Add note about not including MinGW's include directory from within MSVC.
[libav.git] / doc / general.texi
1 \input texinfo @c -*- texinfo -*-
3 @settitle General Documentation
4 @titlepage
5 @sp 7
6 @center @titlefont{General Documentation}
7 @sp 3
8 @end titlepage
11 @chapter external libraries
13 FFmpeg can be hooked up with a number of external libraries to add support
14 for more formats. None of them are used by default, their use has to be
15 explicitly requested by passing the appropriate flags to @file{./configure}.
17 @section AMR
19 AMR comes in two different flavors, wideband and narrowband. FFmpeg can make
20 use of the AMR wideband (floating-point mode) and the AMR narrowband
21 (floating-point mode) reference decoders and encoders.
23 Go to @url{} and follow the instructions for
24 installing the libraries. Then pass @code{--enable-libamr-nb} and/or
25 @code{--enable-libamr-wb} to configure to enable the libraries.
27 Note that libamr is copyrighted without any sort of license grant. This means
28 that you can use it if you legally obtained it but you are not allowed to
29 redistribute it in any way. @strong{Any FFmpeg binaries with libamr support
30 you create are non-free and unredistributable!}
33 @chapter Supported File Formats and Codecs
35 You can use the @code{-formats} option to have an exhaustive list.
37 @section File Formats
39 FFmpeg supports the following file formats through the @code{libavformat}
40 library:
42 @multitable @columnfractions .4 .1 .1 .4
43 @item 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
73 @item 4xm @tab @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
89 @tab .fli/.flc files
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 MAXIS EA XA @tab @tab X
98 @tab Used in Sim City 3000; file extension .xa.
99 @item Nullsoft Video (NSV) format @tab @tab X
100 @item ADTS AAC audio @tab X @tab X
101 @item Creative VOC @tab X @tab X @tab Created for the Sound Blaster Pro.
102 @item American Laser Games MM @tab @tab X
103 @tab Multimedia format used in games like Mad Dog McCree
104 @item AVS @tab @tab X
105 @tab Multimedia format used by the Creature Shock game.
106 @item Smacker @tab @tab X
107 @tab Multimedia format used by many games.
108 @item GXF @tab X @tab X
109 @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley playout servers.
110 @item CIN @tab @tab X
111 @tab Multimedia format used by Delphine Software games.
112 @item MXF @tab @tab X
113 @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
114 @item SEQ @tab @tab X
115 @tab Tiertex .seq files used in the DOS CD-ROM version of the game Flashback.
116 @item DXA @tab @tab X
117 @tab This format is used in non-Windows version of Feeble Files game and
118 different game cutscenes repacked for use with ScummVM.
119 @item THP @tab @tab X
120 @tab Used on the Nintendo GameCube.
121 @item C93 @tab @tab X
122 @tab Used in the game Cyberia from Interplay.
123 @item Bethsoft VID @tab @tab X
124 @tab Used in some games from Bethesda Softworks.
125 @item CRYO APC @tab @tab X
126 @tab Audio format used in some games by CRYO Interactive Entertainment.
127 @item Monkey's Audio @tab @tab X
128 @item SIFF @tab @tab X
129 @tab Audio and video format used in some games by Beam Software
130 @item LMLM4 @tab @tab X
131 @tab Used by Linux Media Labs MPEG-4 PCI boards
132 @item PVA @tab @tab X
133 @tab Used by TechnoTrend DVB PCI boards
134 @item MSN TCP Webcam @tab @tab X
135 @tab Used by MSN Messenger Webcam streams.
136 @item RL2 @tab @tab X
137 @tab Audio and video format used in some games by Entertainment Software Partners
138 @item IFF @tab @tab X
139 @tab Interchange File Format
140 @item BFI @tab @tab X
141 @tab Brute Force & Ignorance, used in Flash Traffic: City of Angels
142 @end multitable
144 @code{X} means that encoding (resp. decoding) is supported.
146 @section Image Formats
148 FFmpeg can read and write images for each frame of a video sequence. The
149 following image formats are supported:
151 @multitable @columnfractions .4 .1 .1 .4
152 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
153 @item PGM, PPM @tab X @tab X
154 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
155 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
156 @item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
157 @item .Y.U.V @tab X @tab X @tab one raw file per component
158 @item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
159 @item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
160 @item Targa @tab @tab X @tab Targa (.TGA) image format.
161 @item TIFF @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
162 @item SGI @tab X @tab X @tab SGI RGB image format
163 @item PTX @tab @tab X @tab V.Flash PTX format
164 @item RAS @tab @tab X @tab Sun Rasterfile
165 @item PCX @tab @tab X @tab PC Paintbrush
166 @end multitable
168 @code{X} means that encoding (resp. decoding) is supported.
