9dfdd3bef04c1462ccd20a508c628f41a4034298
[libav.git] / doc / general.texi
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
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}.
16
17 @section AMR
18
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.
22
23 Go to @url{http://www.penguin.cz/~utx/amr} 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.
26
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!}
31
32
33 @chapter Supported File Formats and Codecs
34
35 You can use the @code{-formats} option to have an exhaustive list.
36
37 @section File Formats
38
39 FFmpeg supports the following file formats through the @code{libavformat}
40 library:
41
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 MOV/QuickTime @tab X @tab X
95 @item MPEG audio @tab X @tab X
96 @item MPEG-1 systems @tab X @tab X
97 @tab muxed audio and video
98 @item MPEG-2 PS @tab X @tab X
99 @tab also known as @code{VOB} file
100 @item MPEG-2 TS @tab @tab X
101 @tab also known as DVB Transport Stream
102 @item MPEG-4 @tab X @tab X
103 @tab MPEG-4 is a variant of QuickTime.
104 @item MSN TCP webcam @tab @tab X
105 @tab Used by MSN Messenger webcam streams.
106 @item MXF @tab @tab X
107 @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
108 @item Nullsoft Video @tab @tab X
109 @item NUT @tab X @tab X
110 @tab NUT Open Container Format
111 @item OMA @tab @tab X
112 @tab Audio format used in Sony Sonic Stage and Sony Vegas.
113 @item PlayStation STR @tab @tab X
114 @item PVA @tab @tab X
115 @tab Used by TechnoTrend DVB PCI boards.
116 @item raw AC-3 @tab X @tab X
117 @item raw CRI ADX audio @tab X @tab X
118 @item raw MJPEG @tab X @tab X
119 @item raw MPEG video @tab X @tab X
120 @item raw MPEG-4 video @tab X @tab X
121 @item raw PCM 8/16 bits, mu-law/A-law @tab X @tab X
122 @item raw Shorten audio @tab @tab X
123 @item RealMedia @tab X @tab X
124 @item RL2 @tab @tab X
125 @tab Audio and video format used in some games by Entertainment Software Partners.
126 @item Sega FILM/CPK @tab @tab X
127 @tab Used in many Sega Saturn console games.
128 @item SEQ @tab @tab X
129 @tab Tiertex .seq files used in the DOS CD-ROM version of the game Flashback.
130 @item Sierra Online @tab @tab X
131 @tab .sol files used in Sierra Online games.
132 @item Sierra VMD @tab @tab X
133 @tab Used in Sierra CD-ROM games.
134 @item SIFF @tab @tab X
135 @tab Audio and video format used in some games by Beam Software.
136 @item Smacker @tab @tab X
137 @tab Multimedia format used by many games.
138 @item SUN AU format @tab X @tab X
139 @item THP @tab @tab X
140 @tab Used on the Nintendo GameCube.
141 @item WAV @tab X @tab X
142 @item WC3 Movie @tab @tab X
143 @tab Multimedia format used in Origin's Wing Commander III computer game.
144 @item Westwood Studios VQA/AUD @tab @tab X
145 @tab Multimedia formats used in Westwood Studios games.
146 @end multitable
147
148 @code{X} means that encoding (resp. decoding) is supported.
149
150 @section Image Formats
151
152 FFmpeg can read and write images for each frame of a video sequence. The
153 following image formats are supported:
154
155 @multitable @columnfractions .4 .1 .1 .4
156 @item Supported Image Format @tab Encoding @tab Decoding @tab Comments
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 JPEG @tab X @tab X @tab Progressive JPEG is not supported.
160 @item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
161 @item PCX @tab @tab X @tab PC Paintbrush
162 @item PGM, PPM @tab X @tab X
163 @item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
164 @item PNG @tab X @tab X @tab 2/4 bpp not supported yet
165 @item PTX @tab @tab X @tab V.Flash PTX format
166 @item RAS @tab @tab X @tab Sun Rasterfile
167 @item SGI @tab X @tab X @tab SGI RGB image format
168 @item Targa @tab @tab X @tab Targa (.TGA) image format
169 @item TIFF @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
170 @end multitable
171
172 @code{X} means that encoding (resp. decoding) is supported.
173
174 @section Video Codecs
175
176 @multitable @columnfractions .4 .1 .1 .4
177 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
178 @item 4X Video @tab @tab X
179 @tab Used in certain computer games.
180 @item American Laser Games Video @tab @tab X
181 @tab Used in games like Mad Dog McCree.
182 @item AMV @tab @tab X
183 @tab Used in Chinese MP3 players.
