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 @item AVM2 (Flash 9) @tab X @tab X
56 @tab Only embedded audio is decoded.
57 @item FLV @tab X @tab X
58 @tab Macromedia Flash video files
59 @item Real Audio and Video @tab X @tab X
60 @item Raw AC3 @tab X @tab X
61 @item Raw MJPEG @tab X @tab X
62 @item Raw MPEG video @tab X @tab X
63 @item Raw PCM8/16 bits, mulaw/Alaw@tab X @tab X
64 @item Raw CRI ADX audio @tab X @tab X
65 @item Raw Shorten audio @tab @tab X
66 @item SUN AU format @tab X @tab X
67 @item NUT @tab X @tab X @tab NUT Open Container Format
68 @item QuickTime @tab X @tab X
69 @item MPEG-4 @tab X @tab X
70 @tab MPEG-4 is a variant of QuickTime.
71 @item Raw MPEG4 video @tab X @tab X
72 @item DV @tab X @tab X
74 @tab 4X Technologies format, used in some games.
75 @item Playstation STR @tab @tab X
76 @item Id RoQ @tab X @tab X
77 @tab Used in Quake III, Jedi Knight 2, other computer games.
78 @item Interplay MVE @tab @tab X
79 @tab Format used in various Interplay computer games.
80 @item WC3 Movie @tab @tab X
81 @tab Multimedia format used in Origin's Wing Commander III computer game.
82 @item Sega FILM/CPK @tab @tab X
83 @tab Used in many Sega Saturn console games.
84 @item Westwood Studios VQA/AUD @tab @tab X
85 @tab Multimedia formats used in Westwood Studios games.
86 @item Id Cinematic (.cin) @tab @tab X
87 @tab Used in Quake II.
88 @item FLIC format @tab @tab X
90 @item Sierra VMD @tab @tab X
91 @tab Used in Sierra CD-ROM games.
92 @item Sierra Online @tab @tab X
93 @tab .sol files used in Sierra Online games.
94 @item Matroska @tab X @tab X
95 @item Electronic Arts Multimedia @tab @tab X
96 @tab Used in various EA games; files have extensions like WVE and UV2.
97 @item Nullsoft Video (NSV) format @tab @tab X
98 @item ADTS AAC audio @tab X @tab X
99 @item Creative VOC @tab X @tab X @tab Created for the Sound Blaster Pro.
100 @item American Laser Games MM @tab @tab X
101 @tab Multimedia format used in games like Mad Dog McCree
102 @item AVS @tab @tab X
103 @tab Multimedia format used by the Creature Shock game.
104 @item Smacker @tab @tab X
105 @tab Multimedia format used by many games.
106 @item GXF @tab X @tab X
107 @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley playout servers.
108 @item CIN @tab @tab X
109 @tab Multimedia format used by Delphine Software games.
110 @item MXF @tab @tab X
111 @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
112 @item SEQ @tab @tab X
113 @tab Tiertex .seq files used in the DOS CDROM version of the game Flashback.
114 @item DXA @tab @tab X
115 @tab This format is used in non-Windows version of Feeble Files game and
116 different game cutscenes repacked for use with ScummVM.
117 @item THP @tab @tab X
118 @tab Used on the Nintendo GameCube.
119 @item C93 @tab @tab X
120 @tab Used in the game Cyberia from Interplay.
121 @item Bethsoft VID @tab @tab X
122 @tab Used in some games from Bethesda Softworks.
123 @item CRYO APC @tab @tab X
124 @tab Audio format used in some games by CRYO Interactive Entertainment.
125 @item Monkey's Audio @tab @tab X
126 @item SIFF @tab @tab X
127 @tab Audio and video format used in some games by Beam Software
128 @item LMLM4 @tab @tab X
129 @tab Used by Linux Media Labs MPEG-4 PCI boards
130 @item PVA @tab @tab X
131 @tab Used by TechnoTrend DVB PCI boards
134 @code{X} means that encoding (resp. decoding) is supported.
136 @section Image Formats
138 FFmpeg can read and write images for each frame of a video sequence. The
139 following image formats are supported:
141 @multitable @columnfractions .4 .1 .1 .4
142 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
143 @item PGM, PPM @tab X @tab X
144 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
145 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
146 @item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
147 @item .Y.U.V @tab X @tab X @tab one raw file per component
148 @item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
149 @item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
150 @item Targa @tab @tab X @tab Targa (.TGA) image format.