170 @section Video Codecs
172 @multitable @columnfractions .4 .1 .1 .4
173 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
174 @item MPEG-1 video @tab X @tab X
175 @item MPEG-2 video @tab X @tab X
176 @item MPEG-4 @tab X @tab X
177 @item MSMPEG4 V1 @tab X @tab X
178 @item MSMPEG4 V2 @tab X @tab X
179 @item MSMPEG4 V3 @tab X @tab X
180 @item WMV7 @tab X @tab X
181 @item WMV8 @tab X @tab X @tab not completely working
182 @item WMV9 @tab @tab X @tab not completely working
183 @item VC1 @tab @tab X
184 @item H.261 @tab X @tab X
185 @item H.263(+) @tab X @tab X @tab also known as RealVideo 1.0
186 @item H.264 @tab @tab X
187 @item RealVideo 1.0 @tab X @tab X
188 @item RealVideo 2.0 @tab X @tab X
189 @item MJPEG @tab X @tab X
190 @item lossless MJPEG @tab X @tab X
191 @item JPEG-LS @tab X @tab X @tab fourcc: MJLS, lossless and near-lossless is supported
192 @item Apple MJPEG-B @tab @tab X
193 @item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
194 @item DV @tab X @tab X
195 @item HuffYUV @tab X @tab X
196 @item FFmpeg Video 1 @tab X @tab X @tab experimental lossless codec (fourcc: FFV1)
197 @item FFmpeg Snow @tab X @tab X @tab experimental wavelet codec (fourcc: SNOW)
198 @item Asus v1 @tab X @tab X @tab fourcc: ASV1
199 @item Asus v2 @tab X @tab X @tab fourcc: ASV2
200 @item Creative YUV @tab @tab X @tab fourcc: CYUV
201 @item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
202 @item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
203 @item On2 VP3 @tab @tab X @tab still experimental
204 @item On2 VP5 @tab @tab X @tab fourcc: VP50
205 @item On2 VP6 @tab @tab X @tab fourcc: VP60,VP61,VP62
206 @item Theora @tab X @tab X @tab still experimental
207 @item Intel Indeo 3 @tab @tab X
208 @item FLV @tab X @tab X @tab Sorenson H.263 used in Flash
209 @item Flash Screen Video @tab X @tab X @tab fourcc: FSV1
210 @item ATI VCR1 @tab @tab X @tab fourcc: VCR1
211 @item ATI VCR2 @tab @tab X @tab fourcc: VCR2
212 @item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
213 @item 4X Video @tab @tab X @tab Used in certain computer games.
214 @item Sony PlayStation MDEC @tab @tab X
215 @item id RoQ @tab X @tab X @tab Used in Quake III, Jedi Knight 2, other computer games.
216 @item Xan/WC3 @tab @tab X @tab Used in Wing Commander III .MVE files.
217 @item Interplay Video @tab @tab X @tab Used in Interplay .MVE files.
218 @item Apple Animation @tab X @tab X @tab fourcc: 'rle '
219 @item Apple Graphics @tab @tab X @tab fourcc: 'smc '
220 @item Apple Video @tab @tab X @tab fourcc: rpza
221 @item Apple QuickDraw @tab @tab X @tab fourcc: qdrw
222 @item Cinepak @tab @tab X
223 @item Microsoft RLE @tab @tab X
224 @item Microsoft Video-1 @tab @tab X
225 @item Westwood VQA @tab @tab X
226 @item id Cinematic Video @tab @tab X @tab Used in Quake II.
227 @item Planar RGB @tab @tab X @tab fourcc: 8BPS
228 @item FLIC video @tab @tab X
229 @item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK
230 @item Duck TrueMotion v2 @tab @tab X @tab fourcc: TM20
231 @item VMD Video @tab @tab X @tab Used in Sierra VMD files.
232 @item MSZH @tab @tab X @tab Part of LCL
233 @item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental
234 @item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC
235 @item IBM Ultimotion @tab @tab X @tab fourcc: ULTI
236 @item Miro VideoXL @tab @tab X @tab fourcc: VIXL
237 @item QPEG @tab @tab X @tab fourccs: QPEG, Q1.0, Q1.1
238 @item LOCO @tab @tab X @tab
239 @item Winnov WNV1 @tab @tab X @tab
240 @item Autodesk Animator Studio Codec @tab @tab X @tab fourcc: AASC
241 @item Fraps FPS1 @tab @tab X @tab
242 @item CamStudio @tab @tab X @tab fourcc: CSCD
243 @item American Laser Games Video @tab @tab X @tab Used in games like Mad Dog McCree
244 @item ZMBV @tab X @tab X @tab Encoder works only on PAL8
245 @item AVS Video @tab @tab X @tab Video encoding used by the Creature Shock game.
