give additional use case for version bumping; remove no longer true statement about...
[libav.git] / doc / general.texi
1 \input texinfo @c -*- texinfo -*-
3 @settitle General Documentation
4 @titlepage
5 @sp 7
6 @center @titlefont{General Documentation}
7 @sp 3
8 @end titlepage
11 @chapter external libraries
13 FFmpeg can be hooked up with a number of external libraries to add support
14 for more formats. None of them are used by default, their use has to be
15 explicitly requested by passing the appropriate flags to @file{./configure}.
17 @section AMR
19 AMR comes in two different flavors, wideband and narrowband. FFmpeg can make
20 use of the AMR wideband (floating-point mode) and the AMR narrowband
21 (floating-point mode) reference decoders and encoders.
23 Go to @url{} and follow the instructions for
24 installing the libraries. Then pass @code{--enable-libamr-nb} and/or
25 @code{--enable-libamr-wb} to configure to enable the libraries.
27 Note that libamr is copyrighted without any sort of license grant. This means
28 that you can use it if you legally obtained it but you are not allowed to
29 redistribute it in any way. @strong{Any FFmpeg binaries with libamr support
30 you create are non-free and unredistributable!}
33 @chapter Supported File Formats and Codecs
35 You can use the @code{-formats} option to have an exhaustive list.
37 @section File Formats
39 FFmpeg supports the following file formats through the @code{libavformat}
40 library:
42 @multitable @columnfractions .4 .1 .1 .4
43 @item Supported File Format @tab Encoding @tab Decoding @tab Comments
44 @item 4xm @tab @tab X
45 @tab 4X Technologies format, used in some games.
46 @item ADTS AAC audio @tab X @tab X
47 @item American Laser Games MM @tab @tab X
48 @tab Multimedia format used in games like Mad Dog McCree.
49 @item ASF @tab X @tab X
50 @item AVI @tab X @tab X
51 @item AVM2 (Flash 9) @tab X @tab X
52 @tab Only embedded audio is decoded.
53 @item AVS @tab @tab X
54 @tab Multimedia format used by the Creature Shock game.
55 @item Bethsoft VID @tab @tab X
56 @tab Used in some games from Bethesda Softworks.
57 @item BFI @tab @tab X
58 @tab Brute Force & Ignorance, used in Flash Traffic: City of Angels.
59 @item C93 @tab @tab X
60 @tab Used in the game Cyberia from Interplay.
61 @item CIN @tab @tab X
62 @tab Multimedia format used by Delphine Software games.
63 @item Creative VOC @tab X @tab X
64 @tab Created for the Sound Blaster Pro.
65 @item CRYO APC @tab @tab X
66 @tab Audio format used in some games by CRYO Interactive Entertainment.
67 @item DV @tab X @tab X
68 @item DXA @tab @tab X
69 @tab This format is used in the non-Windows version of the Feeble Files
70 game and different game cutscenes repacked for use with ScummVM.
71 @item Electronic Arts Multimedia @tab @tab X
72 @tab Used in various EA games; files have extensions like WVE and UV2.
73 @item FLIC @tab @tab X
74 @tab .fli/.flc files
75 @item FLV @tab X @tab X
76 @tab Macromedia Flash video files
77 @item GXF @tab X @tab X
78 @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley
79 playout servers.
80 @item id Cinematic @tab @tab X
81 @tab Used in Quake II.
82 @item id RoQ @tab X @tab X
83 @tab Used in Quake III, Jedi Knight 2, other computer games.
84 @item IFF @tab @tab X
85 @tab Interchange File Format
86 @item Interplay MVE @tab @tab X
87 @tab Format used in various Interplay computer games.
88 @item LMLM4 @tab @tab X
89 @tab Used by Linux Media Labs MPEG-4 PCI boards
90 @item Matroska @tab X @tab X
91 @item MAXIS EA XA @tab @tab X
92 @tab Used in Sim City 3000; file extension .xa.
93 @item Monkey's Audio @tab @tab X
94 @item Motion Pixels MVI @tab @tab X
95 @item MOV/QuickTime @tab X @tab X
96 @item MPEG audio @tab X @tab X
97 @item MPEG-1 systems @tab X @tab X
98 @tab muxed audio and video
99 @item MPEG-2 PS @tab X @tab X
100 @tab also known as @code{VOB} file
101 @item MPEG-2 TS @tab @tab X
102 @tab also known as DVB Transport Stream
103 @item MPEG-4 @tab X @tab X
104 @tab MPEG-4 is a variant of QuickTime.
105 @item MSN TCP webcam @tab @tab X
106 @tab Used by MSN Messenger webcam streams.
107 @item MXF @tab @tab X
108 @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
109 @item Nullsoft Video @tab @tab X
110 @item NUT @tab X @tab X
111 @tab NUT Open Container Format
112 @item OMA @tab @tab X
113 @tab Audio format used in Sony Sonic Stage and Sony Vegas.
114 @item PlayStation STR @tab @tab X
115 @item PVA @tab @tab X
116 @tab Used by TechnoTrend DVB PCI boards.
