Add support for external OpenCORE libraries for AMR-NB/WB support.
[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 (libamr) as well as
22 the OpenCORE libraries for AMR-NB decoding/encoding and AMR-WB decoding.
24 @subsection OpenCORE
26 Go to @url{} and follow the instructions for
27 installing the libraries. Then pass @code{--enable-libopencore-amrnb} and/or
28 @code{--enable-libopencore-amrwb} to configure to enable the libraries.
30 Note that OpenCORE is under the Apache License 2.0 (see
31 @url{} for details), which is
32 incompatible with the LGPL version 2.1 and GPL version 2. You have to
33 upgrade FFmpeg's license to LGPL version 3 (or if you have enabled
34 GPL components, GPL version 3) to use it.
36 @subsection libamr
38 Go to @url{} and follow the instructions for
39 installing the libraries. Then pass @code{--enable-libamr-nb} and/or
40 @code{--enable-libamr-wb} to configure to enable the libraries.
42 Note that libamr is copyrighted without any sort of license grant. This means
43 that you can use it if you legally obtained it but you are not allowed to
44 redistribute it in any way. @strong{Any FFmpeg binaries with libamr support
45 you create are non-free and unredistributable!}
48 @chapter Supported File Formats and Codecs
50 You can use the @code{-formats} option to have an exhaustive list.
52 @section File Formats
54 FFmpeg supports the following file formats through the @code{libavformat}
55 library:
57 @multitable @columnfractions .4 .1 .1 .4
58 @item Name @tab Encoding @tab Decoding @tab Comments
59 @item 4xm @tab @tab X
60 @tab 4X Technologies format, used in some games.
61 @item 8088flex TMV @tab @tab X
62 @item Audio IFF (AIFF) @tab X @tab X
63 @item American Laser Games MM @tab @tab X
64 @tab Multimedia format used in games like Mad Dog McCree.
65 @item 3GPP AMR @tab X @tab X
66 @item ASF @tab X @tab X
67 @item AVI @tab X @tab X
68 @item AVISynth @tab @tab X
69 @item AVS @tab @tab X
70 @tab Multimedia format used by the Creature Shock game.
71 @item Beam Software SIFF @tab @tab X
72 @tab Audio and video format used in some games by Beam Software.
73 @item Bethesda Softworks VID @tab @tab X
74 @tab Used in some games from Bethesda Softworks.
75 @item Brute Force & Ignorance @tab @tab X
76 @tab Used in the game Flash Traffic: City of Angels.
77 @item Interplay C93 @tab @tab X
78 @tab Used in the game Cyberia from Interplay.
79 @item Delphine Software International CIN @tab @tab X
80 @tab Multimedia format used by Delphine Software games.
81 @item CRC testing format @tab X @tab
82 @item Creative Voice @tab X @tab X
83 @tab Created for the Sound Blaster Pro.
84 @item CRYO APC @tab @tab X
85 @tab Audio format used in some games by CRYO Interactive Entertainment.
86 @item D-Cinema audio @tab X @tab X
87 @item DV video @tab X @tab X
88 @item DXA @tab @tab X
89 @tab This format is used in the non-Windows version of the Feeble Files
90 game and different game cutscenes repacked for use with ScummVM.
91 @item Electronic Arts cdata @tab @tab X
92 @item Electronic Arts Multimedia @tab @tab X
93 @tab Used in various EA games; files have extensions like WVE and UV2.
94 @item FFM (FFserver live feed) @tab X @tab X
95 @item Flash (SWF) @tab X @tab X
96 @item Flash 9 (AVM2) @tab X @tab X
97 @tab Only embedded audio is decoded.
98 @item FLI/FLC/FLX animation @tab @tab X
99 @tab .fli/.flc files
100 @item Flash Video (FLV) @tab @tab X
101 @tab Macromedia Flash video files
102 @item framecrc testing format @tab X @tab
103 @item FunCom ISS @tab @tab X
104 @tab Audio format used in various games from FunCom like The Longest Journey.
105 @item GIF Animation @tab X @tab
106 @item GXF @tab X @tab X
107 @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley
108 playout servers.
109 @item id Quake II CIN video @tab @tab X
110 @item id RoQ @tab X @tab X
111 @tab Used in Quake III, Jedi Knight 2, other computer games.
112 @item IFF @tab @tab X
113 @tab Interchange File Format
114 @item Interplay MVE @tab @tab X
115 @tab Format used in various Interplay computer games.
116 @item LMLM4 @tab @tab X
117 @tab Used by Linux Media Labs MPEG-4 PCI boards
118 @item Matroska @tab X @tab X
119 @item Matroska audio @tab X @tab
120 @item MAXIS XA @tab @tab X
121 @tab Used in Sim City 3000; file extension .xa.
122 @item Monkey's Audio @tab @tab X
123 @item Motion Pixels MVI @tab @tab X
124 @item MOV/QuickTime/MP4 @tab X @tab X
125 @tab 3GP, 3GP2, PSP, iPod variants supported
126 @item MP2 @tab X @tab X
127 @item MP3 @tab X @tab X
128 @item MPEG-1 System @tab X @tab X
129 @tab muxed audio and video, VCD format supported
130 @item MPEG-PS (program stream) @tab X @tab X
131 @tab also known as @code{VOB} file, SVCD and DVD format supported
132 @item MPEG-TS (transport stream) @tab X @tab X
133 @tab also known as DVB Transport Stream
134 @item MPEG-4 @tab X @tab X
135 @tab MPEG-4 is a variant of QuickTime.
136 @item MIME multipart JPEG @tab X @tab
137 @item MSN TCP webcam @tab @tab X
138 @tab Used by MSN Messenger webcam streams.
139 @item MTV @tab @tab X
140 @item Musepack @tab @tab X
141 @item Musepack SV8 @tab @tab X
142 @item Material eXchange Format (MXF) @tab X @tab X
143 @tab SMPTE 377M, used by D-Cinema, broadcast industry.
144 @item Material eXchange Format (MXF), D-10 Mapping @tab X @tab X
145 @tab SMPTE 386M, D-10/IMX Mapping.
146 @item NC camera feed @tab @tab X
147 @tab NC (AVIP NC4600) camera streams
148 @item NTT TwinVQ (VQF) @tab @tab X
149 @tab Nippon Telegraph and Telephone Corporation TwinVQ.
150 @item Nullsoft Streaming Video @tab @tab X
151 @item NuppelVideo @tab @tab X
152 @item NUT @tab X @tab X
153 @tab NUT Open Container Format
154 @item Ogg @tab X @tab X
155 @item TechnoTrend PVA @tab @tab X
156 @tab Used by TechnoTrend DVB PCI boards.