246 @item Smacker Video @tab @tab X @tab Video encoding used in Smacker.
247 @item RTjpeg @tab @tab X @tab Video encoding used in NuppelVideo files.
248 @item KMVC @tab @tab X @tab Codec used in Worms games.
249 @item VMware Video @tab @tab X @tab Codec used in videos captured by VMware.
250 @item Cin Video @tab @tab X @tab Codec used in Delphine Software games.
251 @item Tiertex Seq Video @tab @tab X @tab Codec used in DOS CD-ROM FlashBack game.
252 @item DXA Video @tab @tab X @tab Codec originally used in Feeble Files game.
253 @item AVID DNxHD @tab X @tab X @tab aka SMPTE VC3
254 @item C93 Video @tab @tab X @tab Codec used in Cyberia game.
255 @item THP @tab @tab X @tab Used on the Nintendo GameCube.
256 @item Bethsoft VID @tab @tab X @tab Used in some games from Bethesda Softworks.
257 @item Renderware TXD @tab @tab X @tab Texture dictionaries used by the Renderware Engine.
258 @item AMV @tab @tab X @tab Used in Chinese MP3 players.
259 @item Mimic @tab @tab X @tab Used in MSN Messenger Webcam streams.
260 @end multitable
262 @code{X} means that encoding (resp. decoding) is supported.
264 @section Audio Codecs
266 @multitable @columnfractions .4 .1 .1 .1 .7
267 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
268 @item MPEG audio layer 2 @tab IX @tab IX
269 @item MPEG audio layer 1/3 @tab X @tab IX
270 @tab MP3 encoding is supported through the external library LAME.
271 @item AC3 @tab IX @tab IX
272 @tab liba52 is used internally for decoding.
273 @item Vorbis @tab X @tab X
274 @item WMA V1/V2 @tab X @tab X
275 @item AAC @tab X @tab X
276 @tab Supported through the external library libfaac/libfaad.
277 @item Microsoft ADPCM @tab X @tab X
278 @item AMV IMA ADPCM @tab @tab X
279 @tab Used in AMV files
280 @item MS IMA ADPCM @tab X @tab X
281 @item QT IMA ADPCM @tab X @tab X
282 @item 4X IMA ADPCM @tab @tab X
283 @item G.726 ADPCM @tab X @tab X
284 @item Duck DK3 IMA ADPCM @tab @tab X
285 @tab Used in some Sega Saturn console games.
286 @item Duck DK4 IMA ADPCM @tab @tab X
287 @tab Used in some Sega Saturn console games.
288 @item Westwood Studios IMA ADPCM @tab @tab X
289 @tab Used in Westwood Studios games like Command and Conquer.
290 @item SMJPEG IMA ADPCM @tab @tab X
291 @tab Used in certain Loki game ports.
292 @item CD-ROM XA ADPCM @tab @tab X
293 @item CRI ADX ADPCM @tab X @tab X
294 @tab Used in Sega Dreamcast games.
295 @item Electronic Arts ADPCM @tab @tab X
296 @tab Used in various EA titles.
297 @item MAXIS EA ADPCM @tab @tab X
298 @tab Used in Sim City 3000.
299 @item Creative ADPCM @tab @tab X
300 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
301 @item THP ADPCM @tab @tab X
302 @tab Used on the Nintendo GameCube.
303 @item RA144 @tab @tab X
304 @tab Real 14400 bit/s codec
305 @item RA288 @tab @tab X
306 @tab Real 28800 bit/s codec
307 @item RADnet @tab X @tab IX
308 @tab Real low bitrate AC3 codec, liba52 is used for decoding.
309 @item AMR-NB @tab X @tab X
310 @tab Supported through an external library.
311 @item AMR-WB @tab X @tab X
312 @tab Supported through an external library.
313 @item DV audio @tab @tab X
314 @item id RoQ DPCM @tab X @tab X
315 @tab Used in Quake III, Jedi Knight 2, other computer games.
316 @item Interplay MVE DPCM @tab @tab X
317 @tab Used in various Interplay computer games.
318 @item Xan DPCM @tab @tab X
319 @tab Used in Origin's Wing Commander IV AVI files.
320 @item Sierra Online DPCM @tab @tab X
321 @tab Used in Sierra Online game audio files.