117 @item raw AC-3 @tab X @tab X
118 @item raw CRI ADX audio @tab X @tab X
119 @item raw MJPEG @tab X @tab X
120 @item raw MPEG video @tab X @tab X
121 @item raw MPEG-4 video @tab X @tab X
122 @item raw PCM 8/16/32 bits, mu-law/A-law @tab X @tab X
123 @item raw Shorten audio @tab @tab X
124 @item RealMedia @tab X @tab X
125 @item RL2 @tab @tab X
126 @tab Audio and video format used in some games by Entertainment Software Partners.
127 @item Sega FILM/CPK @tab @tab X
128 @tab Used in many Sega Saturn console games.
129 @item SEQ @tab @tab X
130 @tab Tiertex .seq files used in the DOS CD-ROM version of the game Flashback.
131 @item Sierra Online @tab @tab X
132 @tab .sol files used in Sierra Online games.
133 @item Sierra VMD @tab @tab X
134 @tab Used in Sierra CD-ROM games.
135 @item SIFF @tab @tab X
136 @tab Audio and video format used in some games by Beam Software.
137 @item Smacker @tab @tab X
138 @tab Multimedia format used by many games.
139 @item SUN AU format @tab X @tab X
140 @item THP @tab @tab X
141 @tab Used on the Nintendo GameCube.
142 @item WAV @tab X @tab X
143 @item WC3 Movie @tab @tab X
144 @tab Multimedia format used in Origin's Wing Commander III computer game.
145 @item Westwood Studios VQA/AUD @tab @tab X
146 @tab Multimedia formats used in Westwood Studios games.
147 @end multitable
149 @code{X} means that encoding (resp. decoding) is supported.
151 @section Image Formats
153 FFmpeg can read and write images for each frame of a video sequence. The
154 following image formats are supported:
156 @multitable @columnfractions .4 .1 .1 .4
157 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
158 @item .Y.U.V @tab X @tab X @tab one raw file per component
159 @item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
160 @item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
161 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
162 @item PCX @tab @tab X @tab PC Paintbrush
163 @item PGM, PPM @tab X @tab X
164 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
165 @item PNG @tab X @tab X @tab 2/4 bpp not supported yet
166 @item PTX @tab @tab X @tab V.Flash PTX format
167 @item RAS @tab @tab X @tab Sun Rasterfile
168 @item SGI @tab X @tab X @tab SGI RGB image format
169 @item Targa @tab @tab X @tab Targa (.TGA) image format
170 @item TIFF @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
171 @end multitable
173 @code{X} means that encoding (resp. decoding) is supported.
175 @section Video Codecs
177 @multitable @columnfractions .4 .1 .1 .4
178 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
179 @item 4X Video @tab @tab X
180 @tab Used in certain computer games.
181 @item American Laser Games Video @tab @tab X
182 @tab Used in games like Mad Dog McCree.
183 @item AMV @tab @tab X
184 @tab Used in Chinese MP3 players.
185 @item Apple Animation @tab X @tab X
186 @tab fourcc: 'rle '
187 @item Apple Graphics @tab @tab X
188 @tab fourcc: 'smc '
189 @item Apple MJPEG-B @tab @tab X
190 @item Apple QuickDraw @tab @tab X
191 @tab fourcc: qdrw
192 @item Apple Video @tab @tab X
193 @tab fourcc: rpza
194 @item Asus v1 @tab X @tab X
195 @tab fourcc: ASV1
196 @item Asus v2 @tab X @tab X
197 @tab fourcc: ASV2
198 @item ATI VCR1 @tab @tab X
199 @tab fourcc: VCR1
200 @item ATI VCR2 @tab @tab X
201 @tab fourcc: VCR2
202 @item Autodesk RLE @tab @tab X
203 @tab fourcc: AASC
204 @item AVID DNxHD @tab X @tab X
205 @tab aka SMPTE VC3
206 @item AVS video @tab @tab X
207 @tab Video encoding used by the Creature Shock game.
208 @item Bethsoft VID @tab @tab X
209 @tab Used in some games from Bethesda Softworks.
210 @item C93 video @tab @tab X
211 @tab Codec used in Cyberia game.
212 @item CamStudio @tab @tab X
213 @tab fourcc: CSCD
214 @item Cin video @tab @tab X
215 @tab Codec used in Delphine Software games.
216 @item Cinepak @tab @tab X
217 @item Cirrus Logic AccuPak @tab @tab X
218 @tab fourcc: CLJR
219 @item Creative YUV @tab @tab X
220 @tab fourcc: CYUV
221 @item Dirac @tab X @tab X
222 @tab Supported through the external libdirac/libschroedinger libraries.
223 @item Duck TrueMotion v1 @tab @tab X
224 @tab fourcc: DUCK
225 @item Duck TrueMotion v2 @tab @tab X
226 @tab fourcc: TM20
227 @item DV @tab X @tab X
228 @item DXA Video @tab @tab X
229 @tab Codec originally used in Feeble Files game.
230 @item Electronic Arts CMV @tab @tab X
231 @tab Used in NHL 95 game.
232 @item FFmpeg Video 1 @tab X @tab X
233 @tab experimental lossless codec (fourcc: FFV1)
234 @item Flash Screen Video @tab X @tab X
235 @tab fourcc: FSV1
236 @item FLIC video @tab @tab X
237 @item FLV @tab X @tab X
238 @tab Sorenson H.263 used in Flash
239 @item Fraps FPS1 @tab @tab X
240 @item H.261 @tab X @tab X
241 @item H.263(+) @tab X @tab X
242 @tab also known as RealVideo 1.0
243 @item H.264 @tab @tab X
244 @item HuffYUV @tab X @tab X
245 @item IBM Ultimotion @tab @tab X
246 @tab fourcc: ULTI
247 @item id Cinematic video @tab @tab X
248 @tab Used in Quake II.
