Monkey Audio decoder
[libav.git] / doc / general.texi
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1\input texinfo @c -*- texinfo -*-
2
3@settitle General Documentation
4@titlepage
5@sp 7
6@center @titlefont{General Documentation}
7@sp 3
8@end titlepage
9
10
11@chapter external libraries
12
13FFmpeg can be hooked up with a number of external libraries to add support
14for more formats. None of them are used by default, their use has to be
15explicitly requested by passing the appropriate flags to @file{./configure}.
16
17@section AMR
18
19AMR comes in two different flavors, WB and NB. FFmpeg can make use of the
20AMR WB (floating-point mode) and the AMR NB (floating-point mode) reference
21decoders and encoders.
22
23Go to @url{http://www.penguin.cz/~utx/amr} and follow the instructions for
24installing the libraries. Then pass @code{--enable-libamr-nb} and/or
25@code{--enable-libamr-wb} to configure to enable the libraries.
26
27
28@chapter Supported File Formats and Codecs
29
30You can use the @code{-formats} option to have an exhaustive list.
31
32@section File Formats
33
34FFmpeg supports the following file formats through the @code{libavformat}
35library:
36
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
67@item 4xm @tab @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
83@tab .fli/.flc files
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.
e09f7d61 88@item Matroska @tab X @tab X
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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
96@item AVS @tab @tab X
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
110different 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.
bf4a1f17 119@item Monkey's Audio @tab @tab X
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120@end multitable
121
122@code{X} means that encoding (resp. decoding) is supported.
123
124@section Image Formats
125
126FFmpeg can read and write images for each frame of a video sequence. The
127following image formats are supported:
128
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
142@end multitable
143
144@code{X} means that encoding (resp. decoding) is supported.
145
146@section Video Codecs
147
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 @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@end multitable
235
236@code{X} means that encoding (resp. decoding) is supported.
237
238@section Audio Codecs
239
240@multitable @columnfractions .4 .1 .1 .1 .7
241@item Supported Codec @tab Encoding @tab Decoding @tab Comments
242@item MPEG audio layer 2 @tab IX @tab IX
243@item MPEG audio layer 1/3 @tab IX @tab IX
244@tab MP3 encoding is supported through the external library LAME.
245@item AC3 @tab IX @tab IX
246@tab liba52 is used internally for decoding.
247@item Vorbis @tab X @tab X
248@item WMA V1/V2 @tab X @tab X
249@item AAC @tab X @tab X
250@tab Supported through the external library libfaac/libfaad.
251@item Microsoft ADPCM @tab X @tab X
252@item MS IMA ADPCM @tab X @tab X
253@item QT IMA ADPCM @tab @tab X
254@item 4X IMA ADPCM @tab @tab X
255@item G.726 ADPCM @tab X @tab X
256@item Duck DK3 IMA ADPCM @tab @tab X
257@tab Used in some Sega Saturn console games.
258@item Duck DK4 IMA ADPCM @tab @tab X
259@tab Used in some Sega Saturn console games.
260@item Westwood Studios IMA ADPCM @tab @tab X
261@tab Used in Westwood Studios games like Command and Conquer.
262@item SMJPEG IMA ADPCM @tab @tab X
263@tab Used in certain Loki game ports.
264@item CD-ROM XA ADPCM @tab @tab X
265@item CRI ADX ADPCM @tab X @tab X
266@tab Used in Sega Dreamcast games.
267@item Electronic Arts ADPCM @tab @tab X
268@tab Used in various EA titles.
269@item Creative ADPCM @tab @tab X
270@tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
271@item THP ADPCM @tab @tab X
272@tab Used on the Nintendo GameCube.
273@item RA144 @tab @tab X
274@tab Real 14400 bit/s codec
275@item RA288 @tab @tab X
276@tab Real 28800 bit/s codec
277@item RADnet @tab X @tab IX
278@tab Real low bitrate AC3 codec, liba52 is used for decoding.
279@item AMR-NB @tab X @tab X
280@tab Supported through an external library.
281@item AMR-WB @tab X @tab X
282@tab Supported through an external library.