322 @item Apple MACE 3 @tab @tab X
323 @item Apple MACE 6 @tab @tab X
324 @item FLAC lossless audio @tab X @tab X
325 @item Shorten lossless audio @tab @tab X
326 @item Apple lossless audio @tab @tab X
327 @tab QuickTime fourcc 'alac'
328 @item FFmpeg Sonic @tab X @tab X
329 @tab experimental lossy/lossless codec
330 @item Qdesign QDM2 @tab @tab X
331 @tab there are still some distortions
332 @item Real COOK @tab @tab X
333 @tab All versions except 5.1 are supported
334 @item DSP Group TrueSpeech @tab @tab X
335 @item True Audio (TTA) @tab @tab X
336 @item Smacker Audio @tab @tab X
337 @item WavPack Audio @tab @tab X
338 @item Cin Audio @tab @tab X
339 @tab Codec used in Delphine Software games.
340 @item Intel Music Coder @tab @tab X
341 @item Musepack @tab @tab X
342 @tab SV7 and SV8 are supported
343 @item DTS Coherent Audio @tab @tab X
344 @item ATRAC 3 @tab @tab X
345 @item Monkey's Audio @tab @tab X @tab Only versions 3.97-3.99 are supported
346 @item Nellymoser ASAO @tab @tab X
347 @item 8SVX Audio @tab @tab X
348 @end multitable
350 @code{X} means that encoding (resp. decoding) is supported.
352 @code{I} means that an integer-only version is available, too (ensures high
353 performance on systems without hardware floating point support).
355 @chapter Platform Specific information
357 @section BSD
359 BSD make will not build FFmpeg, you need to install and use GNU Make
360 (@file{gmake}).
362 @section Windows
364 To get help and instructions for building FFmpeg under Windows, check out
365 the FFmpeg Windows Help Forum at
366 @url{}.
368 @subsection Native Windows compilation
370 FFmpeg can be built to run natively on Windows using the MinGW tools. Install
371 the current versions of MSYS and MinGW from @url{}. Also
372 install the coreutils package, and update to the latest MSYS make (note: not
373 mingw32-make). You can find detailed installation
374 instructions in the download section and the FAQ.
376 Within the MSYS shell, configure and make with:
378 @example
379 ./configure --enable-memalign-hack
380 make
381 make install
382 @end example
384 This will install @file{ffmpeg.exe} along with many other development files
385 to @file{/usr/local}. You may specify another install path using the
386 @code{--prefix} option in @file{configure}.
388 Notes:
390 @itemize
392 @item Use at least bash 3.1. Older versions are known to fail on the
393 configure script.
395 @item In order to compile vhooks, you must have a POSIX-compliant libdl in
396 your MinGW system. Get dlfcn-win32 from
397 @url{}.
399 @item In order to compile FFplay, you must have the MinGW development library
400 of SDL. Get it from @url{}.
401 Edit the @file{bin/sdl-config} script so that it points to the correct prefix
402 where SDL was installed. Verify that @file{sdl-config} can be launched from
403 the MSYS command line.
405 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
406 you can build libavutil, libavcodec and libavformat as DLLs.
408 @end itemize
410 @subsection Microsoft Visual C++ compatibility
412 As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
413 want to use the libav* libraries in your own applications, you can still
414 compile those applications using MSVC++. But the libav* libraries you link
415 to @emph{must} be built with MinGW. However, you will not be able to debug
416 inside the libav* libraries, since MSVC++ does not recognize the debug
417 symbols generated by GCC.
418 We strongly recommend you to move over from MSVC++ to MinGW tools.
420 This description of how to use the FFmpeg libraries with MSVC++ is based on
421 Microsoft Visual C++ 2005 Express Edition. If you have a different version,
422 you might have to modify the procedures slightly.
424 @subsubsection Using static libraries
426 Assuming you have just built and installed FFmpeg in @file{/usr/local}.
428 @enumerate
430 @item Create a new console application ("File / New / Project") and then
431 select "Win32 Console Application". On the appropriate page of the
432 Application Wizard, uncheck the "Precompiled headers" option.
434 @item Write the source code for your application, or, for testing, just
435 copy the code from an existing sample application into the source file
436 that MSVC++ has already created for you. For example, you can copy
437 @file{output_example.c} from the FFmpeg distribution.
439 @item Open the "Project / Properties" dialog box. In the "Configuration"
440 combo box, select "All Configurations" so that the changes you make will
441 affect both debug and release builds. In the tree view on the left hand
442 side, select "C/C++ / General", then edit the "Additional Include
443 Directories" setting to contain the path where the FFmpeg includes were
444 installed (i.e. @file{c:\msys\1.0\local\include}).
445 Do not add MinGW's include directory here, or the include files will
446 conflict with MSVC's.