249 @item id RoQ @tab X @tab X
250 @tab Used in Quake III, Jedi Knight 2, other computer games.
251 @item Intel Indeo 3 @tab @tab X
252 @item Interplay Video @tab @tab X
253 @tab Used in Interplay .MVE files.
254 @item JPEG-LS @tab X @tab X
255 @tab fourcc: MJLS, lossless and near-lossless is supported.
256 @item KMVC @tab @tab X
257 @tab Codec used in Worms games.
258 @item LOCO @tab @tab X
259 @item lossless MJPEG @tab X @tab X
260 @item Microsoft RLE @tab @tab X
261 @item Microsoft Video-1 @tab @tab X
262 @item Mimic @tab @tab X
263 @tab Used in MSN Messenger Webcam streams.
264 @item Miro VideoXL @tab @tab X
265 @tab fourcc: VIXL
266 @item MJPEG @tab X @tab X
267 @item Motion Pixels Video @tab @tab X
268 @item MPEG-1 @tab X @tab X
269 @item MPEG-2 @tab X @tab X
270 @item MPEG-4 @tab X @tab X
271 @item MSMPEG4 V1 @tab X @tab X
272 @item MSMPEG4 V2 @tab X @tab X
273 @item MSMPEG4 V3 @tab X @tab X
274 @item MSZH @tab @tab X
275 @tab Part of LCL
276 @item On2 VP3 @tab @tab X
277 @tab still experimental
278 @item On2 VP5 @tab @tab X
279 @tab fourcc: VP50
280 @item On2 VP6 @tab @tab X
281 @tab fourcc: VP60,VP61,VP62
282 @item planar RGB @tab @tab X
283 @tab fourcc: 8BPS
284 @item QPEG @tab @tab X
285 @tab fourccs: QPEG, Q1.0, Q1.1
286 @item RealVideo 1.0 @tab X @tab X
287 @item RealVideo 2.0 @tab X @tab X
288 @item Renderware TXD @tab @tab X
289 @tab Texture dictionaries used by the Renderware Engine.
290 @item RTjpeg @tab @tab X
291 @tab Video encoding used in NuppelVideo files.
292 @item Smacker video @tab @tab X
293 @tab Video encoding used in Smacker.
294 @item Snow @tab X @tab X
295 @tab experimental wavelet codec (fourcc: SNOW)
296 @item Sony PlayStation MDEC @tab @tab X
297 @item Sorenson Video 1 @tab X @tab X
298 @tab fourcc: SVQ1
299 @item Sorenson Video 3 @tab @tab X
300 @tab fourcc: SVQ3
301 @item Sunplus MJPEG @tab @tab X
302 @tab fourcc: SP5X
303 @item TechSmith Camtasia @tab @tab X
304 @tab fourcc: TSCC
305 @item Theora @tab X @tab X
306 @tab still experimental
307 @item THP @tab @tab X
308 @tab Used on the Nintendo GameCube.
309 @item Tiertex Seq video @tab @tab X
310 @tab Codec used in DOS CD-ROM FlashBack game.
311 @item VC-1 @tab @tab X
312 @item VMD Video @tab @tab X
313 @tab Used in Sierra VMD files.
314 @item VMware Video @tab @tab X
315 @tab Codec used in videos captured by VMware.
316 @item Westwood VQA @tab @tab X
317 @item Winnov WNV1 @tab @tab X
318 @item WMV7 @tab X @tab X
319 @item WMV8 @tab X @tab X
320 @item WMV9 @tab @tab X
321 @tab not completely working
322 @item Xan/WC3 @tab @tab X
323 @tab Used in Wing Commander III .MVE files.
324 @item ZLIB @tab X @tab X
325 @tab part of LCL, encoder experimental
326 @item ZMBV @tab X @tab X
327 @tab Encoder works only in PAL8.
328 @end multitable
330 @code{X} means that encoding (resp. decoding) is supported.
332 @section Audio Codecs
334 @multitable @columnfractions .4 .1 .1 .1 .7
335 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
336 @item 4X IMA ADPCM @tab @tab X
337 @item 8SVX audio @tab @tab X
338 @item AAC @tab X @tab X
339 @tab Supported through the external library libfaac/libfaad.
340 @item AC-3 @tab IX @tab IX
341 @tab liba52 can be used alternatively for decoding.
342 @item AMR-NB @tab X @tab X
343 @tab Supported through an external library.
344 @item AMR-WB @tab X @tab X
345 @tab Supported through an external library.
346 @item AMV IMA ADPCM @tab @tab X
347 @tab Used in AMV files
348 @item Apple lossless audio @tab @tab X
349 @tab QuickTime fourcc 'alac'
350 @item Apple MACE 3 @tab @tab X
351 @item Apple MACE 6 @tab @tab X
352 @item ATRAC 3 @tab @tab X
353 @item CD-ROM XA ADPCM @tab @tab X
354 @item Cin audio @tab @tab X
355 @tab Codec used in Delphine Software International games.
