minor spelling/grammar fixes
[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
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19AMR comes in two different flavors, wideband and narrowband. FFmpeg can make
20use of the AMR wideband (floating-point mode) and the AMR narrowband
21(floating-point mode) reference decoders and encoders.
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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
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27Note that libamr is copyrighted without any sort of license grant. This means
28that you can use it if you legally obtained it but you are not allowed to
29redistribute it in any way. @strong{Any FFmpeg binaries with libamr support
30you create are non-free and unredistributable!}
31
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32
33@chapter Supported File Formats and Codecs
34
35You can use the @code{-formats} option to have an exhaustive list.
36
37@section File Formats
38
39FFmpeg supports the following file formats through the @code{libavformat}
40library:
41
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
b264a084 55@item AVM2 (Flash 9) @tab X @tab X
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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.
e09f7d61 94@item Matroska @tab X @tab X
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95@item Electronic Arts Multimedia @tab @tab X
96@tab Used in various EA games; files have extensions like WVE and UV2.
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97@item MAXIS EA XA @tab @tab X
98@tab Used in Sim City 3000; file extension .xa.
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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 CDROM 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
118different 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.
bf4a1f17 127@item Monkey's Audio @tab @tab X
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128@item SIFF @tab @tab X
129@tab Audio and video format used in some games by Beam Software
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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
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134@item MSN TCP Webcam @tab @tab X
135@tab Used by MSN Messenger Webcam streams.
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136@item RL2 @tab @tab X
137@tab Audio and video format used in some games by Entertainment Software Partners
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138@item IFF @tab @tab X
139@tab Interchange File Format
2003d3da 140@item BFI @tab @tab X
b64c096b 141@tab Brute Force & Ignorance, used in Flash Traffic: City of Angels
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142@end multitable
143
144@code{X} means that encoding (resp. decoding) is supported.
145
146@section Image Formats
147
148FFmpeg can read and write images for each frame of a video sequence. The
149following image formats are supported:
150
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
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164@item RAS @tab @tab X @tab Sun Rasterfile
165@item PCX @tab @tab X @tab PC Paintbrush
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166@end multitable
167
168@code{X} means that encoding (resp. decoding) is supported.
169
170@section Video Codecs
171
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 CDROM FlashBack game.
252@item DXA Video @tab @tab X @tab Codec originally used in Feeble Files game.
fc4cbc16 253@item AVID DNxHD @tab X @tab X @tab aka SMPTE VC3
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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.
03b8e292 258@item AMV @tab @tab X @tab Used in Chinese MP3 players.
10cac9f9 259@item Mimic @tab @tab X @tab Used in MSN Messenger Webcam streams.
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260@end multitable
261
262@code{X} means that encoding (resp. decoding) is supported.
263
264@section Audio Codecs
265
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
cd15bbc9 269@item MPEG audio layer 1/3 @tab X @tab IX
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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
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278@item AMV IMA ADPCM @tab @tab X
279@tab Used in AMV files
d0e1cd3d 280@item MS IMA ADPCM @tab X @tab X
9dc92a38 281@item QT IMA ADPCM @tab X @tab X
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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.
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297@item MAXIS EA ADPCM @tab @tab X
298@tab Used in Sim City 3000.
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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
12877faf 342@tab SV7 and SV8 are supported
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343@item DT$ Coherent Audio @tab @tab X
344@item ATRAC 3 @tab @tab X
bf4a1f17 345@item Monkey's Audio @tab @tab X @tab Only versions 3.97-3.99 are supported
636b13c5 346@item Nellymoser ASAO @tab @tab X
d299be08 347@item 8SVX Audio @tab @tab X
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348@end multitable
349
350@code{X} means that encoding (resp. decoding) is supported.
351
352@code{I} means that an integer-only version is available, too (ensures high
353performance on systems without hardware floating point support).
354
355@chapter Platform Specific information
356
357@section BSD
358
359BSD make will not build FFmpeg, you need to install and use GNU Make
360(@file{gmake}).
361
362@section Windows
363
46a845d0 364To get help and instructions for building FFmpeg under Windows, check out
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365the FFmpeg Windows Help Forum at
366@url{http://arrozcru.no-ip.org/ffmpeg/}.
367
368@subsection Native Windows compilation
369
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370FFmpeg can be built to run natively on Windows using the MinGW tools. Install
371the current versions of MSYS and MinGW from @url{http://www.mingw.org/}. Also
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372install the coreutils package, and update to the latest MSYS make (note: not
373mingw32-make). You can find detailed installation
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374instructions in the download section and the FAQ.