283@item DV audio @tab @tab X
284@item Id RoQ DPCM @tab X @tab X
285@tab Used in Quake III, Jedi Knight 2, other computer games.
286@item Interplay MVE DPCM @tab @tab X
287@tab Used in various Interplay computer games.
288@item Xan DPCM @tab @tab X
289@tab Used in Origin's Wing Commander IV AVI files.
290@item Sierra Online DPCM @tab @tab X
291@tab Used in Sierra Online game audio files.
292@item Apple MACE 3 @tab @tab X
293@item Apple MACE 6 @tab @tab X
294@item FLAC lossless audio @tab X @tab X
295@item Shorten lossless audio @tab @tab X
296@item Apple lossless audio @tab @tab X
297@tab QuickTime fourcc 'alac'
298@item FFmpeg Sonic @tab X @tab X
299@tab experimental lossy/lossless codec
300@item Qdesign QDM2 @tab @tab X
301@tab there are still some distortions
302@item Real COOK @tab @tab X
303@tab All versions except 5.1 are supported
304@item DSP Group TrueSpeech @tab @tab X
305@item True Audio (TTA) @tab @tab X
306@item Smacker Audio @tab @tab X
307@item WavPack Audio @tab @tab X
308@item Cin Audio @tab @tab X
309@tab Codec used in Delphine Software games.
310@item Intel Music Coder @tab @tab X
311@item Musepack @tab @tab X
312@tab Only SV7 is supported
313@item DT$ Coherent Audio @tab @tab X
314@item ATRAC 3 @tab @tab X
bf4a1f17 315@item Monkey's Audio @tab @tab X @tab Only versions 3.97-3.99 are supported
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316@end multitable
317
318@code{X} means that encoding (resp. decoding) is supported.
319
320@code{I} means that an integer-only version is available, too (ensures high
321performance on systems without hardware floating point support).
322
323@chapter Platform Specific information
324
325@section BSD
326
327BSD make will not build FFmpeg, you need to install and use GNU Make
328(@file{gmake}).
329
330@section Windows
331
332To get help and instructions for using FFmpeg under Windows, check out
333the FFmpeg Windows Help Forum at
334@url{http://arrozcru.no-ip.org/ffmpeg/}.
335
336@subsection Native Windows compilation
337
338@itemize
339@item Install the current versions of MSYS and MinGW from
340@url{http://www.mingw.org/}. You can find detailed installation
341instructions in the download section and the FAQ.
342
343NOTE: Use at least bash 3.1. Older versions are known to be failing on the
344configure script.
345
346@item If you want to test the FFplay, also download
347the MinGW development library of SDL 1.2.x
348(@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
349@url{http://www.libsdl.org}. Unpack it in a temporary directory, and
350unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
351directory. Edit the @file{sdl-config} script so that it gives the
352correct SDL directory when invoked.
353
354@item If you want to use vhooks, you must have a POSIX compliant libdl in your
355MinGW system. Get dlfcn-win32 from @url{http://code.google.com/p/dlfcn-win32}.
356
357@item Extract the current version of FFmpeg.
358
359@item Start the MSYS shell (file @file{msys.bat}).
360
361@item Change to the FFmpeg directory and follow
362 the instructions of how to compile FFmpeg (file
363@file{INSTALL}). Usually, launching @file{./configure} and @file{make}
364suffices. If you have problems using SDL, verify that
365@file{sdl-config} can be launched from the MSYS command line.
366
367@item You can install FFmpeg in @file{Program Files/FFmpeg} by typing
368@file{make install}. Do not forget to copy @file{SDL.dll} to the place
369you launch @file{ffplay} from.
370
371@end itemize
372
373Notes:
374@itemize
375
376@item The target @file{make wininstaller} can be used to create a
377Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
378must be copied to the FFmpeg directory in order to build the
379installer.
380
381@item By using @code{./configure --enable-shared} when configuring FFmpeg,
382you can build @file{avcodec.dll} and @file{avformat.dll}. With
383@code{make install} you install the FFmpeg DLLs and the associated
384headers in @file{Program Files/FFmpeg}.
