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, WB and NB. FFmpeg can make use of the
20 AMR WB (floating-point mode) and the AMR NB (floating-point mode) reference
21 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.
28 @chapter Supported File Formats and Codecs
30 You can use the @code{-formats} option to have an exhaustive list.
34 FFmpeg supports the following file formats through the @code{libavformat}
37 @multitable @columnfractions .4 .1 .1 .4
38 @item Supported File Format @tab Encoding @tab Decoding @tab Comments
39 @item MPEG audio @tab X @tab X
40 @item MPEG-1 systems @tab X @tab X
41 @tab muxed audio and video
42 @item MPEG-2 PS @tab X @tab X
43 @tab also known as @code{VOB} file
44 @item MPEG-2 TS @tab @tab X
45 @tab also known as DVB Transport Stream
46 @item ASF@tab X @tab X
47 @item AVI@tab X @tab X
48 @item WAV@tab X @tab X
49 @item Macromedia Flash@tab X @tab X
50 @tab Only embedded audio is decoded.
51 @item FLV @tab X @tab X
52 @tab Macromedia Flash video files
53 @item Real Audio and Video @tab X @tab X
54 @item Raw AC3 @tab X @tab X
55 @item Raw MJPEG @tab X @tab X
56 @item Raw MPEG video @tab X @tab X
57 @item Raw PCM8/16 bits, mulaw/Alaw@tab X @tab X
58 @item Raw CRI ADX audio @tab X @tab X
59 @item Raw Shorten audio @tab @tab X
60 @item SUN AU format @tab X @tab X
61 @item NUT @tab X @tab X @tab NUT Open Container Format
62 @item QuickTime @tab X @tab X
63 @item MPEG-4 @tab X @tab X
64 @tab MPEG-4 is a variant of QuickTime.
65 @item Raw MPEG4 video @tab X @tab X
66 @item DV @tab X @tab X
68 @tab 4X Technologies format, used in some games.
69 @item Playstation STR @tab @tab X
70 @item Id RoQ @tab X @tab X
71 @tab Used in Quake III, Jedi Knight 2, other computer games.
72 @item Interplay MVE @tab @tab X
73 @tab Format used in various Interplay computer games.
74 @item WC3 Movie @tab @tab X
75 @tab Multimedia format used in Origin's Wing Commander III computer game.
76 @item Sega FILM/CPK @tab @tab X
77 @tab Used in many Sega Saturn console games.
78 @item Westwood Studios VQA/AUD @tab @tab X
79 @tab Multimedia formats used in Westwood Studios games.
80 @item Id Cinematic (.cin) @tab @tab X
81 @tab Used in Quake II.
82 @item FLIC format @tab @tab X
84 @item Sierra VMD @tab @tab X
85 @tab Used in Sierra CD-ROM games.
86 @item Sierra Online @tab @tab X
87 @tab .sol files used in Sierra Online games.
88 @item Matroska @tab X @tab X
89 @item Electronic Arts Multimedia @tab @tab X
90 @tab Used in various EA games; files have extensions like WVE and UV2.
91 @item Nullsoft Video (NSV) format @tab @tab X
92 @item ADTS AAC audio @tab X @tab X
93 @item Creative VOC @tab X @tab X @tab Created for the Sound Blaster Pro.
94 @item American Laser Games MM @tab @tab X
95 @tab Multimedia format used in games like Mad Dog McCree
97 @tab Multimedia format used by the Creature Shock game.
98 @item Smacker @tab @tab X
99 @tab Multimedia format used by many games.
100 @item GXF @tab X @tab X
101 @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley playout servers.
102 @item CIN @tab @tab X
103 @tab Multimedia format used by Delphine Software games.
104 @item MXF @tab @tab X
105 @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
106 @item SEQ @tab @tab X
107 @tab Tiertex .seq files used in the DOS CDROM version of the game Flashback.
108 @item DXA @tab @tab X
109 @tab This format is used in non-Windows version of Feeble Files game and
110 different game cutscenes repacked for use with ScummVM.
111 @item THP @tab @tab X
112 @tab Used on the Nintendo GameCube.
113 @item C93 @tab @tab X
114 @tab Used in the game Cyberia from Interplay.
115 @item Bethsoft VID @tab @tab X
116 @tab Used in some games from Bethesda Softworks.
117 @item CRYO APC @tab @tab X
118 @tab Audio format used in some games by CRYO Interactive Entertainment.
119 @item Monkey's Audio @tab @tab X
122 @code{X} means that encoding (resp. decoding) is supported.