448 @item Still in the "Project / Properties" dialog box, select
449 "Linker / General" from the tree view and edit the
450 "Additional Library Directories" setting to contain the @file{lib}
451 directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
452 the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
453 and the directory where MinGW's GCC libs are installed
454 (i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
455 "Linker / Input" from the tree view, and add the files @file{libavformat.a},
456 @file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
457 @file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
458 to the end of "Additional Dependencies".
460 @item Now, select "C/C++ / Code Generation" from the tree view. Select
461 "Debug" in the "Configuration" combo box. Make sure that "Runtime
462 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
463 the "Configuration" combo box and make sure that "Runtime Library" is
464 set to "Multi-threaded DLL".
466 @item Click "OK" to close the "Project / Properties" dialog box.
468 @item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
469 Get msinttypes from @url{}
470 and install it in MSVC++'s include directory
471 (i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
473 @item MSVC++ also does not understand the @code{inline} keyword used by
474 FFmpeg, so you must add this line before @code{#include}ing libav*:
475 @example
476 #define inline _inline
477 @end example
479 @item Build your application, everything should work.
481 @end enumerate
483 @subsubsection Using shared libraries
485 This is how to create DLL and LIB files that are compatible with MSVC++:
487 @enumerate
489 @item Add a call to @file{vcvars32.bat} (which sets up the environment
490 variables for the Visual C++ tools) as the first line of @file{msys.bat}.
491 The standard location for @file{vcvars32.bat} is
492 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
493 and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
494 If this corresponds to your setup, add the following line as the first line
495 of @file{msys.bat}:
497 @example
498 call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
499 @end example
501 Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
502 and run @file{c:\msys\1.0\msys.bat} from there.
504 @item Within the MSYS shell, run @code{lib.exe}. If you get a help message
505 from @file{Microsoft (R) Library Manager}, this means your environment
506 variables are set up correctly, the @file{Microsoft (R) Library Manager}
507 is on the path and will be used by FFmpeg to create
508 MSVC++-compatible import libraries.
510 @item Build FFmpeg with
512 @example
513 ./configure --enable-shared --enable-memalign-hack
514 make
515 make install
516 @end example
518 Your install path (@file{/usr/local/} by default) should now have the
519 necessary DLL and LIB files under the @file{bin} directory.
521 @end enumerate
523 To use those files with MSVC++, do the same as you would do with
524 the static libraries, as described above. But in Step 4,
525 you should only need to add the directory where the LIB files are installed
526 (i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
527 installed in the @file{bin} directory. And instead of adding @file{libxx.a}
528 files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
529 @file{avutil.lib}. There should be no need for @file{libmingwex.a},
530 @file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
531 statically linked into the DLLs. The @file{bin} directory contains a bunch
532 of DLL files, but the ones that are actually used to run your application
533 are the ones with a major version number in their filenames
534 (i.e. @file{avcodec-51.dll}).
536 @subsection Cross compilation for Windows with Linux
538 You must use the MinGW cross compilation tools available at
539 @url{}.
541 Then configure FFmpeg with the following options:
542 @example
543 ./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
544 @end example
545 (you can change the cross-prefix according to the prefix chosen for the
546 MinGW tools).
548 Then you can easily test FFmpeg with Wine
549 (@url{}).
551 @subsection Compilation under Cygwin
553 The main issue with Cygwin is that newlib, its C library, does not
554 contain llrint(). However, it is possible to leverage the
555 implementation in MinGW.
557 Just install your Cygwin with all the "Base" packages, plus the
558 following "Devel" ones:
559 @example
560 binutils, gcc-core, make, subversion, mingw-runtime
561 @end example
563 Do not install binutils-20060709-1 (they are buggy on shared builds);
564 use binutils-20050610-1 instead.
566 Then create a small library that just contains llrint():
568 @example
569 ar x /usr/lib/mingw/libmingwex.a llrint.o
570 ar cq /usr/local/lib/libllrint.a llrint.o
571 @end example
573 Then run
575 @example
576 ./configure --enable-static --disable-shared --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
577 @end example
579 to make a static build or
581 @example
582 ./configure --enable-shared --disable-static --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
583 @end example
585 to build shared libraries.
587 If you want to build FFmpeg with additional libraries, download Cygwin
588 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository
589 and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
590 (@url{}).
592 @subsection Crosscompilation for Windows under Cygwin
594 With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
596 Just install your Cygwin as explained before, plus these additional
597 "Devel" packages:
598 @example
599 gcc-mingw-core, mingw-runtime, mingw-zlib
600 @end example
602 and add some special flags to your configure invocation.
604 For a static build run
605 @example
606 ./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
607 @end example
609 and for a build with shared libraries
610 @example
611 ./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
612 @end example
614 @section BeOS
616 BeOS support is broken in mysterious ways.
618 @section OS/2
620 For information about compiling FFmpeg on OS/2 see
621 @url{}.