184 @item Apple Animation @tab X @tab X
185 @tab fourcc: 'rle '
186 @item Apple Graphics @tab @tab X
187 @tab fourcc: 'smc '
188 @item Apple MJPEG-B @tab @tab X
189 @item Apple QuickDraw @tab @tab X
190 @tab fourcc: qdrw
191 @item Apple Video @tab @tab X
192 @tab fourcc: rpza
193 @item Asus v1 @tab X @tab X
194 @tab fourcc: ASV1
195 @item Asus v2 @tab X @tab X
196 @tab fourcc: ASV2
197 @item ATI VCR1 @tab @tab X
198 @tab fourcc: VCR1
199 @item ATI VCR2 @tab @tab X
200 @tab fourcc: VCR2
201 @item Autodesk RLE @tab @tab X
202 @tab fourcc: AASC
203 @item AVID DNxHD @tab X @tab X
204 @tab aka SMPTE VC3
205 @item AVS video @tab @tab X
206 @tab Video encoding used by the Creature Shock game.
207 @item Bethsoft VID @tab @tab X
208 @tab Used in some games from Bethesda Softworks.
209 @item C93 video @tab @tab X
210 @tab Codec used in Cyberia game.
211 @item CamStudio @tab @tab X
212 @tab fourcc: CSCD
213 @item Cin video @tab @tab X
214 @tab Codec used in Delphine Software games.
215 @item Cinepak @tab @tab X
216 @item Cirrus Logic AccuPak @tab @tab X
217 @tab fourcc: CLJR
218 @item Creative YUV @tab @tab X
219 @tab fourcc: CYUV
220 @item Duck TrueMotion v1 @tab @tab X
221 @tab fourcc: DUCK
222 @item Duck TrueMotion v2 @tab @tab X
223 @tab fourcc: TM20
224 @item DV @tab X @tab X
225 @item DXA Video @tab @tab X
226 @tab Codec originally used in Feeble Files game.
227 @item Electronic Arts CMV @tab @tab X
228 @tab Used in NHL 95 game.
229 @item FFmpeg Video 1 @tab X @tab X
230 @tab experimental lossless codec (fourcc: FFV1)
231 @item Flash Screen Video @tab X @tab X
232 @tab fourcc: FSV1
233 @item FLIC video @tab @tab X
234 @item FLV @tab X @tab X
235 @tab Sorenson H.263 used in Flash
236 @item Fraps FPS1 @tab @tab X
237 @item H.261 @tab X @tab X
238 @item H.263(+) @tab X @tab X
239 @tab also known as RealVideo 1.0
240 @item H.264 @tab @tab X
241 @item HuffYUV @tab X @tab X
242 @item IBM Ultimotion @tab @tab X
243 @tab fourcc: ULTI
244 @item id Cinematic video @tab @tab X
245 @tab Used in Quake II.
246 @item id RoQ @tab X @tab X
247 @tab Used in Quake III, Jedi Knight 2, other computer games.
248 @item Intel Indeo 3 @tab @tab X
249 @item Interplay Video @tab @tab X
250 @tab Used in Interplay .MVE files.
251 @item JPEG-LS @tab X @tab X
252 @tab fourcc: MJLS, lossless and near-lossless is supported.
253 @item KMVC @tab @tab X
254 @tab Codec used in Worms games.
255 @item LOCO @tab @tab X
256 @item lossless MJPEG @tab X @tab X
257 @item Microsoft RLE @tab @tab X
258 @item Microsoft Video-1 @tab @tab X
259 @item Mimic @tab @tab X
260 @tab Used in MSN Messenger Webcam streams.
261 @item Miro VideoXL @tab @tab X
262 @tab fourcc: VIXL
263 @item MJPEG @tab X @tab X
264 @item MPEG-1 @tab X @tab X
265 @item MPEG-2 @tab X @tab X
266 @item MPEG-4 @tab X @tab X
267 @item MSMPEG4 V1 @tab X @tab X
268 @item MSMPEG4 V2 @tab X @tab X
269 @item MSMPEG4 V3 @tab X @tab X
270 @item MSZH @tab @tab X
271 @tab Part of LCL
272 @item On2 VP3 @tab @tab X
273 @tab still experimental
274 @item On2 VP5 @tab @tab X
275 @tab fourcc: VP50
276 @item On2 VP6 @tab @tab X
277 @tab fourcc: VP60,VP61,VP62
278 @item planar RGB @tab @tab X
279 @tab fourcc: 8BPS
280 @item QPEG @tab @tab X
281 @tab fourccs: QPEG, Q1.0, Q1.1
282 @item RealVideo 1.0 @tab X @tab X
283 @item RealVideo 2.0 @tab X @tab X
284 @item Renderware TXD @tab @tab X
285 @tab Texture dictionaries used by the Renderware Engine.
286 @item RTjpeg @tab @tab X
287 @tab Video encoding used in NuppelVideo files.
288 @item Smacker video @tab @tab X
289 @tab Video encoding used in Smacker.