151 @item TIFF @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
152 @item SGI @tab X @tab X @tab SGI RGB image format
153 @item PTX @tab @tab X @tab V.Flash PTX format
154 @item RAS @tab @tab X @tab Sun Rasterfile
155 @item PCX @tab @tab X @tab PC Paintbrush
158 @code{X} means that encoding (resp. decoding) is supported.
160 @section Video Codecs
162 @multitable @columnfractions .4 .1 .1 .4
163 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
164 @item MPEG-1 video @tab X @tab X
165 @item MPEG-2 video @tab X @tab X
166 @item MPEG-4 @tab X @tab X
167 @item MSMPEG4 V1 @tab X @tab X
168 @item MSMPEG4 V2 @tab X @tab X
169 @item MSMPEG4 V3 @tab X @tab X
170 @item WMV7 @tab X @tab X
171 @item WMV8 @tab X @tab X @tab not completely working
172 @item WMV9 @tab @tab X @tab not completely working
173 @item VC1 @tab @tab X
174 @item H.261 @tab X @tab X
175 @item H.263(+) @tab X @tab X @tab also known as RealVideo 1.0
176 @item H.264 @tab @tab X
177 @item RealVideo 1.0 @tab X @tab X
178 @item RealVideo 2.0 @tab X @tab X
179 @item MJPEG @tab X @tab X
180 @item lossless MJPEG @tab X @tab X
181 @item JPEG-LS @tab X @tab X @tab fourcc: MJLS, lossless and near-lossless is supported
182 @item Apple MJPEG-B @tab @tab X
183 @item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
184 @item DV @tab X @tab X
185 @item HuffYUV @tab X @tab X
186 @item FFmpeg Video 1 @tab X @tab X @tab experimental lossless codec (fourcc: FFV1)
187 @item FFmpeg Snow @tab X @tab X @tab experimental wavelet codec (fourcc: SNOW)
188 @item Asus v1 @tab X @tab X @tab fourcc: ASV1
189 @item Asus v2 @tab X @tab X @tab fourcc: ASV2
190 @item Creative YUV @tab @tab X @tab fourcc: CYUV
191 @item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
192 @item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
193 @item On2 VP3 @tab @tab X @tab still experimental
194 @item On2 VP5 @tab @tab X @tab fourcc: VP50
195 @item On2 VP6 @tab @tab X @tab fourcc: VP60,VP61,VP62
196 @item Theora @tab X @tab X @tab still experimental
197 @item Intel Indeo 3 @tab @tab X
198 @item FLV @tab X @tab X @tab Sorenson H.263 used in Flash
199 @item Flash Screen Video @tab X @tab X @tab fourcc: FSV1
200 @item ATI VCR1 @tab @tab X @tab fourcc: VCR1
201 @item ATI VCR2 @tab @tab X @tab fourcc: VCR2
202 @item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
203 @item 4X Video @tab @tab X @tab Used in certain computer games.
204 @item Sony Playstation MDEC @tab @tab X
205 @item Id RoQ @tab X @tab X @tab Used in Quake III, Jedi Knight 2, other computer games.
206 @item Xan/WC3 @tab @tab X @tab Used in Wing Commander III .MVE files.
207 @item Interplay Video @tab @tab X @tab Used in Interplay .MVE files.
208 @item Apple Animation @tab X @tab X @tab fourcc: 'rle '
209 @item Apple Graphics @tab @tab X @tab fourcc: 'smc '
210 @item Apple Video @tab @tab X @tab fourcc: rpza
211 @item Apple QuickDraw @tab @tab X @tab fourcc: qdrw
212 @item Cinepak @tab @tab X
213 @item Microsoft RLE @tab @tab X
214 @item Microsoft Video-1 @tab @tab X
215 @item Westwood VQA @tab @tab X
216 @item Id Cinematic Video @tab @tab X @tab Used in Quake II.
217 @item Planar RGB @tab @tab X @tab fourcc: 8BPS
218 @item FLIC video @tab @tab X
219 @item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK
220 @item Duck TrueMotion v2 @tab @tab X @tab fourcc: TM20
221 @item VMD Video @tab @tab X @tab Used in Sierra VMD files.
