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[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@item SIFF @tab @tab X
121@tab Audio and video format used in some games by Beam Software
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122@end multitable
123
124@code{X} means that encoding (resp. decoding) is supported.
125
126@section Image Formats
127
128FFmpeg can read and write images for each frame of a video sequence. The
129following image formats are supported:
130
131@multitable @columnfractions .4 .1 .1 .4
132@item Supported Image Format @tab Encoding @tab Decoding @tab Comments
133@item PGM, PPM @tab X @tab X
134@item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
135@item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
136@item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
137@item .Y.U.V @tab X @tab X @tab one raw file per component
138@item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
139@item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
140@item Targa @tab @tab X @tab Targa (.TGA) image format.
141@item TIFF @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
142@item SGI @tab X @tab X @tab SGI RGB image format
143@item PTX @tab @tab X @tab V.Flash PTX format
144@end multitable
145
146@code{X} means that encoding (resp. decoding) is supported.
147
148@section Video Codecs
149
150@multitable @columnfractions .4 .1 .1 .4
151@item Supported Codec @tab Encoding @tab Decoding @tab Comments
152@item MPEG-1 video @tab X @tab X
153@item MPEG-2 video @tab X @tab X
154@item MPEG-4 @tab X @tab X
155@item MSMPEG4 V1 @tab X @tab X
156@item MSMPEG4 V2 @tab X @tab X
157@item MSMPEG4 V3 @tab X @tab X
158@item WMV7 @tab X @tab X
159@item WMV8 @tab X @tab X @tab not completely working
160@item WMV9 @tab @tab X @tab not completely working
161@item VC1 @tab @tab X
162@item H.261 @tab X @tab X
163@item H.263(+) @tab X @tab X @tab also known as RealVideo 1.0
164@item H.264 @tab @tab X
165@item RealVideo 1.0 @tab X @tab X
166@item RealVideo 2.0 @tab X @tab X
167@item MJPEG @tab X @tab X
168@item lossless MJPEG @tab X @tab X
169@item JPEG-LS @tab X @tab X @tab fourcc: MJLS, lossless and near-lossless is supported
170@item Apple MJPEG-B @tab @tab X
171@item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
172@item DV @tab X @tab X
173@item HuffYUV @tab X @tab X
174@item FFmpeg Video 1 @tab X @tab X @tab experimental lossless codec (fourcc: FFV1)
175@item FFmpeg Snow @tab X @tab X @tab experimental wavelet codec (fourcc: SNOW)
176@item Asus v1 @tab X @tab X @tab fourcc: ASV1
177@item Asus v2 @tab X @tab X @tab fourcc: ASV2
178@item Creative YUV @tab @tab X @tab fourcc: CYUV
179@item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
180@item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
181@item On2 VP3 @tab @tab X @tab still experimental
182@item On2 VP5 @tab @tab X @tab fourcc: VP50
183@item On2 VP6 @tab @tab X @tab fourcc: VP60,VP61,VP62
184@item Theora @tab X @tab X @tab still experimental
185@item Intel Indeo 3 @tab @tab X
186@item FLV @tab X @tab X @tab Sorenson H.263 used in Flash
187@item Flash Screen Video @tab X @tab X @tab fourcc: FSV1
188@item ATI VCR1 @tab @tab X @tab fourcc: VCR1
189@item ATI VCR2 @tab @tab X @tab fourcc: VCR2
190@item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
191@item 4X Video @tab @tab X @tab Used in certain computer games.
192@item Sony Playstation MDEC @tab @tab X
193@item Id RoQ @tab X @tab X @tab Used in Quake III, Jedi Knight 2, other computer games.
194@item Xan/WC3 @tab @tab X @tab Used in Wing Commander III .MVE files.
195@item Interplay Video @tab @tab X @tab Used in Interplay .MVE files.
196@item Apple Animation @tab X @tab X @tab fourcc: 'rle '
197@item Apple Graphics @tab @tab X @tab fourcc: 'smc '
198@item Apple Video @tab @tab X @tab fourcc: rpza
199@item Apple QuickDraw @tab @tab X @tab fourcc: qdrw
200@item Cinepak @tab @tab X
201@item Microsoft RLE @tab @tab X
202@item Microsoft Video-1 @tab @tab X
203@item Westwood VQA @tab @tab X
204@item Id Cinematic Video @tab @tab X @tab Used in Quake II.