385
386@item Visual C++ compatibility: If you used @code{./configure --enable-shared}
387when configuring FFmpeg, FFmpeg tries to use the Microsoft Visual
388C++ @code{lib} tool to build @code{avcodec.lib} and
389@code{avformat.lib}. With these libraries you can link your Visual C++
390code directly with the FFmpeg DLLs (see below).
391
392@end itemize
393
394@subsection Visual C++ compatibility
395
396FFmpeg will not compile under Visual C++ -- and it has too many
397dependencies on the GCC compiler to make a port viable. However,
398if you want to use the FFmpeg libraries in your own applications,
399you can still compile those applications using Visual C++. An
400important restriction to this is that you have to use the
401dynamically linked versions of the FFmpeg libraries (i.e. the
402DLLs), and you have to make sure that Visual-C++-compatible
403import libraries are created during the FFmpeg build process.
404
405This description of how to use the FFmpeg libraries with Visual C++ is
406based on Visual C++ 2005 Express Edition Beta 2. If you have a different
407version, you might have to modify the procedures slightly.
408
409Here are the step-by-step instructions for building the FFmpeg libraries
410so they can be used with Visual C++:
411
412@enumerate
413
414@item Install Visual C++ (if you have not done so already).
415
416@item Install MinGW and MSYS as described above.
417
418@item Add a call to @file{vcvars32.bat} (which sets up the environment
419variables for the Visual C++ tools) as the first line of
420@file{msys.bat}. The standard location for @file{vcvars32.bat} is
421@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
422and the standard location for @file{msys.bat} is
423@file{C:\msys\1.0\msys.bat}. If this corresponds to your setup, add the
424following line as the first line of @file{msys.bat}:
425
426@code{call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"}
427
428@item Start the MSYS shell (file @file{msys.bat}) and type @code{link.exe}.
429If you get a help message with the command line options of @code{link.exe},
430this means your environment variables are set up correctly, the
431Microsoft linker is on the path and will be used by FFmpeg to
432create Visual-C++-compatible import libraries.
433
434@item Extract the current version of FFmpeg and change to the FFmpeg directory.
435
436@item Type the command
437@code{./configure --enable-shared --disable-static --enable-memalign-hack}
438to configure and, if that did not produce any errors,
439type @code{make} to build FFmpeg.
440
441@item The subdirectories @file{libavformat}, @file{libavcodec}, and
442@file{libavutil} should now contain the files @file{avformat.dll},
443@file{avformat.lib}, @file{avcodec.dll}, @file{avcodec.lib},
444@file{avutil.dll}, and @file{avutil.lib}, respectively. Copy the three
445DLLs to your System32 directory (typically @file{C:\Windows\System32}).
446
447@end enumerate
448
449And here is how to use these libraries with Visual C++:
450
451@enumerate
452
453@item Create a new console application ("File / New / Project") and then
454select "Win32 Console Application". On the appropriate page of the
455Application Wizard, uncheck the "Precompiled headers" option.
456
457@item Write the source code for your application, or, for testing, just
458copy the code from an existing sample application into the source file
459that Visual C++ has already created for you. (Note that your source
460filehas to have a @code{.cpp} extension; otherwise, Visual C++ will not
461compile the FFmpeg headers correctly because in C mode, it does not
462recognize the @code{inline} keyword.) For example, you can copy
463@file{output_example.c} from the FFmpeg distribution (but you will
464have to make minor modifications so the code will compile under
465C++, see below).
466
467@item Open the "Project / Properties" dialog box. In the "Configuration"
468combo box, select "All Configurations" so that the changes you make will
469affect both debug and release builds. In the tree view on the left hand
470side, select "C/C++ / General", then edit the "Additional Include
471Directories" setting to contain the complete paths to the
472@file{libavformat}, @file{libavcodec}, and @file{libavutil}
473subdirectories of your FFmpeg directory. Note that the directories have
474to be separated using semicolons. Now select "Linker / General" from the
475tree view and edit the "Additional Library Directories" setting to
476contain the same three directories.