222 @item MSZH @tab @tab X @tab Part of LCL
223 @item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental
224 @item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC
225 @item IBM Ultimotion @tab @tab X @tab fourcc: ULTI
226 @item Miro VideoXL @tab @tab X @tab fourcc: VIXL
227 @item QPEG @tab @tab X @tab fourccs: QPEG, Q1.0, Q1.1
228 @item LOCO @tab @tab X @tab
229 @item Winnov WNV1 @tab @tab X @tab
230 @item Autodesk Animator Studio Codec @tab @tab X @tab fourcc: AASC
231 @item Fraps FPS1 @tab @tab X @tab
232 @item CamStudio @tab @tab X @tab fourcc: CSCD
233 @item American Laser Games Video @tab @tab X @tab Used in games like Mad Dog McCree
234 @item ZMBV @tab X @tab X @tab Encoder works only on PAL8
235 @item AVS Video @tab @tab X @tab Video encoding used by the Creature Shock game.
236 @item Smacker Video @tab @tab X @tab Video encoding used in Smacker.
237 @item RTjpeg @tab @tab X @tab Video encoding used in NuppelVideo files.
238 @item KMVC @tab @tab X @tab Codec used in Worms games.
239 @item VMware Video @tab @tab X @tab Codec used in videos captured by VMware.
240 @item Cin Video @tab @tab X @tab Codec used in Delphine Software games.
241 @item Tiertex Seq Video @tab @tab X @tab Codec used in DOS CDROM FlashBack game.
242 @item DXA Video @tab @tab X @tab Codec originally used in Feeble Files game.
243 @item AVID DNxHD @tab X @tab X @tab aka SMPTE VC3
244 @item C93 Video @tab @tab X @tab Codec used in Cyberia game.
245 @item THP @tab @tab X @tab Used on the Nintendo GameCube.
246 @item Bethsoft VID @tab @tab X @tab Used in some games from Bethesda Softworks.
247 @item Renderware TXD @tab @tab X @tab Texture dictionaries used by the Renderware Engine.
248 @item AMV @tab @tab X @tab Used in Chinese MP3 players.
251 @code{X} means that encoding (resp. decoding) is supported.
253 @section Audio Codecs
255 @multitable @columnfractions .4 .1 .1 .1 .7
256 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
257 @item MPEG audio layer 2 @tab IX @tab IX
258 @item MPEG audio layer 1/3 @tab X @tab IX
259 @tab MP3 encoding is supported through the external library LAME.
260 @item AC3 @tab IX @tab IX
261 @tab liba52 is used internally for decoding.
262 @item Vorbis @tab X @tab X
263 @item WMA V1/V2 @tab X @tab X
264 @item AAC @tab X @tab X
265 @tab Supported through the external library libfaac/libfaad.
266 @item Microsoft ADPCM @tab X @tab X
267 @item AMV IMA ADPCM @tab @tab X
268 @tab Used in AMV files
269 @item MS IMA ADPCM @tab X @tab X
270 @item QT IMA ADPCM @tab X @tab X
271 @item 4X IMA ADPCM @tab @tab X
272 @item G.726 ADPCM @tab X @tab X
273 @item Duck DK3 IMA ADPCM @tab @tab X
274 @tab Used in some Sega Saturn console games.
275 @item Duck DK4 IMA ADPCM @tab @tab X
276 @tab Used in some Sega Saturn console games.
277 @item Westwood Studios IMA ADPCM @tab @tab X
278 @tab Used in Westwood Studios games like Command and Conquer.
279 @item SMJPEG IMA ADPCM @tab @tab X
280 @tab Used in certain Loki game ports.
281 @item CD-ROM XA ADPCM @tab @tab X
282 @item CRI ADX ADPCM @tab X @tab X
283 @tab Used in Sega Dreamcast games.
284 @item Electronic Arts ADPCM @tab @tab X
285 @tab Used in various EA titles.
286 @item Creative ADPCM @tab @tab X
287 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
288 @item THP ADPCM @tab @tab X
289 @tab Used on the Nintendo GameCube.
290 @item RA144 @tab @tab X
291 @tab Real 14400 bit/s codec
292 @item RA288 @tab @tab X
293 @tab Real 28800 bit/s codec
294 @item RADnet @tab X @tab IX
295 @tab Real low bitrate AC3 codec, liba52 is used for decoding.
296 @item AMR-NB @tab X @tab X
297 @tab Supported through an external library.
298 @item AMR-WB @tab X @tab X
299 @tab Supported through an external library.