157 @item QCP @tab @tab X
158 @item raw ADTS (AAC) @tab X @tab X
159 @item raw AC-3 @tab X @tab X
160 @item raw Chinese AVS video @tab @tab X
161 @item raw CRI ADX @tab X @tab X
162 @item raw Dirac @tab X @tab X
163 @item raw DNxHD @tab X @tab X
164 @item raw DTS @tab X @tab X
165 @item raw E-AC-3 @tab X @tab X
166 @item raw FLAC @tab X @tab X
167 @item raw GSM @tab @tab X
168 @item raw H.261 @tab X @tab X
169 @item raw H.263 @tab X @tab X
170 @item raw H.264 @tab X @tab X
171 @item raw Ingenient MJPEG @tab @tab X
172 @item raw MJPEG @tab X @tab X
173 @item raw MLP @tab @tab X
174 @item raw MPEG @tab @tab X
175 @item raw MPEG-1 @tab @tab X
176 @item raw MPEG-2 @tab @tab X
177 @item raw MPEG-4 @tab X @tab X
178 @item raw NULL @tab X @tab
179 @item raw video @tab X @tab X
180 @item raw id RoQ @tab X @tab
181 @item raw Shorten @tab @tab X
182 @item raw TrueHD @tab X @tab X
183 @item raw VC-1 @tab @tab X
184 @item raw PCM A-law @tab X @tab X
185 @item raw PCM mu-law @tab X @tab X
186 @item raw PCM signed 8 bit @tab X @tab X
187 @item raw PCM signed 16 bit big-endian @tab X @tab X
188 @item raw PCM signed 16 bit little-endian @tab X @tab X
189 @item raw PCM signed 24 bit big-endian @tab X @tab X
190 @item raw PCM signed 24 bit little-endian @tab X @tab X
191 @item raw PCM signed 32 bit big-endian @tab X @tab X
192 @item raw PCM signed 32 bit little-endian @tab X @tab X
193 @item raw PCM unsigned 8 bit @tab X @tab X
194 @item raw PCM unsigned 16 bit big-endian @tab X @tab X
195 @item raw PCM unsigned 16 bit little-endian @tab X @tab X
196 @item raw PCM unsigned 24 bit big-endian @tab X @tab X
197 @item raw PCM unsigned 24 bit little-endian @tab X @tab X
198 @item raw PCM unsigned 32 bit big-endian @tab X @tab X
199 @item raw PCM unsigned 32 bit little-endian @tab X @tab X
200 @item raw PCM floating-point 32 bit big-endian @tab X @tab X
201 @item raw PCM floating-point 32 bit little-endian @tab X @tab X
202 @item raw PCM floating-point 64 bit big-endian @tab X @tab X
203 @item raw PCM floating-point 64 bit little-endian @tab X @tab X
204 @item RDT @tab @tab X
205 @item REDCODE R3D @tab @tab X
206 @tab File format used by RED Digital cameras, contains JPEG 2000 frames and PCM audio.
207 @item RealMedia @tab X @tab X
208 @item Redirector @tab @tab X
209 @item Renderware TeXture Dictionary @tab @tab X
210 @item RL2 @tab @tab X
211 @tab Audio and video format used in some games by Entertainment Software Partners.
212 @item RPL/ARMovie @tab @tab X
213 @item RTP @tab @tab X
214 @item RTSP @tab @tab X
215 @item SDP @tab @tab X
216 @item Sega FILM/CPK @tab @tab X
217 @tab Used in many Sega Saturn console games.
218 @item Sierra SOL @tab @tab X
219 @tab .sol files used in Sierra Online games.
220 @item Sierra VMD @tab @tab X
221 @tab Used in Sierra CD-ROM games.
222 @item Smacker @tab @tab X
223 @tab Multimedia format used by many games.
224 @item Sony OpenMG (OMA) @tab @tab X
225 @tab Audio format used in Sony Sonic Stage and Sony Vegas.
226 @item Sony PlayStation STR @tab @tab X
227 @item SoX native format @tab X @tab X
228 @item SUN AU format @tab X @tab X
229 @item THP @tab @tab X
230 @tab Used on the Nintendo GameCube.
231 @item Tiertex Limited SEQ @tab @tab X
232 @tab Tiertex .seq files used in the DOS CD-ROM version of the game Flashback.
233 @item True Audio @tab @tab X
234 @item VC-1 test bitstream @tab X @tab X
235 @item WAV @tab X @tab X
236 @item WavPack @tab @tab X
237 @item Wing Commander III movie @tab @tab X
238 @tab Multimedia format used in Origin's Wing Commander III computer game.
239 @item Westwood Studios audio @tab @tab X
240 @tab Multimedia format used in Westwood Studios games.
241 @item Westwood Studios VQA @tab @tab X
242 @tab Multimedia format used in Westwood Studios games.
243 @item YUV4MPEG pipe @tab X @tab X
244 @end multitable
246 @code{X} means that encoding (resp. decoding) is supported.
248 @section Image Formats
250 FFmpeg can read and write images for each frame of a video sequence. The
251 following image formats are supported:
253 @multitable @columnfractions .4 .1 .1 .4
254 @item Name @tab Encoding @tab Decoding @tab Comments
255 @item .Y.U.V @tab X @tab X
256 @tab one raw file per component
257 @item animated GIF @tab X @tab X
258 @tab Only uncompressed GIFs are generated.
259 @item BMP @tab X @tab X
260 @tab Microsoft BMP image
261 @item JPEG @tab X @tab X
262 @tab Progressive JPEG is not supported.
263 @item JPEG 2000 @tab @tab E
264 @tab decoding supported through external library libopenjpeg
265 @item JPEG-LS @tab X @tab X
266 @item LJPEG @tab X @tab
267 @tab Lossless JPEG
268 @item PAM @tab X @tab X
269 @tab PAM is a PNM extension with alpha support.
270 @item PBM @tab X @tab X
271 @tab Portable BitMap image
272 @item PCX @tab X @tab X
273 @tab PC Paintbrush
274 @item PGM @tab X @tab X
275 @tab Portable GrayMap image
276 @item PGMYUV @tab X @tab X
277 @tab PGM with U and V components in YUV 4:2:0
278 @item PNG @tab X @tab X
279 @tab 2/4 bpp not supported yet
280 @item PPM @tab X @tab X
281 @tab Portable PixelMap image
282 @item PTX @tab @tab X
283 @tab V.Flash PTX format
284 @item SGI @tab X @tab X
285 @tab SGI RGB image format
286 @item Sun Rasterfile @tab @tab X
287 @tab Sun RAS image format
288 @item TIFF @tab X @tab X
289 @tab YUV, JPEG and some extension is not supported yet.
290 @item Truevision Targa @tab X @tab X
291 @tab Targa (.TGA) image format
292 @end multitable
294 @code{X} means that encoding (resp. decoding) is supported.
296 @code{E} means that support is provided through an external library.
298 @section Video Codecs
300 @multitable @columnfractions .4 .1 .1 .4
301 @item Name @tab Encoding @tab Decoding @tab Comments
302 @item 4X Movie @tab @tab X
303 @tab Used in certain computer games.
304 @item 8088flex TMV @tab @tab X
305 @item 8SVX exponential @tab @tab X
306 @item 8SVX fibonacci @tab @tab X
307 @item American Laser Games MM @tab @tab X
308 @tab Used in games like Mad Dog McCree.
309 @item AMV Video @tab @tab X
310 @tab Used in Chinese MP3 players.