356 @item Creative ADPCM @tab @tab X
357 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
358 @item CRI ADX ADPCM @tab X @tab X
359 @tab Used in Sega Dreamcast games.
360 @item DSP Group TrueSpeech @tab @tab X
361 @item DTS Coherent Audio @tab @tab X
362 @item Duck DK3 IMA ADPCM @tab @tab X
363 @tab Used in some Sega Saturn console games.
364 @item Duck DK4 IMA ADPCM @tab @tab X
365 @tab Used in some Sega Saturn console games.
366 @item DV audio @tab @tab X
367 @item Electronic Arts ADPCM @tab @tab X
368 @tab Used in various EA titles.
369 @item Sonic @tab X @tab X
370 @tab experimental codec
371 @item Sonic lossless @tab X @tab X
372 @tab experimental codec
373 @item FLAC lossless audio @tab X @tab X
374 @item G.726 ADPCM @tab X @tab X
375 @item id RoQ DPCM @tab X @tab X
376 @tab Used in Quake III, Jedi Knight 2, other computer games.
377 @item Intel Music Coder @tab @tab X
378 @item Interplay MVE DPCM @tab @tab X
379 @tab Used in various Interplay computer games.
380 @item MAXIS EA ADPCM @tab @tab X
381 @tab Used in Sim City 3000.
382 @item Microsoft ADPCM @tab X @tab X
383 @item MLP/TrueHD @tab @tab X
384 @tab Used in DVD-Audio and Blu-Ray discs.
385 @item Monkey's Audio @tab @tab X
386 @tab Only versions 3.97-3.99 are supported.
387 @item MPEG audio layer 1/3 @tab X @tab IX
388 @tab MP3 encoding is supported through the external library LAME.
389 @item MPEG audio layer 2 @tab IX @tab IX
390 @item MS IMA ADPCM @tab X @tab X
391 @item Musepack @tab @tab X
392 @tab SV7 and SV8 are supported.
393 @item Nellymoser ASAO @tab @tab X
394 @item Qdesign QDM2 @tab @tab X
395 @tab There are still some distortions.
396 @item QT IMA ADPCM @tab X @tab X
397 @item RA144 @tab @tab X
398 @tab Real 14400 bit/s codec
399 @item RA288 @tab @tab X
400 @tab Real 28800 bit/s codec
401 @item RADnet @tab X @tab IX
402 @tab real low bitrate AC-3 codec
403 @item Real COOK @tab @tab X
404 @tab All versions except 5.1 are supported.
405 @item Shorten @tab @tab X
406 @item Sierra Online DPCM @tab @tab X
407 @tab Used in Sierra Online game audio files.
408 @item Smacker audio @tab @tab X
409 @item SMJPEG IMA ADPCM @tab @tab X
410 @tab Used in certain Loki game ports.
411 @item THP ADPCM @tab @tab X
412 @tab Used on the Nintendo GameCube.
413 @item True Audio (TTA) @tab @tab X
414 @item Vorbis @tab X @tab X
415 @item WavPack @tab @tab X
416 @item Westwood Studios IMA ADPCM @tab @tab X
417 @tab Used in Westwood Studios games like Command and Conquer.
418 @item WMA v1/v2 @tab X @tab X
419 @item Xan DPCM @tab @tab X
420 @tab Used in Origin's Wing Commander IV AVI files.
421 @end multitable
423 @code{X} means that encoding (resp. decoding) is supported.
425 @code{I} means that an integer-only version is available, too (ensures high
426 performance on systems without hardware floating point support).
428 @chapter Platform Specific information
430 @section BSD
432 BSD make will not build FFmpeg, you need to install and use GNU Make
433 (@file{gmake}).
435 @section Windows
437 To get help and instructions for building FFmpeg under Windows, check out
438 the FFmpeg Windows Help Forum at
439 @url{}.
441 @subsection Native Windows compilation
443 FFmpeg can be built to run natively on Windows using the MinGW tools. Install
444 the current versions of MSYS and MinGW from @url{}. Also
445 install the coreutils package, and update to the latest MSYS make (note: not
446 mingw32-make). You can find detailed installation
447 instructions in the download section and the FAQ.
449 Within the MSYS shell, configure and make with:
451 @example
452 ./configure --enable-memalign-hack
453 make
454 make install
455 @end example
457 This will install @file{ffmpeg.exe} along with many other development files
458 to @file{/usr/local}. You may specify another install path using the
459 @code{--prefix} option in @file{configure}.
461 Notes:
463 @itemize
465 @item Use at least bash 3.1. Older versions are known to fail on the
466 configure script.
468 @item In order to compile vhooks, you must have a POSIX-compliant libdl in
469 your MinGW system. Get dlfcn-win32 from
470 @url{}.
472 @item In order to compile FFplay, you must have the MinGW development library
473 of SDL. Get it from @url{}.
474 Edit the @file{bin/sdl-config} script so that it points to the correct prefix
475 where SDL was installed. Verify that @file{sdl-config} can be launched from
476 the MSYS command line.
478 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
479 you can build libavutil, libavcodec and libavformat as DLLs.
481 @end itemize
483 @subsection Microsoft Visual C++ compatibility
485 As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
486 want to use the libav* libraries in your own applications, you can still
487 compile those applications using MSVC++. But the libav* libraries you link
488 to @emph{must} be built with MinGW. However, you will not be able to debug
489 inside the libav* libraries, since MSVC++ does not recognize the debug
490 symbols generated by GCC.