300 @item DV audio @tab @tab X
301 @item Id RoQ DPCM @tab X @tab X
302 @tab Used in Quake III, Jedi Knight 2, other computer games.
303 @item Interplay MVE DPCM @tab @tab X
304 @tab Used in various Interplay computer games.
305 @item Xan DPCM @tab @tab X
306 @tab Used in Origin's Wing Commander IV AVI files.
307 @item Sierra Online DPCM @tab @tab X
308 @tab Used in Sierra Online game audio files.
309 @item Apple MACE 3 @tab @tab X
310 @item Apple MACE 6 @tab @tab X
311 @item FLAC lossless audio @tab X @tab X
312 @item Shorten lossless audio @tab @tab X
313 @item Apple lossless audio @tab @tab X
314 @tab QuickTime fourcc 'alac'
315 @item FFmpeg Sonic @tab X @tab X
316 @tab experimental lossy/lossless codec
317 @item Qdesign QDM2 @tab @tab X
318 @tab there are still some distortions
319 @item Real COOK @tab @tab X
320 @tab All versions except 5.1 are supported
321 @item DSP Group TrueSpeech @tab @tab X
322 @item True Audio (TTA) @tab @tab X
323 @item Smacker Audio @tab @tab X
324 @item WavPack Audio @tab @tab X
325 @item Cin Audio @tab @tab X
326 @tab Codec used in Delphine Software games.
327 @item Intel Music Coder @tab @tab X
328 @item Musepack @tab @tab X
329 @tab SV7 and SV8 are supported
330 @item DT$ Coherent Audio @tab @tab X
331 @item ATRAC 3 @tab @tab X
332 @item Monkey's Audio @tab @tab X @tab Only versions 3.97-3.99 are supported
333 @item Nellymoser ASAO @tab @tab X
336 @code{X} means that encoding (resp. decoding) is supported.
338 @code{I} means that an integer-only version is available, too (ensures high
339 performance on systems without hardware floating point support).
341 @chapter Platform Specific information
345 BSD make will not build FFmpeg, you need to install and use GNU Make
350 To get help and instructions for building FFmpeg under Windows, check out
351 the FFmpeg Windows Help Forum at
352 @url{http://arrozcru.no-ip.org/ffmpeg/}.
354 @subsection Native Windows compilation
356 FFmpeg can be built to run natively on Windows using the MinGW tools. Install
357 the current versions of MSYS and MinGW from @url{http://www.mingw.org/}. Also
358 install the coreutils package. You can find detailed installation
359 instructions in the download section and the FAQ.
361 Within the MSYS shell, configure and make with:
364 ./configure --enable-memalign-hack
369 This will install @file{ffmpeg.exe} along with many other development files
370 to @file{/usr/local}. You may specify another install path using the
371 @code{--prefix} option in @file{configure}.
377 @item Use at least bash 3.1. Older versions are known to fail on the
380 @item In order to compile vhooks, you must have a POSIX-compliant libdl in
381 your MinGW system. Get dlfcn-win32 from
382 @url{http://code.google.com/p/dlfcn-win32}.
384 @item In order to compile FFplay, you must have the MinGW development library
385 of SDL. Get it from @url{http://www.libsdl.org}.
386 Edit the @file{bin/sdl-config} script so that it points to the correct prefix
387 where SDL was installed. Verify that @file{sdl-config} can be launched from
388 the MSYS command line.
390 @item The target @code{make wininstaller} can be used to create a
391 Nullsoft-based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
392 must be copied to the FFmpeg directory in order to build the
395 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
396 you can build libavutil, libavcodec and libavformat as DLLs.
400 @subsection Microsoft Visual C++ compatibility
402 As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
403 want to use the libav* libraries in your own applications, you can still
404 compile those applications using MSVC++. But the libav* libraries you link
405 to @emph{must} be built with MinGW. However, you will not be able to debug
406 inside the libav* libraries, since MSVC++ does not recognize the debug
407 symbols generated by GCC.
408 We strongly recommend you to move over from MSVC++ to MinGW tools.
410 This description of how to use the FFmpeg libraries with MSVC++ is based on
411 Microsoft Visual C++ 2005 Express Edition. If you have a different version,
412 you might have to modify the procedures slightly.