311 @item Apple MJPEG-B @tab @tab X
312 @item Apple QuickDraw @tab @tab X
313 @tab fourcc: qdrw
314 @item Asus v1 @tab X @tab X
315 @tab fourcc: ASV1
316 @item Asus v2 @tab X @tab X
317 @tab fourcc: ASV2
318 @item ATI VCR1 @tab @tab X
319 @tab fourcc: VCR1
320 @item ATI VCR2 @tab @tab X
321 @tab fourcc: VCR2
322 @item Autodesk Animator Flic video @tab @tab X
323 @item Autodesk RLE @tab @tab X
324 @tab fourcc: AASC
325 @item AVS (Audio Video Standard) video @tab @tab X
326 @tab Video encoding used by the Creature Shock game.
327 @item Beam Software VB @tab @tab X
328 @item Bethesda VID video @tab @tab X
329 @tab Used in some games from Bethesda Softworks.
330 @item Brute Force & Ignorance @tab @tab X
331 @tab Used in the game Flash Traffic: City of Angels.
332 @item C93 video @tab @tab X
333 @tab Codec used in Cyberia game.
334 @item CamStudio @tab @tab X
335 @tab fourcc: CSCD
336 @item Chinese AVS video @tab @tab X
337 @tab AVS1-P2, JiZhun profile
338 @item Delphine Software International CIN video @tab @tab X
339 @tab Codec used in Delphine Software International games.
340 @item Cinepak @tab @tab X
341 @item Cirrus Logic AccuPak @tab @tab X
342 @tab fourcc: CLJR
343 @item Creative YUV (CYUV) @tab @tab X
344 @item Dirac @tab E @tab E
345 @tab supported through external libdirac/libschroedinger libraries
346 @item DNxHD @tab X @tab X
347 @tab aka SMPTE VC3
348 @item Duck TrueMotion 1.0 @tab @tab X
349 @tab fourcc: DUCK
350 @item Duck TrueMotion 2.0 @tab @tab X
351 @tab fourcc: TM20
352 @item DV (Digital Video) @tab X @tab X
353 @item Feeble Files/ScummVM DXA @tab @tab X
354 @tab Codec originally used in Feeble Files game.
355 @item Electronic Arts CMV video @tab @tab X
356 @tab Used in NHL 95 game.
357 @item Electronic Arts TGV video @tab @tab X
358 @item Electronic Arts TGQ video @tab @tab X
359 @item Electronic Arts TQI video @tab @tab X
360 @item Escape 124 @tab @tab X
361 @item FFmpeg codec #1 @tab X @tab X
362 @tab experimental lossless codec (fourcc: FFV1)
363 @item Flash Screen Video v1 @tab X @tab X
364 @tab fourcc: FSV1
365 @item Flash Video (FLV) @tab X @tab X
366 @tab Sorenson H.263 used in Flash
367 @item Fraps @tab @tab X
368 @item H.261 @tab X @tab X
369 @item H.263 / H.263-1996 @tab X @tab X
370 @item H.263+ / H.263-1998 / H.263 version 2 @tab X @tab X
371 @item H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 @tab E @tab X
372 @tab encoding supported through external library libx264
373 @item H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (VDPAU acceleration) @tab E @tab X
374 @item HuffYUV @tab X @tab X
375 @item HuffYUV FFmpeg variant @tab X @tab X
376 @item IBM Ultimotion @tab @tab X
377 @tab fourcc: ULTI
378 @item id Cinematic video @tab @tab X
379 @tab Used in Quake II.
380 @item id RoQ video @tab X @tab X
381 @tab Used in Quake III, Jedi Knight 2, other computer games.
382 @item Intel H.263 @tab @tab X
383 @item Intel Indeo 2 @tab @tab X
384 @item Intel Indeo 3 @tab @tab X
385 @item Interplay C93 @tab @tab X
386 @tab Used in the game Cyberia from Interplay.
387 @item Interplay MVE video @tab @tab X
388 @tab Used in Interplay .MVE files.
389 @item Karl Morton's video codec @tab @tab X
390 @tab Codec used in Worms games.
391 @item LCL (LossLess Codec Library) MSZH @tab @tab X
392 @item LCL (LossLess Codec Library) ZLIB @tab E @tab E
393 @item LOCO @tab @tab X
394 @item lossless MJPEG @tab X @tab X
395 @item Microsoft RLE @tab @tab X
396 @item Microsoft Video 1 @tab @tab X
397 @item Mimic @tab @tab X
398 @tab Used in MSN Messenger Webcam streams.
399 @item Miro VideoXL @tab @tab X
400 @tab fourcc: VIXL
401 @item MJPEG (Motion JPEG) @tab X @tab X
402 @item Motion Pixels video @tab @tab X
403 @item MPEG-1 video @tab X @tab X
404 @item MPEG-1/2 video XvMC (X-Video Motion Compensation) @tab @tab X
405 @item MPEG-1/2 video (VDPAU acceleration) @tab @tab X
406 @item MPEG-2 video @tab X @tab X
407 @item MPEG-4 part 2 @tab X @tab X
408 @ libxvidcore can be used alternatively for encoding.
409 @item MPEG-4 part 2 Microsoft variant version 1 @tab X @tab X
410 @item MPEG-4 part 2 Microsoft variant version 2 @tab X @tab X
411 @item MPEG-4 part 2 Microsoft variant version 3 @tab X @tab X
412 @item Nintendo Gamecube THP video @tab @tab X
413 @item NuppelVideo/RTjpeg @tab @tab X
414 @tab Video encoding used in NuppelVideo files.
415 @item On2 VP3 @tab @tab X
416 @tab still experimental
417 @item On2 VP5 @tab @tab X
418 @tab fourcc: VP50
419 @item On2 VP6 @tab @tab X
420 @tab fourcc: VP60,VP61,VP62
421 @item planar RGB @tab @tab X
422 @tab fourcc: 8BPS
423 @item Q-team QPEG @tab @tab X
424 @tab fourccs: QPEG, Q1.0, Q1.1
425 @item QuickTime 8BPS video @tab @tab X
426 @item QuickTime Animation (RLE) video @tab X @tab X
427 @tab fourcc: 'rle '
428 @item QuickTime Graphics (SMC) @tab @tab X
429 @tab fourcc: 'smc '
430 @item QuickTime video (RPZA) @tab @tab X
431 @tab fourcc: rpza
432 @item Raw Video @tab X @tab X
433 @item RealVideo 1.0 @tab X @tab X
434 @item RealVideo 2.0 @tab X @tab X
435 @item RealVideo 3.0 @tab @tab X
436 @tab still far from ideal
437 @item RealVideo 4.0 @tab @tab X
438 @item Renderware TXD (TeXture Dictionary) @tab @tab X
439 @tab Texture dictionaries used by the Renderware Engine.
440 @item RL2 video @tab @tab X
441 @tab used in some games by Entertainment Software Partners
442 @item Sierra VMD video @tab @tab X
443 @tab Used in Sierra VMD files.
444 @item Smacker video @tab @tab X
445 @tab Video encoding used in Smacker.
446 @item SMPTE VC-1 @tab @tab X
447 @item Snow @tab X @tab X
448 @tab experimental wavelet codec (fourcc: SNOW)
449 @item Sony PlayStation MDEC (Motion DECoder) @tab @tab X
450 @item Sorenson Vector Quantizer 1 @tab X @tab X
451 @tab fourcc: SVQ1
452 @item Sorenson Vector Quantizer 3 @tab @tab X
453 @tab fourcc: SVQ3
454 @item Sunplus JPEG (SP5X) @tab @tab X
455 @tab fourcc: SP5X
456 @item TechSmith Screen Capture Codec @tab @tab X
457 @tab fourcc: TSCC
458 @item Theora @tab E @tab X
459 @tab encoding supported through external library libtheora
460 @item Tiertex Limited SEQ video @tab @tab X
461 @tab Codec used in DOS CD-ROM FlashBack game.