124 @section Image Formats
126 FFmpeg can read and write images for each frame of a video sequence. The
127 following image formats are supported:
129 @multitable @columnfractions .4 .1 .1 .4
130 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
131 @item PGM, PPM @tab X @tab X
132 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
133 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
134 @item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
135 @item .Y.U.V @tab X @tab X @tab one raw file per component
136 @item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
137 @item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
138 @item Targa @tab @tab X @tab Targa (.TGA) image format.
139 @item TIFF @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
140 @item SGI @tab X @tab X @tab SGI RGB image format
141 @item PTX @tab @tab X @tab V.Flash PTX format
144 @code{X} means that encoding (resp. decoding) is supported.
146 @section Video Codecs
148 @multitable @columnfractions .4 .1 .1 .4
149 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
150 @item MPEG-1 video @tab X @tab X
151 @item MPEG-2 video @tab X @tab X
152 @item MPEG-4 @tab X @tab X
153 @item MSMPEG4 V1 @tab X @tab X
154 @item MSMPEG4 V2 @tab X @tab X
155 @item MSMPEG4 V3 @tab X @tab X
156 @item WMV7 @tab X @tab X
157 @item WMV8 @tab X @tab X @tab not completely working
158 @item WMV9 @tab @tab X @tab not completely working
159 @item VC1 @tab @tab X
160 @item H.261 @tab X @tab X
161 @item H.263(+) @tab X @tab X @tab also known as RealVideo 1.0
162 @item H.264 @tab @tab X
163 @item RealVideo 1.0 @tab X @tab X
164 @item RealVideo 2.0 @tab X @tab X
165 @item MJPEG @tab X @tab X
166 @item lossless MJPEG @tab X @tab X
167 @item JPEG-LS @tab X @tab X @tab fourcc: MJLS, lossless and near-lossless is supported
168 @item Apple MJPEG-B @tab @tab X
169 @item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
170 @item DV @tab X @tab X
171 @item HuffYUV @tab X @tab X
172 @item FFmpeg Video 1 @tab X @tab X @tab experimental lossless codec (fourcc: FFV1)
173 @item FFmpeg Snow @tab X @tab X @tab experimental wavelet codec (fourcc: SNOW)
174 @item Asus v1 @tab X @tab X @tab fourcc: ASV1
175 @item Asus v2 @tab X @tab X @tab fourcc: ASV2
176 @item Creative YUV @tab @tab X @tab fourcc: CYUV
177 @item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
178 @item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
179 @item On2 VP3 @tab @tab X @tab still experimental
180 @item On2 VP5 @tab @tab X @tab fourcc: VP50
181 @item On2 VP6 @tab @tab X @tab fourcc: VP60,VP61,VP62
182 @item Theora @tab X @tab X @tab still experimental
183 @item Intel Indeo 3 @tab @tab X
184 @item FLV @tab X @tab X @tab Sorenson H.263 used in Flash
185 @item Flash Screen Video @tab X @tab X @tab fourcc: FSV1
186 @item ATI VCR1 @tab @tab X @tab fourcc: VCR1
187 @item ATI VCR2 @tab @tab X @tab fourcc: VCR2
188 @item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
189 @item 4X Video @tab @tab X @tab Used in certain computer games.
190 @item Sony Playstation MDEC @tab @tab X
191 @item Id RoQ @tab X @tab X @tab Used in Quake III, Jedi Knight 2, other computer games.
192 @item Xan/WC3 @tab @tab X @tab Used in Wing Commander III .MVE files.
193 @item Interplay Video @tab @tab X @tab Used in Interplay .MVE files.
194 @item Apple Animation @tab X @tab X @tab fourcc: 'rle '
195 @item Apple Graphics @tab @tab X @tab fourcc: 'smc '
196 @item Apple Video @tab @tab X @tab fourcc: rpza
197 @item Apple QuickDraw @tab @tab X @tab fourcc: qdrw
198 @item Cinepak @tab @tab X
199 @item Microsoft RLE @tab @tab X
200 @item Microsoft Video-1 @tab @tab X
201 @item Westwood VQA @tab @tab X
202 @item Id Cinematic Video @tab @tab X @tab Used in Quake II.
203 @item Planar RGB @tab @tab X @tab fourcc: 8BPS
204 @item FLIC video @tab @tab X
205 @item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK
206 @item Duck TrueMotion v2 @tab @tab X @tab fourcc: TM20
207 @item VMD Video @tab @tab X @tab Used in Sierra VMD files.