623 @chapter Developers Guide
625 @section API
626 @itemize @bullet
627 @item libavcodec is the library containing the codecs (both encoding and
628 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
630 @item libavformat is the library containing the file format handling (mux and
631 demux code for several formats). Look at @file{ffplay.c} to use it in a
632 player. See @file{output_example.c} to use it to generate audio or video
633 streams.
635 @end itemize
637 @section Integrating libavcodec or libavformat in your program
639 You can integrate all the source code of the libraries to link them
640 statically to avoid any version problem. All you need is to provide a
641 'config.mak' and a 'config.h' in the parent directory. See the defines
642 generated by ./configure to understand what is needed.
644 You can use libavcodec or libavformat in your commercial program, but
645 @emph{any patch you make must be published}. The best way to proceed is
646 to send your patches to the FFmpeg mailing list.
648 @node Coding Rules
649 @section Coding Rules
651 FFmpeg is programmed in the ISO C90 language with a few additional
652 features from ISO C99, namely:
653 @itemize @bullet
654 @item
655 the @samp{inline} keyword;
656 @item
657 @samp{//} comments;
658 @item
659 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
660 @item
661 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
662 @end itemize
664 These features are supported by all compilers we care about, so we will not
665 accept patches to remove their use unless they absolutely do not impair
666 clarity and performance.
668 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
669 compiles with several other compilers, such as the Compaq ccc compiler
670 or Sun Studio 9, and we would like to keep it that way unless it would
671 be exceedingly involved. To ensure compatibility, please do not use any
672 additional C99 features or GCC extensions. Especially watch out for:
673 @itemize @bullet
674 @item
675 mixing statements and declarations;
676 @item
677 @samp{long long} (use @samp{int64_t} instead);
678 @item
679 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
680 @item
681 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
682 @end itemize
684 Indent size is 4.
685 The presentation is the one specified by 'indent -i4 -kr -nut'.
686 The TAB character is forbidden outside of Makefiles as is any
687 form of trailing whitespace. Commits containing either will be
688 rejected by the Subversion repository.
690 The main priority in FFmpeg is simplicity and small code size in order to
691 minimize the bug count.
693 Comments: Use the JavaDoc/Doxygen
694 format (see examples below) so that code documentation
695 can be generated automatically. All nontrivial functions should have a comment
696 above them explaining what the function does, even if it is just one sentence.
697 All structures and their member variables should be documented, too.
698 @example
699 /**
700 * @@file mpeg.c
701 * MPEG codec.
702 * @@author ...
703 */
705 /**
706 * Summary sentence.
707 * more text ...
708 * ...
709 */
710 typedef struct Foobar@{
711 int var1; /**< var1 description */
712 int var2; ///< var2 description
713 /** var3 description */
714 int var3;
715 @} Foobar;
717 /**
718 * Summary sentence.
719 * more text ...
720 * ...
721 * @@param my_parameter description of my_parameter
722 * @@return return value description
723 */
724 int myfunc(int my_parameter)
725 ...
726 @end example
728 fprintf and printf are forbidden in libavformat and libavcodec,
729 please use av_log() instead.
731 Casts should be used only when necessary. Unneeded parentheses
732 should also be avoided if they don't make the code easier to understand.
734 @section Development Policy
736 @enumerate
737 @item
738 Contributions should be licensed under the LGPL 2.1, including an
739 "or any later version" clause, or the MIT license. GPL 2 including
740 an "or any later version" clause is also acceptable, but LGPL is
741 preferred.
742 @item
743 You must not commit code which breaks FFmpeg! (Meaning unfinished but
744 enabled code which breaks compilation or compiles but does not work or
745 breaks the regression tests)
746 You can commit unfinished stuff (for testing etc), but it must be disabled
747 (#ifdef etc) by default so it does not interfere with other developers'
748 work.
749 @item
750 You do not have to over-test things. If it works for you, and you think it
751 should work for others, then commit. If your code has problems
752 (portability, triggers compiler bugs, unusual environment etc) they will be
753 reported and eventually fixed.
754 @item
755 Do not commit unrelated changes together, split them into self-contained
756 pieces. Also do not forget that if part B depends on part A, but A does not
757 depend on B, then A can and should be committed first and separate from B.
758 Keeping changes well split into self-contained parts makes reviewing and
759 understanding them on the commit log mailing list easier. This also helps
760 in case of debugging later on.
761 Also if you have doubts about splitting or not splitting, do not hesitate to
762 ask/discuss it on the developer mailing list.