375
c1989552 376Within the MSYS shell, configure and make with:
d0e1cd3d 377
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378@example
379./configure --enable-memalign-hack
380make
381make install
382@end example
d0e1cd3d 383
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384This will install @file{ffmpeg.exe} along with many other development files
385to @file{/usr/local}. You may specify another install path using the
386@code{--prefix} option in @file{configure}.
d0e1cd3d 387
c1989552 388Notes:
d0e1cd3d 389
c1989552 390@itemize
d0e1cd3d 391
751a6493 392@item Use at least bash 3.1. Older versions are known to fail on the
c1989552 393configure script.
d0e1cd3d 394
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395@item In order to compile vhooks, you must have a POSIX-compliant libdl in
396your MinGW system. Get dlfcn-win32 from
397@url{http://code.google.com/p/dlfcn-win32}.
d0e1cd3d 398
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399@item In order to compile FFplay, you must have the MinGW development library
400of SDL. Get it from @url{http://www.libsdl.org}.
401Edit the @file{bin/sdl-config} script so that it points to the correct prefix
402where SDL was installed. Verify that @file{sdl-config} can be launched from
403the MSYS command line.
d0e1cd3d 404
d0e1cd3d 405@item By using @code{./configure --enable-shared} when configuring FFmpeg,
c1989552 406you can build libavutil, libavcodec and libavformat as DLLs.
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407
408@end itemize
409
c1989552 410@subsection Microsoft Visual C++ compatibility
d0e1cd3d 411
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412As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
413want to use the libav* libraries in your own applications, you can still
414compile those applications using MSVC++. But the libav* libraries you link
415to @emph{must} be built with MinGW. However, you will not be able to debug
416inside the libav* libraries, since MSVC++ does not recognize the debug
417symbols generated by GCC.
418We strongly recommend you to move over from MSVC++ to MinGW tools.
d0e1cd3d 419
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420This description of how to use the FFmpeg libraries with MSVC++ is based on
421Microsoft Visual C++ 2005 Express Edition. If you have a different version,
422you might have to modify the procedures slightly.
d0e1cd3d 423
c1989552 424@subsubsection Using static libraries
d0e1cd3d 425
c1989552 426Assuming you have just built and installed FFmpeg in @file{/usr/local}.
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427
428@enumerate
429
430@item Create a new console application ("File / New / Project") and then
431select "Win32 Console Application". On the appropriate page of the
432Application Wizard, uncheck the "Precompiled headers" option.
433
434@item Write the source code for your application, or, for testing, just
435copy the code from an existing sample application into the source file
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436that MSVC++ has already created for you. For example, you can copy
437@file{output_example.c} from the FFmpeg distribution.
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438
439@item Open the "Project / Properties" dialog box. In the "Configuration"
440combo box, select "All Configurations" so that the changes you make will
441affect both debug and release builds. In the tree view on the left hand
442side, select "C/C++ / General", then edit the "Additional Include
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443Directories" setting to contain the path where the FFmpeg includes were
444installed (i.e. @file{c:\msys\1.0\local\include}).
445
446@item Still in the "Project / Properties" dialog box, select
447"Linker / General" from the tree view and edit the
448"Additional Library Directories" setting to contain the @file{lib}
449directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
450the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
451and the directory where MinGW's GCC libs are installed
452(i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
453"Linker / Input" from the tree view, and add the files @file{libavformat.a},
454@file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
455@file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
456to the end of "Additional Dependencies".
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457
458@item Now, select "C/C++ / Code Generation" from the tree view. Select
459"Debug" in the "Configuration" combo box. Make sure that "Runtime
460Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
461the "Configuration" combo box and make sure that "Runtime Library" is
462set to "Multi-threaded DLL".
463
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464@item Click "OK" to close the "Project / Properties" dialog box.
465
466@item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
467Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
468and install it in MSVC++'s include directory
469(i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
470
471@item MSVC++ also does not understand the @code{inline} keyword used by
472FFmpeg, so you must add this line before @code{#include}ing libav*:
473@example
474#define inline _inline
475@end example
476
477@item If you used @file{output_example.c} as your sample application,
478you will have to edit the @code{#include}s to point to the files which
479are under the @file{ffmpeg} directory (i.e. @code{<ffmpeg/avformat.h>}).
480
481@item Build your application, everything should work.