290 @item Snow @tab X @tab X
291 @tab experimental wavelet codec (fourcc: SNOW)
292 @item Sony PlayStation MDEC @tab @tab X
293 @item Sorenson Video 1 @tab X @tab X
294 @tab fourcc: SVQ1
295 @item Sorenson Video 3 @tab @tab X
296 @tab fourcc: SVQ3
297 @item Sunplus MJPEG @tab @tab X
298 @tab fourcc: SP5X
299 @item TechSmith Camtasia @tab @tab X
300 @tab fourcc: TSCC
301 @item Theora @tab X @tab X
302 @tab still experimental
303 @item THP @tab @tab X
304 @tab Used on the Nintendo GameCube.
305 @item Tiertex Seq video @tab @tab X
306 @tab Codec used in DOS CD-ROM FlashBack game.
307 @item VC-1 @tab @tab X
308 @item VMD Video @tab @tab X
309 @tab Used in Sierra VMD files.
310 @item VMware Video @tab @tab X
311 @tab Codec used in videos captured by VMware.
312 @item Westwood VQA @tab @tab X
313 @item Winnov WNV1 @tab @tab X
314 @item WMV7 @tab X @tab X
315 @item WMV8 @tab X @tab X
316 @item WMV9 @tab @tab X
317 @tab not completely working
318 @item Xan/WC3 @tab @tab X
319 @tab Used in Wing Commander III .MVE files.
320 @item ZLIB @tab X @tab X
321 @tab part of LCL, encoder experimental
322 @item ZMBV @tab X @tab X
323 @tab Encoder works only in PAL8.
324 @end multitable
325
326 @code{X} means that encoding (resp. decoding) is supported.
327
328 @section Audio Codecs
329
330 @multitable @columnfractions .4 .1 .1 .1 .7
331 @item Supported Codec @tab Encoding @tab Decoding @tab Comments
332 @item 4X IMA ADPCM @tab @tab X
333 @item 8SVX audio @tab @tab X
334 @item AAC @tab X @tab X
335 @tab Supported through the external library libfaac/libfaad.
336 @item AC-3 @tab IX @tab IX
337 @tab liba52 can be used alternatively for decoding.
338 @item AMR-NB @tab X @tab X
339 @tab Supported through an external library.
340 @item AMR-WB @tab X @tab X
341 @tab Supported through an external library.
342 @item AMV IMA ADPCM @tab @tab X
343 @tab Used in AMV files
344 @item Apple lossless audio @tab @tab X
345 @tab QuickTime fourcc 'alac'
346 @item Apple MACE 3 @tab @tab X
347 @item Apple MACE 6 @tab @tab X
348 @item ATRAC 3 @tab @tab X
349 @item CD-ROM XA ADPCM @tab @tab X
350 @item Cin audio @tab @tab X
351 @tab Codec used in Delphine Software International games.
352 @item Creative ADPCM @tab @tab X
353 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
354 @item CRI ADX ADPCM @tab X @tab X
355 @tab Used in Sega Dreamcast games.
356 @item DSP Group TrueSpeech @tab @tab X
357 @item DTS Coherent Audio @tab @tab X
358 @item Duck DK3 IMA ADPCM @tab @tab X
359 @tab Used in some Sega Saturn console games.
360 @item Duck DK4 IMA ADPCM @tab @tab X
361 @tab Used in some Sega Saturn console games.
362 @item DV audio @tab @tab X
363 @item Electronic Arts ADPCM @tab @tab X
364 @tab Used in various EA titles.
365 @item FFmpeg Sonic @tab X @tab X
366 @tab experimental lossy/lossless codec
367 @item FLAC lossless audio @tab X @tab X
368 @item G.726 ADPCM @tab X @tab X
369 @item id RoQ DPCM @tab X @tab X
370 @tab Used in Quake III, Jedi Knight 2, other computer games.
371 @item Intel Music Coder @tab @tab X
372 @item Interplay MVE DPCM @tab @tab X
373 @tab Used in various Interplay computer games.
374 @item MAXIS EA ADPCM @tab @tab X
375 @tab Used in Sim City 3000.
376 @item Microsoft ADPCM @tab X @tab X
377 @item MLP/TrueHD @tab @tab X
378 @tab Used in DVD-Audio and Blu-Ray discs.
379 @item Monkey's Audio @tab @tab X
380 @tab Only versions 3.97-3.99 are supported.
381 @item MPEG audio layer 1/3 @tab X @tab IX
382 @tab MP3 encoding is supported through the external library LAME.
383 @item MPEG audio layer 2 @tab IX @tab IX
384 @item MS IMA ADPCM @tab X @tab X
385 @item Musepack @tab @tab X
386 @tab SV7 and SV8 are supported.
387 @item Nellymoser ASAO @tab @tab X
388 @item Qdesign QDM2 @tab @tab X
389 @tab There are still some distortions.