477
478@item Still in the "Project / Properties" dialog box, select "Linker / Input"
479from the tree view, then add the files @file{avformat.lib},
480@file{avcodec.lib}, and @file{avutil.lib} to the end of the "Additional
481Dependencies". Note that the names of the libraries have to be separated
482using spaces.
483
484@item Now, select "C/C++ / Code Generation" from the tree view. Select
485"Debug" in the "Configuration" combo box. Make sure that "Runtime
486Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
487the "Configuration" combo box and make sure that "Runtime Library" is
488set to "Multi-threaded DLL".
489
490@item Click "OK" to close the "Project / Properties" dialog box and build
491the application. Hopefully, it should compile and run cleanly. If you
492used @file{output_example.c} as your sample application, you will get a
493few compiler errors, but they are easy to fix. The first type of error
494occurs because Visual C++ does not allow an @code{int} to be converted to
495an @code{enum} without a cast. To solve the problem, insert the required
496casts (this error occurs once for a @code{CodecID} and once for a
497@code{CodecType}). The second type of error occurs because C++ requires
498the return value of @code{malloc} to be cast to the exact type of the
499pointer it is being assigned to. Visual C++ will complain that, for
500example, @code{(void *)} is being assigned to @code{(uint8_t *)} without
501an explicit cast. So insert an explicit cast in these places to silence
502the compiler. The third type of error occurs because the @code{snprintf}
503library function is called @code{_snprintf} under Visual C++. So just
504add an underscore to fix the problem. With these changes,
505@file{output_example.c} should compile under Visual C++, and the
506resulting executable should produce valid video files.
507
508@end enumerate
509
510@subsection Cross compilation for Windows with Linux
511
512You must use the MinGW cross compilation tools available at
513@url{http://www.mingw.org/}.
514
515Then configure FFmpeg with the following options:
516@example
517./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
518@end example
519(you can change the cross-prefix according to the prefix chosen for the
520MinGW tools).
521
522Then you can easily test FFmpeg with Wine
523(@url{http://www.winehq.com/}).
524
525@subsection Compilation under Cygwin
526
527Cygwin works very much like Unix.
528
529Just install your Cygwin with all the "Base" packages, plus the
530following "Devel" ones:
531@example
532binutils, gcc-core, make, subversion
533@end example
534
535Do not install binutils-20060709-1 (they are buggy on shared builds);
536use binutils-20050610-1 instead.
537
538Then run
539
540@example
541./configure --enable-static --disable-shared
542@end example
543
544to make a static build or
545
546@example
547./configure --enable-shared --disable-static
548@end example
549
550to build shared libraries.
551
552If you want to build FFmpeg with additional libraries, download Cygwin
553"Devel" packages for Ogg and Vorbis from any Cygwin packages repository
554and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
555(@url{http://cygwinports.dotsrc.org/}).
556
557@subsection Crosscompilation for Windows under Cygwin
558
559With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
560
561Just install your Cygwin as explained before, plus these additional
562"Devel" packages:
563@example
564gcc-mingw-core, mingw-runtime, mingw-zlib
565@end example
566
567and add some special flags to your configure invocation.
568
569For a static build run
570@example
571./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
572@end example
573
574and for a build with shared libraries
575@example
576./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
577@end example
578
579@section BeOS
580
5f757b85 581BeOS support is broken in mysterious ways.
d0e1cd3d
DB
582
583@chapter Developers Guide
584
585@section API
586@itemize @bullet
587@item libavcodec is the library containing the codecs (both encoding and
588decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
589
590@item libavformat is the library containing the file format handling (mux and
591demux code for several formats). Look at @file{ffplay.c} to use it in a
592player. See @file{output_example.c} to use it to generate audio or video
593streams.
594
595@end itemize
596
597@section Integrating libavcodec or libavformat in your program
598
599You can integrate all the source code of the libraries to link them
600statically to avoid any version problem. All you need is to provide a
601'config.mak' and a 'config.h' in the parent directory. See the defines
602generated by ./configure to understand what is needed.
603
604You can use libavcodec or libavformat in your commercial program, but
605@emph{any patch you make must be published}. The best way to proceed is
606to send your patches to the FFmpeg mailing list.
