
679 format (see examples below) so that code documentation
680 can be generated automatically. All nontrivial functions should have a comment
681 above them explaining what the function does, even if it is just one sentence.
682 All structures and their member variables should be documented, too.
695 typedef struct Foobar@{
696 int var1; /**< var1 description */
697 int var2; ///< var2 description
698 /** var3 description */
706 * @@param my_parameter description of my_parameter
707 * @@return return value description
709 int myfunc(int my_parameter)
713 fprintf and printf are forbidden in libavformat and libavcodec,
714 please use av_log() instead.
716 Casts should be used only when necessary. Unneeded parentheses
717 should also be avoided if they don't make the code easier to understand.
719 @section Development Policy
723 Contributions should be licensed under the LGPL 2.1, including an
724 "or any later version" clause, or the MIT license. GPL 2 including
725 an "or any later version" clause is also acceptable, but LGPL is
728 You must not commit code which breaks FFmpeg! (Meaning unfinished but
729 enabled code which breaks compilation or compiles but does not work or
730 breaks the regression tests)
731 You can commit unfinished stuff (for testing etc), but it must be disabled
732 (#ifdef etc) by default so it does not interfere with other developers'
735 You do not have to over-test things. If it works for you, and you think it
736 should work for others, then commit. If your code has problems
737 (portability, triggers compiler bugs, unusual environment etc) they will be
738 reported and eventually fixed.
740 Do not commit unrelated changes together, split them into self-contained
741 pieces. Also do not forget that if part B depends on part A, but A does not
742 depend on B, then A can and should be committed first and separate from B.
743 Keeping changes well split into self-contained parts makes reviewing and
744 understanding them on the commit log mailing list easier. This also helps
745 in case of debugging later on.
746 Also if you have doubts about splitting or not splitting, do not hesitate to
747 ask/discuss it on the developer mailing list.
749 Do not change behavior of the program (renaming options etc) without
750 first discussing it on the ffmpeg-devel mailing list. Do not remove
751 functionality from the code. Just improve!
753 Note: Redundant code can be removed.
755 Do not commit changes to the build system (Makefiles, configure script)
756 which change behavior, defaults etc, without asking first. The same
757 applies to compiler warning fixes, trivial looking fixes and to code
758 maintained by other developers. We usually have a reason for doing things
759 the way we do. Send your changes as patches to the ffmpeg-devel mailing
760 list, and if the code maintainers say OK, you may commit. This does not
761 apply to files you wrote and/or maintain.
763 We refuse source indentation and other cosmetic changes if they are mixed
764 with functional changes, such commits will be rejected and removed. Every
765 developer has his own indentation style, you should not change it. Of course
766 if you (re)write something, you can use your own style, even though we would
767 prefer if the indentation throughout FFmpeg was consistent (Many projects
768 force a given indentation style - we do not.). If you really need to make
769 indentation changes (try to avoid this), separate them strictly from real
772 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
773 then either do NOT change the indentation of the inner part within (do not
774 move it to the right)! or do so in a separate commit
776 Always fill out the commit log message. Describe in a few lines what you
777 changed and why. You can refer to mailing list postings if you fix a
778 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
780 If you apply a patch by someone else, include the name and email address in
781 the log message. Since the ffmpeg-cvslog mailing list is publicly
782 archived you should add some SPAM protection to the email address. Send an
783 answer to ffmpeg-devel (or wherever you got the patch from) saying that
784 you applied the patch.
786 When applying patches that have been discussed (at length) on the mailing
787 list, reference the thread in the log message.
789 Do NOT commit to code actively maintained by others without permission.
790 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
791 timeframe (12h for build failures and security fixes, 3 days small changes,
792 1 week for big patches) then commit your patch if you think it is OK.
793 Also note, the maintainer can simply ask for more time to review!
795 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
796 are sent there and reviewed by all the other developers. Bugs and possible
797 improvements or general questions regarding commits are discussed there. We
798 expect you to react if problems with your code are uncovered.
800 Update the documentation if you change behavior or add features. If you are
801 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
802 maintainer(s) will review and commit your stuff.
804 Try to keep important discussions and requests (also) on the public
805 developer mailing list, so that all developers can benefit from them.
807 Never write to unallocated memory, never write over the end of arrays,
808 always check values read from some untrusted source before using them
809 as array index or other risky things.
811 Remember to check if you need to bump versions for the specific libav
812 parts (libavutil, libavcodec, libavformat) you are changing. You need
813 to change the version integer and the version string.
814 Incrementing the first component means no backward compatibility to
815 previous versions (e.g. removal of a function from the public API).
816 Incrementing the second component means backward compatible change
817 (e.g. addition of a function to the public API).
818 Incrementing the third component means a noteworthy binary compatible
819 change (e.g. encoder bug fix that matters for the decoder).
821 If you add a new codec, remember to update the changelog, add it to
822 the supported codecs table in the documentation and bump the second
823 component of the @file{libavcodec} version number appropriately. If
824 it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
827 Do not change code to hide warnings without ensuring that the underlying
828 logic is correct and thus the warning was inappropriate.