462 @item V210 Quicktime Uncompressed 4:2:2 10-bit @tab X @tab X
463 @item VMware Screen Codec / VMware Video @tab @tab X
464 @tab Codec used in videos captured by VMware.
465 @item Westwood Studios VQA (Vector Quantized Animation) video @tab @tab X
466 @item Windows Media Video 7 @tab X @tab X
467 @item Windows Media Video 8 @tab X @tab X
468 @item Windows Media Video 9 @tab @tab X
469 @tab not completely working
470 @item Wing Commander III / Xan @tab @tab X
471 @tab Used in Wing Commander III .MVE files.
472 @item Winnov WNV1 @tab @tab X
473 @item WMV7 @tab X @tab X
474 @item YAMAHA SMAF @tab X @tab X
475 @item ZLIB @tab X @tab X
476 @tab part of LCL, encoder experimental
477 @item Zip Motion Blocks Video @tab X @tab X
478 @tab Encoder works only in PAL8.
479 @end multitable
481 @code{X} means that encoding (resp. decoding) is supported.
483 @code{E} means that support is provided through an external library.
485 @section Audio Codecs
487 @multitable @columnfractions .4 .1 .1 .4
488 @item Name @tab Encoding @tab Decoding @tab Comments
489 @item 8SVX audio @tab @tab X
490 @item AAC @tab E @tab X
491 @tab encoding supported through external library libfaac
492 @item AC-3 @tab IX @tab X
493 @item ADPCM 4X Movie @tab @tab X
494 @item ADPCM CDROM XA @tab @tab X
495 @item ADPCM Creative Technology @tab @tab X
496 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
497 @item ADPCM Electronic Arts @tab @tab X
498 @tab Used in various EA titles.
499 @item ADPCM Electronic Arts Maxis CDROM XS @tab @tab X
500 @tab Used in Sim City 3000.
501 @item ADPCM Electronic Arts R1 @tab @tab X
502 @item ADPCM Electronic Arts R2 @tab @tab X
503 @item ADPCM Electronic Arts R3 @tab @tab X
504 @item ADPCM Electronic Arts XAS @tab @tab X
505 @item ADPCM G.726 @tab X @tab X
506 @item ADPCM IMA AMV @tab @tab X
507 @tab Used in AMV files
508 @item ADPCM IMA Electronic Arts EACS @tab @tab X
509 @item ADPCM IMA Electronic Arts SEAD @tab @tab X
510 @item ADPCM IMA Funcom @tab @tab X
511 @item ADPCM IMA QuickTime @tab X @tab X
512 @item ADPCM IMA Loki SDL MJPEG @tab @tab X
513 @item ADPCM IMA WAV @tab X @tab X
514 @item ADPCM IMA Westwood @tab @tab X
515 @item ADPCM ISS IMA @tab @tab X
516 @tab Used in FunCom games.
517 @item ADPCM IMA Duck DK3 @tab @tab X
518 @tab Used in some Sega Saturn console games.
519 @item ADPCM IMA Duck DK4 @tab @tab X
520 @tab Used in some Sega Saturn console games.
521 @item ADPCM Microsoft @tab X @tab X
522 @item ADPCM MS IMA @tab X @tab X
523 @item ADPCM Nintendo Gamecube THP @tab @tab X
524 @item ADPCM QT IMA @tab X @tab X
525 @item ADPCM SEGA CRI ADX @tab X @tab X
526 @tab Used in Sega Dreamcast games.
527 @item ADPCM Shockwave Flash @tab X @tab X
528 @item ADPCM SMJPEG IMA @tab @tab X
529 @tab Used in certain Loki game ports.
530 @item ADPCM Sound Blaster Pro 2-bit @tab @tab X
531 @item ADPCM Sound Blaster Pro 2.6-bit @tab @tab X
532 @item ADPCM Sound Blaster Pro 4-bit @tab @tab X
533 @item ADPCM Westwood Studios IMA @tab @tab X
534 @tab Used in Westwood Studios games like Command and Conquer.
535 @item ADPCM Yamaha @tab X @tab X
536 @item AMR-NB @tab E @tab E
537 @tab supported through external libraries libamrnb and libopencore-amrnb
538 @item AMR-WB @tab E @tab E
539 @tab decoding supported through external libraries libamrwb and libopencore-amrwb,
540 encoding supported through external library libamrwb
541 @item Apple lossless audio @tab X @tab X
542 @tab QuickTime fourcc 'alac'
543 @item Atrac 3 @tab @tab X
544 @item Delphine Software International CIN audio @tab @tab X
545 @tab Codec used in Delphine Software International games.
546 @item COOK @tab @tab X
547 @tab All versions except 5.1 are supported.
548 @item DCA (DTS Coherent Acoustics) @tab @tab X
549 @item DPCM id RoQ @tab X @tab X
550 @tab Used in Quake III, Jedi Knight 2, other computer games.
551 @item DPCM Interplay @tab @tab X
552 @tab Used in various Interplay computer games.
553 @item DPCM Sierra Online @tab @tab X
554 @tab Used in Sierra Online game audio files.
555 @item DPCM Sol @tab @tab X
556 @item DPCM Xan @tab @tab X
557 @item DSP Group TrueSpeech @tab @tab X
558 @item DV audio @tab @tab X
559 @item Enhanced AC-3 @tab @tab X
560 @item FLAC (Free Lossless Audio Codec) @tab X @tab IX
561 @item G.729 @tab @tab X
562 @item GSM @tab E @tab E
563 @tab supported through external library libgsm
564 @item GSM Microsoft variant @tab E @tab E
565 @tab supported through external library libgsm
566 @item IMC (Intel Music Coder) @tab @tab X
567 @item MACE (Macintosh Audio Compression/Expansion) 3:1 @tab @tab X
568 @item MACE (Macintosh Audio Compression/Expansion) 6:1 @tab @tab X
569 @item MLP (Meridian Lossless Packing) @tab @tab X
570 @tab Used in DVD-Audio discs.
571 @item Monkey's Audio @tab @tab X
572 @tab Only versions 3.97-3.99 are supported.