491 We strongly recommend you to move over from MSVC++ to MinGW tools.
493 This description of how to use the FFmpeg libraries with MSVC++ is based on
494 Microsoft Visual C++ 2005 Express Edition. If you have a different version,
495 you might have to modify the procedures slightly.
497 @subsubsection Using static libraries
499 Assuming you have just built and installed FFmpeg in @file{/usr/local}.
501 @enumerate
503 @item Create a new console application ("File / New / Project") and then
504 select "Win32 Console Application". On the appropriate page of the
505 Application Wizard, uncheck the "Precompiled headers" option.
507 @item Write the source code for your application, or, for testing, just
508 copy the code from an existing sample application into the source file
509 that MSVC++ has already created for you. For example, you can copy
510 @file{output_example.c} from the FFmpeg distribution.
512 @item Open the "Project / Properties" dialog box. In the "Configuration"
513 combo box, select "All Configurations" so that the changes you make will
514 affect both debug and release builds. In the tree view on the left hand
515 side, select "C/C++ / General", then edit the "Additional Include
516 Directories" setting to contain the path where the FFmpeg includes were
517 installed (i.e. @file{c:\msys\1.0\local\include}).
518 Do not add MinGW's include directory here, or the include files will
519 conflict with MSVC's.
521 @item Still in the "Project / Properties" dialog box, select
522 "Linker / General" from the tree view and edit the
523 "Additional Library Directories" setting to contain the @file{lib}
524 directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
525 the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
526 and the directory where MinGW's GCC libs are installed
527 (i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
528 "Linker / Input" from the tree view, and add the files @file{libavformat.a},
529 @file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
530 @file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
531 to the end of "Additional Dependencies".
533 @item Now, select "C/C++ / Code Generation" from the tree view. Select
534 "Debug" in the "Configuration" combo box. Make sure that "Runtime
535 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
536 the "Configuration" combo box and make sure that "Runtime Library" is
537 set to "Multi-threaded DLL".
539 @item Click "OK" to close the "Project / Properties" dialog box.
541 @item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
542 Get msinttypes from @url{}
543 and install it in MSVC++'s include directory
544 (i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
546 @item MSVC++ also does not understand the @code{inline} keyword used by
547 FFmpeg, so you must add this line before @code{#include}ing libav*:
548 @example
549 #define inline _inline
550 @end example
552 @item Build your application, everything should work.
554 @end enumerate
556 @subsubsection Using shared libraries
558 This is how to create DLL and LIB files that are compatible with MSVC++:
560 @enumerate
562 @item Add a call to @file{vcvars32.bat} (which sets up the environment
563 variables for the Visual C++ tools) as the first line of @file{msys.bat}.
564 The standard location for @file{vcvars32.bat} is
565 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
566 and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
567 If this corresponds to your setup, add the following line as the first line
568 of @file{msys.bat}:
570 @example
571 call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
572 @end example
574 Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
575 and run @file{c:\msys\1.0\msys.bat} from there.
577 @item Within the MSYS shell, run @code{lib.exe}. If you get a help message
578 from @file{Microsoft (R) Library Manager}, this means your environment
579 variables are set up correctly, the @file{Microsoft (R) Library Manager}
580 is on the path and will be used by FFmpeg to create
581 MSVC++-compatible import libraries.
583 @item Build FFmpeg with
585 @example
586 ./configure --enable-shared --enable-memalign-hack
587 make
588 make install
589 @end example
591 Your install path (@file{/usr/local/} by default) should now have the
592 necessary DLL and LIB files under the @file{bin} directory.
594 @end enumerate
596 To use those files with MSVC++, do the same as you would do with
597 the static libraries, as described above. But in Step 4,
598 you should only need to add the directory where the LIB files are installed
599 (i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
600 installed in the @file{bin} directory. And instead of adding @file{libxx.a}
601 files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
602 @file{avutil.lib}. There should be no need for @file{libmingwex.a},
603 @file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
604 statically linked into the DLLs. The @file{bin} directory contains a bunch
605 of DLL files, but the ones that are actually used to run your application
606 are the ones with a major version number in their filenames
607 (i.e. @file{avcodec-51.dll}).
609 @subsection Cross compilation for Windows with Linux
611 You must use the MinGW cross compilation tools available at
612 @url{}.
614 Then configure FFmpeg with the following options:
615 @example
616 ./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
617 @end example
618 (you can change the cross-prefix according to the prefix chosen for the
619 MinGW tools).
621 Then you can easily test FFmpeg with Wine
622 (@url{}).
624 @subsection Compilation under Cygwin
626 The main issue with Cygwin is that newlib, its C library, does not
627 contain llrint(). However, it is possible to leverage the
628 implementation in MinGW.
630 Just install your Cygwin with all the "Base" packages, plus the
631 following "Devel" ones:
632 @example
633 binutils, gcc-core, make, subversion, mingw-runtime
634 @end example
636 Do not install binutils-20060709-1 (they are buggy on shared builds);
637 use binutils-20050610-1 instead.