390 @item QT IMA ADPCM @tab X @tab X
391 @item RA144 @tab @tab X
392 @tab Real 14400 bit/s codec
393 @item RA288 @tab @tab X
394 @tab Real 28800 bit/s codec
395 @item RADnet @tab X @tab IX
396 @tab real low bitrate AC-3 codec
397 @item Real COOK @tab @tab X
398 @tab All versions except 5.1 are supported.
399 @item Shorten @tab @tab X
400 @item Sierra Online DPCM @tab @tab X
401 @tab Used in Sierra Online game audio files.
402 @item Smacker audio @tab @tab X
403 @item SMJPEG IMA ADPCM @tab @tab X
404 @tab Used in certain Loki game ports.
405 @item THP ADPCM @tab @tab X
406 @tab Used on the Nintendo GameCube.
407 @item True Audio (TTA) @tab @tab X
408 @item Vorbis @tab X @tab X
409 @item WavPack @tab @tab X
410 @item Westwood Studios IMA ADPCM @tab @tab X
411 @tab Used in Westwood Studios games like Command and Conquer.
412 @item WMA v1/v2 @tab X @tab X
413 @item Xan DPCM @tab @tab X
414 @tab Used in Origin's Wing Commander IV AVI files.
415 @end multitable
416
417 @code{X} means that encoding (resp. decoding) is supported.
418
419 @code{I} means that an integer-only version is available, too (ensures high
420 performance on systems without hardware floating point support).
421
422 @chapter Platform Specific information
423
424 @section BSD
425
426 BSD make will not build FFmpeg, you need to install and use GNU Make
427 (@file{gmake}).
428
429 @section Windows
430
431 To get help and instructions for building FFmpeg under Windows, check out
432 the FFmpeg Windows Help Forum at
433 @url{http://arrozcru.no-ip.org/ffmpeg/}.
434
435 @subsection Native Windows compilation
436
437 FFmpeg can be built to run natively on Windows using the MinGW tools. Install
438 the current versions of MSYS and MinGW from @url{http://www.mingw.org/}. Also
439 install the coreutils package, and update to the latest MSYS make (note: not
440 mingw32-make). You can find detailed installation
441 instructions in the download section and the FAQ.
442
443 Within the MSYS shell, configure and make with:
444
445 @example
446 ./configure --enable-memalign-hack
447 make
448 make install
449 @end example
450
451 This will install @file{ffmpeg.exe} along with many other development files
452 to @file{/usr/local}. You may specify another install path using the
453 @code{--prefix} option in @file{configure}.
454
455 Notes:
456
457 @itemize
458
459 @item Use at least bash 3.1. Older versions are known to fail on the
460 configure script.
461
462 @item In order to compile vhooks, you must have a POSIX-compliant libdl in
463 your MinGW system. Get dlfcn-win32 from
464 @url{http://code.google.com/p/dlfcn-win32}.
465
466 @item In order to compile FFplay, you must have the MinGW development library
467 of SDL. Get it from @url{http://www.libsdl.org}.
468 Edit the @file{bin/sdl-config} script so that it points to the correct prefix
469 where SDL was installed. Verify that @file{sdl-config} can be launched from
470 the MSYS command line.
471
472 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
473 you can build libavutil, libavcodec and libavformat as DLLs.
474
475 @end itemize
476
477 @subsection Microsoft Visual C++ compatibility
478
479 As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
480 want to use the libav* libraries in your own applications, you can still
481 compile those applications using MSVC++. But the libav* libraries you link
482 to @emph{must} be built with MinGW. However, you will not be able to debug
483 inside the libav* libraries, since MSVC++ does not recognize the debug
484 symbols generated by GCC.
485 We strongly recommend you to move over from MSVC++ to MinGW tools.
486
487 This description of how to use the FFmpeg libraries with MSVC++ is based on
488 Microsoft Visual C++ 2005 Express Edition. If you have a different version,
489 you might have to modify the procedures slightly.
490
491 @subsubsection Using static libraries
492
493 Assuming you have just built and installed FFmpeg in @file{/usr/local}.
494
495 @enumerate
496
497 @item Create a new console application ("File / New / Project") and then
498 select "Win32 Console Application". On the appropriate page of the
499 Application Wizard, uncheck the "Precompiled headers" option.
500
501 @item Write the source code for your application, or, for testing, just
502 copy the code from an existing sample application into the source file
503 that MSVC++ has already created for you. For example, you can copy
504 @file{output_example.c} from the FFmpeg distribution.
505
506 @item Open the "Project / Properties" dialog box. In the "Configuration"
507 combo box, select "All Configurations" so that the changes you make will
508 affect both debug and release builds. In the tree view on the left hand
509 side, select "C/C++ / General", then edit the "Additional Include
510 Directories" setting to contain the path where the FFmpeg includes were
511 installed (i.e. @file{c:\msys\1.0\local\include}).
512 Do not add MinGW's include directory here, or the include files will
513 conflict with MSVC's.