414 @subsubsection Using static libraries
416 Assuming you have just built and installed FFmpeg in @file{/usr/local}.
420 @item Create a new console application ("File / New / Project") and then
421 select "Win32 Console Application". On the appropriate page of the
422 Application Wizard, uncheck the "Precompiled headers" option.
424 @item Write the source code for your application, or, for testing, just
425 copy the code from an existing sample application into the source file
426 that MSVC++ has already created for you. For example, you can copy
427 @file{output_example.c} from the FFmpeg distribution.
429 @item Open the "Project / Properties" dialog box. In the "Configuration"
430 combo box, select "All Configurations" so that the changes you make will
431 affect both debug and release builds. In the tree view on the left hand
432 side, select "C/C++ / General", then edit the "Additional Include
433 Directories" setting to contain the path where the FFmpeg includes were
434 installed (i.e. @file{c:\msys\1.0\local\include}).
436 @item Still in the "Project / Properties" dialog box, select
437 "Linker / General" from the tree view and edit the
438 "Additional Library Directories" setting to contain the @file{lib}
439 directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
440 the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
441 and the directory where MinGW's GCC libs are installed
442 (i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
443 "Linker / Input" from the tree view, and add the files @file{libavformat.a},
444 @file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
445 @file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
446 to the end of "Additional Dependencies".
448 @item Now, select "C/C++ / Code Generation" from the tree view. Select
449 "Debug" in the "Configuration" combo box. Make sure that "Runtime
450 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
451 the "Configuration" combo box and make sure that "Runtime Library" is
452 set to "Multi-threaded DLL".
454 @item Click "OK" to close the "Project / Properties" dialog box.
456 @item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
457 Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
458 and install it in MSVC++'s include directory
459 (i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
461 @item MSVC++ also does not understand the @code{inline} keyword used by
462 FFmpeg, so you must add this line before @code{#include}ing libav*:
464 #define inline _inline
467 @item If you used @file{output_example.c} as your sample application,
468 you will have to edit the @code{#include}s to point to the files which
469 are under the @file{ffmpeg} directory (i.e. @code{<ffmpeg/avformat.h>}).
471 @item Build your application, everything should work.
475 @subsubsection Using shared libraries
477 This is how to create DLL and LIB files that are compatible with MSVC++:
481 @item Add a call to @file{vcvars32.bat} (which sets up the environment
482 variables for the Visual C++ tools) as the first line of @file{msys.bat}.
483 The standard location for @file{vcvars32.bat} is
484 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
485 and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
486 If this corresponds to your setup, add the following line as the first line
490 call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
493 Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
494 and run @file{c:\msys\1.0\msys.bat} from there.
496 @item Within the MSYS shell, run @code{lib.exe}. If you get a help message
497 from @file{Microsoft (R) Library Manager}, this means your environment
498 variables are set up correctly, the @file{Microsoft (R) Library Manager}
499 is on the path and will be used by FFmpeg to create
500 MSVC++-compatible import libraries.
502 @item Build FFmpeg with
505 ./configure --enable-shared --enable-memalign-hack
510 Your install path (@file{/usr/local/} by default) should now have the
511 necessary DLL and LIB files under the @file{bin} directory.
515 To use those files with MSVC++, do the same as you would do with
516 the static libraries, as described above. But in Step 4,
517 you should only need to add the directory where the LIB files are installed
518 (i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
519 installed in the @file{bin} directory. And instead of adding @file{libxx.a}
520 files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
521 @file{avutil.lib}. There should be no need for @file{libmingwex.a},
522 @file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
523 statically linked into the DLLs. The @file{bin} directory contains a bunch
524 of DLL files, but the ones that are actually used to run your application
525 are the ones with a major version number in their filenames
526 (i.e. @file{avcodec-51.dll}).
528 @subsection Cross compilation for Windows with Linux
530 You must use the MinGW cross compilation tools available at
531 @url{http://www.mingw.org/}.
533 Then configure FFmpeg with the following options:
535 ./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
537 (you can change the cross-prefix according to the prefix chosen for the
540 Then you can easily test FFmpeg with Wine
541 (@url{http://www.winehq.com/}).
543 @subsection Compilation under Cygwin
545 The main issue with Cygwin is that newlib, its C library, does not
546 contain llrint(). However, it is possible to leverage the
547 implementation in MinGW.
549 Just install your Cygwin with all the "Base" packages, plus the
550 following "Devel" ones:
552 binutils, gcc-core, make, subversion, mingw-runtime
555 Do not install binutils-20060709-1 (they are buggy on shared builds);
556 use binutils-20050610-1 instead.