607
608@node Coding Rules
609@section Coding Rules
610
611FFmpeg is programmed in the ISO C90 language with a few additional
612features from ISO C99, namely:
613@itemize @bullet
614@item
615the @samp{inline} keyword;
616@item
617@samp{//} comments;
618@item
619designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
620@item
621compound literals (@samp{x = (struct s) @{ 17, 23 @};})
622@end itemize
623
624These features are supported by all compilers we care about, so we will not
625accept patches to remove their use unless they absolutely do not impair
626clarity and performance.
627
628All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
629compiles with several other compilers, such as the Compaq ccc compiler
630or Sun Studio 9, and we would like to keep it that way unless it would
631be exceedingly involved. To ensure compatibility, please do not use any
632additional C99 features or GCC extensions. Especially watch out for:
633@itemize @bullet
634@item
635mixing statements and declarations;
636@item
637@samp{long long} (use @samp{int64_t} instead);
638@item
639@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
640@item
641GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
642@end itemize
643
644Indent size is 4.
645The presentation is the one specified by 'indent -i4 -kr -nut'.
646The TAB character is forbidden outside of Makefiles as is any
647form of trailing whitespace. Commits containing either will be
648rejected by the Subversion repository.
649
650The main priority in FFmpeg is simplicity and small code size in order to
651minimize the bug count.
652
653Comments: Use the JavaDoc/Doxygen
654format (see examples below) so that code documentation
655can be generated automatically. All nontrivial functions should have a comment
656above them explaining what the function does, even if it is just one sentence.
657All structures and their member variables should be documented, too.
658@example
659/**
660 * @@file mpeg.c
661 * MPEG codec.
662 * @@author ...
663 */
664
665/**
666 * Summary sentence.
667 * more text ...
668 * ...
669 */
670typedef struct Foobar@{
671 int var1; /**< var1 description */
672 int var2; ///< var2 description
673 /** var3 description */
674 int var3;
675@} Foobar;
676
677/**
678 * Summary sentence.
679 * more text ...
680 * ...
681 * @@param my_parameter description of my_parameter
682 * @@return return value description
683 */
684int myfunc(int my_parameter)
685...
686@end example
687
688fprintf and printf are forbidden in libavformat and libavcodec,
689please use av_log() instead.
690
691Casts should be used only when necessary. Unneeded parentheses
692should also be avoided if they don't make the code easier to understand.
693
694@section Development Policy
695
696@enumerate
697@item
698 Contributions should be licensed under the LGPL 2.1, including an
699 "or any later version" clause, or the MIT license. GPL 2 including
700 an "or any later version" clause is also acceptable, but LGPL is
701 preferred.
702@item
703 You must not commit code which breaks FFmpeg! (Meaning unfinished but
704 enabled code which breaks compilation or compiles but does not work or
705 breaks the regression tests)
706 You can commit unfinished stuff (for testing etc), but it must be disabled
707 (#ifdef etc) by default so it does not interfere with other developers'
708 work.
709@item
710 You do not have to over-test things. If it works for you, and you think it
711 should work for others, then commit. If your code has problems
712 (portability, triggers compiler bugs, unusual environment etc) they will be
713 reported and eventually fixed.
714@item
715 Do not commit unrelated changes together, split them into self-contained
716 pieces. Also do not forget that if part B depends on part A, but A does not
717 depend on B, then A can and should be committed first and separate from B.
718 Keeping changes well split into self-contained parts makes reviewing and
719 understanding them on the commit log mailing list easier. This also helps
720 in case of debugging later on.
721 Also if you have doubts about splitting or not splitting, do not hesitate to
722 ask/discuss it on the developer mailing list.
723@item
724 Do not change behavior of the program (renaming options etc) without
725 first discussing it on the ffmpeg-devel mailing list. Do not remove
726 functionality from the code. Just improve!
727
728 Note: Redundant code can be removed.
729@item
730 Do not commit changes to the build system (Makefiles, configure script)
731 which change behavior, defaults etc, without asking first. The same
732 applies to compiler warning fixes, trivial looking fixes and to code
733 maintained by other developers. We usually have a reason for doing things
734 the way we do. Send your changes as patches to the ffmpeg-devel mailing
735 list, and if the code maintainers say OK, you may commit. This does not
736 apply to files you wrote and/or maintain.