573 @item MP1 (MPEG audio layer 1) @tab @tab IX
574 @item MP2 (MPEG audio layer 2) @tab IX @tab IX
575 @item MP3 (MPEG audio layer 3) @tab E @tab IX
576 @tab encoding supported through external library LAME, ADU MP3 and MP3onMP4 also supported
577 @item Musepack SV7 @tab @tab X
578 @item Musepack SV8 @tab @tab X
579 @item Nellymoser Asao @tab X @tab X
580 @item PCM A-law @tab X @tab X
581 @item PCM mu-law @tab X @tab X
582 @item PCM 16-bit little-endian planar @tab @tab X
583 @item PCM 32-bit floating point big-endian @tab X @tab X
584 @item PCM 32-bit floating point little-endian @tab X @tab X
585 @item PCM 64-bit floating point big-endian @tab X @tab X
586 @item PCM 64-bit floating point little-endian @tab X @tab X
587 @item PCM D-Cinema audio signed 24-bit @tab X @tab X
588 @item PCM signed 8-bit @tab X @tab X
589 @item PCM signed 16-bit big-endian @tab X @tab X
590 @item PCM signed 16-bit little-endian @tab X @tab X
591 @item PCM signed 24-bit big-endian @tab X @tab X
592 @item PCM signed 24-bit little-endian @tab X @tab X
593 @item PCM signed 32-bit big-endian @tab X @tab X
594 @item PCM signed 32-bit little-endian @tab X @tab X
595 @item PCM unsigned 8-bit @tab X @tab X
596 @item PCM unsigned 16-bit big-endian @tab X @tab X
597 @item PCM unsigned 16-bit little-endian @tab X @tab X
598 @item PCM unsigned 24-bit big-endian @tab X @tab X
599 @item PCM unsigned 24-bit little-endian @tab X @tab X
600 @item PCM unsigned 32-bit big-endian @tab X @tab X
601 @item PCM unsigned 32-bit little-endian @tab X @tab X
602 @item PCM Zork @tab X @tab X
603 @item QCELP / PureVoice @tab @tab X
604 @item QDesign Music Codec 2 @tab @tab X
605 @tab There are still some distortions.
606 @item RealAudio 1.0 (14.4K) @tab @tab X
607 @tab Real 14400 bit/s codec
608 @item RealAudio 2.0 (28.8K) @tab @tab X
609 @tab Real 28800 bit/s codec
610 @item RealAudio 3.0 (dnet) @tab IX @tab X
611 @tab Real low bitrate AC-3 codec
612 @item Shorten @tab @tab X
613 @item Sierra VMD audio @tab @tab X
614 @tab Used in Sierra VMD files.
615 @item Smacker audio @tab @tab X
616 @item Sonic @tab X @tab X
617 @tab experimental codec
618 @item Sonic lossless @tab X @tab X
619 @tab experimental codec
620 @item Speex @tab @tab E
621 @tab supported through external library libspeex
622 @item True Audio (TTA) @tab @tab X
623 @item TrueHD @tab @tab X
624 @tab Used in HD-DVD and Blu-Ray discs.
625 @item Vorbis @tab E @tab X
626 @ A native but very primitive encoder exists.
627 @item WavPack @tab @tab X
628 @item Westwood Audio (SND1) @tab @tab X
629 @item Windows Media Audio 1 @tab X @tab X
630 @item Windows Media Audio 2 @tab X @tab X
631 @tab Used in Origin's Wing Commander IV AVI files.
632 @end multitable
634 @code{X} means that encoding (resp. decoding) is supported.
636 @code{E} means that support is provided through an external library.
638 @code{I} means that an integer-only version is available, too (ensures high
639 performance on systems without hardware floating point support).
641 @section Subtitle Formats
643 @multitable @columnfractions .4 .1 .1 .1 .1
644 @item Name @tab Muxing @tab Demuxing @tab Encoding @tab Decoding
645 @item SSA/ASS @tab X @tab X
646 @item DVB @tab X @tab X @tab X @tab X
647 @item DVD @tab X @tab X @tab X @tab X
648 @item XSUB @tab @tab @tab @tab X
649 @end multitable
651 @code{X} means that the feature is supported.
653 @section Network Protocols
655 @multitable @columnfractions .4 .1
656 @item Name @tab Support
657 @item file @tab X
658 @item Gopher @tab X
659 @item HTTP @tab X
660 @item pipe @tab X
661 @item RTP @tab X
662 @item TCP @tab X
663 @item UDP @tab X
664 @end multitable
666 @code{X} means that the protocol is supported.
669 @section Input/Output Devices
671 @multitable @columnfractions .4 .1 .1
672 @item Name @tab Input @tab Output
673 @item ALSA @tab X @tab X
674 @item BEOS audio @tab X @tab X
675 @item BKTR @tab X @tab
676 @item DV1394 @tab X @tab
677 @item JACK @tab X @tab
678 @item LIBDC1394 @tab X @tab
679 @item OSS @tab X @tab X
680 @item Video4Linux @tab X @tab
681 @item Video4Linux2 @tab X @tab
682 @item VfW capture @tab X @tab
683 @item X11 grabbing @tab X @tab
684 @end multitable
686 @code{X} means that input/output is supported.
689 @chapter Platform Specific information
691 @section BSD
693 BSD make will not build FFmpeg, you need to install and use GNU Make
694 (@file{gmake}).
696 @section Windows
698 To get help and instructions for building FFmpeg under Windows, check out
699 the FFmpeg Windows Help Forum at
700 @url{}.
702 @subsection Native Windows compilation
704 FFmpeg can be built to run natively on Windows using the MinGW tools. Install
705 the latest versions of MSYS and MinGW from @url{}.
706 You can find detailed installation
707 instructions in the download section and the FAQ.
709 FFmpeg does not build out-of-the-box with the packages the automated MinGW
710 installer provides. It also requires coreutils to be installed and many other
711 packages updated to the latest version. The minimum version for some packages
712 are listed below:
714 @itemize
715 @item bash 3.1
716 @item msys-make 3.81-2 (note: not mingw32-make)
717 @item w32api 3.13
718 @item mingw-runtime 3.15
719 @end itemize
721 FFmpeg automatically passes @code{-fno-common} to the compiler to work around
722 a GCC bug (see @url{}).
724 Within the MSYS shell, configure and make with:
726 @example
727 ./configure --enable-memalign-hack --extra-cflags=-fno-common
728 make
729 make install
730 @end example
732 This will install @file{ffmpeg.exe} along with many other development files
733 to @file{/usr/local}. You may specify another install path using the
734 @code{--prefix} option in @file{configure}.
736 Notes:
738 @itemize
740 @item In order to compile FFplay, you must have the MinGW development library
741 of SDL. Get it from @url{}.
742 Edit the @file{bin/sdl-config} script so that it points to the correct prefix
743 where SDL was installed. Verify that @file{sdl-config} can be launched from
744 the MSYS command line.
746 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
747 you can build libavutil, libavcodec and libavformat as DLLs.
749 @end itemize
751 @subsection Microsoft Visual C++ compatibility
753 As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
754 want to use the libav* libraries in your own applications, you can still
755 compile those applications using MSVC++. But the libav* libraries you link
756 to @emph{must} be built with MinGW. However, you will not be able to debug
757 inside the libav* libraries, since MSVC++ does not recognize the debug
758 symbols generated by GCC.
759 We strongly recommend you to move over from MSVC++ to MinGW tools.
761 This description of how to use the FFmpeg libraries with MSVC++ is based on
762 Microsoft Visual C++ 2005 Express Edition. If you have a different version,
763 you might have to modify the procedures slightly.
765 @subsubsection Using static libraries
767 Assuming you have just built and installed FFmpeg in @file{/usr/local}.
769 @enumerate
771 @item Create a new console application ("File / New / Project") and then
772 select "Win32 Console Application". On the appropriate page of the
773 Application Wizard, uncheck the "Precompiled headers" option.
775 @item Write the source code for your application, or, for testing, just
776 copy the code from an existing sample application into the source file
777 that MSVC++ has already created for you. For example, you can copy
778 @file{libavformat/output-example.c} from the FFmpeg distribution.