558 Then create a small library that just contains llrint():
561 ar x /usr/lib/mingw/libmingwex.a llrint.o
562 ar cq /usr/local/lib/libllrint.a llrint.o
568 ./configure --enable-static --disable-shared --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
571 to make a static build or
574 ./configure --enable-shared --disable-static --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
577 to build shared libraries.
579 If you want to build FFmpeg with additional libraries, download Cygwin
580 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository
581 and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
582 (@url{http://cygwinports.dotsrc.org/}).
584 @subsection Crosscompilation for Windows under Cygwin
586 With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
588 Just install your Cygwin as explained before, plus these additional
591 gcc-mingw-core, mingw-runtime, mingw-zlib
594 and add some special flags to your configure invocation.
596 For a static build run
598 ./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
601 and for a build with shared libraries
603 ./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
608 BeOS support is broken in mysterious ways.
612 For information about compiling FFmpeg on OS/2 see
613 @url{http://www.edm2.com/index.php/FFmpeg}.
615 @chapter Developers Guide
619 @item libavcodec is the library containing the codecs (both encoding and
620 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
622 @item libavformat is the library containing the file format handling (mux and
623 demux code for several formats). Look at @file{ffplay.c} to use it in a
624 player. See @file{output_example.c} to use it to generate audio or video
629 @section Integrating libavcodec or libavformat in your program
631 You can integrate all the source code of the libraries to link them
632 statically to avoid any version problem. All you need is to provide a
633 'config.mak' and a 'config.h' in the parent directory. See the defines
634 generated by ./configure to understand what is needed.
636 You can use libavcodec or libavformat in your commercial program, but
637 @emph{any patch you make must be published}. The best way to proceed is
638 to send your patches to the FFmpeg mailing list.
641 @section Coding Rules
643 FFmpeg is programmed in the ISO C90 language with a few additional
644 features from ISO C99, namely:
647 the @samp{inline} keyword;
651 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
653 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
656 These features are supported by all compilers we care about, so we will not
657 accept patches to remove their use unless they absolutely do not impair
658 clarity and performance.
660 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
661 compiles with several other compilers, such as the Compaq ccc compiler
662 or Sun Studio 9, and we would like to keep it that way unless it would
663 be exceedingly involved. To ensure compatibility, please do not use any
664 additional C99 features or GCC extensions. Especially watch out for:
667 mixing statements and declarations;
669 @samp{long long} (use @samp{int64_t} instead);
671 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
673 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
677 The presentation is the one specified by 'indent -i4 -kr -nut'.
678 The TAB character is forbidden outside of Makefiles as is any
679 form of trailing whitespace. Commits containing either will be
680 rejected by the Subversion repository.
682 The main priority in FFmpeg is simplicity and small code size in order to
683 minimize the bug count.
685 Comments: Use the JavaDoc/Doxygen
686 format (see examples below) so that code documentation
687 can be generated automatically. All nontrivial functions should have a comment
688 above them explaining what the function does, even if it is just one sentence.
689 All structures and their member variables should be documented, too.
702 typedef struct Foobar@{
703 int var1; /**< var1 description */
704 int var2; ///< var2 description
705 /** var3 description */
713 * @@param my_parameter description of my_parameter
714 * @@return return value description
716 int myfunc(int my_parameter)
720 fprintf and printf are forbidden in libavformat and libavcodec,
721 please use av_log() instead.
723 Casts should be used only when necessary. Unneeded parentheses
724 should also be avoided if they don't make the code easier to understand.
726 @section Development Policy
730 Contributions should be licensed under the LGPL 2.1, including an
731 "or any later version" clause, or the MIT license. GPL 2 including
732 an "or any later version" clause is also acceptable, but LGPL is
735 You must not commit code which breaks FFmpeg! (Meaning unfinished but
736 enabled code which breaks compilation or compiles but does not work or
737 breaks the regression tests)
738 You can commit unfinished stuff (for testing etc), but it must be disabled
739 (#ifdef etc) by default so it does not interfere with other developers'
742 You do not have to over-test things. If it works for you, and you think it
743 should work for others, then commit. If your code has problems
744 (portability, triggers compiler bugs, unusual environment etc) they will be
745 reported and eventually fixed.
747 Do not commit unrelated changes together, split them into self-contained
748 pieces. Also do not forget that if part B depends on part A, but A does not
749 depend on B, then A can and should be committed first and separate from B.