205@item Planar RGB @tab @tab X @tab fourcc: 8BPS
206@item FLIC video @tab @tab X
207@item Duck TrueMotion v1 @tab @tab X @tab fourcc: DUCK
208@item Duck TrueMotion v2 @tab @tab X @tab fourcc: TM20
209@item VMD Video @tab @tab X @tab Used in Sierra VMD files.
210@item MSZH @tab @tab X @tab Part of LCL
211@item ZLIB @tab X @tab X @tab Part of LCL, encoder experimental
212@item TechSmith Camtasia @tab @tab X @tab fourcc: TSCC
213@item IBM Ultimotion @tab @tab X @tab fourcc: ULTI
214@item Miro VideoXL @tab @tab X @tab fourcc: VIXL
215@item QPEG @tab @tab X @tab fourccs: QPEG, Q1.0, Q1.1
216@item LOCO @tab @tab X @tab
217@item Winnov WNV1 @tab @tab X @tab
218@item Autodesk Animator Studio Codec @tab @tab X @tab fourcc: AASC
219@item Fraps FPS1 @tab @tab X @tab
220@item CamStudio @tab @tab X @tab fourcc: CSCD
221@item American Laser Games Video @tab @tab X @tab Used in games like Mad Dog McCree
222@item ZMBV @tab X @tab X @tab Encoder works only on PAL8
223@item AVS Video @tab @tab X @tab Video encoding used by the Creature Shock game.
224@item Smacker Video @tab @tab X @tab Video encoding used in Smacker.
225@item RTjpeg @tab @tab X @tab Video encoding used in NuppelVideo files.
226@item KMVC @tab @tab X @tab Codec used in Worms games.
227@item VMware Video @tab @tab X @tab Codec used in videos captured by VMware.
228@item Cin Video @tab @tab X @tab Codec used in Delphine Software games.
229@item Tiertex Seq Video @tab @tab X @tab Codec used in DOS CDROM FlashBack game.
230@item DXA Video @tab @tab X @tab Codec originally used in Feeble Files game.
fc4cbc16 231@item AVID DNxHD @tab X @tab X @tab aka SMPTE VC3
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232@item C93 Video @tab @tab X @tab Codec used in Cyberia game.
233@item THP @tab @tab X @tab Used on the Nintendo GameCube.
234@item Bethsoft VID @tab @tab X @tab Used in some games from Bethesda Softworks.
235@item Renderware TXD @tab @tab X @tab Texture dictionaries used by the Renderware Engine.
03b8e292 236@item AMV @tab @tab X @tab Used in Chinese MP3 players.
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237@end multitable
238
239@code{X} means that encoding (resp. decoding) is supported.
240
241@section Audio Codecs
242
243@multitable @columnfractions .4 .1 .1 .1 .7
244@item Supported Codec @tab Encoding @tab Decoding @tab Comments
245@item MPEG audio layer 2 @tab IX @tab IX
246@item MPEG audio layer 1/3 @tab IX @tab IX
247@tab MP3 encoding is supported through the external library LAME.
248@item AC3 @tab IX @tab IX
249@tab liba52 is used internally for decoding.
250@item Vorbis @tab X @tab X
251@item WMA V1/V2 @tab X @tab X
252@item AAC @tab X @tab X
253@tab Supported through the external library libfaac/libfaad.
254@item Microsoft ADPCM @tab X @tab X
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255@item AMV IMA ADPCM @tab @tab X
256@tab Used in AMV files
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257@item MS IMA ADPCM @tab X @tab X
258@item QT IMA ADPCM @tab @tab X
259@item 4X IMA ADPCM @tab @tab X
260@item G.726 ADPCM @tab X @tab X
261@item Duck DK3 IMA ADPCM @tab @tab X
262@tab Used in some Sega Saturn console games.
263@item Duck DK4 IMA ADPCM @tab @tab X
264@tab Used in some Sega Saturn console games.
265@item Westwood Studios IMA ADPCM @tab @tab X
266@tab Used in Westwood Studios games like Command and Conquer.
267@item SMJPEG IMA ADPCM @tab @tab X
268@tab Used in certain Loki game ports.