639 Then create a small library that just contains llrint():
641 @example
642 ar x /usr/lib/mingw/libmingwex.a llrint.o
643 ar cq /usr/local/lib/libllrint.a llrint.o
644 @end example
646 Then run
648 @example
649 ./configure --enable-static --disable-shared --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
650 @end example
652 to make a static build or
654 @example
655 ./configure --enable-shared --disable-static --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
656 @end example
658 to build shared libraries.
660 If you want to build FFmpeg with additional libraries, download Cygwin
661 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository
662 and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
663 (@url{}).
665 @subsection Crosscompilation for Windows under Cygwin
667 With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
669 Just install your Cygwin as explained before, plus these additional
670 "Devel" packages:
671 @example
672 gcc-mingw-core, mingw-runtime, mingw-zlib
673 @end example
675 and add some special flags to your configure invocation.
677 For a static build run
678 @example
679 ./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
680 @end example
682 and for a build with shared libraries
683 @example
684 ./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
685 @end example
687 @section BeOS
689 BeOS support is broken in mysterious ways.
691 @section OS/2
693 For information about compiling FFmpeg on OS/2 see
694 @url{}.
696 @chapter Developers Guide
698 @section API
699 @itemize @bullet
700 @item libavcodec is the library containing the codecs (both encoding and
701 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
703 @item libavformat is the library containing the file format handling (mux and
704 demux code for several formats). Look at @file{ffplay.c} to use it in a
705 player. See @file{output_example.c} to use it to generate audio or video
706 streams.
708 @end itemize
710 @section Integrating libavcodec or libavformat in your program
712 You can integrate all the source code of the libraries to link them
713 statically to avoid any version problem. All you need is to provide a
714 'config.mak' and a 'config.h' in the parent directory. See the defines
715 generated by ./configure to understand what is needed.
717 You can use libavcodec or libavformat in your commercial program, but
718 @emph{any patch you make must be published}. The best way to proceed is
719 to send your patches to the FFmpeg mailing list.
721 @node Coding Rules
722 @section Coding Rules
724 FFmpeg is programmed in the ISO C90 language with a few additional
725 features from ISO C99, namely:
726 @itemize @bullet
727 @item
728 the @samp{inline} keyword;
729 @item
730 @samp{//} comments;
731 @item
732 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
733 @item
734 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
735 @end itemize
737 These features are supported by all compilers we care about, so we will not
738 accept patches to remove their use unless they absolutely do not impair
739 clarity and performance.
741 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
742 compiles with several other compilers, such as the Compaq ccc compiler
743 or Sun Studio 9, and we would like to keep it that way unless it would
744 be exceedingly involved. To ensure compatibility, please do not use any
745 additional C99 features or GCC extensions. Especially watch out for:
746 @itemize @bullet
747 @item
748 mixing statements and declarations;
749 @item
750 @samp{long long} (use @samp{int64_t} instead);
751 @item
752 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
753 @item
754 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
755 @end itemize
757 Indent size is 4.
758 The presentation is the one specified by 'indent -i4 -kr -nut'.
759 The TAB character is forbidden outside of Makefiles as is any
760 form of trailing whitespace. Commits containing either will be
761 rejected by the Subversion repository.
763 The main priority in FFmpeg is simplicity and small code size in order to
764 minimize the bug count.
766 Comments: Use the JavaDoc/Doxygen
767 format (see examples below) so that code documentation
768 can be generated automatically. All nontrivial functions should have a comment
769 above them explaining what the function does, even if it is just one sentence.
770 All structures and their member variables should be documented, too.
771 @example
772 /**
773 * @@file mpeg.c
774 * MPEG codec.
775 * @@author ...
776 */
778 /**
779 * Summary sentence.
780 * more text ...
781 * ...
782 */
783 typedef struct Foobar@{
784 int var1; /**< var1 description */
785 int var2; ///< var2 description
786 /** var3 description */
787 int var3;
788 @} Foobar;
790 /**
791 * Summary sentence.
792 * more text ...
793 * ...
794 * @@param my_parameter description of my_parameter
795 * @@return return value description
796 */
797 int myfunc(int my_parameter)
798 ...
799 @end example
801 fprintf and printf are forbidden in libavformat and libavcodec,
802 please use av_log() instead.
804 Casts should be used only when necessary. Unneeded parentheses
805 should also be avoided if they don't make the code easier to understand.
807 @section Development Policy
809 @enumerate
810 @item
811 Contributions should be licensed under the LGPL 2.1, including an
812 "or any later version" clause, or the MIT license. GPL 2 including
813 an "or any later version" clause is also acceptable, but LGPL is
814 preferred.
815 @item
816 You must not commit code which breaks FFmpeg! (Meaning unfinished but
817 enabled code which breaks compilation or compiles but does not work or
818 breaks the regression tests)
819 You can commit unfinished stuff (for testing etc), but it must be disabled
820 (#ifdef etc) by default so it does not interfere with other developers'
821 work.
822 @item
823 You do not have to over-test things. If it works for you, and you think it
824 should work for others, then commit. If your code has problems
825 (portability, triggers compiler bugs, unusual environment etc) they will be
826 reported and eventually fixed.
827 @item
828 Do not commit unrelated changes together, split them into self-contained
829 pieces. Also do not forget that if part B depends on part A, but A does not
830 depend on B, then A can and should be committed first and separate from B.