208 @item MSZH @tab @tab X @tab Part of LCL
209 @item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental
210 @item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC
211 @item IBM Ultimotion @tab @tab X @tab fourcc: ULTI
212 @item Miro VideoXL @tab @tab X @tab fourcc: VIXL
213 @item QPEG @tab @tab X @tab fourccs: QPEG, Q1.0, Q1.1
214 @item LOCO @tab @tab X @tab
215 @item Winnov WNV1 @tab @tab X @tab
216 @item Autodesk Animator Studio Codec @tab @tab X @tab fourcc: AASC
217 @item Fraps FPS1 @tab @tab X @tab
218 @item CamStudio @tab @tab X @tab fourcc: CSCD
219 @item American Laser Games Video @tab @tab X @tab Used in games like Mad Dog McCree
220 @item ZMBV @tab X @tab X @tab Encoder works only on PAL8
221 @item AVS Video @tab @tab X @tab Video encoding used by the Creature Shock game.
222 @item Smacker Video @tab @tab X @tab Video encoding used in Smacker.
223 @item RTjpeg @tab @tab X @tab Video encoding used in NuppelVideo files.
224 @item KMVC @tab @tab X @tab Codec used in Worms games.
225 @item VMware Video @tab @tab X @tab Codec used in videos captured by VMware.
226 @item Cin Video @tab @tab X @tab Codec used in Delphine Software games.
227 @item Tiertex Seq Video @tab @tab X @tab Codec used in DOS CDROM FlashBack game.
228 @item DXA Video @tab @tab X @tab Codec originally used in Feeble Files game.
229 @item AVID DNxHD @tab X @tab X @tab aka SMPTE VC3
230 @item C93 Video @tab @tab X @tab Codec used in Cyberia game.
231 @item THP @tab @tab X @tab Used on the Nintendo GameCube.
232 @item Bethsoft VID @tab @tab X @tab Used in some games from Bethesda Softworks.
233 @item Renderware TXD @tab @tab X @tab Texture dictionaries used by the Renderware Engine.
234 @item AMV @tab @tab X @tab Used in Chinese MP3 players.
237 @code{X} means that encoding (resp. decoding) is supported.
239 @section Audio Codecs
241 @multitable @columnfractions .4 .1 .1 .1 .7
242 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
243 @item MPEG audio layer 2 @tab IX @tab IX
244 @item MPEG audio layer 1/3 @tab IX @tab IX
245 @tab MP3 encoding is supported through the external library LAME.
246 @item AC3 @tab IX @tab IX
247 @tab liba52 is used internally for decoding.
248 @item Vorbis @tab X @tab X
249 @item WMA V1/V2 @tab X @tab X
250 @item AAC @tab X @tab X
251 @tab Supported through the external library libfaac/libfaad.
252 @item Microsoft ADPCM @tab X @tab X
253 @item AMV IMA ADPCM @tab @tab X
254 @tab Used in AMV files
255 @item MS IMA ADPCM @tab X @tab X
256 @item QT IMA ADPCM @tab @tab X
257 @item 4X IMA ADPCM @tab @tab X
258 @item G.726 ADPCM @tab X @tab X
259 @item Duck DK3 IMA ADPCM @tab @tab X
260 @tab Used in some Sega Saturn console games.
261 @item Duck DK4 IMA ADPCM @tab @tab X
262 @tab Used in some Sega Saturn console games.
263 @item Westwood Studios IMA ADPCM @tab @tab X
264 @tab Used in Westwood Studios games like Command and Conquer.
265 @item SMJPEG IMA ADPCM @tab @tab X
266 @tab Used in certain Loki game ports.
267 @item CD-ROM XA ADPCM @tab @tab X
268 @item CRI ADX ADPCM @tab X @tab X
269 @tab Used in Sega Dreamcast games.
270 @item Electronic Arts ADPCM @tab @tab X
271 @tab Used in various EA titles.
272 @item Creative ADPCM @tab @tab X
273 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
274 @item THP ADPCM @tab @tab X
275 @tab Used on the Nintendo GameCube.
276 @item RA144 @tab @tab X
277 @tab Real 14400 bit/s codec
278 @item RA288 @tab @tab X
279 @tab Real 28800 bit/s codec
280 @item RADnet @tab X @tab IX
281 @tab Real low bitrate AC3 codec, liba52 is used for decoding.
282 @item AMR-NB @tab X @tab X
283 @tab Supported through an external library.
284 @item AMR-WB @tab X @tab X
285 @tab Supported through an external library.