269@item CD-ROM XA ADPCM @tab @tab X
270@item CRI ADX ADPCM @tab X @tab X
271@tab Used in Sega Dreamcast games.
272@item Electronic Arts ADPCM @tab @tab X
273@tab Used in various EA titles.
274@item Creative ADPCM @tab @tab X
275@tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
276@item THP ADPCM @tab @tab X
277@tab Used on the Nintendo GameCube.
278@item RA144 @tab @tab X
279@tab Real 14400 bit/s codec
280@item RA288 @tab @tab X
281@tab Real 28800 bit/s codec
282@item RADnet @tab X @tab IX
283@tab Real low bitrate AC3 codec, liba52 is used for decoding.
284@item AMR-NB @tab X @tab X
285@tab Supported through an external library.
286@item AMR-WB @tab X @tab X
287@tab Supported through an external library.
288@item DV audio @tab @tab X
289@item Id RoQ DPCM @tab X @tab X
290@tab Used in Quake III, Jedi Knight 2, other computer games.
291@item Interplay MVE DPCM @tab @tab X
292@tab Used in various Interplay computer games.
293@item Xan DPCM @tab @tab X
294@tab Used in Origin's Wing Commander IV AVI files.
295@item Sierra Online DPCM @tab @tab X
296@tab Used in Sierra Online game audio files.
297@item Apple MACE 3 @tab @tab X
298@item Apple MACE 6 @tab @tab X
299@item FLAC lossless audio @tab X @tab X
300@item Shorten lossless audio @tab @tab X
301@item Apple lossless audio @tab @tab X
302@tab QuickTime fourcc 'alac'
303@item FFmpeg Sonic @tab X @tab X
304@tab experimental lossy/lossless codec
305@item Qdesign QDM2 @tab @tab X
306@tab there are still some distortions
307@item Real COOK @tab @tab X
308@tab All versions except 5.1 are supported
309@item DSP Group TrueSpeech @tab @tab X
310@item True Audio (TTA) @tab @tab X
311@item Smacker Audio @tab @tab X
312@item WavPack Audio @tab @tab X
313@item Cin Audio @tab @tab X
314@tab Codec used in Delphine Software games.
315@item Intel Music Coder @tab @tab X
316@item Musepack @tab @tab X
317@tab Only SV7 is supported
318@item DT$ Coherent Audio @tab @tab X
319@item ATRAC 3 @tab @tab X
bf4a1f17 320@item Monkey's Audio @tab @tab X @tab Only versions 3.97-3.99 are supported
636b13c5 321@item Nellymoser ASAO @tab @tab X
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322@end multitable
323
324@code{X} means that encoding (resp. decoding) is supported.
325
326@code{I} means that an integer-only version is available, too (ensures high
327performance on systems without hardware floating point support).
328
329@chapter Platform Specific information
330
331@section BSD
332
333BSD make will not build FFmpeg, you need to install and use GNU Make
334(@file{gmake}).
335
336@section Windows
337
338To get help and instructions for using FFmpeg under Windows, check out
339the FFmpeg Windows Help Forum at
340@url{http://arrozcru.no-ip.org/ffmpeg/}.
341
342@subsection Native Windows compilation
343
344@itemize
345@item Install the current versions of MSYS and MinGW from
346@url{http://www.mingw.org/}. You can find detailed installation
347instructions in the download section and the FAQ.
348
349NOTE: Use at least bash 3.1. Older versions are known to be failing on the
350configure script.
351
352@item If you want to test the FFplay, also download
353the MinGW development library of SDL 1.2.x
354(@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
355@url{http://www.libsdl.org}. Unpack it in a temporary directory, and
356unpack the archive @file{i386-mingw32msvc.tar.gz} in the MinGW tool
357directory. Edit the @file{sdl-config} script so that it gives the
358correct SDL directory when invoked.
359
360@item If you want to use vhooks, you must have a POSIX compliant libdl in your
361MinGW system. Get dlfcn-win32 from @url{http://code.google.com/p/dlfcn-win32}.
362
363@item Extract the current version of FFmpeg.
364
365@item Start the MSYS shell (file @file{msys.bat}).
366
367@item Change to the FFmpeg directory and follow
368 the instructions of how to compile FFmpeg (file
369@file{INSTALL}). Usually, launching @file{./configure} and @file{make}
370suffices. If you have problems using SDL, verify that
371@file{sdl-config} can be launched from the MSYS command line.