737@item
738 We refuse source indentation and other cosmetic changes if they are mixed
739 with functional changes, such commits will be rejected and removed. Every
740 developer has his own indentation style, you should not change it. Of course
741 if you (re)write something, you can use your own style, even though we would
742 prefer if the indentation throughout FFmpeg was consistent (Many projects
743 force a given indentation style - we do not.). If you really need to make
744 indentation changes (try to avoid this), separate them strictly from real
745 changes.
746
747 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
748 then either do NOT change the indentation of the inner part within (do not
749 move it to the right)! or do so in a separate commit
750@item
751 Always fill out the commit log message. Describe in a few lines what you
752 changed and why. You can refer to mailing list postings if you fix a
753 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
754@item
755 If you apply a patch by someone else, include the name and email address in
756 the log message. Since the ffmpeg-cvslog mailing list is publicly
757 archived you should add some SPAM protection to the email address. Send an
758 answer to ffmpeg-devel (or wherever you got the patch from) saying that
759 you applied the patch.
760@item
761 When applying patches that have been discussed (at length) on the mailing
762 list, reference the thread in the log message.
763@item
764 Do NOT commit to code actively maintained by others without permission.
765 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
766 timeframe (12h for build failures and security fixes, 3 days small changes,
767 1 week for big patches) then commit your patch if you think it is OK.
768 Also note, the maintainer can simply ask for more time to review!
769@item
770 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
771 are sent there and reviewed by all the other developers. Bugs and possible
772 improvements or general questions regarding commits are discussed there. We
773 expect you to react if problems with your code are uncovered.
774@item
775 Update the documentation if you change behavior or add features. If you are
776 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
777 maintainer(s) will review and commit your stuff.
778@item
779 Try to keep important discussions and requests (also) on the public
780 developer mailing list, so that all developers can benefit from them.
781@item
782 Never write to unallocated memory, never write over the end of arrays,
783 always check values read from some untrusted source before using them
784 as array index or other risky things.
785@item
786 Remember to check if you need to bump versions for the specific libav
787 parts (libavutil, libavcodec, libavformat) you are changing. You need
788 to change the version integer and the version string.
789 Incrementing the first component means no backward compatibility to
790 previous versions (e.g. removal of a function from the public API).
791 Incrementing the second component means backward compatible change
792 (e.g. addition of a function to the public API).
793 Incrementing the third component means a noteworthy binary compatible
794 change (e.g. encoder bug fix that matters for the decoder).
795@item
796 If you add a new codec, remember to update the changelog, add it to
797 the supported codecs table in the documentation and bump the second
798 component of the @file{libavcodec} version number appropriately. If
799 it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
800 is only a decoder.
801@item
802 Do not change code to hide warnings without ensuring that the underlying
803 logic is correct and thus the warning was inappropriate.
804@item
805 If you add a new file, give it a proper license header. Do not copy and
806 paste it from a random place, use an existing file as template.
807@end enumerate
808
809We think our rules are not too hard. If you have comments, contact us.
810
811Note, these rules are mostly borrowed from the MPlayer project.
812
813@section Submitting patches
814
815First, (@pxref{Coding Rules}) above if you did not yet.
816
817When you submit your patch, try to send a unified diff (diff '-up'
818option). We cannot read other diffs :-)
819
820Also please do not submit a patch which contains several unrelated changes.
821Split it into separate, self-contained pieces. This does not mean splitting
822file by file. Instead, make the patch as small as possible while still
823keeping it as a logical unit that contains an individual change, even
824if it spans multiple files. This makes reviewing your patches much easier
825for us and greatly increases your chances of getting your patch applied.
826
827Run the regression tests before submitting a patch so that you can
828verify that there are no big problems.