286 @item DV audio @tab @tab X
287 @item Id RoQ DPCM @tab X @tab X
288 @tab Used in Quake III, Jedi Knight 2, other computer games.
289 @item Interplay MVE DPCM @tab @tab X
290 @tab Used in various Interplay computer games.
291 @item Xan DPCM @tab @tab X
292 @tab Used in Origin's Wing Commander IV AVI files.
293 @item Sierra Online DPCM @tab @tab X
294 @tab Used in Sierra Online game audio files.
295 @item Apple MACE 3 @tab @tab X
296 @item Apple MACE 6 @tab @tab X
297 @item FLAC lossless audio @tab X @tab X
298 @item Shorten lossless audio @tab @tab X
299 @item Apple lossless audio @tab @tab X
300 @tab QuickTime fourcc 'alac'
301 @item FFmpeg Sonic @tab X @tab X
302 @tab experimental lossy/lossless codec
303 @item Qdesign QDM2 @tab @tab X
304 @tab there are still some distortions
305 @item Real COOK @tab @tab X
306 @tab All versions except 5.1 are supported
307 @item DSP Group TrueSpeech @tab @tab X
308 @item True Audio (TTA) @tab @tab X
309 @item Smacker Audio @tab @tab X
310 @item WavPack Audio @tab @tab X
311 @item Cin Audio @tab @tab X
312 @tab Codec used in Delphine Software games.
313 @item Intel Music Coder @tab @tab X
314 @item Musepack @tab @tab X
315 @tab Only SV7 is supported
316 @item DT$ Coherent Audio @tab @tab X
317 @item ATRAC 3 @tab @tab X
318 @item Monkey's Audio @tab @tab X @tab Only versions 3.97-3.99 are supported
319 @item Nellymoser ASAO @tab @tab X
322 @code{X} means that encoding (resp. decoding) is supported.
324 @code{I} means that an integer-only version is available, too (ensures high
325 performance on systems without hardware floating point support).
327 @chapter Platform Specific information
331 BSD make will not build FFmpeg, you need to install and use GNU Make
336 To get help and instructions for using FFmpeg under Windows, check out
337 the FFmpeg Windows Help Forum at
338 @url{http://arrozcru.no-ip.org/ffmpeg/}.
340 @subsection Native Windows compilation
343 @item Install the current versions of MSYS and MinGW from
344 @url{http://www.mingw.org/}. You can find detailed installation
345 instructions in the download section and the FAQ.
347 NOTE: Use at least bash 3.1. Older versions are known to be failing on the
350 @item If you want to test the FFplay, also download
351 the MinGW development library of SDL 1.2.x
352 (@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
353 @url{http://www.libsdl.org}. Unpack it in a temporary directory, and
354 unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
355 directory. Edit the @file{sdl-config} script so that it gives the
356 correct SDL directory when invoked.
358 @item If you want to use vhooks, you must have a POSIX compliant libdl in your
359 MinGW system. Get dlfcn-win32 from @url{http://code.google.com/p/dlfcn-win32}.
361 @item Extract the current version of FFmpeg.
363 @item Start the MSYS shell (file @file{msys.bat}).
365 @item Change to the FFmpeg directory and follow
366 the instructions of how to compile FFmpeg (file
367 @file{INSTALL}). Usually, launching @file{./configure} and @file{make}
368 suffices. If you have problems using SDL, verify that
369 @file{sdl-config} can be launched from the MSYS command line.
371 @item You can install FFmpeg in @file{Program Files/FFmpeg} by typing
372 @file{make install}. Do not forget to copy @file{SDL.dll} to the place
373 you launch @file{ffplay} from.
380 @item The target @file{make wininstaller} can be used to create a
381 Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
382 must be copied to the FFmpeg directory in order to build the
385 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
386 you can build @file{avcodec.dll} and @file{avformat.dll}. With
387 @code{make install} you install the FFmpeg DLLs and the associated
388 headers in @file{Program Files/FFmpeg}.
390 @item Visual C++ compatibility: If you used @code{./configure --enable-shared}
391 when configuring FFmpeg, FFmpeg tries to use the Microsoft Visual
392 C++ @code{lib} tool to build @code{avcodec.lib} and
393 @code{avformat.lib}. With these libraries you can link your Visual C++
394 code directly with the FFmpeg DLLs (see below).