750 Keeping changes well split into self-contained parts makes reviewing and
751 understanding them on the commit log mailing list easier. This also helps
752 in case of debugging later on.
753 Also if you have doubts about splitting or not splitting, do not hesitate to
754 ask/discuss it on the developer mailing list.
756 Do not change behavior of the program (renaming options etc) without
757 first discussing it on the ffmpeg-devel mailing list. Do not remove
758 functionality from the code. Just improve!
760 Note: Redundant code can be removed.
762 Do not commit changes to the build system (Makefiles, configure script)
763 which change behavior, defaults etc, without asking first. The same
764 applies to compiler warning fixes, trivial looking fixes and to code
765 maintained by other developers. We usually have a reason for doing things
766 the way we do. Send your changes as patches to the ffmpeg-devel mailing
767 list, and if the code maintainers say OK, you may commit. This does not
768 apply to files you wrote and/or maintain.
770 We refuse source indentation and other cosmetic changes if they are mixed
771 with functional changes, such commits will be rejected and removed. Every
772 developer has his own indentation style, you should not change it. Of course
773 if you (re)write something, you can use your own style, even though we would
774 prefer if the indentation throughout FFmpeg was consistent (Many projects
775 force a given indentation style - we do not.). If you really need to make
776 indentation changes (try to avoid this), separate them strictly from real
779 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
780 then either do NOT change the indentation of the inner part within (do not
781 move it to the right)! or do so in a separate commit
783 Always fill out the commit log message. Describe in a few lines what you
784 changed and why. You can refer to mailing list postings if you fix a
785 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
787 If you apply a patch by someone else, include the name and email address in
788 the log message. Since the ffmpeg-cvslog mailing list is publicly
789 archived you should add some SPAM protection to the email address. Send an
790 answer to ffmpeg-devel (or wherever you got the patch from) saying that
791 you applied the patch.
793 When applying patches that have been discussed (at length) on the mailing
794 list, reference the thread in the log message.
796 Do NOT commit to code actively maintained by others without permission.
797 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
798 timeframe (12h for build failures and security fixes, 3 days small changes,
799 1 week for big patches) then commit your patch if you think it is OK.
800 Also note, the maintainer can simply ask for more time to review!
802 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
803 are sent there and reviewed by all the other developers. Bugs and possible
804 improvements or general questions regarding commits are discussed there. We
805 expect you to react if problems with your code are uncovered.
807 Update the documentation if you change behavior or add features. If you are
808 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
809 maintainer(s) will review and commit your stuff.
811 Try to keep important discussions and requests (also) on the public
812 developer mailing list, so that all developers can benefit from them.
814 Never write to unallocated memory, never write over the end of arrays,
815 always check values read from some untrusted source before using them
816 as array index or other risky things.
818 Remember to check if you need to bump versions for the specific libav
819 parts (libavutil, libavcodec, libavformat) you are changing. You need
820 to change the version integer and the version string.
821 Incrementing the first component means no backward compatibility to
822 previous versions (e.g. removal of a function from the public API).
823 Incrementing the second component means backward compatible change
824 (e.g. addition of a function to the public API).
825 Incrementing the third component means a noteworthy binary compatible
826 change (e.g. encoder bug fix that matters for the decoder).
828 If you add a new codec, remember to update the changelog, add it to
829 the supported codecs table in the documentation and bump the second
830 component of the @file{libavcodec} version number appropriately. If
831 it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
834 Compiler warnings indicate potential bugs or code with bad style. If a type of
835 warning always points to correct and clean code, that warning should
836 be disabled, not the code changed.
837 Thus the remaining warnings can either be bugs or correct code.
838 If it is a bug, the bug has to be fixed. If it is not, the code should
839 be changed to not generate a warning unless that causes a slowdown
840 or obfuscates the code.
842 If you add a new file, give it a proper license header. Do not copy and
843 paste it from a random place, use an existing file as template.
846 We think our rules are not too hard. If you have comments, contact us.
848 Note, these rules are mostly borrowed from the MPlayer project.
850 @section Submitting patches
852 First, (@pxref{Coding Rules}) above if you did not yet.
854 When you submit your patch, try to send a unified diff (diff '-up'
855 option). We cannot read other diffs :-)
857 Also please do not submit a patch which contains several unrelated changes.
858 Split it into separate, self-contained pieces. This does not mean splitting
859 file by file. Instead, make the patch as small as possible while still
860 keeping it as a logical unit that contains an individual change, even
861 if it spans multiple files. This makes reviewing your patches much easier
862 for us and greatly increases your chances of getting your patch applied.