780 @item Open the "Project / Properties" dialog box. In the "Configuration"
781 combo box, select "All Configurations" so that the changes you make will
782 affect both debug and release builds. In the tree view on the left hand
783 side, select "C/C++ / General", then edit the "Additional Include
784 Directories" setting to contain the path where the FFmpeg includes were
785 installed (i.e. @file{c:\msys\1.0\local\include}).
786 Do not add MinGW's include directory here, or the include files will
787 conflict with MSVC's.
789 @item Still in the "Project / Properties" dialog box, select
790 "Linker / General" from the tree view and edit the
791 "Additional Library Directories" setting to contain the @file{lib}
792 directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
793 the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
794 and the directory where MinGW's GCC libs are installed
795 (i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
796 "Linker / Input" from the tree view, and add the files @file{libavformat.a},
797 @file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
798 @file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
799 to the end of "Additional Dependencies".
801 @item Now, select "C/C++ / Code Generation" from the tree view. Select
802 "Debug" in the "Configuration" combo box. Make sure that "Runtime
803 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
804 the "Configuration" combo box and make sure that "Runtime Library" is
805 set to "Multi-threaded DLL".
807 @item Click "OK" to close the "Project / Properties" dialog box.
809 @item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
810 Get msinttypes from @url{}
811 and install it in MSVC++'s include directory
812 (i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
814 @item MSVC++ also does not understand the @code{inline} keyword used by
815 FFmpeg, so you must add this line before @code{#include}ing libav*:
816 @example
817 #define inline _inline
818 @end example
820 @item Build your application, everything should work.
822 @end enumerate
824 @subsubsection Using shared libraries
826 This is how to create DLL and LIB files that are compatible with MSVC++:
828 @enumerate
830 @item Add a call to @file{vcvars32.bat} (which sets up the environment
831 variables for the Visual C++ tools) as the first line of @file{msys.bat}.
832 The standard location for @file{vcvars32.bat} is
833 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
834 and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
835 If this corresponds to your setup, add the following line as the first line
836 of @file{msys.bat}:
838 @example
839 call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
840 @end example
842 Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
843 and run @file{c:\msys\1.0\msys.bat} from there.
845 @item Within the MSYS shell, run @code{lib.exe}. If you get a help message
846 from @file{Microsoft (R) Library Manager}, this means your environment
847 variables are set up correctly, the @file{Microsoft (R) Library Manager}
848 is on the path and will be used by FFmpeg to create
849 MSVC++-compatible import libraries.
851 @item Build FFmpeg with
853 @example
854 ./configure --enable-shared --enable-memalign-hack
855 make
856 make install
857 @end example
859 Your install path (@file{/usr/local/} by default) should now have the
860 necessary DLL and LIB files under the @file{bin} directory.
862 @end enumerate
864 To use those files with MSVC++, do the same as you would do with
865 the static libraries, as described above. But in Step 4,
866 you should only need to add the directory where the LIB files are installed
867 (i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
868 installed in the @file{bin} directory. And instead of adding @file{libxx.a}
869 files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
870 @file{avutil.lib}. There should be no need for @file{libmingwex.a},
871 @file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
872 statically linked into the DLLs. The @file{bin} directory contains a bunch
873 of DLL files, but the ones that are actually used to run your application
874 are the ones with a major version number in their filenames
875 (i.e. @file{avcodec-51.dll}).
877 @subsection Cross compilation for Windows with Linux
879 You must use the MinGW cross compilation tools available at
880 @url{}.
882 Then configure FFmpeg with the following options:
883 @example
884 ./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
885 @end example
886 (you can change the cross-prefix according to the prefix chosen for the
887 MinGW tools).
889 Then you can easily test FFmpeg with Wine
890 (@url{}).
892 @subsection Compilation under Cygwin
894 The main issue with the 1.5.x Cygwin versions is that newlib, its C library,
895 does not contain llrint(). You need to upgrade to the unstable 1.7.x versions,
896 or leverage the implementation in MinGW (as explained below).
898 Just install your Cygwin with all the "Base" packages, plus the
899 following "Devel" ones:
900 @example
901 binutils, gcc-core, make, subversion, mingw-runtime, diffutils
902 @end example
904 The experimental gcc4 package is still buggy, hence please
905 use the official gcc 3.4.4 or a 4.2.x compiled from source by yourself.
907 Install the current binutils-20080624-2 as they work fine (the old
908 binutils-20060709-1 proved buggy on shared builds).
910 Then create a small library that just contains llrint():
912 @example
913 ar x /usr/lib/mingw/libmingwex.a llrint.o
914 ar cq /usr/local/lib/libllrint.a llrint.o
915 @end example
917 Then run
919 @example
920 ./configure --enable-static --disable-shared --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
921 @end example
923 to make a static build or
925 @example
926 ./configure --enable-shared --disable-static --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
927 @end example
929 to build shared libraries.
931 If you want to build FFmpeg with additional libraries, download Cygwin
932 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository:
933 @example
934 libogg-devel, libvorbis-devel
935 @end example
937 These library packages are only available from Cygwin Ports
938 (@url{}) :
940 @example
941 yasm, libSDL-devel, libdirac-devel, libfaac-devel, libfaad-devel, libgsm-devel,
942 libmp3lame-devel, libschroedinger1.0-devel, speex-devel, libtheora-devel,
943 libxvidcore-devel
944 @end example
946 The recommendation for libnut and x264 is to build them from source by
947 yourself, as they evolve too quickly for Cygwin Ports to be up to date.
949 Cygwin 1.7.x has IPv6 support. You can add IPv6 to Cygwin 1.5.x by means
950 of the @code{libgetaddrinfo-devel} package, available at Cygwin Ports.
952 @subsection Crosscompilation for Windows under Cygwin
954 With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
956 Just install your Cygwin as explained before, plus these additional
957 "Devel" packages:
958 @example
959 gcc-mingw-core, mingw-runtime, mingw-zlib
960 @end example
962 and add some special flags to your configure invocation.
964 For a static build run
965 @example
966 ./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
967 @end example
969 and for a build with shared libraries
970 @example
971 ./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
972 @end example
974 @section BeOS
976 BeOS support is broken in mysterious ways.
978 @section OS/2
980 For information about compiling FFmpeg on OS/2 see
981 @url{}.
983 @chapter Developers Guide
985 @section API
986 @itemize @bullet
987 @item libavcodec is the library containing the codecs (both encoding and
988 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
990 @item libavformat is the library containing the file format handling (mux and
991 demux code for several formats). Look at @file{ffplay.c} to use it in a
992 player. See @file{libavformat/output-example.c} to use it to generate
993 audio or video streams.
995 @end itemize
997 @section Integrating libavcodec or libavformat in your program
999 You can integrate all the source code of the libraries to link them
1000 statically to avoid any version problem. All you need is to provide a
1001 'config.mak' and a 'config.h' in the parent directory. See the defines
1002 generated by ./configure to understand what is needed.
1004 You can use libavcodec or libavformat in your commercial program, but
1005 @emph{any patch you make must be published}. The best way to proceed is
1006 to send your patches to the FFmpeg mailing list.