763 @item
764 Do not change behavior of the program (renaming options etc) without
765 first discussing it on the ffmpeg-devel mailing list. Do not remove
766 functionality from the code. Just improve!
768 Note: Redundant code can be removed.
769 @item
770 Do not commit changes to the build system (Makefiles, configure script)
771 which change behavior, defaults etc, without asking first. The same
772 applies to compiler warning fixes, trivial looking fixes and to code
773 maintained by other developers. We usually have a reason for doing things
774 the way we do. Send your changes as patches to the ffmpeg-devel mailing
775 list, and if the code maintainers say OK, you may commit. This does not
776 apply to files you wrote and/or maintain.
777 @item
778 We refuse source indentation and other cosmetic changes if they are mixed
779 with functional changes, such commits will be rejected and removed. Every
780 developer has his own indentation style, you should not change it. Of course
781 if you (re)write something, you can use your own style, even though we would
782 prefer if the indentation throughout FFmpeg was consistent (Many projects
783 force a given indentation style - we do not.). If you really need to make
784 indentation changes (try to avoid this), separate them strictly from real
785 changes.
787 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
788 then either do NOT change the indentation of the inner part within (do not
789 move it to the right)! or do so in a separate commit
790 @item
791 Always fill out the commit log message. Describe in a few lines what you
792 changed and why. You can refer to mailing list postings if you fix a
793 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
794 @item
795 If you apply a patch by someone else, include the name and email address in
796 the log message. Since the ffmpeg-cvslog mailing list is publicly
797 archived you should add some SPAM protection to the email address. Send an
798 answer to ffmpeg-devel (or wherever you got the patch from) saying that
799 you applied the patch.
800 @item
801 When applying patches that have been discussed (at length) on the mailing
802 list, reference the thread in the log message.
803 @item
804 Do NOT commit to code actively maintained by others without permission.
805 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
806 timeframe (12h for build failures and security fixes, 3 days small changes,
807 1 week for big patches) then commit your patch if you think it is OK.
808 Also note, the maintainer can simply ask for more time to review!
809 @item
810 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
811 are sent there and reviewed by all the other developers. Bugs and possible
812 improvements or general questions regarding commits are discussed there. We
813 expect you to react if problems with your code are uncovered.
814 @item
815 Update the documentation if you change behavior or add features. If you are
816 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
817 maintainer(s) will review and commit your stuff.
818 @item
819 Try to keep important discussions and requests (also) on the public
820 developer mailing list, so that all developers can benefit from them.
821 @item
822 Never write to unallocated memory, never write over the end of arrays,
823 always check values read from some untrusted source before using them
824 as array index or other risky things.
825 @item
826 Remember to check if you need to bump versions for the specific libav
827 parts (libavutil, libavcodec, libavformat) you are changing. You need
828 to change the version integer and the version string.
829 Incrementing the first component means no backward compatibility to
830 previous versions (e.g. removal of a function from the public API).
831 Incrementing the second component means backward compatible change
832 (e.g. addition of a function to the public API).
833 Incrementing the third component means a noteworthy binary compatible
834 change (e.g. encoder bug fix that matters for the decoder).
835 @item
836 If you add a new codec, remember to update the changelog, add it to
837 the supported codecs table in the documentation and bump the second
838 component of the @file{libavcodec} version number appropriately. If
839 it has a fourcc, add it to @file{libavformat/riff.c}, even if it
840 is only a decoder.
841 @item
842 Compiler warnings indicate potential bugs or code with bad style. If a type of
843 warning always points to correct and clean code, that warning should
844 be disabled, not the code changed.
845 Thus the remaining warnings can either be bugs or correct code.
846 If it is a bug, the bug has to be fixed. If it is not, the code should
847 be changed to not generate a warning unless that causes a slowdown
848 or obfuscates the code.
849 @item
850 If you add a new file, give it a proper license header. Do not copy and
851 paste it from a random place, use an existing file as template.
852 @end enumerate
854 We think our rules are not too hard. If you have comments, contact us.
856 Note, these rules are mostly borrowed from the MPlayer project.
858 @section Submitting patches
860 First, (@pxref{Coding Rules}) above if you did not yet.
862 When you submit your patch, try to send a unified diff (diff '-up'
863 option). We cannot read other diffs :-)
865 Also please do not submit a patch which contains several unrelated changes.
866 Split it into separate, self-contained pieces. This does not mean splitting
867 file by file. Instead, make the patch as small as possible while still
868 keeping it as a logical unit that contains an individual change, even
869 if it spans multiple files. This makes reviewing your patches much easier
870 for us and greatly increases your chances of getting your patch applied.
872 Run the regression tests before submitting a patch so that you can
873 verify that there are no big problems.