514
515 @item Still in the "Project / Properties" dialog box, select
516 "Linker / General" from the tree view and edit the
517 "Additional Library Directories" setting to contain the @file{lib}
518 directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
519 the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
520 and the directory where MinGW's GCC libs are installed
521 (i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
522 "Linker / Input" from the tree view, and add the files @file{libavformat.a},
523 @file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
524 @file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
525 to the end of "Additional Dependencies".
526
527 @item Now, select "C/C++ / Code Generation" from the tree view. Select
528 "Debug" in the "Configuration" combo box. Make sure that "Runtime
529 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
530 the "Configuration" combo box and make sure that "Runtime Library" is
531 set to "Multi-threaded DLL".
532
533 @item Click "OK" to close the "Project / Properties" dialog box.
534
535 @item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
536 Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
537 and install it in MSVC++'s include directory
538 (i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
539
540 @item MSVC++ also does not understand the @code{inline} keyword used by
541 FFmpeg, so you must add this line before @code{#include}ing libav*:
542 @example
543 #define inline _inline
544 @end example
545
546 @item Build your application, everything should work.
547
548 @end enumerate
549
550 @subsubsection Using shared libraries
551
552 This is how to create DLL and LIB files that are compatible with MSVC++:
553
554 @enumerate
555
556 @item Add a call to @file{vcvars32.bat} (which sets up the environment
557 variables for the Visual C++ tools) as the first line of @file{msys.bat}.
558 The standard location for @file{vcvars32.bat} is
559 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
560 and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
561 If this corresponds to your setup, add the following line as the first line
562 of @file{msys.bat}:
563
564 @example
565 call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
566 @end example
567
568 Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
569 and run @file{c:\msys\1.0\msys.bat} from there.
570
571 @item Within the MSYS shell, run @code{lib.exe}. If you get a help message
572 from @file{Microsoft (R) Library Manager}, this means your environment
573 variables are set up correctly, the @file{Microsoft (R) Library Manager}
574 is on the path and will be used by FFmpeg to create
575 MSVC++-compatible import libraries.
576
577 @item Build FFmpeg with
578
579 @example
580 ./configure --enable-shared --enable-memalign-hack
581 make
582 make install
583 @end example
584
585 Your install path (@file{/usr/local/} by default) should now have the
586 necessary DLL and LIB files under the @file{bin} directory.
587
588 @end enumerate
589
590 To use those files with MSVC++, do the same as you would do with
591 the static libraries, as described above. But in Step 4,
592 you should only need to add the directory where the LIB files are installed
593 (i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
594 installed in the @file{bin} directory. And instead of adding @file{libxx.a}
595 files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
596 @file{avutil.lib}. There should be no need for @file{libmingwex.a},
597 @file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
598 statically linked into the DLLs. The @file{bin} directory contains a bunch
599 of DLL files, but the ones that are actually used to run your application
600 are the ones with a major version number in their filenames
601 (i.e. @file{avcodec-51.dll}).
602
603 @subsection Cross compilation for Windows with Linux
604
605 You must use the MinGW cross compilation tools available at
606 @url{http://www.mingw.org/}.
607
608 Then configure FFmpeg with the following options:
609 @example
610 ./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
611 @end example
612 (you can change the cross-prefix according to the prefix chosen for the
613 MinGW tools).
614
615 Then you can easily test FFmpeg with Wine
616 (@url{http://www.winehq.com/}).
617
618 @subsection Compilation under Cygwin
619
620 The main issue with Cygwin is that newlib, its C library, does not
621 contain llrint(). However, it is possible to leverage the
622 implementation in MinGW.
623
624 Just install your Cygwin with all the "Base" packages, plus the
625 following "Devel" ones:
626 @example
627 binutils, gcc-core, make, subversion, mingw-runtime
628 @end example
629
630 Do not install binutils-20060709-1 (they are buggy on shared builds);
631 use binutils-20050610-1 instead.
632
633 Then create a small library that just contains llrint():
634
635 @example
636 ar x /usr/lib/mingw/libmingwex.a llrint.o
637 ar cq /usr/local/lib/libllrint.a llrint.o
638 @end example
639
640 Then run
641
642 @example
643 ./configure --enable-static --disable-shared --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
644 @end example
645
646 to make a static build or
647
648 @example
649 ./configure --enable-shared --disable-static --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
650 @end example
651
652 to build shared libraries.
653
654 If you want to build FFmpeg with additional libraries, download Cygwin
655 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository
656 and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
657 (@url{http://cygwinports.dotsrc.org/}).
658
659 @subsection Crosscompilation for Windows under Cygwin
660
661 With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
662
663 Just install your Cygwin as explained before, plus these additional
664 "Devel" packages:
665 @example
666 gcc-mingw-core, mingw-runtime, mingw-zlib
667 @end example
668
669 and add some special flags to your configure invocation.