831 Keeping changes well split into self-contained parts makes reviewing and
832 understanding them on the commit log mailing list easier. This also helps
833 in case of debugging later on.
834 Also if you have doubts about splitting or not splitting, do not hesitate to
835 ask/discuss it on the developer mailing list.
836 @item
837 Do not change behavior of the program (renaming options etc) without
838 first discussing it on the ffmpeg-devel mailing list. Do not remove
839 functionality from the code. Just improve!
841 Note: Redundant code can be removed.
842 @item
843 Do not commit changes to the build system (Makefiles, configure script)
844 which change behavior, defaults etc, without asking first. The same
845 applies to compiler warning fixes, trivial looking fixes and to code
846 maintained by other developers. We usually have a reason for doing things
847 the way we do. Send your changes as patches to the ffmpeg-devel mailing
848 list, and if the code maintainers say OK, you may commit. This does not
849 apply to files you wrote and/or maintain.
850 @item
851 We refuse source indentation and other cosmetic changes if they are mixed
852 with functional changes, such commits will be rejected and removed. Every
853 developer has his own indentation style, you should not change it. Of course
854 if you (re)write something, you can use your own style, even though we would
855 prefer if the indentation throughout FFmpeg was consistent (Many projects
856 force a given indentation style - we do not.). If you really need to make
857 indentation changes (try to avoid this), separate them strictly from real
858 changes.
860 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
861 then either do NOT change the indentation of the inner part within (do not
862 move it to the right)! or do so in a separate commit
863 @item
864 Always fill out the commit log message. Describe in a few lines what you
865 changed and why. You can refer to mailing list postings if you fix a
866 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
867 @item
868 If you apply a patch by someone else, include the name and email address in
869 the log message. Since the ffmpeg-cvslog mailing list is publicly
870 archived you should add some SPAM protection to the email address. Send an
871 answer to ffmpeg-devel (or wherever you got the patch from) saying that
872 you applied the patch.
873 @item
874 When applying patches that have been discussed (at length) on the mailing
875 list, reference the thread in the log message.
876 @item
877 Do NOT commit to code actively maintained by others without permission.
878 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
879 timeframe (12h for build failures and security fixes, 3 days small changes,
880 1 week for big patches) then commit your patch if you think it is OK.
881 Also note, the maintainer can simply ask for more time to review!
882 @item
883 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
884 are sent there and reviewed by all the other developers. Bugs and possible
885 improvements or general questions regarding commits are discussed there. We
886 expect you to react if problems with your code are uncovered.
887 @item
888 Update the documentation if you change behavior or add features. If you are
889 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
890 maintainer(s) will review and commit your stuff.
891 @item
892 Try to keep important discussions and requests (also) on the public
893 developer mailing list, so that all developers can benefit from them.
894 @item
895 Never write to unallocated memory, never write over the end of arrays,
896 always check values read from some untrusted source before using them
897 as array index or other risky things.
898 @item
899 Remember to check if you need to bump versions for the specific libav
900 parts (libavutil, libavcodec, libavformat) you are changing. You need
901 to change the version integer.
902 Incrementing the first component means no backward compatibility to
903 previous versions (e.g. removal of a function from the public API).
904 Incrementing the second component means backward compatible change
905 (e.g. addition of a function to the public API or extension of an
906 existing data structure).
907 Incrementing the third component means a noteworthy binary compatible
908 change (e.g. encoder bug fix that matters for the decoder).
909 @item
910 Compiler warnings indicate potential bugs or code with bad style. If a type of
911 warning always points to correct and clean code, that warning should
912 be disabled, not the code changed.
913 Thus the remaining warnings can either be bugs or correct code.
914 If it is a bug, the bug has to be fixed. If it is not, the code should
915 be changed to not generate a warning unless that causes a slowdown
916 or obfuscates the code.
917 @item
918 If you add a new file, give it a proper license header. Do not copy and
919 paste it from a random place, use an existing file as template.
920 @end enumerate
922 We think our rules are not too hard. If you have comments, contact us.
924 Note, these rules are mostly borrowed from the MPlayer project.
926 @section Submitting patches
928 First, (@pxref{Coding Rules}) above if you did not yet.
930 When you submit your patch, try to send a unified diff (diff '-up'
931 option). We cannot read other diffs :-)
933 Also please do not submit a patch which contains several unrelated changes.
934 Split it into separate, self-contained pieces. This does not mean splitting
935 file by file. Instead, make the patch as small as possible while still
936 keeping it as a logical unit that contains an individual change, even
937 if it spans multiple files. This makes reviewing your patches much easier
938 for us and greatly increases your chances of getting your patch applied.
940 Run the regression tests before submitting a patch so that you can
941 verify that there are no big problems.
943 Patches should be posted as base64 encoded attachments (or any other
944 encoding which ensures that the patch will not be trashed during
945 transmission) to the ffmpeg-devel mailing list, see
946 @url{}
948 It also helps quite a bit if you tell us what the patch does (for example
949 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
950 and has no lrint()')
952 Also please if you send several patches, send each patch as a separate mail,
953 do not attach several unrelated patches to the same mail.
955 @section New codecs or formats checklist
957 @enumerate
958 @item
959 Did you use av_cold for codec initialization and close functions?
960 @item
961 Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
962 AVInputFormat/AVOutputFormat struct?
963 @item
964 Did you bump the minor version number in @file{avcodec.h} or
965 @file{avformat.h}?