1008 @node Coding Rules
1009 @section Coding Rules
1011 FFmpeg is programmed in the ISO C90 language with a few additional
1012 features from ISO C99, namely:
1013 @itemize @bullet
1014 @item
1015 the @samp{inline} keyword;
1016 @item
1017 @samp{//} comments;
1018 @item
1019 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
1020 @item
1021 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
1022 @end itemize
1024 These features are supported by all compilers we care about, so we will not
1025 accept patches to remove their use unless they absolutely do not impair
1026 clarity and performance.
1028 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
1029 compiles with several other compilers, such as the Compaq ccc compiler
1030 or Sun Studio 9, and we would like to keep it that way unless it would
1031 be exceedingly involved. To ensure compatibility, please do not use any
1032 additional C99 features or GCC extensions. Especially watch out for:
1033 @itemize @bullet
1034 @item
1035 mixing statements and declarations;
1036 @item
1037 @samp{long long} (use @samp{int64_t} instead);
1038 @item
1039 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
1040 @item
1041 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
1042 @end itemize
1044 Indent size is 4.
1045 The presentation is the one specified by 'indent -i4 -kr -nut'.
1046 The TAB character is forbidden outside of Makefiles as is any
1047 form of trailing whitespace. Commits containing either will be
1048 rejected by the Subversion repository.
1050 The main priority in FFmpeg is simplicity and small code size in order to
1051 minimize the bug count.
1053 Comments: Use the JavaDoc/Doxygen
1054 format (see examples below) so that code documentation
1055 can be generated automatically. All nontrivial functions should have a comment
1056 above them explaining what the function does, even if it is just one sentence.
1057 All structures and their member variables should be documented, too.
1058 @example
1059 /**
1060 * @@file mpeg.c
1061 * MPEG codec.
1062 * @@author ...
1063 */
1065 /**
1066 * Summary sentence.
1067 * more text ...
1068 * ...
1069 */
1070 typedef struct Foobar@{
1071 int var1; /**< var1 description */
1072 int var2; ///< var2 description
1073 /** var3 description */
1074 int var3;
1075 @} Foobar;
1077 /**
1078 * Summary sentence.
1079 * more text ...
1080 * ...
1081 * @@param my_parameter description of my_parameter
1082 * @@return return value description
1083 */
1084 int myfunc(int my_parameter)
1085 ...
1086 @end example
1088 fprintf and printf are forbidden in libavformat and libavcodec,
1089 please use av_log() instead.
1091 Casts should be used only when necessary. Unneeded parentheses
1092 should also be avoided if they don't make the code easier to understand.
1094 @section Development Policy
1096 @enumerate
1097 @item
1098 Contributions should be licensed under the LGPL 2.1, including an
1099 "or any later version" clause, or the MIT license. GPL 2 including
1100 an "or any later version" clause is also acceptable, but LGPL is
1101 preferred.
1102 @item
1103 You must not commit code which breaks FFmpeg! (Meaning unfinished but
1104 enabled code which breaks compilation or compiles but does not work or
1105 breaks the regression tests)
1106 You can commit unfinished stuff (for testing etc), but it must be disabled
1107 (#ifdef etc) by default so it does not interfere with other developers'
1108 work.
1109 @item
1110 You do not have to over-test things. If it works for you, and you think it
1111 should work for others, then commit. If your code has problems
1112 (portability, triggers compiler bugs, unusual environment etc) they will be
1113 reported and eventually fixed.
1114 @item
1115 Do not commit unrelated changes together, split them into self-contained
1116 pieces. Also do not forget that if part B depends on part A, but A does not
1117 depend on B, then A can and should be committed first and separate from B.
1118 Keeping changes well split into self-contained parts makes reviewing and
1119 understanding them on the commit log mailing list easier. This also helps
1120 in case of debugging later on.
1121 Also if you have doubts about splitting or not splitting, do not hesitate to
1122 ask/discuss it on the developer mailing list.
1123 @item
1124 Do not change behavior of the program (renaming options etc) without
1125 first discussing it on the ffmpeg-devel mailing list. Do not remove
1126 functionality from the code. Just improve!
1128 Note: Redundant code can be removed.
1129 @item
1130 Do not commit changes to the build system (Makefiles, configure script)
1131 which change behavior, defaults etc, without asking first. The same
1132 applies to compiler warning fixes, trivial looking fixes and to code
1133 maintained by other developers. We usually have a reason for doing things
1134 the way we do. Send your changes as patches to the ffmpeg-devel mailing
1135 list, and if the code maintainers say OK, you may commit. This does not
1136 apply to files you wrote and/or maintain.
1137 @item
1138 We refuse source indentation and other cosmetic changes if they are mixed
1139 with functional changes, such commits will be rejected and removed. Every
1140 developer has his own indentation style, you should not change it. Of course
1141 if you (re)write something, you can use your own style, even though we would
1142 prefer if the indentation throughout FFmpeg was consistent (Many projects
1143 force a given indentation style - we do not.). If you really need to make
1144 indentation changes (try to avoid this), separate them strictly from real
1145 changes.
1147 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
1148 then either do NOT change the indentation of the inner part within (do not
1149 move it to the right)! or do so in a separate commit
1150 @item
1151 Always fill out the commit log message. Describe in a few lines what you
1152 changed and why. You can refer to mailing list postings if you fix a
1153 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1154 @item
1155 If you apply a patch by someone else, include the name and email address in
1156 the log message. Since the ffmpeg-cvslog mailing list is publicly
1157 archived you should add some SPAM protection to the email address. Send an
1158 answer to ffmpeg-devel (or wherever you got the patch from) saying that
1159 you applied the patch.
1160 @item
1161 When applying patches that have been discussed (at length) on the mailing
1162 list, reference the thread in the log message.
1163 @item
1164 Do NOT commit to code actively maintained by others without permission.
1165 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
1166 timeframe (12h for build failures and security fixes, 3 days small changes,
1167 1 week for big patches) then commit your patch if you think it is OK.
1168 Also note, the maintainer can simply ask for more time to review!
1169 @item
1170 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
1171 are sent there and reviewed by all the other developers. Bugs and possible
1172 improvements or general questions regarding commits are discussed there. We
1173 expect you to react if problems with your code are uncovered.
1174 @item
1175 Update the documentation if you change behavior or add features. If you are
1176 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
1177 maintainer(s) will review and commit your stuff.
1178 @item
1179 Try to keep important discussions and requests (also) on the public
1180 developer mailing list, so that all developers can benefit from them.
1181 @item
1182 Never write to unallocated memory, never write over the end of arrays,
1183 always check values read from some untrusted source before using them
1184 as array index or other risky things.
1185 @item
1186 Remember to check if you need to bump versions for the specific libav
1187 parts (libavutil, libavcodec, libavformat) you are changing. You need
1188 to change the version integer.
1189 Incrementing the first component means no backward compatibility to
1190 previous versions (e.g. removal of a function from the public API).
1191 Incrementing the second component means backward compatible change
1192 (e.g. addition of a function to the public API or extension of an
1193 existing data structure).
1194 Incrementing the third component means a noteworthy binary compatible
1195 change (e.g. encoder bug fix that matters for the decoder).