875 Patches should be posted as base64 encoded attachments (or any other
876 encoding which ensures that the patch will not be trashed during
877 transmission) to the ffmpeg-devel mailing list, see
878 @url{}
880 It also helps quite a bit if you tell us what the patch does (for example
881 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
882 and has no lrint()')
884 Also please if you send several patches, send each patch as a separate mail,
885 do not attach several unrelated patches to the same mail.
887 @section patch submission checklist
889 @enumerate
890 @item
891 Do the regression tests pass with the patch applied?
892 @item
893 Is the patch a unified diff?
894 @item
895 Is the patch against latest FFmpeg SVN?
896 @item
897 Are you subscribed to ffmpeg-dev?
898 (the list is subscribers only due to spam)
899 @item
900 Have you checked that the changes are minimal, so that the same cannot be
901 achieved with a smaller patch and/or simpler final code?
902 @item
903 If the change is to speed critical code, did you benchmark it?
904 @item
905 If you did any benchmarks, did you provide them in the mail?
906 @item
907 Have you checked that the patch does not introduce buffer overflows or
908 other security issues?
909 @item
910 If you add a new demuxer or decoder, have you checked that it does not
911 crash with damaged input (see tools/trasher)?
912 @item
913 Is the patch created from the root of the source tree, so it can be
914 applied with @code{patch -p0}?
915 @item
916 Does the patch not mix functional and cosmetic changes?
917 @item
918 Did you add tabs or trailing whitespace to the code? Both are forbidden.
919 @item
920 Is the patch attached to the email you send?
921 @item
922 Is the mime type of the patch correct? It should be text/x-diff or
923 text/x-patch or at least text/plain and not application/octet-stream.
924 @item
925 If the patch fixes a bug, did you provide a verbose analysis of the bug?
926 @item
927 If the patch fixes a bug, did you provide enough information, including
928 a sample, so the bug can be reproduced and the fix can be verified?
929 Note please do not attach samples >100k to mails but rather provide a
930 URL, you can upload to
931 @item
932 Did you provide a verbose summary about what the patch does change?
933 @item
934 Did you provide a verbose explanation why it changes things like it does?
935 @item
936 Did you provide a verbose summary of the user visible advantages and
937 disadvantages if the patch is applied?
938 @item
939 Did you provide an example so we can verify the new feature added by the
940 patch easily?
941 @item
942 If you added a new file, did you insert a license header? It should be
943 taken from FFmpeg, not randomly copied and pasted from somewhere else.
944 @item
945 You should maintain alphabetical order in alphabetically ordered lists as
946 long as doing so does not break API/ABI compatibility.
947 @item
948 Lines with similar content should be aligned vertically when doing so
949 improves readability.
950 @item
951 Did you provide a suggestion for a clear commit log message?
952 @item
953 Did you test your decoder or demuxer against damaged data? If no, see
954 tools/trasher and the noise bitstream filter. Your decoder or demuxer
955 should not crash or end in a (near) infinite loop when fed damaged data.
956 @end enumerate
958 @section Patch review process
960 All patches posted to ffmpeg-devel will be reviewed, unless they contain a
961 clear note that the patch is not for SVN.
962 Reviews and comments will be posted as replies to the patch on the
963 mailing list. The patch submitter then has to take care of every comment,
964 that can be by resubmitting a changed patch or by discussion. Resubmitted
965 patches will themselves be reviewed like any other patch. If at some point
966 a patch passes review with no comments then it is approved, that can for
967 simple and small patches happen immediately while large patches will generally
968 have to be changed and reviewed many times before they are approved.
969 After a patch is approved it will be committed to the repository.
971 We will review all submitted patches, but sometimes we are quite busy so
972 especially for large patches this can take several weeks.
974 When resubmitting patches, please do not make any significant changes
975 not related to the comments received during review. Such patches will
976 be rejected. Instead, submit significant changes or new features as
977 separate patches.
979 @section Regression tests
981 Before submitting a patch (or committing to the repository), you should at least
982 test that you did not break anything.
984 The regression tests build a synthetic video stream and a synthetic
985 audio stream. These are then encoded and decoded with all codecs or
986 formats. The CRC (or MD5) of each generated file is recorded in a
987 result file. A 'diff' is launched to compare the reference results and
988 the result file.
990 The regression tests then go on to test the FFserver code with a
991 limited set of streams. It is important that this step runs correctly
992 as well.
994 Run 'make test' to test all the codecs and formats.
996 Run 'make fulltest' to test all the codecs, formats and FFserver.
998 [Of course, some patches may change the results of the regression tests. In
999 this case, the reference results of the regression tests shall be modified
1000 accordingly].
1002 @bye