670
671 For a static build run
672 @example
673 ./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
674 @end example
675
676 and for a build with shared libraries
677 @example
678 ./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
679 @end example
680
681 @section BeOS
682
683 BeOS support is broken in mysterious ways.
684
685 @section OS/2
686
687 For information about compiling FFmpeg on OS/2 see
688 @url{http://www.edm2.com/index.php/FFmpeg}.
689
690 @chapter Developers Guide
691
692 @section API
693 @itemize @bullet
694 @item libavcodec is the library containing the codecs (both encoding and
695 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
696
697 @item libavformat is the library containing the file format handling (mux and
698 demux code for several formats). Look at @file{ffplay.c} to use it in a
699 player. See @file{output_example.c} to use it to generate audio or video
700 streams.
701
702 @end itemize
703
704 @section Integrating libavcodec or libavformat in your program
705
706 You can integrate all the source code of the libraries to link them
707 statically to avoid any version problem. All you need is to provide a
708 'config.mak' and a 'config.h' in the parent directory. See the defines
709 generated by ./configure to understand what is needed.
710
711 You can use libavcodec or libavformat in your commercial program, but
712 @emph{any patch you make must be published}. The best way to proceed is
713 to send your patches to the FFmpeg mailing list.
714
715 @node Coding Rules
716 @section Coding Rules
717
718 FFmpeg is programmed in the ISO C90 language with a few additional
719 features from ISO C99, namely:
720 @itemize @bullet
721 @item
722 the @samp{inline} keyword;
723 @item
724 @samp{//} comments;
725 @item
726 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
727 @item
728 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
729 @end itemize
730
731 These features are supported by all compilers we care about, so we will not
732 accept patches to remove their use unless they absolutely do not impair
733 clarity and performance.
734
735 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
736 compiles with several other compilers, such as the Compaq ccc compiler
737 or Sun Studio 9, and we would like to keep it that way unless it would
738 be exceedingly involved. To ensure compatibility, please do not use any
739 additional C99 features or GCC extensions. Especially watch out for:
740 @itemize @bullet
741 @item
742 mixing statements and declarations;
743 @item
744 @samp{long long} (use @samp{int64_t} instead);
745 @item
746 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
747 @item
748 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
749 @end itemize
750
751 Indent size is 4.
752 The presentation is the one specified by 'indent -i4 -kr -nut'.
753 The TAB character is forbidden outside of Makefiles as is any
754 form of trailing whitespace. Commits containing either will be
755 rejected by the Subversion repository.
756
757 The main priority in FFmpeg is simplicity and small code size in order to
758 minimize the bug count.
759
760 Comments: Use the JavaDoc/Doxygen
761 format (see examples below) so that code documentation
762 can be generated automatically. All nontrivial functions should have a comment
763 above them explaining what the function does, even if it is just one sentence.
764 All structures and their member variables should be documented, too.
765 @example
766 /**
767 * @@file mpeg.c
768 * MPEG codec.
769 * @@author ...
770 */
771
772 /**
773 * Summary sentence.
774 * more text ...
775 * ...
776 */
777 typedef struct Foobar@{
778 int var1; /**< var1 description */
779 int var2; ///< var2 description
780 /** var3 description */
781 int var3;
782 @} Foobar;
783
784 /**
785 * Summary sentence.
786 * more text ...
787 * ...
788 * @@param my_parameter description of my_parameter
789 * @@return return value description
790 */
791 int myfunc(int my_parameter)
792 ...
793 @end example
794
795 fprintf and printf are forbidden in libavformat and libavcodec,
796 please use av_log() instead.
797
798 Casts should be used only when necessary. Unneeded parentheses
799 should also be avoided if they don't make the code easier to understand.
800
801 @section Development Policy
802
803 @enumerate
804 @item
805 Contributions should be licensed under the LGPL 2.1, including an
806 "or any later version" clause, or the MIT license. GPL 2 including
807 an "or any later version" clause is also acceptable, but LGPL is
808 preferred.
809 @item
810 You must not commit code which breaks FFmpeg! (Meaning unfinished but
811 enabled code which breaks compilation or compiles but does not work or
812 breaks the regression tests)
813 You can commit unfinished stuff (for testing etc), but it must be disabled
814 (#ifdef etc) by default so it does not interfere with other developers'
815 work.
816 @item
817 You do not have to over-test things. If it works for you, and you think it
818 should work for others, then commit. If your code has problems
819 (portability, triggers compiler bugs, unusual environment etc) they will be
820 reported and eventually fixed.
821 @item
822 Do not commit unrelated changes together, split them into self-contained
823 pieces. Also do not forget that if part B depends on part A, but A does not
824 depend on B, then A can and should be committed first and separate from B.
825 Keeping changes well split into self-contained parts makes reviewing and
826 understanding them on the commit log mailing list easier. This also helps
827 in case of debugging later on.