372
373@item You can install FFmpeg in @file{Program Files/FFmpeg} by typing
374@file{make install}. Do not forget to copy @file{SDL.dll} to the place
375you launch @file{ffplay} from.
376
377@end itemize
378
379Notes:
380@itemize
381
382@item The target @file{make wininstaller} can be used to create a
383Nullsoft based Windows installer for FFmpeg and FFplay. @file{SDL.dll}
384must be copied to the FFmpeg directory in order to build the
385installer.
386
387@item By using @code{./configure --enable-shared} when configuring FFmpeg,
388you can build @file{avcodec.dll} and @file{avformat.dll}. With
389@code{make install} you install the FFmpeg DLLs and the associated
390headers in @file{Program Files/FFmpeg}.
391
392@item Visual C++ compatibility: If you used @code{./configure --enable-shared}
393when configuring FFmpeg, FFmpeg tries to use the Microsoft Visual
394C++ @code{lib} tool to build @code{avcodec.lib} and
395@code{avformat.lib}. With these libraries you can link your Visual C++
396code directly with the FFmpeg DLLs (see below).
397
398@end itemize
399
400@subsection Visual C++ compatibility
401
402FFmpeg will not compile under Visual C++ -- and it has too many
403dependencies on the GCC compiler to make a port viable. However,
404if you want to use the FFmpeg libraries in your own applications,
405you can still compile those applications using Visual C++. An
406important restriction to this is that you have to use the
407dynamically linked versions of the FFmpeg libraries (i.e. the
408DLLs), and you have to make sure that Visual-C++-compatible
409import libraries are created during the FFmpeg build process.
410
411This description of how to use the FFmpeg libraries with Visual C++ is
412based on Visual C++ 2005 Express Edition Beta 2. If you have a different
413version, you might have to modify the procedures slightly.
414
415Here are the step-by-step instructions for building the FFmpeg libraries
416so they can be used with Visual C++:
417
418@enumerate
419
420@item Install Visual C++ (if you have not done so already).
421
422@item Install MinGW and MSYS as described above.
423
424@item Add a call to @file{vcvars32.bat} (which sets up the environment
425variables for the Visual C++ tools) as the first line of
426@file{msys.bat}. The standard location for @file{vcvars32.bat} is
427@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
428and the standard location for @file{msys.bat} is
429@file{C:\msys\1.0\msys.bat}. If this corresponds to your setup, add the
430following line as the first line of @file{msys.bat}:
431
432@code{call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"}
433
434@item Start the MSYS shell (file @file{msys.bat}) and type @code{link.exe}.
435If you get a help message with the command line options of @code{link.exe},
436this means your environment variables are set up correctly, the
437Microsoft linker is on the path and will be used by FFmpeg to
438create Visual-C++-compatible import libraries.
439
440@item Extract the current version of FFmpeg and change to the FFmpeg directory.
441
442@item Type the command
443@code{./configure --enable-shared --disable-static --enable-memalign-hack}
444to configure and, if that did not produce any errors,
445type @code{make} to build FFmpeg.
446
447@item The subdirectories @file{libavformat}, @file{libavcodec}, and
448@file{libavutil} should now contain the files @file{avformat.dll},
449@file{avformat.lib}, @file{avcodec.dll}, @file{avcodec.lib},
450@file{avutil.dll}, and @file{avutil.lib}, respectively. Copy the three
451DLLs to your System32 directory (typically @file{C:\Windows\System32}).
452
453@end enumerate
454
455And here is how to use these libraries with Visual C++:
456
457@enumerate
458
459@item Create a new console application ("File / New / Project") and then
460select "Win32 Console Application". On the appropriate page of the
461Application Wizard, uncheck the "Precompiled headers" option.
462
463@item Write the source code for your application, or, for testing, just
464copy the code from an existing sample application into the source file
465that Visual C++ has already created for you. (Note that your source
466filehas to have a @code{.cpp} extension; otherwise, Visual C++ will not
467compile the FFmpeg headers correctly because in C mode, it does not
468recognize the @code{inline} keyword.) For example, you can copy
469@file{output_example.c} from the FFmpeg distribution (but you will
470have to make minor modifications so the code will compile under
471C++, see below).