398 @subsection Visual C++ compatibility
400 FFmpeg will not compile under Visual C++ -- and it has too many
401 dependencies on the GCC compiler to make a port viable. However,
402 if you want to use the FFmpeg libraries in your own applications,
403 you can still compile those applications using Visual C++. An
404 important restriction to this is that you have to use the
405 dynamically linked versions of the FFmpeg libraries (i.e. the
406 DLLs), and you have to make sure that Visual-C++-compatible
407 import libraries are created during the FFmpeg build process.
409 This description of how to use the FFmpeg libraries with Visual C++ is
410 based on Visual C++ 2005 Express Edition Beta 2. If you have a different
411 version, you might have to modify the procedures slightly.
413 Here are the step-by-step instructions for building the FFmpeg libraries
414 so they can be used with Visual C++:
418 @item Install Visual C++ (if you have not done so already).
420 @item Install MinGW and MSYS as described above.
422 @item Add a call to @file{vcvars32.bat} (which sets up the environment
423 variables for the Visual C++ tools) as the first line of
424 @file{msys.bat}. The standard location for @file{vcvars32.bat} is
425 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
426 and the standard location for @file{msys.bat} is
427 @file{C:\msys\1.0\msys.bat}. If this corresponds to your setup, add the
428 following line as the first line of @file{msys.bat}:
430 @code{call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"}
432 @item Start the MSYS shell (file @file{msys.bat}) and type @code{link.exe}.
433 If you get a help message with the command line options of @code{link.exe},
434 this means your environment variables are set up correctly, the
435 Microsoft linker is on the path and will be used by FFmpeg to
436 create Visual-C++-compatible import libraries.
438 @item Extract the current version of FFmpeg and change to the FFmpeg directory.
440 @item Type the command
441 @code{./configure --enable-shared --disable-static --enable-memalign-hack}
442 to configure and, if that did not produce any errors,
443 type @code{make} to build FFmpeg.
445 @item The subdirectories @file{libavformat}, @file{libavcodec}, and
446 @file{libavutil} should now contain the files @file{avformat.dll},
447 @file{avformat.lib}, @file{avcodec.dll}, @file{avcodec.lib},
448 @file{avutil.dll}, and @file{avutil.lib}, respectively. Copy the three
449 DLLs to your System32 directory (typically @file{C:\Windows\System32}).
453 And here is how to use these libraries with Visual C++:
457 @item Create a new console application ("File / New / Project") and then
458 select "Win32 Console Application". On the appropriate page of the
459 Application Wizard, uncheck the "Precompiled headers" option.
461 @item Write the source code for your application, or, for testing, just
462 copy the code from an existing sample application into the source file
463 that Visual C++ has already created for you. (Note that your source
464 filehas to have a @code{.cpp} extension; otherwise, Visual C++ will not
465 compile the FFmpeg headers correctly because in C mode, it does not
466 recognize the @code{inline} keyword.) For example, you can copy
467 @file{output_example.c} from the FFmpeg distribution (but you will
468 have to make minor modifications so the code will compile under
471 @item Open the "Project / Properties" dialog box. In the "Configuration"
472 combo box, select "All Configurations" so that the changes you make will
473 affect both debug and release builds. In the tree view on the left hand
474 side, select "C/C++ / General", then edit the "Additional Include
475 Directories" setting to contain the complete paths to the
476 @file{libavformat}, @file{libavcodec}, and @file{libavutil}
477 subdirectories of your FFmpeg directory. Note that the directories have
478 to be separated using semicolons. Now select "Linker / General" from the
479 tree view and edit the "Additional Library Directories" setting to
480 contain the same three directories.
482 @item Still in the "Project / Properties" dialog box, select "Linker / Input"
483 from the tree view, then add the files @file{avformat.lib},
484 @file{avcodec.lib}, and @file{avutil.lib} to the end of the "Additional
485 Dependencies". Note that the names of the libraries have to be separated
488 @item Now, select "C/C++ / Code Generation" from the tree view. Select
489 "Debug" in the "Configuration" combo box. Make sure that "Runtime
490 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
491 the "Configuration" combo box and make sure that "Runtime Library" is
492 set to "Multi-threaded DLL".
494 @item Click "OK" to close the "Project / Properties" dialog box and build
495 the application. Hopefully, it should compile and run cleanly. If you
496 used @file{output_example.c} as your sample application, you will get a
497 few compiler errors, but they are easy to fix. The first type of error
498 occurs because Visual C++ does not allow an @code{int} to be converted to
499 an @code{enum} without a cast. To solve the problem, insert the required
500 casts (this error occurs once for a @code{CodecID} and once for a
501 @code{CodecType}). The second type of error occurs because C++ requires
502 the return value of @code{malloc} to be cast to the exact type of the
503 pointer it is being assigned to. Visual C++ will complain that, for
504 example, @code{(void *)} is being assigned to @code{(uint8_t *)} without
505 an explicit cast. So insert an explicit cast in these places to silence
506 the compiler. The third type of error occurs because the @code{snprintf}
507 library function is called @code{_snprintf} under Visual C++. So just
508 add an underscore to fix the problem. With these changes,
509 @file{output_example.c} should compile under Visual C++, and the
510 resulting executable should produce valid video files.