828 Also if you have doubts about splitting or not splitting, do not hesitate to
829 ask/discuss it on the developer mailing list.
830 @item
831 Do not change behavior of the program (renaming options etc) without
832 first discussing it on the ffmpeg-devel mailing list. Do not remove
833 functionality from the code. Just improve!
834
835 Note: Redundant code can be removed.
836 @item
837 Do not commit changes to the build system (Makefiles, configure script)
838 which change behavior, defaults etc, without asking first. The same
839 applies to compiler warning fixes, trivial looking fixes and to code
840 maintained by other developers. We usually have a reason for doing things
841 the way we do. Send your changes as patches to the ffmpeg-devel mailing
842 list, and if the code maintainers say OK, you may commit. This does not
843 apply to files you wrote and/or maintain.
844 @item
845 We refuse source indentation and other cosmetic changes if they are mixed
846 with functional changes, such commits will be rejected and removed. Every
847 developer has his own indentation style, you should not change it. Of course
848 if you (re)write something, you can use your own style, even though we would
849 prefer if the indentation throughout FFmpeg was consistent (Many projects
850 force a given indentation style - we do not.). If you really need to make
851 indentation changes (try to avoid this), separate them strictly from real
852 changes.
853
854 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
855 then either do NOT change the indentation of the inner part within (do not
856 move it to the right)! or do so in a separate commit
857 @item
858 Always fill out the commit log message. Describe in a few lines what you
859 changed and why. You can refer to mailing list postings if you fix a
860 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
861 @item
862 If you apply a patch by someone else, include the name and email address in
863 the log message. Since the ffmpeg-cvslog mailing list is publicly
864 archived you should add some SPAM protection to the email address. Send an
865 answer to ffmpeg-devel (or wherever you got the patch from) saying that
866 you applied the patch.
867 @item
868 When applying patches that have been discussed (at length) on the mailing
869 list, reference the thread in the log message.
870 @item
871 Do NOT commit to code actively maintained by others without permission.
872 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
873 timeframe (12h for build failures and security fixes, 3 days small changes,
874 1 week for big patches) then commit your patch if you think it is OK.
875 Also note, the maintainer can simply ask for more time to review!
876 @item
877 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
878 are sent there and reviewed by all the other developers. Bugs and possible
879 improvements or general questions regarding commits are discussed there. We
880 expect you to react if problems with your code are uncovered.
881 @item
882 Update the documentation if you change behavior or add features. If you are
883 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
884 maintainer(s) will review and commit your stuff.
885 @item
886 Try to keep important discussions and requests (also) on the public
887 developer mailing list, so that all developers can benefit from them.
888 @item
889 Never write to unallocated memory, never write over the end of arrays,
890 always check values read from some untrusted source before using them
891 as array index or other risky things.
892 @item
893 Remember to check if you need to bump versions for the specific libav
894 parts (libavutil, libavcodec, libavformat) you are changing. You need
895 to change the version integer and the version string.
896 Incrementing the first component means no backward compatibility to
897 previous versions (e.g. removal of a function from the public API).
898 Incrementing the second component means backward compatible change
899 (e.g. addition of a function to the public API).
900 Incrementing the third component means a noteworthy binary compatible
901 change (e.g. encoder bug fix that matters for the decoder).
902 @item
903 If you add a new codec, remember to update the changelog, add it to
904 the supported codecs table in the documentation and bump the second
905 component of the @file{libavcodec} version number appropriately. If
906 it has a fourcc, add it to @file{libavformat/riff.c}, even if it
907 is only a decoder.
908 @item
909 Compiler warnings indicate potential bugs or code with bad style. If a type of
910 warning always points to correct and clean code, that warning should
911 be disabled, not the code changed.
912 Thus the remaining warnings can either be bugs or correct code.
913 If it is a bug, the bug has to be fixed. If it is not, the code should
914 be changed to not generate a warning unless that causes a slowdown
915 or obfuscates the code.
916 @item
917 If you add a new file, give it a proper license header. Do not copy and
918 paste it from a random place, use an existing file as template.
919 @end enumerate
920
921 We think our rules are not too hard. If you have comments, contact us.
922
923 Note, these rules are mostly borrowed from the MPlayer project.
924
925 @section Submitting patches
926
927 First, (@pxref{Coding Rules}) above if you did not yet.
928
929 When you submit your patch, try to send a unified diff (diff '-up'
930 option). We cannot read other diffs :-)
931
932 Also please do not submit a patch which contains several unrelated changes.
933 Split it into separate, self-contained pieces. This does not mean splitting
934 file by file. Instead, make the patch as small as possible while still
935 keeping it as a logical unit that contains an individual change, even
936 if it spans multiple files. This makes reviewing your patches much easier
937 for us and greatly increases your chances of getting your patch applied.
938
939 Run the regression tests before submitting a patch so that you can
940 verify that there are no big problems.