482
483@end enumerate
484
485@subsubsection Using shared libraries
486
487This is how to create DLL and LIB files that are compatible with MSVC++:
488
489@enumerate
490
491@item Add a call to @file{vcvars32.bat} (which sets up the environment
492variables for the Visual C++ tools) as the first line of @file{msys.bat}.
493The standard location for @file{vcvars32.bat} is
494@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
495and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
496If this corresponds to your setup, add the following line as the first line
497of @file{msys.bat}:
498
499@example
500call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
501@end example
502
503Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
504and run @file{c:\msys\1.0\msys.bat} from there.
505
506@item Within the MSYS shell, run @code{lib.exe}. If you get a help message
507from @file{Microsoft (R) Library Manager}, this means your environment
508variables are set up correctly, the @file{Microsoft (R) Library Manager}
509is on the path and will be used by FFmpeg to create
510MSVC++-compatible import libraries.
511
512@item Build FFmpeg with
513
514@example
515./configure --enable-shared --enable-memalign-hack
516make
517make install
518@end example
519
520Your install path (@file{/usr/local/} by default) should now have the
521necessary DLL and LIB files under the @file{bin} directory.
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522
523@end enumerate
524
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525To use those files with MSVC++, do the same as you would do with
526the static libraries, as described above. But in Step 4,
527you should only need to add the directory where the LIB files are installed
528(i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
529installed in the @file{bin} directory. And instead of adding @file{libxx.a}
530files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
531@file{avutil.lib}. There should be no need for @file{libmingwex.a},
532@file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
533statically linked into the DLLs. The @file{bin} directory contains a bunch
534of DLL files, but the ones that are actually used to run your application
535are the ones with a major version number in their filenames
536(i.e. @file{avcodec-51.dll}).
537
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538@subsection Cross compilation for Windows with Linux
539
540You must use the MinGW cross compilation tools available at
541@url{http://www.mingw.org/}.
542
543Then configure FFmpeg with the following options:
544@example
545./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
546@end example
547(you can change the cross-prefix according to the prefix chosen for the
548MinGW tools).
549
550Then you can easily test FFmpeg with Wine
551(@url{http://www.winehq.com/}).
552
553@subsection Compilation under Cygwin
554
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555The main issue with Cygwin is that newlib, its C library, does not
556contain llrint(). However, it is possible to leverage the
557implementation in MinGW.
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558
559Just install your Cygwin with all the "Base" packages, plus the
560following "Devel" ones:
561@example
29c3d42b 562binutils, gcc-core, make, subversion, mingw-runtime
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563@end example
564
565Do not install binutils-20060709-1 (they are buggy on shared builds);
566use binutils-20050610-1 instead.
567
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568Then create a small library that just contains llrint():
569
570@example
571ar x /usr/lib/mingw/libmingwex.a llrint.o
572ar cq /usr/local/lib/libllrint.a llrint.o
573@end example
574
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575Then run
576
577@example
29c3d42b 578./configure --enable-static --disable-shared --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
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579@end example
580
581to make a static build or
582
583@example
29c3d42b 584./configure --enable-shared --disable-static --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
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585@end example
586
587to build shared libraries.
588
589If you want to build FFmpeg with additional libraries, download Cygwin
590"Devel" packages for Ogg and Vorbis from any Cygwin packages repository
591and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
592(@url{http://cygwinports.dotsrc.org/}).
593
594@subsection Crosscompilation for Windows under Cygwin
595
596With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
597
598Just install your Cygwin as explained before, plus these additional
599"Devel" packages:
600@example
601gcc-mingw-core, mingw-runtime, mingw-zlib
602@end example
603
604and add some special flags to your configure invocation.
605
606For a static build run
607@example
608./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
609@end example
610
611and for a build with shared libraries
612@example
613./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
614@end example
615
616@section BeOS
617
5f757b85 618BeOS support is broken in mysterious ways.
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620@section OS/2
621
622For information about compiling FFmpeg on OS/2 see
623@url{http://www.edm2.com/index.php/FFmpeg}.
624
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625@chapter Developers Guide
626
627@section API
628@itemize @bullet
629@item libavcodec is the library containing the codecs (both encoding and
630decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
631
632@item libavformat is the library containing the file format handling (mux and
633demux code for several formats). Look at @file{ffplay.c} to use it in a
634player. See @file{output_example.c} to use it to generate audio or video
635streams.