829
830Patches should be posted as base64 encoded attachments (or any other
831encoding which ensures that the patch will not be trashed during
832transmission) to the ffmpeg-devel mailing list, see
833@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
834
835It also helps quite a bit if you tell us what the patch does (for example
836'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
837and has no lrint()')
838
839Also please if you send several patches, send each patch as a separate mail,
840do not attach several unrelated patches to the same mail.
841
842@section patch submission checklist
843
844@enumerate
845@item
846 Do the regression tests pass with the patch applied?
847@item
848 Is the patch a unified diff?
849@item
850 Is the patch against latest FFmpeg SVN?
851@item
852 Are you subscribed to ffmpeg-dev?
853 (the list is subscribers only due to spam)
854@item
855 Have you checked that the changes are minimal, so that the same cannot be
856 achieved with a smaller patch and/or simpler final code?
857@item
858 If the change is to speed critical code, did you benchmark it?
859@item
860 If you did any benchmarks, did you provide them in the mail?
861@item
862 Have you checked that the patch does not introduce buffer overflows or
863 other security issues?
864@item
865 Is the patch created from the root of the source tree, so it can be
866 applied with @code{patch -p0}?
867@item
868 Does the patch not mix functional and cosmetic changes?
869@item
870 Did you add tabs or trailing whitespace to the code? Both are forbidden.
871@item
872 Is the patch attached to the email you send?
873@item
874 Is the mime type of the patch correct? It should be text/x-diff or
875 text/x-patch or at least text/plain and not application/octet-stream.
876@item
877 If the patch fixes a bug, did you provide a verbose analysis of the bug?
878@item
879 If the patch fixes a bug, did you provide enough information, including
880 a sample, so the bug can be reproduced and the fix can be verified?
881 Note please do not attach samples >100k to mails but rather provide a
882 URL, you can upload to ftp://upload.mplayerhq.hu
883@item
884 Did you provide a verbose summary about what the patch does change?
885@item
886 Did you provide a verbose explanation why it changes things like it does?
887@item
888 Did you provide a verbose summary of the user visible advantages and
889 disadvantages if the patch is applied?
890@item
891 Did you provide an example so we can verify the new feature added by the
892 patch easily?
893@item
894 If you added a new file, did you insert a license header? It should be
895 taken from FFmpeg, not randomly copied and pasted from somewhere else.
896@item
897 You should maintain alphabetical order in alphabetically ordered lists as
898 long as doing so does not break API/ABI compatibility.
899@item
900 Lines with similar content should be aligned vertically when doing so
901 improves readability.
902@item
903 Did you provide a suggestion for a clear commit log message?
904@end enumerate
905
906@section Patch review process
907
908All patches posted to ffmpeg-devel will be reviewed, unless they contain a
909clear note that the patch is not for SVN.
910Reviews and comments will be posted as replies to the patch on the
911mailing list. The patch submitter then has to take care of every comment,
912that can be by resubmitting a changed patch or by discussion. Resubmitted
913patches will themselves be reviewed like any other patch. If at some point
914a patch passes review with no comments then it is approved, that can for
915simple and small patches happen immediately while large patches will generally
916have to be changed and reviewed many times before they are approved.
917After a patch is approved it will be committed to the repository.
918
919We will review all submitted patches, but sometimes we are quite busy so
920especially for large patches this can take several weeks.
921
922When resubmitting patches, please do not make any significant changes
923not related to the comments received during review. Such patches will
924be rejected. Instead, submit significant changes or new features as
925separate patches.
926
927@section Regression tests
928
929Before submitting a patch (or committing to the repository), you should at least
930test that you did not break anything.
931
932The regression tests build a synthetic video stream and a synthetic
933audio stream. These are then encoded and decoded with all codecs or
934formats. The CRC (or MD5) of each generated file is recorded in a
935result file. A 'diff' is launched to compare the reference results and
936the result file.
937
938The regression tests then go on to test the FFserver code with a
939limited set of streams. It is important that this step runs correctly
940as well.
941
942Run 'make test' to test all the codecs and formats.
943
944Run 'make fulltest' to test all the codecs, formats and FFserver.
945
946[Of course, some patches may change the results of the regression tests. In
947this case, the reference results of the regression tests shall be modified
948accordingly].
949
950@bye