472
473@item Open the "Project / Properties" dialog box. In the "Configuration"
474combo box, select "All Configurations" so that the changes you make will
475affect both debug and release builds. In the tree view on the left hand
476side, select "C/C++ / General", then edit the "Additional Include
477Directories" setting to contain the complete paths to the
478@file{libavformat}, @file{libavcodec}, and @file{libavutil}
479subdirectories of your FFmpeg directory. Note that the directories have
480to be separated using semicolons. Now select "Linker / General" from the
481tree view and edit the "Additional Library Directories" setting to
482contain the same three directories.
483
484@item Still in the "Project / Properties" dialog box, select "Linker / Input"
485from the tree view, then add the files @file{avformat.lib},
486@file{avcodec.lib}, and @file{avutil.lib} to the end of the "Additional
487Dependencies". Note that the names of the libraries have to be separated
488using spaces.
489
490@item Now, select "C/C++ / Code Generation" from the tree view. Select
491"Debug" in the "Configuration" combo box. Make sure that "Runtime
492Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
493the "Configuration" combo box and make sure that "Runtime Library" is
494set to "Multi-threaded DLL".
495
496@item Click "OK" to close the "Project / Properties" dialog box and build
497the application. Hopefully, it should compile and run cleanly. If you
498used @file{output_example.c} as your sample application, you will get a
499few compiler errors, but they are easy to fix. The first type of error
500occurs because Visual C++ does not allow an @code{int} to be converted to
501an @code{enum} without a cast. To solve the problem, insert the required
502casts (this error occurs once for a @code{CodecID} and once for a
503@code{CodecType}). The second type of error occurs because C++ requires
504the return value of @code{malloc} to be cast to the exact type of the
505pointer it is being assigned to. Visual C++ will complain that, for
506example, @code{(void *)} is being assigned to @code{(uint8_t *)} without
507an explicit cast. So insert an explicit cast in these places to silence
508the compiler. The third type of error occurs because the @code{snprintf}
509library function is called @code{_snprintf} under Visual C++. So just
510add an underscore to fix the problem. With these changes,
511@file{output_example.c} should compile under Visual C++, and the
512resulting executable should produce valid video files.
513
514@end enumerate
515
516@subsection Cross compilation for Windows with Linux
517
518You must use the MinGW cross compilation tools available at
519@url{http://www.mingw.org/}.
520
521Then configure FFmpeg with the following options:
522@example
523./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
524@end example
525(you can change the cross-prefix according to the prefix chosen for the
526MinGW tools).
527
528Then you can easily test FFmpeg with Wine
529(@url{http://www.winehq.com/}).
530
531@subsection Compilation under Cygwin
532
533Cygwin works very much like Unix.
534
535Just install your Cygwin with all the "Base" packages, plus the
536following "Devel" ones:
537@example
538binutils, gcc-core, make, subversion
539@end example
540
541Do not install binutils-20060709-1 (they are buggy on shared builds);
542use binutils-20050610-1 instead.
543
544Then run
545
546@example
547./configure --enable-static --disable-shared
548@end example
549
550to make a static build or
551
552@example
553./configure --enable-shared --disable-static
554@end example
555
556to build shared libraries.
557
558If you want to build FFmpeg with additional libraries, download Cygwin
559"Devel" packages for Ogg and Vorbis from any Cygwin packages repository
560and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
561(@url{http://cygwinports.dotsrc.org/}).
562
563@subsection Crosscompilation for Windows under Cygwin
564
565With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
566
567Just install your Cygwin as explained before, plus these additional
568"Devel" packages:
569@example
570gcc-mingw-core, mingw-runtime, mingw-zlib
571@end example
572
573and add some special flags to your configure invocation.
574
575For a static build run
576@example
577./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
578@end example
579
580and for a build with shared libraries
581@example
582./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
583@end example
584
585@section BeOS
586
5f757b85 587BeOS support is broken in mysterious ways.
d0e1cd3d
DB
588
589@chapter Developers Guide
590
591@section API
592@itemize @bullet
593@item libavcodec is the library containing the codecs (both encoding and
594decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
595
596@item libavformat is the library containing the file format handling (mux and
597demux code for several formats). Look at @file{ffplay.c} to use it in a
598player. See @file{output_example.c} to use it to generate audio or video
599streams.