636
637@end itemize
638
639@section Integrating libavcodec or libavformat in your program
640
641You can integrate all the source code of the libraries to link them
642statically to avoid any version problem. All you need is to provide a
643'config.mak' and a 'config.h' in the parent directory. See the defines
644generated by ./configure to understand what is needed.
645
646You can use libavcodec or libavformat in your commercial program, but
647@emph{any patch you make must be published}. The best way to proceed is
648to send your patches to the FFmpeg mailing list.
649
650@node Coding Rules
651@section Coding Rules
652
653FFmpeg is programmed in the ISO C90 language with a few additional
654features from ISO C99, namely:
655@itemize @bullet
656@item
657the @samp{inline} keyword;
658@item
659@samp{//} comments;
660@item
661designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
662@item
663compound literals (@samp{x = (struct s) @{ 17, 23 @};})
664@end itemize
665
666These features are supported by all compilers we care about, so we will not
667accept patches to remove their use unless they absolutely do not impair
668clarity and performance.
669
670All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
671compiles with several other compilers, such as the Compaq ccc compiler
672or Sun Studio 9, and we would like to keep it that way unless it would
673be exceedingly involved. To ensure compatibility, please do not use any
674additional C99 features or GCC extensions. Especially watch out for:
675@itemize @bullet
676@item
677mixing statements and declarations;
678@item
679@samp{long long} (use @samp{int64_t} instead);
680@item
681@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
682@item
683GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
684@end itemize
685
686Indent size is 4.
687The presentation is the one specified by 'indent -i4 -kr -nut'.
688The TAB character is forbidden outside of Makefiles as is any
689form of trailing whitespace. Commits containing either will be
690rejected by the Subversion repository.
691
692The main priority in FFmpeg is simplicity and small code size in order to
693minimize the bug count.
694
695Comments: Use the JavaDoc/Doxygen
696format (see examples below) so that code documentation
697can be generated automatically. All nontrivial functions should have a comment
698above them explaining what the function does, even if it is just one sentence.
699All structures and their member variables should be documented, too.
700@example
701/**
702 * @@file mpeg.c
703 * MPEG codec.
704 * @@author ...
705 */
706
707/**
708 * Summary sentence.
709 * more text ...
710 * ...
711 */
712typedef struct Foobar@{
713 int var1; /**< var1 description */
714 int var2; ///< var2 description
715 /** var3 description */
716 int var3;
717@} Foobar;
718
719/**
720 * Summary sentence.
721 * more text ...
722 * ...
723 * @@param my_parameter description of my_parameter
724 * @@return return value description
725 */
726int myfunc(int my_parameter)
727...
728@end example
729
730fprintf and printf are forbidden in libavformat and libavcodec,
731please use av_log() instead.
732
733Casts should be used only when necessary. Unneeded parentheses
734should also be avoided if they don't make the code easier to understand.
735
736@section Development Policy
737
738@enumerate
739@item
740 Contributions should be licensed under the LGPL 2.1, including an
741 "or any later version" clause, or the MIT license. GPL 2 including
742 an "or any later version" clause is also acceptable, but LGPL is
743 preferred.
744@item
745 You must not commit code which breaks FFmpeg! (Meaning unfinished but
746 enabled code which breaks compilation or compiles but does not work or
747 breaks the regression tests)
748 You can commit unfinished stuff (for testing etc), but it must be disabled
749 (#ifdef etc) by default so it does not interfere with other developers'
750 work.
751@item
752 You do not have to over-test things. If it works for you, and you think it
753 should work for others, then commit. If your code has problems
754 (portability, triggers compiler bugs, unusual environment etc) they will be
755 reported and eventually fixed.
756@item
757 Do not commit unrelated changes together, split them into self-contained
758 pieces. Also do not forget that if part B depends on part A, but A does not
759 depend on B, then A can and should be committed first and separate from B.
760 Keeping changes well split into self-contained parts makes reviewing and
761 understanding them on the commit log mailing list easier. This also helps
762 in case of debugging later on.
763 Also if you have doubts about splitting or not splitting, do not hesitate to
764 ask/discuss it on the developer mailing list.
765@item
766 Do not change behavior of the program (renaming options etc) without
767 first discussing it on the ffmpeg-devel mailing list. Do not remove
768 functionality from the code. Just improve!
769
770 Note: Redundant code can be removed.
771@item
772 Do not commit changes to the build system (Makefiles, configure script)
773 which change behavior, defaults etc, without asking first. The same
774 applies to compiler warning fixes, trivial looking fixes and to code
775 maintained by other developers. We usually have a reason for doing things
776 the way we do. Send your changes as patches to the ffmpeg-devel mailing
777 list, and if the code maintainers say OK, you may commit. This does not
778 apply to files you wrote and/or maintain.