864 Run the regression tests before submitting a patch so that you can
865 verify that there are no big problems.
867 Patches should be posted as base64 encoded attachments (or any other
868 encoding which ensures that the patch will not be trashed during
869 transmission) to the ffmpeg-devel mailing list, see
870 @url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
872 It also helps quite a bit if you tell us what the patch does (for example
873 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
876 Also please if you send several patches, send each patch as a separate mail,
877 do not attach several unrelated patches to the same mail.
879 @section patch submission checklist
883 Do the regression tests pass with the patch applied?
885 Is the patch a unified diff?
887 Is the patch against latest FFmpeg SVN?
889 Are you subscribed to ffmpeg-dev?
890 (the list is subscribers only due to spam)
892 Have you checked that the changes are minimal, so that the same cannot be
893 achieved with a smaller patch and/or simpler final code?
895 If the change is to speed critical code, did you benchmark it?
897 If you did any benchmarks, did you provide them in the mail?
899 Have you checked that the patch does not introduce buffer overflows or
900 other security issues?
902 Is the patch created from the root of the source tree, so it can be
903 applied with @code{patch -p0}?
905 Does the patch not mix functional and cosmetic changes?
907 Did you add tabs or trailing whitespace to the code? Both are forbidden.
909 Is the patch attached to the email you send?
911 Is the mime type of the patch correct? It should be text/x-diff or
912 text/x-patch or at least text/plain and not application/octet-stream.
914 If the patch fixes a bug, did you provide a verbose analysis of the bug?
916 If the patch fixes a bug, did you provide enough information, including
917 a sample, so the bug can be reproduced and the fix can be verified?
918 Note please do not attach samples >100k to mails but rather provide a
919 URL, you can upload to ftp://upload.mplayerhq.hu
921 Did you provide a verbose summary about what the patch does change?
923 Did you provide a verbose explanation why it changes things like it does?
925 Did you provide a verbose summary of the user visible advantages and
926 disadvantages if the patch is applied?
928 Did you provide an example so we can verify the new feature added by the
931 If you added a new file, did you insert a license header? It should be
932 taken from FFmpeg, not randomly copied and pasted from somewhere else.
934 You should maintain alphabetical order in alphabetically ordered lists as
935 long as doing so does not break API/ABI compatibility.
937 Lines with similar content should be aligned vertically when doing so
938 improves readability.
940 Did you provide a suggestion for a clear commit log message?
942 Did you test your decoder or demuxer against damaged data? If no, see
943 tools/trasher and the noise bitstream filter. Your decoder or demuxer
944 should not crash or end in a (near) infinite loop when fed damaged data.
947 @section Patch review process
949 All patches posted to ffmpeg-devel will be reviewed, unless they contain a
950 clear note that the patch is not for SVN.
951 Reviews and comments will be posted as replies to the patch on the
952 mailing list. The patch submitter then has to take care of every comment,
953 that can be by resubmitting a changed patch or by discussion. Resubmitted
954 patches will themselves be reviewed like any other patch. If at some point
955 a patch passes review with no comments then it is approved, that can for
956 simple and small patches happen immediately while large patches will generally
957 have to be changed and reviewed many times before they are approved.
958 After a patch is approved it will be committed to the repository.
960 We will review all submitted patches, but sometimes we are quite busy so
961 especially for large patches this can take several weeks.
963 When resubmitting patches, please do not make any significant changes
964 not related to the comments received during review. Such patches will
965 be rejected. Instead, submit significant changes or new features as
968 @section Regression tests
970 Before submitting a patch (or committing to the repository), you should at least
971 test that you did not break anything.
973 The regression tests build a synthetic video stream and a synthetic
974 audio stream. These are then encoded and decoded with all codecs or
975 formats. The CRC (or MD5) of each generated file is recorded in a
976 result file. A 'diff' is launched to compare the reference results and
979 The regression tests then go on to test the FFserver code with a
980 limited set of streams. It is important that this step runs correctly
983 Run 'make test' to test all the codecs and formats.
985 Run 'make fulltest' to test all the codecs, formats and FFserver.
987 [Of course, some patches may change the results of the regression tests. In
988 this case, the reference results of the regression tests shall be modified