1196 @item
1197 Compiler warnings indicate potential bugs or code with bad style. If a type of
1198 warning always points to correct and clean code, that warning should
1199 be disabled, not the code changed.
1200 Thus the remaining warnings can either be bugs or correct code.
1201 If it is a bug, the bug has to be fixed. If it is not, the code should
1202 be changed to not generate a warning unless that causes a slowdown
1203 or obfuscates the code.
1204 @item
1205 If you add a new file, give it a proper license header. Do not copy and
1206 paste it from a random place, use an existing file as template.
1207 @end enumerate
1209 We think our rules are not too hard. If you have comments, contact us.
1211 Note, these rules are mostly borrowed from the MPlayer project.
1213 @section Submitting patches
1215 First, (@pxref{Coding Rules}) above if you did not yet.
1217 When you submit your patch, try to send a unified diff (diff '-up'
1218 option). We cannot read other diffs :-)
1220 Also please do not submit a patch which contains several unrelated changes.
1221 Split it into separate, self-contained pieces. This does not mean splitting
1222 file by file. Instead, make the patch as small as possible while still
1223 keeping it as a logical unit that contains an individual change, even
1224 if it spans multiple files. This makes reviewing your patches much easier
1225 for us and greatly increases your chances of getting your patch applied.
1227 Run the regression tests before submitting a patch so that you can
1228 verify that there are no big problems.
1230 Patches should be posted as base64 encoded attachments (or any other
1231 encoding which ensures that the patch will not be trashed during
1232 transmission) to the ffmpeg-devel mailing list, see
1233 @url{}
1235 It also helps quite a bit if you tell us what the patch does (for example
1236 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
1237 and has no lrint()')
1239 Also please if you send several patches, send each patch as a separate mail,
1240 do not attach several unrelated patches to the same mail.
1242 @section New codecs or formats checklist
1244 @enumerate
1245 @item
1246 Did you use av_cold for codec initialization and close functions?
1247 @item
1248 Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
1249 AVInputFormat/AVOutputFormat struct?
1250 @item
1251 Did you bump the minor version number in @file{avcodec.h} or
1252 @file{avformat.h}?
1253 @item
1254 Did you register it in @file{allcodecs.c} or @file{allformats.c}?
1255 @item
1256 Did you add the CodecID to @file{avcodec.h}?
1257 @item
1258 If it has a fourcc, did you add it to @file{libavformat/riff.c},
1259 even if it is only a decoder?
1260 @item
1261 Did you add a rule to compile the appropriate files in the Makefile?
1262 Remember to do this even if you're just adding a format to a file that is
1263 already being compiled by some other rule, like a raw demuxer.
1264 @item
1265 Did you add an entry to the table of supported formats or codecs in the
1266 documentation?
1267 @item
1268 Did you add an entry in the Changelog?
1269 @item
1270 If it depends on a parser or a library, did you add that dependency in
1271 configure?
1272 @item
1273 Did you "svn add" the appropriate files before commiting?
1274 @end enumerate
1276 @section patch submission checklist
1278 @enumerate
1279 @item
1280 Do the regression tests pass with the patch applied?
1281 @item
1282 Does @code{make checkheaders} pass with the patch applied?
1283 @item
1284 Is the patch a unified diff?
1285 @item
1286 Is the patch against latest FFmpeg SVN?
1287 @item
1288 Are you subscribed to ffmpeg-dev?
1289 (the list is subscribers only due to spam)
1290 @item
1291 Have you checked that the changes are minimal, so that the same cannot be
1292 achieved with a smaller patch and/or simpler final code?
1293 @item
1294 If the change is to speed critical code, did you benchmark it?
1295 @item
1296 If you did any benchmarks, did you provide them in the mail?
1297 @item
1298 Have you checked that the patch does not introduce buffer overflows or
1299 other security issues?
1300 @item
1301 Did you test your decoder or demuxer against damaged data? If no, see
1302 tools/trasher and the noise bitstream filter. Your decoder or demuxer
1303 should not crash or end in a (near) infinite loop when fed damaged data.
1304 @item
1305 Is the patch created from the root of the source tree, so it can be
1306 applied with @code{patch -p0}?
1307 @item
1308 Does the patch not mix functional and cosmetic changes?
1309 @item
1310 Did you add tabs or trailing whitespace to the code? Both are forbidden.
1311 @item
1312 Is the patch attached to the email you send?
1313 @item
1314 Is the mime type of the patch correct? It should be text/x-diff or
1315 text/x-patch or at least text/plain and not application/octet-stream.
1316 @item
1317 If the patch fixes a bug, did you provide a verbose analysis of the bug?
1318 @item
1319 If the patch fixes a bug, did you provide enough information, including
1320 a sample, so the bug can be reproduced and the fix can be verified?
1321 Note please do not attach samples >100k to mails but rather provide a
1322 URL, you can upload to
1323 @item
1324 Did you provide a verbose summary about what the patch does change?
1325 @item
1326 Did you provide a verbose explanation why it changes things like it does?
1327 @item
1328 Did you provide a verbose summary of the user visible advantages and
1329 disadvantages if the patch is applied?
1330 @item
1331 Did you provide an example so we can verify the new feature added by the
1332 patch easily?
1333 @item
1334 If you added a new file, did you insert a license header? It should be
1335 taken from FFmpeg, not randomly copied and pasted from somewhere else.
1336 @item
1337 You should maintain alphabetical order in alphabetically ordered lists as
1338 long as doing so does not break API/ABI compatibility.
1339 @item
1340 Lines with similar content should be aligned vertically when doing so
1341 improves readability.
1342 @item
1343 Did you provide a suggestion for a clear commit log message?
1344 @end enumerate
1346 @section Patch review process
1348 All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1349 clear note that the patch is not for SVN.
1350 Reviews and comments will be posted as replies to the patch on the
1351 mailing list. The patch submitter then has to take care of every comment,
1352 that can be by resubmitting a changed patch or by discussion. Resubmitted
1353 patches will themselves be reviewed like any other patch. If at some point
1354 a patch passes review with no comments then it is approved, that can for
1355 simple and small patches happen immediately while large patches will generally
1356 have to be changed and reviewed many times before they are approved.
1357 After a patch is approved it will be committed to the repository.
1359 We will review all submitted patches, but sometimes we are quite busy so
1360 especially for large patches this can take several weeks.
1362 When resubmitting patches, please do not make any significant changes
1363 not related to the comments received during review. Such patches will
1364 be rejected. Instead, submit significant changes or new features as
1365 separate patches.
1367 @section Regression tests
1369 Before submitting a patch (or committing to the repository), you should at least
1370 test that you did not break anything.
1372 The regression tests build a synthetic video stream and a synthetic
1373 audio stream. These are then encoded and decoded with all codecs or
1374 formats. The CRC (or MD5) of each generated file is recorded in a
1375 result file. A 'diff' is launched to compare the reference results and
1376 the result file.
1378 The regression tests then go on to test the FFserver code with a
1379 limited set of streams. It is important that this step runs correctly
1380 as well.
1382 Run 'make test' to test all the codecs and formats.
1384 Run 'make fulltest' to test all the codecs, formats and FFserver.
1386 [Of course, some patches may change the results of the regression tests. In
1387 this case, the reference results of the regression tests shall be modified
1388 accordingly].
1390 @bye