779@item
780 We refuse source indentation and other cosmetic changes if they are mixed
781 with functional changes, such commits will be rejected and removed. Every
782 developer has his own indentation style, you should not change it. Of course
783 if you (re)write something, you can use your own style, even though we would
784 prefer if the indentation throughout FFmpeg was consistent (Many projects
785 force a given indentation style - we do not.). If you really need to make
786 indentation changes (try to avoid this), separate them strictly from real
787 changes.
788
789 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
790 then either do NOT change the indentation of the inner part within (do not
791 move it to the right)! or do so in a separate commit
792@item
793 Always fill out the commit log message. Describe in a few lines what you
794 changed and why. You can refer to mailing list postings if you fix a
795 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
796@item
797 If you apply a patch by someone else, include the name and email address in
798 the log message. Since the ffmpeg-cvslog mailing list is publicly
799 archived you should add some SPAM protection to the email address. Send an
800 answer to ffmpeg-devel (or wherever you got the patch from) saying that
801 you applied the patch.
802@item
803 When applying patches that have been discussed (at length) on the mailing
804 list, reference the thread in the log message.
805@item
806 Do NOT commit to code actively maintained by others without permission.
807 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
808 timeframe (12h for build failures and security fixes, 3 days small changes,
809 1 week for big patches) then commit your patch if you think it is OK.
810 Also note, the maintainer can simply ask for more time to review!
811@item
812 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
813 are sent there and reviewed by all the other developers. Bugs and possible
814 improvements or general questions regarding commits are discussed there. We
815 expect you to react if problems with your code are uncovered.
816@item
817 Update the documentation if you change behavior or add features. If you are
818 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
819 maintainer(s) will review and commit your stuff.
820@item
821 Try to keep important discussions and requests (also) on the public
822 developer mailing list, so that all developers can benefit from them.
823@item
824 Never write to unallocated memory, never write over the end of arrays,
825 always check values read from some untrusted source before using them
826 as array index or other risky things.
827@item
828 Remember to check if you need to bump versions for the specific libav
829 parts (libavutil, libavcodec, libavformat) you are changing. You need
830 to change the version integer and the version string.
831 Incrementing the first component means no backward compatibility to
832 previous versions (e.g. removal of a function from the public API).
833 Incrementing the second component means backward compatible change
834 (e.g. addition of a function to the public API).
835 Incrementing the third component means a noteworthy binary compatible
836 change (e.g. encoder bug fix that matters for the decoder).
837@item
838 If you add a new codec, remember to update the changelog, add it to
839 the supported codecs table in the documentation and bump the second
840 component of the @file{libavcodec} version number appropriately. If
74a926ff 841 it has a fourcc, add it to @file{libavformat/riff.c}, even if it
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842 is only a decoder.
843@item
53407b64 844 Compiler warnings indicate potential bugs or code with bad style. If a type of
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845 warning always points to correct and clean code, that warning should
846 be disabled, not the code changed.
847 Thus the remaining warnings can either be bugs or correct code.
beaa4a91 848 If it is a bug, the bug has to be fixed. If it is not, the code should
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849 be changed to not generate a warning unless that causes a slowdown
850 or obfuscates the code.
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851@item
852 If you add a new file, give it a proper license header. Do not copy and
853 paste it from a random place, use an existing file as template.
854@end enumerate
855
856We think our rules are not too hard. If you have comments, contact us.
857
858Note, these rules are mostly borrowed from the MPlayer project.
859
860@section Submitting patches
861
862First, (@pxref{Coding Rules}) above if you did not yet.
863
864When you submit your patch, try to send a unified diff (diff '-up'
865option). We cannot read other diffs :-)
866
867Also please do not submit a patch which contains several unrelated changes.
868Split it into separate, self-contained pieces. This does not mean splitting
869file by file. Instead, make the patch as small as possible while still
870keeping it as a logical unit that contains an individual change, even
871if it spans multiple files. This makes reviewing your patches much easier
872for us and greatly increases your chances of getting your patch applied.
873
874Run the regression tests before submitting a patch so that you can
875verify that there are no big problems.