600
601@end itemize
602
603@section Integrating libavcodec or libavformat in your program
604
605You can integrate all the source code of the libraries to link them
606statically to avoid any version problem. All you need is to provide a
607'config.mak' and a 'config.h' in the parent directory. See the defines
608generated by ./configure to understand what is needed.
609
610You can use libavcodec or libavformat in your commercial program, but
611@emph{any patch you make must be published}. The best way to proceed is
612to send your patches to the FFmpeg mailing list.
613
614@node Coding Rules
615@section Coding Rules
616
617FFmpeg is programmed in the ISO C90 language with a few additional
618features from ISO C99, namely:
619@itemize @bullet
620@item
621the @samp{inline} keyword;
622@item
623@samp{//} comments;
624@item
625designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
626@item
627compound literals (@samp{x = (struct s) @{ 17, 23 @};})
628@end itemize
629
630These features are supported by all compilers we care about, so we will not
631accept patches to remove their use unless they absolutely do not impair
632clarity and performance.
633
634All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
635compiles with several other compilers, such as the Compaq ccc compiler
636or Sun Studio 9, and we would like to keep it that way unless it would
637be exceedingly involved. To ensure compatibility, please do not use any
638additional C99 features or GCC extensions. Especially watch out for:
639@itemize @bullet
640@item
641mixing statements and declarations;
642@item
643@samp{long long} (use @samp{int64_t} instead);
644@item
645@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
646@item
647GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
648@end itemize
649
650Indent size is 4.
651The presentation is the one specified by 'indent -i4 -kr -nut'.
652The TAB character is forbidden outside of Makefiles as is any
653form of trailing whitespace. Commits containing either will be
654rejected by the Subversion repository.
655
656The main priority in FFmpeg is simplicity and small code size in order to
657minimize the bug count.
658
659Comments: Use the JavaDoc/Doxygen
660format (see examples below) so that code documentation
661can be generated automatically. All nontrivial functions should have a comment
662above them explaining what the function does, even if it is just one sentence.
663All structures and their member variables should be documented, too.
664@example
665/**
666 * @@file mpeg.c
667 * MPEG codec.
668 * @@author ...
669 */
670
671/**
672 * Summary sentence.
673 * more text ...
674 * ...
675 */
676typedef struct Foobar@{
677 int var1; /**< var1 description */
678 int var2; ///< var2 description
679 /** var3 description */
680 int var3;
681@} Foobar;
682
683/**
684 * Summary sentence.
685 * more text ...
686 * ...
687 * @@param my_parameter description of my_parameter
688 * @@return return value description
689 */
690int myfunc(int my_parameter)
691...
692@end example
693
694fprintf and printf are forbidden in libavformat and libavcodec,
695please use av_log() instead.
696
697Casts should be used only when necessary. Unneeded parentheses
698should also be avoided if they don't make the code easier to understand.
699
700@section Development Policy
701
702@enumerate
703@item
704 Contributions should be licensed under the LGPL 2.1, including an
705 "or any later version" clause, or the MIT license. GPL 2 including
706 an "or any later version" clause is also acceptable, but LGPL is
707 preferred.
708@item
709 You must not commit code which breaks FFmpeg! (Meaning unfinished but
710 enabled code which breaks compilation or compiles but does not work or
711 breaks the regression tests)
712 You can commit unfinished stuff (for testing etc), but it must be disabled
713 (#ifdef etc) by default so it does not interfere with other developers'
714 work.
715@item
716 You do not have to over-test things. If it works for you, and you think it
717 should work for others, then commit. If your code has problems
718 (portability, triggers compiler bugs, unusual environment etc) they will be
719 reported and eventually fixed.
720@item
721 Do not commit unrelated changes together, split them into self-contained
722 pieces. Also do not forget that if part B depends on part A, but A does not
723 depend on B, then A can and should be committed first and separate from B.
724 Keeping changes well split into self-contained parts makes reviewing and
725 understanding them on the commit log mailing list easier. This also helps
726 in case of debugging later on.
727 Also if you have doubts about splitting or not splitting, do not hesitate to
728 ask/discuss it on the developer mailing list.