941
942 Patches should be posted as base64 encoded attachments (or any other
943 encoding which ensures that the patch will not be trashed during
944 transmission) to the ffmpeg-devel mailing list, see
945 @url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
946
947 It also helps quite a bit if you tell us what the patch does (for example
948 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
949 and has no lrint()')
950
951 Also please if you send several patches, send each patch as a separate mail,
952 do not attach several unrelated patches to the same mail.
953
954 @section patch submission checklist
955
956 @enumerate
957 @item
958 Do the regression tests pass with the patch applied?
959 @item
960 Is the patch a unified diff?
961 @item
962 Is the patch against latest FFmpeg SVN?
963 @item
964 Are you subscribed to ffmpeg-dev?
965 (the list is subscribers only due to spam)
966 @item
967 Have you checked that the changes are minimal, so that the same cannot be
968 achieved with a smaller patch and/or simpler final code?
969 @item
970 If the change is to speed critical code, did you benchmark it?
971 @item
972 If you did any benchmarks, did you provide them in the mail?
973 @item
974 Have you checked that the patch does not introduce buffer overflows or
975 other security issues?
976 @item
977 If you add a new demuxer or decoder, have you checked that it does not
978 crash with damaged input (see tools/trasher)?
979 @item
980 Is the patch created from the root of the source tree, so it can be
981 applied with @code{patch -p0}?
982 @item
983 Does the patch not mix functional and cosmetic changes?
984 @item
985 Did you add tabs or trailing whitespace to the code? Both are forbidden.
986 @item
987 Is the patch attached to the email you send?
988 @item
989 Is the mime type of the patch correct? It should be text/x-diff or
990 text/x-patch or at least text/plain and not application/octet-stream.
991 @item
992 If the patch fixes a bug, did you provide a verbose analysis of the bug?
993 @item
994 If the patch fixes a bug, did you provide enough information, including
995 a sample, so the bug can be reproduced and the fix can be verified?
996 Note please do not attach samples >100k to mails but rather provide a
997 URL, you can upload to ftp://upload.mplayerhq.hu
998 @item
999 Did you provide a verbose summary about what the patch does change?
1000 @item
1001 Did you provide a verbose explanation why it changes things like it does?
1002 @item
1003 Did you provide a verbose summary of the user visible advantages and
1004 disadvantages if the patch is applied?
1005 @item
1006 Did you provide an example so we can verify the new feature added by the
1007 patch easily?
1008 @item
1009 If you added a new file, did you insert a license header? It should be
1010 taken from FFmpeg, not randomly copied and pasted from somewhere else.
1011 @item
1012 You should maintain alphabetical order in alphabetically ordered lists as
1013 long as doing so does not break API/ABI compatibility.
1014 @item
1015 Lines with similar content should be aligned vertically when doing so
1016 improves readability.
1017 @item
1018 Did you provide a suggestion for a clear commit log message?
1019 @item
1020 Did you test your decoder or demuxer against damaged data? If no, see
1021 tools/trasher and the noise bitstream filter. Your decoder or demuxer
1022 should not crash or end in a (near) infinite loop when fed damaged data.
1023 @end enumerate
1024
1025 @section Patch review process
1026
1027 All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1028 clear note that the patch is not for SVN.
1029 Reviews and comments will be posted as replies to the patch on the
1030 mailing list. The patch submitter then has to take care of every comment,
1031 that can be by resubmitting a changed patch or by discussion. Resubmitted
1032 patches will themselves be reviewed like any other patch. If at some point
1033 a patch passes review with no comments then it is approved, that can for
1034 simple and small patches happen immediately while large patches will generally
1035 have to be changed and reviewed many times before they are approved.
1036 After a patch is approved it will be committed to the repository.
1037
1038 We will review all submitted patches, but sometimes we are quite busy so
1039 especially for large patches this can take several weeks.
1040
1041 When resubmitting patches, please do not make any significant changes
1042 not related to the comments received during review. Such patches will
1043 be rejected. Instead, submit significant changes or new features as
1044 separate patches.
1045
1046 @section Regression tests
1047
1048 Before submitting a patch (or committing to the repository), you should at least
1049 test that you did not break anything.
1050
1051 The regression tests build a synthetic video stream and a synthetic
1052 audio stream. These are then encoded and decoded with all codecs or
1053 formats. The CRC (or MD5) of each generated file is recorded in a
1054 result file. A 'diff' is launched to compare the reference results and
1055 the result file.
1056
1057 The regression tests then go on to test the FFserver code with a
1058 limited set of streams. It is important that this step runs correctly
1059 as well.
1060
1061 Run 'make test' to test all the codecs and formats.
1062
1063 Run 'make fulltest' to test all the codecs, formats and FFserver.
1064
1065 [Of course, some patches may change the results of the regression tests. In
1066 this case, the reference results of the regression tests shall be modified
1067 accordingly].
1068
1069 @bye