514 @subsection Cross compilation for Windows with Linux
516 You must use the MinGW cross compilation tools available at
517 @url{http://www.mingw.org/}.
519 Then configure FFmpeg with the following options:
521 ./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
523 (you can change the cross-prefix according to the prefix chosen for the
526 Then you can easily test FFmpeg with Wine
527 (@url{http://www.winehq.com/}).
529 @subsection Compilation under Cygwin
531 Cygwin works very much like Unix.
533 Just install your Cygwin with all the "Base" packages, plus the
534 following "Devel" ones:
536 binutils, gcc-core, make, subversion
539 Do not install binutils-20060709-1 (they are buggy on shared builds);
540 use binutils-20050610-1 instead.
545 ./configure --enable-static --disable-shared
548 to make a static build or
551 ./configure --enable-shared --disable-static
554 to build shared libraries.
556 If you want to build FFmpeg with additional libraries, download Cygwin
557 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository
558 and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
559 (@url{http://cygwinports.dotsrc.org/}).
561 @subsection Crosscompilation for Windows under Cygwin
563 With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
565 Just install your Cygwin as explained before, plus these additional
568 gcc-mingw-core, mingw-runtime, mingw-zlib
571 and add some special flags to your configure invocation.
573 For a static build run
575 ./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
578 and for a build with shared libraries
580 ./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
585 BeOS support is broken in mysterious ways.
587 @chapter Developers Guide
591 @item libavcodec is the library containing the codecs (both encoding and
592 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
594 @item libavformat is the library containing the file format handling (mux and
595 demux code for several formats). Look at @file{ffplay.c} to use it in a
596 player. See @file{output_example.c} to use it to generate audio or video
601 @section Integrating libavcodec or libavformat in your program
603 You can integrate all the source code of the libraries to link them
604 statically to avoid any version problem. All you need is to provide a
605 'config.mak' and a 'config.h' in the parent directory. See the defines
606 generated by ./configure to understand what is needed.
608 You can use libavcodec or libavformat in your commercial program, but
609 @emph{any patch you make must be published}. The best way to proceed is
610 to send your patches to the FFmpeg mailing list.
613 @section Coding Rules
615 FFmpeg is programmed in the ISO C90 language with a few additional
616 features from ISO C99, namely:
619 the @samp{inline} keyword;
623 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
625 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
628 These features are supported by all compilers we care about, so we will not
629 accept patches to remove their use unless they absolutely do not impair
630 clarity and performance.
632 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
633 compiles with several other compilers, such as the Compaq ccc compiler
634 or Sun Studio 9, and we would like to keep it that way unless it would
635 be exceedingly involved. To ensure compatibility, please do not use any
636 additional C99 features or GCC extensions. Especially watch out for:
639 mixing statements and declarations;
641 @samp{long long} (use @samp{int64_t} instead);
643 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
645 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
649 The presentation is the one specified by 'indent -i4 -kr -nut'.
650 The TAB character is forbidden outside of Makefiles as is any
651 form of trailing whitespace. Commits containing either will be
652 rejected by the Subversion repository.
654 The main priority in FFmpeg is simplicity and small code size in order to
655 minimize the bug count.
657 Comments: Use the JavaDoc/Doxygen
658 format (see examples below) so that code documentation
659 can be generated automatically. All nontrivial functions should have a comment
660 above them explaining what the function does, even if it is just one sentence.
661 All structures and their member variables should be documented, too.
674 typedef struct Foobar@{
675 int var1; /**< var1 description */
676 int var2; ///< var2 description
677 /** var3 description */
685 * @@param my_parameter description of my_parameter
686 * @@return return value description
688 int myfunc(int my_parameter)
692 fprintf and printf are forbidden in libavformat and libavcodec,
693 please use av_log() instead.
695 Casts should be used only when necessary. Unneeded parentheses
696 should also be avoided if they don't make the code easier to understand.