729@item
730 Do not change behavior of the program (renaming options etc) without
731 first discussing it on the ffmpeg-devel mailing list. Do not remove
732 functionality from the code. Just improve!
733
734 Note: Redundant code can be removed.
735@item
736 Do not commit changes to the build system (Makefiles, configure script)
737 which change behavior, defaults etc, without asking first. The same
738 applies to compiler warning fixes, trivial looking fixes and to code
739 maintained by other developers. We usually have a reason for doing things
740 the way we do. Send your changes as patches to the ffmpeg-devel mailing
741 list, and if the code maintainers say OK, you may commit. This does not
742 apply to files you wrote and/or maintain.
743@item
744 We refuse source indentation and other cosmetic changes if they are mixed
745 with functional changes, such commits will be rejected and removed. Every
746 developer has his own indentation style, you should not change it. Of course
747 if you (re)write something, you can use your own style, even though we would
748 prefer if the indentation throughout FFmpeg was consistent (Many projects
749 force a given indentation style - we do not.). If you really need to make
750 indentation changes (try to avoid this), separate them strictly from real
751 changes.
752
753 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
754 then either do NOT change the indentation of the inner part within (do not
755 move it to the right)! or do so in a separate commit
756@item
757 Always fill out the commit log message. Describe in a few lines what you
758 changed and why. You can refer to mailing list postings if you fix a
759 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
760@item
761 If you apply a patch by someone else, include the name and email address in
762 the log message. Since the ffmpeg-cvslog mailing list is publicly
763 archived you should add some SPAM protection to the email address. Send an
764 answer to ffmpeg-devel (or wherever you got the patch from) saying that
765 you applied the patch.
766@item
767 When applying patches that have been discussed (at length) on the mailing
768 list, reference the thread in the log message.
769@item
770 Do NOT commit to code actively maintained by others without permission.
771 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
772 timeframe (12h for build failures and security fixes, 3 days small changes,
773 1 week for big patches) then commit your patch if you think it is OK.
774 Also note, the maintainer can simply ask for more time to review!
775@item
776 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
777 are sent there and reviewed by all the other developers. Bugs and possible
778 improvements or general questions regarding commits are discussed there. We
779 expect you to react if problems with your code are uncovered.
780@item
781 Update the documentation if you change behavior or add features. If you are
782 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
783 maintainer(s) will review and commit your stuff.
784@item
785 Try to keep important discussions and requests (also) on the public
786 developer mailing list, so that all developers can benefit from them.
787@item
788 Never write to unallocated memory, never write over the end of arrays,
789 always check values read from some untrusted source before using them
790 as array index or other risky things.
791@item
792 Remember to check if you need to bump versions for the specific libav
793 parts (libavutil, libavcodec, libavformat) you are changing. You need
794 to change the version integer and the version string.
795 Incrementing the first component means no backward compatibility to
796 previous versions (e.g. removal of a function from the public API).
797 Incrementing the second component means backward compatible change
798 (e.g. addition of a function to the public API).
799 Incrementing the third component means a noteworthy binary compatible
800 change (e.g. encoder bug fix that matters for the decoder).
801@item
802 If you add a new codec, remember to update the changelog, add it to
803 the supported codecs table in the documentation and bump the second
804 component of the @file{libavcodec} version number appropriately. If
805 it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
806 is only a decoder.
807@item
808 Do not change code to hide warnings without ensuring that the underlying
809 logic is correct and thus the warning was inappropriate.
810@item
811 If you add a new file, give it a proper license header. Do not copy and
812 paste it from a random place, use an existing file as template.
813@end enumerate
814
815We think our rules are not too hard. If you have comments, contact us.
816
817Note, these rules are mostly borrowed from the MPlayer project.
818
819@section Submitting patches
820
821First, (@pxref{Coding Rules}) above if you did not yet.
822
823When you submit your patch, try to send a unified diff (diff '-up'
824option). We cannot read other diffs :-)
825
826Also please do not submit a patch which contains several unrelated changes.
827Split it into separate, self-contained pieces. This does not mean splitting
828file by file. Instead, make the patch as small as possible while still
829keeping it as a logical unit that contains an individual change, even
830if it spans multiple files. This makes reviewing your patches much easier
831for us and greatly increases your chances of getting your patch applied.
832
833Run the regression tests before submitting a patch so that you can
834verify that there are no big problems.