966 @item
967 Did you register it in @file{allcodecs.c} or @file{allformats.c}?
968 @item
969 Did you add the CodecID to @file{avcodec.h}?
970 @item
971 If it has a fourcc, did you add it to @file{libavformat/riff.c},
972 even if it is only a decoder?
973 @item
974 Did you add a rule to compile the appropriate files in the Makefile?
975 Remember to do this even if you're just adding a format to a file that is
976 already being compiled by some other rule, like a raw demuxer.
977 @item
978 Did you add an entry to the table of supported formats or codecs in the
979 documentation?
980 @item
981 Did you add an entry in the Changelog?
982 @item
983 If it depends on a parser or a library, did you add that dependency in
984 configure?
985 @item
986 Did you "svn add" the appropriate files before commiting?
987 @end enumerate
989 @section patch submission checklist
991 @enumerate
992 @item
993 Do the regression tests pass with the patch applied?
994 @item
995 Is the patch a unified diff?
996 @item
997 Is the patch against latest FFmpeg SVN?
998 @item
999 Are you subscribed to ffmpeg-dev?
1000 (the list is subscribers only due to spam)
1001 @item
1002 Have you checked that the changes are minimal, so that the same cannot be
1003 achieved with a smaller patch and/or simpler final code?
1004 @item
1005 If the change is to speed critical code, did you benchmark it?
1006 @item
1007 If you did any benchmarks, did you provide them in the mail?
1008 @item
1009 Have you checked that the patch does not introduce buffer overflows or
1010 other security issues?
1011 @item
1012 If you add a new demuxer or decoder, have you checked that it does not
1013 crash with damaged input (see tools/trasher)?
1014 @item
1015 Is the patch created from the root of the source tree, so it can be
1016 applied with @code{patch -p0}?
1017 @item
1018 Does the patch not mix functional and cosmetic changes?
1019 @item
1020 Did you add tabs or trailing whitespace to the code? Both are forbidden.
1021 @item
1022 Is the patch attached to the email you send?
1023 @item
1024 Is the mime type of the patch correct? It should be text/x-diff or
1025 text/x-patch or at least text/plain and not application/octet-stream.
1026 @item
1027 If the patch fixes a bug, did you provide a verbose analysis of the bug?
1028 @item
1029 If the patch fixes a bug, did you provide enough information, including
1030 a sample, so the bug can be reproduced and the fix can be verified?
1031 Note please do not attach samples >100k to mails but rather provide a
1032 URL, you can upload to
1033 @item
1034 Did you provide a verbose summary about what the patch does change?
1035 @item
1036 Did you provide a verbose explanation why it changes things like it does?
1037 @item
1038 Did you provide a verbose summary of the user visible advantages and
1039 disadvantages if the patch is applied?
1040 @item
1041 Did you provide an example so we can verify the new feature added by the
1042 patch easily?
1043 @item
1044 If you added a new file, did you insert a license header? It should be
1045 taken from FFmpeg, not randomly copied and pasted from somewhere else.
1046 @item
1047 You should maintain alphabetical order in alphabetically ordered lists as
1048 long as doing so does not break API/ABI compatibility.
1049 @item
1050 Lines with similar content should be aligned vertically when doing so
1051 improves readability.
1052 @item
1053 Did you provide a suggestion for a clear commit log message?
1054 @item
1055 Did you test your decoder or demuxer against damaged data? If no, see
1056 tools/trasher and the noise bitstream filter. Your decoder or demuxer
1057 should not crash or end in a (near) infinite loop when fed damaged data.
1058 @end enumerate
1060 @section Patch review process
1062 All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1063 clear note that the patch is not for SVN.
1064 Reviews and comments will be posted as replies to the patch on the
1065 mailing list. The patch submitter then has to take care of every comment,
1066 that can be by resubmitting a changed patch or by discussion. Resubmitted
1067 patches will themselves be reviewed like any other patch. If at some point
1068 a patch passes review with no comments then it is approved, that can for
1069 simple and small patches happen immediately while large patches will generally
1070 have to be changed and reviewed many times before they are approved.
1071 After a patch is approved it will be committed to the repository.
1073 We will review all submitted patches, but sometimes we are quite busy so
1074 especially for large patches this can take several weeks.
1076 When resubmitting patches, please do not make any significant changes
1077 not related to the comments received during review. Such patches will
1078 be rejected. Instead, submit significant changes or new features as
1079 separate patches.
1081 @section Regression tests
1083 Before submitting a patch (or committing to the repository), you should at least
1084 test that you did not break anything.
1086 The regression tests build a synthetic video stream and a synthetic
1087 audio stream. These are then encoded and decoded with all codecs or
1088 formats. The CRC (or MD5) of each generated file is recorded in a
1089 result file. A 'diff' is launched to compare the reference results and
1090 the result file.
1092 The regression tests then go on to test the FFserver code with a
1093 limited set of streams. It is important that this step runs correctly
1094 as well.
1096 Run 'make test' to test all the codecs and formats.
1098 Run 'make fulltest' to test all the codecs, formats and FFserver.
1100 [Of course, some patches may change the results of the regression tests. In
1101 this case, the reference results of the regression tests shall be modified
1102 accordingly].
1104 @bye