830 If you add a new file, give it a proper license header. Do not copy and
831 paste it from a random place, use an existing file as template.
834 We think our rules are not too hard. If you have comments, contact us.
836 Note, these rules are mostly borrowed from the MPlayer project.
838 @section Submitting patches
840 First, (@pxref{Coding Rules}) above if you did not yet.
842 When you submit your patch, try to send a unified diff (diff '-up'
843 option). We cannot read other diffs :-)
845 Also please do not submit a patch which contains several unrelated changes.
846 Split it into separate, self-contained pieces. This does not mean splitting
847 file by file. Instead, make the patch as small as possible while still
848 keeping it as a logical unit that contains an individual change, even
849 if it spans multiple files. This makes reviewing your patches much easier
850 for us and greatly increases your chances of getting your patch applied.
852 Run the regression tests before submitting a patch so that you can
853 verify that there are no big problems.
855 Patches should be posted as base64 encoded attachments (or any other
856 encoding which ensures that the patch will not be trashed during
857 transmission) to the ffmpeg-devel mailing list, see
858 @url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
860 It also helps quite a bit if you tell us what the patch does (for example
861 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
864 Also please if you send several patches, send each patch as a separate mail,
865 do not attach several unrelated patches to the same mail.
867 @section patch submission checklist
871 Do the regression tests pass with the patch applied?
873 Is the patch a unified diff?
875 Is the patch against latest FFmpeg SVN?
877 Are you subscribed to ffmpeg-dev?
878 (the list is subscribers only due to spam)
880 Have you checked that the changes are minimal, so that the same cannot be
881 achieved with a smaller patch and/or simpler final code?
883 If the change is to speed critical code, did you benchmark it?
885 If you did any benchmarks, did you provide them in the mail?
887 Have you checked that the patch does not introduce buffer overflows or
888 other security issues?
890 Is the patch created from the root of the source tree, so it can be
891 applied with @code{patch -p0}?
893 Does the patch not mix functional and cosmetic changes?
895 Did you add tabs or trailing whitespace to the code? Both are forbidden.
897 Is the patch attached to the email you send?
899 Is the mime type of the patch correct? It should be text/x-diff or
900 text/x-patch or at least text/plain and not application/octet-stream.
902 If the patch fixes a bug, did you provide a verbose analysis of the bug?
904 If the patch fixes a bug, did you provide enough information, including
905 a sample, so the bug can be reproduced and the fix can be verified?
906 Note please do not attach samples >100k to mails but rather provide a
907 URL, you can upload to ftp://upload.mplayerhq.hu
909 Did you provide a verbose summary about what the patch does change?
911 Did you provide a verbose explanation why it changes things like it does?
913 Did you provide a verbose summary of the user visible advantages and
914 disadvantages if the patch is applied?
916 Did you provide an example so we can verify the new feature added by the
919 If you added a new file, did you insert a license header? It should be
920 taken from FFmpeg, not randomly copied and pasted from somewhere else.
922 You should maintain alphabetical order in alphabetically ordered lists as
923 long as doing so does not break API/ABI compatibility.
925 Lines with similar content should be aligned vertically when doing so
926 improves readability.
928 Did you provide a suggestion for a clear commit log message?
930 Did you test your decoder or demuxer against damaged data? If no, see
931 tools/trasher and the noise bitstream filter. Your decoder or demuxer
932 should not crash or end in a (near) infinite loop when feeded with
936 @section Patch review process
938 All patches posted to ffmpeg-devel will be reviewed, unless they contain a
939 clear note that the patch is not for SVN.
940 Reviews and comments will be posted as replies to the patch on the
941 mailing list. The patch submitter then has to take care of every comment,
942 that can be by resubmitting a changed patch or by discussion. Resubmitted
943 patches will themselves be reviewed like any other patch. If at some point
944 a patch passes review with no comments then it is approved, that can for
945 simple and small patches happen immediately while large patches will generally
946 have to be changed and reviewed many times before they are approved.
947 After a patch is approved it will be committed to the repository.
949 We will review all submitted patches, but sometimes we are quite busy so
950 especially for large patches this can take several weeks.
952 When resubmitting patches, please do not make any significant changes
953 not related to the comments received during review. Such patches will
954 be rejected. Instead, submit significant changes or new features as
957 @section Regression tests
959 Before submitting a patch (or committing to the repository), you should at least
960 test that you did not break anything.
962 The regression tests build a synthetic video stream and a synthetic
963 audio stream. These are then encoded and decoded with all codecs or
964 formats. The CRC (or MD5) of each generated file is recorded in a
965 result file. A 'diff' is launched to compare the reference results and
968 The regression tests then go on to test the FFserver code with a
969 limited set of streams. It is important that this step runs correctly
972 Run 'make test' to test all the codecs and formats.
974 Run 'make fulltest' to test all the codecs, formats and FFserver.
976 [Of course, some patches may change the results of the regression tests. In
977 this case, the reference results of the regression tests shall be modified