835
836Patches should be posted as base64 encoded attachments (or any other
837encoding which ensures that the patch will not be trashed during
838transmission) to the ffmpeg-devel mailing list, see
839@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
840
841It also helps quite a bit if you tell us what the patch does (for example
842'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
843and has no lrint()')
844
845Also please if you send several patches, send each patch as a separate mail,
846do not attach several unrelated patches to the same mail.
847
848@section patch submission checklist
849
850@enumerate
851@item
852 Do the regression tests pass with the patch applied?
853@item
854 Is the patch a unified diff?
855@item
856 Is the patch against latest FFmpeg SVN?
857@item
858 Are you subscribed to ffmpeg-dev?
859 (the list is subscribers only due to spam)
860@item
861 Have you checked that the changes are minimal, so that the same cannot be
862 achieved with a smaller patch and/or simpler final code?
863@item
864 If the change is to speed critical code, did you benchmark it?
865@item
866 If you did any benchmarks, did you provide them in the mail?
867@item
868 Have you checked that the patch does not introduce buffer overflows or
869 other security issues?
870@item
871 Is the patch created from the root of the source tree, so it can be
872 applied with @code{patch -p0}?
873@item
874 Does the patch not mix functional and cosmetic changes?
875@item
876 Did you add tabs or trailing whitespace to the code? Both are forbidden.
877@item
878 Is the patch attached to the email you send?
879@item
880 Is the mime type of the patch correct? It should be text/x-diff or
881 text/x-patch or at least text/plain and not application/octet-stream.
882@item
883 If the patch fixes a bug, did you provide a verbose analysis of the bug?
884@item
885 If the patch fixes a bug, did you provide enough information, including
886 a sample, so the bug can be reproduced and the fix can be verified?
887 Note please do not attach samples >100k to mails but rather provide a
888 URL, you can upload to ftp://upload.mplayerhq.hu
889@item
890 Did you provide a verbose summary about what the patch does change?
891@item
892 Did you provide a verbose explanation why it changes things like it does?
893@item
894 Did you provide a verbose summary of the user visible advantages and
895 disadvantages if the patch is applied?
896@item
897 Did you provide an example so we can verify the new feature added by the
898 patch easily?
899@item
900 If you added a new file, did you insert a license header? It should be
901 taken from FFmpeg, not randomly copied and pasted from somewhere else.
902@item
903 You should maintain alphabetical order in alphabetically ordered lists as
904 long as doing so does not break API/ABI compatibility.
905@item
906 Lines with similar content should be aligned vertically when doing so
907 improves readability.
908@item
909 Did you provide a suggestion for a clear commit log message?
910@end enumerate
911
912@section Patch review process
913
914All patches posted to ffmpeg-devel will be reviewed, unless they contain a
915clear note that the patch is not for SVN.
916Reviews and comments will be posted as replies to the patch on the
917mailing list. The patch submitter then has to take care of every comment,
918that can be by resubmitting a changed patch or by discussion. Resubmitted
919patches will themselves be reviewed like any other patch. If at some point
920a patch passes review with no comments then it is approved, that can for
921simple and small patches happen immediately while large patches will generally
922have to be changed and reviewed many times before they are approved.
923After a patch is approved it will be committed to the repository.
924
925We will review all submitted patches, but sometimes we are quite busy so
926especially for large patches this can take several weeks.
927
928When resubmitting patches, please do not make any significant changes
929not related to the comments received during review. Such patches will
930be rejected. Instead, submit significant changes or new features as
931separate patches.
932
933@section Regression tests
934
935Before submitting a patch (or committing to the repository), you should at least
936test that you did not break anything.
937
938The regression tests build a synthetic video stream and a synthetic
939audio stream. These are then encoded and decoded with all codecs or
940formats. The CRC (or MD5) of each generated file is recorded in a
941result file. A 'diff' is launched to compare the reference results and
942the result file.
943
944The regression tests then go on to test the FFserver code with a
945limited set of streams. It is important that this step runs correctly
946as well.
947
948Run 'make test' to test all the codecs and formats.
949
950Run 'make fulltest' to test all the codecs, formats and FFserver.
951
952[Of course, some patches may change the results of the regression tests. In
953this case, the reference results of the regression tests shall be modified
954accordingly].
955
956@bye