698 @section Development Policy
702 Contributions should be licensed under the LGPL 2.1, including an
703 "or any later version" clause, or the MIT license. GPL 2 including
704 an "or any later version" clause is also acceptable, but LGPL is
707 You must not commit code which breaks FFmpeg! (Meaning unfinished but
708 enabled code which breaks compilation or compiles but does not work or
709 breaks the regression tests)
710 You can commit unfinished stuff (for testing etc), but it must be disabled
711 (#ifdef etc) by default so it does not interfere with other developers'
714 You do not have to over-test things. If it works for you, and you think it
715 should work for others, then commit. If your code has problems
716 (portability, triggers compiler bugs, unusual environment etc) they will be
717 reported and eventually fixed.
719 Do not commit unrelated changes together, split them into self-contained
720 pieces. Also do not forget that if part B depends on part A, but A does not
721 depend on B, then A can and should be committed first and separate from B.
722 Keeping changes well split into self-contained parts makes reviewing and
723 understanding them on the commit log mailing list easier. This also helps
724 in case of debugging later on.
725 Also if you have doubts about splitting or not splitting, do not hesitate to
726 ask/discuss it on the developer mailing list.
728 Do not change behavior of the program (renaming options etc) without
729 first discussing it on the ffmpeg-devel mailing list. Do not remove
730 functionality from the code. Just improve!
732 Note: Redundant code can be removed.
734 Do not commit changes to the build system (Makefiles, configure script)
735 which change behavior, defaults etc, without asking first. The same
736 applies to compiler warning fixes, trivial looking fixes and to code
737 maintained by other developers. We usually have a reason for doing things
738 the way we do. Send your changes as patches to the ffmpeg-devel mailing
739 list, and if the code maintainers say OK, you may commit. This does not
740 apply to files you wrote and/or maintain.
742 We refuse source indentation and other cosmetic changes if they are mixed
743 with functional changes, such commits will be rejected and removed. Every
744 developer has his own indentation style, you should not change it. Of course
745 if you (re)write something, you can use your own style, even though we would
746 prefer if the indentation throughout FFmpeg was consistent (Many projects
747 force a given indentation style - we do not.). If you really need to make
748 indentation changes (try to avoid this), separate them strictly from real
751 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
752 then either do NOT change the indentation of the inner part within (do not
753 move it to the right)! or do so in a separate commit
755 Always fill out the commit log message. Describe in a few lines what you
756 changed and why. You can refer to mailing list postings if you fix a
757 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
759 If you apply a patch by someone else, include the name and email address in
760 the log message. Since the ffmpeg-cvslog mailing list is publicly
761 archived you should add some SPAM protection to the email address. Send an
762 answer to ffmpeg-devel (or wherever you got the patch from) saying that
763 you applied the patch.
765 When applying patches that have been discussed (at length) on the mailing
766 list, reference the thread in the log message.
768 Do NOT commit to code actively maintained by others without permission.
769 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
770 timeframe (12h for build failures and security fixes, 3 days small changes,
771 1 week for big patches) then commit your patch if you think it is OK.
772 Also note, the maintainer can simply ask for more time to review!
774 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
775 are sent there and reviewed by all the other developers. Bugs and possible
776 improvements or general questions regarding commits are discussed there. We
777 expect you to react if problems with your code are uncovered.
779 Update the documentation if you change behavior or add features. If you are
780 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
781 maintainer(s) will review and commit your stuff.
783 Try to keep important discussions and requests (also) on the public
784 developer mailing list, so that all developers can benefit from them.
786 Never write to unallocated memory, never write over the end of arrays,
787 always check values read from some untrusted source before using them
788 as array index or other risky things.
790 Remember to check if you need to bump versions for the specific libav
791 parts (libavutil, libavcodec, libavformat) you are changing. You need
792 to change the version integer and the version string.
793 Incrementing the first component means no backward compatibility to
794 previous versions (e.g. removal of a function from the public API).
795 Incrementing the second component means backward compatible change
796 (e.g. addition of a function to the public API).
797 Incrementing the third component means a noteworthy binary compatible
798 change (e.g. encoder bug fix that matters for the decoder).
800 If you add a new codec, remember to update the changelog, add it to
801 the supported codecs table in the documentation and bump the second
802 component of the @file{libavcodec} version number appropriately. If
803 it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
806 Do not change code to hide warnings without ensuring that the underlying
807 logic is correct and thus the warning was inappropriate.
809 If you add a new file, give it a proper license header. Do not copy and
810 paste it from a random place, use an existing file as template.