876
877Patches should be posted as base64 encoded attachments (or any other
878encoding which ensures that the patch will not be trashed during
879transmission) to the ffmpeg-devel mailing list, see
880@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
881
882It also helps quite a bit if you tell us what the patch does (for example
883'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
884and has no lrint()')
885
886Also please if you send several patches, send each patch as a separate mail,
887do not attach several unrelated patches to the same mail.
888
889@section patch submission checklist
890
891@enumerate
892@item
893 Do the regression tests pass with the patch applied?
894@item
895 Is the patch a unified diff?
896@item
897 Is the patch against latest FFmpeg SVN?
898@item
899 Are you subscribed to ffmpeg-dev?
900 (the list is subscribers only due to spam)
901@item
902 Have you checked that the changes are minimal, so that the same cannot be
903 achieved with a smaller patch and/or simpler final code?
904@item
905 If the change is to speed critical code, did you benchmark it?
906@item
907 If you did any benchmarks, did you provide them in the mail?
908@item
909 Have you checked that the patch does not introduce buffer overflows or
910 other security issues?
911@item
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912 If you add a new demuxer or decoder, have you checked that it does not
913 crash with damaged input (see tools/trasher)?
914@item
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915 Is the patch created from the root of the source tree, so it can be
916 applied with @code{patch -p0}?
917@item
918 Does the patch not mix functional and cosmetic changes?
919@item
920 Did you add tabs or trailing whitespace to the code? Both are forbidden.
921@item
922 Is the patch attached to the email you send?
923@item
924 Is the mime type of the patch correct? It should be text/x-diff or
925 text/x-patch or at least text/plain and not application/octet-stream.
926@item
927 If the patch fixes a bug, did you provide a verbose analysis of the bug?
928@item
929 If the patch fixes a bug, did you provide enough information, including
930 a sample, so the bug can be reproduced and the fix can be verified?
931 Note please do not attach samples >100k to mails but rather provide a
932 URL, you can upload to ftp://upload.mplayerhq.hu
933@item
934 Did you provide a verbose summary about what the patch does change?
935@item
936 Did you provide a verbose explanation why it changes things like it does?
937@item
938 Did you provide a verbose summary of the user visible advantages and
939 disadvantages if the patch is applied?
940@item
941 Did you provide an example so we can verify the new feature added by the
942 patch easily?
943@item
944 If you added a new file, did you insert a license header? It should be
945 taken from FFmpeg, not randomly copied and pasted from somewhere else.
946@item
947 You should maintain alphabetical order in alphabetically ordered lists as
948 long as doing so does not break API/ABI compatibility.
949@item
950 Lines with similar content should be aligned vertically when doing so
951 improves readability.
952@item
953 Did you provide a suggestion for a clear commit log message?
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954@item
955 Did you test your decoder or demuxer against damaged data? If no, see
956 tools/trasher and the noise bitstream filter. Your decoder or demuxer
fe74278f 957 should not crash or end in a (near) infinite loop when fed damaged data.
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958@end enumerate
959
960@section Patch review process
961
962All patches posted to ffmpeg-devel will be reviewed, unless they contain a
963clear note that the patch is not for SVN.
964Reviews and comments will be posted as replies to the patch on the
965mailing list. The patch submitter then has to take care of every comment,
966that can be by resubmitting a changed patch or by discussion. Resubmitted
967patches will themselves be reviewed like any other patch. If at some point
968a patch passes review with no comments then it is approved, that can for
969simple and small patches happen immediately while large patches will generally
970have to be changed and reviewed many times before they are approved.
971After a patch is approved it will be committed to the repository.
972
973We will review all submitted patches, but sometimes we are quite busy so
974especially for large patches this can take several weeks.
975
976When resubmitting patches, please do not make any significant changes
977not related to the comments received during review. Such patches will
978be rejected. Instead, submit significant changes or new features as
979separate patches.
980
981@section Regression tests
982
983Before submitting a patch (or committing to the repository), you should at least
984test that you did not break anything.
985
986The regression tests build a synthetic video stream and a synthetic
987audio stream. These are then encoded and decoded with all codecs or
988formats. The CRC (or MD5) of each generated file is recorded in a
989result file. A 'diff' is launched to compare the reference results and
990the result file.
991
992The regression tests then go on to test the FFserver code with a
993limited set of streams. It is important that this step runs correctly
994as well.
995
996Run 'make test' to test all the codecs and formats.
997
998Run 'make fulltest' to test all the codecs, formats and FFserver.
999
1000[Of course, some patches may change the results of the regression tests. In
1001this case, the reference results of the regression tests shall be modified
1002accordingly].
1003
1004@bye