813 We think our rules are not too hard. If you have comments, contact us.
815 Note, these rules are mostly borrowed from the MPlayer project.
817 @section Submitting patches
819 First, (@pxref{Coding Rules}) above if you did not yet.
821 When you submit your patch, try to send a unified diff (diff '-up'
822 option). We cannot read other diffs :-)
824 Also please do not submit a patch which contains several unrelated changes.
825 Split it into separate, self-contained pieces. This does not mean splitting
826 file by file. Instead, make the patch as small as possible while still
827 keeping it as a logical unit that contains an individual change, even
828 if it spans multiple files. This makes reviewing your patches much easier
829 for us and greatly increases your chances of getting your patch applied.
831 Run the regression tests before submitting a patch so that you can
832 verify that there are no big problems.
834 Patches should be posted as base64 encoded attachments (or any other
835 encoding which ensures that the patch will not be trashed during
836 transmission) to the ffmpeg-devel mailing list, see
837 @url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
839 It also helps quite a bit if you tell us what the patch does (for example
840 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
843 Also please if you send several patches, send each patch as a separate mail,
844 do not attach several unrelated patches to the same mail.
846 @section patch submission checklist
850 Do the regression tests pass with the patch applied?
852 Is the patch a unified diff?
854 Is the patch against latest FFmpeg SVN?
856 Are you subscribed to ffmpeg-dev?
857 (the list is subscribers only due to spam)
859 Have you checked that the changes are minimal, so that the same cannot be
860 achieved with a smaller patch and/or simpler final code?
862 If the change is to speed critical code, did you benchmark it?
864 If you did any benchmarks, did you provide them in the mail?
866 Have you checked that the patch does not introduce buffer overflows or
867 other security issues?
869 Is the patch created from the root of the source tree, so it can be
870 applied with @code{patch -p0}?
872 Does the patch not mix functional and cosmetic changes?
874 Did you add tabs or trailing whitespace to the code? Both are forbidden.
876 Is the patch attached to the email you send?
878 Is the mime type of the patch correct? It should be text/x-diff or
879 text/x-patch or at least text/plain and not application/octet-stream.
881 If the patch fixes a bug, did you provide a verbose analysis of the bug?
883 If the patch fixes a bug, did you provide enough information, including
884 a sample, so the bug can be reproduced and the fix can be verified?
885 Note please do not attach samples >100k to mails but rather provide a
886 URL, you can upload to ftp://upload.mplayerhq.hu
888 Did you provide a verbose summary about what the patch does change?
890 Did you provide a verbose explanation why it changes things like it does?
892 Did you provide a verbose summary of the user visible advantages and
893 disadvantages if the patch is applied?
895 Did you provide an example so we can verify the new feature added by the
898 If you added a new file, did you insert a license header? It should be
899 taken from FFmpeg, not randomly copied and pasted from somewhere else.
901 You should maintain alphabetical order in alphabetically ordered lists as
902 long as doing so does not break API/ABI compatibility.
904 Lines with similar content should be aligned vertically when doing so
905 improves readability.
907 Did you provide a suggestion for a clear commit log message?
910 @section Patch review process
912 All patches posted to ffmpeg-devel will be reviewed, unless they contain a
913 clear note that the patch is not for SVN.
914 Reviews and comments will be posted as replies to the patch on the
915 mailing list. The patch submitter then has to take care of every comment,
916 that can be by resubmitting a changed patch or by discussion. Resubmitted
917 patches will themselves be reviewed like any other patch. If at some point
918 a patch passes review with no comments then it is approved, that can for
919 simple and small patches happen immediately while large patches will generally
920 have to be changed and reviewed many times before they are approved.
921 After a patch is approved it will be committed to the repository.
923 We will review all submitted patches, but sometimes we are quite busy so
924 especially for large patches this can take several weeks.
926 When resubmitting patches, please do not make any significant changes
927 not related to the comments received during review. Such patches will
928 be rejected. Instead, submit significant changes or new features as
931 @section Regression tests
933 Before submitting a patch (or committing to the repository), you should at least
934 test that you did not break anything.
936 The regression tests build a synthetic video stream and a synthetic
937 audio stream. These are then encoded and decoded with all codecs or
938 formats. The CRC (or MD5) of each generated file is recorded in a
939 result file. A 'diff' is launched to compare the reference results and
942 The regression tests then go on to test the FFserver code with a
943 limited set of streams. It is important that this step runs correctly
946 Run 'make test' to test all the codecs and formats.
948 Run 'make fulltest' to test all the codecs, formats and FFserver.
950 [Of course, some patches may change the results of the regression tests. In
951 this case, the reference results of the regression tests shall be modified