Update after the last API change.
[libav.git] / doc / general.texi
1 \input texinfo @c -*- texinfo -*-
3 @settitle General Documentation
4 @titlepage
5 @sp 7
6 @center @titlefont{General Documentation}
7 @sp 3
8 @end titlepage
11 @chapter external libraries
13 FFmpeg can be hooked up with a number of external libraries to add support
14 for more formats. None of them are used by default, their use has to be
15 explicitly requested by passing the appropriate flags to @file{./configure}.
17 @section AMR
19 AMR comes in two different flavors, wideband and narrowband. FFmpeg can make
20 use of the AMR wideband (floating-point mode) and the AMR narrowband
21 (floating-point mode) reference decoders and encoders.
23 Go to @url{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.
27 Note that libamr is copyrighted without any sort of license grant. This means
28 that you can use it if you legally obtained it but you are not allowed to
29 redistribute it in any way. @strong{Any FFmpeg binaries with libamr support
30 you create are non-free and unredistributable!}
33 @chapter Supported File Formats and Codecs
35 You can use the @code{-formats} option to have an exhaustive list.
37 @section File Formats
39 FFmpeg supports the following file formats through the @code{libavformat}
40 library:
42 @multitable @columnfractions .4 .1 .1 .4
43 @item Name @tab Encoding @tab Decoding @tab Comments
44 @item 4xm @tab @tab X
45 @tab 4X Technologies format, used in some games.
46 @item Audio IFF (AIFF) @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 3GPP AMR @tab X @tab X
50 @item ASF @tab X @tab X
51 @item AVI @tab X @tab X
52 @item AVISynth @tab @tab X
53 @item AVS @tab @tab X
54 @tab Multimedia format used by the Creature Shock game.
55 @item Beam Software SIFF @tab @tab X
56 @tab Audio and video format used in some games by Beam Software.
57 @item Bethesda Softworks VID @tab @tab X
58 @tab Used in some games from Bethesda Softworks.
59 @item Brute Force & Ignorance @tab @tab X
60 @tab Used in the game Flash Traffic: City of Angels.
61 @item Interplay C93 @tab @tab X
62 @tab Used in the game Cyberia from Interplay.
63 @item Delphine Software International CIN @tab @tab X
64 @tab Multimedia format used by Delphine Software games.
65 @item CRC testing format @tab X @tab
66 @item Creative Voice @tab X @tab X
67 @tab Created for the Sound Blaster Pro.
68 @item CRYO APC @tab @tab X
69 @tab Audio format used in some games by CRYO Interactive Entertainment.
70 @item D-Cinema audio @tab X @tab X
71 @item DV video @tab X @tab X
72 @item DXA @tab @tab X
73 @tab This format is used in the non-Windows version of the Feeble Files
74 game and different game cutscenes repacked for use with ScummVM.
75 @item Electronic Arts cdata @tab @tab X
76 @item Electronic Arts Multimedia @tab @tab X
77 @tab Used in various EA games; files have extensions like WVE and UV2.
78 @item FFM (FFserver live feed) @tab X @tab X
79 @item Flash (SWF) @tab X @tab X
80 @item Flash 9 (AVM2) @tab X @tab X
81 @tab Only embedded audio is decoded.
82 @item FLI/FLC/FLX animation @tab @tab X
83 @tab .fli/.flc files
84 @item Flash Video (FLV) @tab @tab X
85 @tab Macromedia Flash video files
86 @item framecrc testing format @tab X @tab
87 @item FunCom ISS @tab @tab X
88 @tab Audio format used in various games from FunCom like The Longest Journey.
89 @item GIF Animation @tab X @tab
90 @item GXF @tab X @tab X
91 @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley
92 playout servers.
93 @item id Quake II CIN video @tab @tab X
94 @item id RoQ @tab X @tab X
95 @tab Used in Quake III, Jedi Knight 2, other computer games.
96 @item IFF @tab @tab X
97 @tab Interchange File Format
98 @item Interplay MVE @tab @tab X
99 @tab Format used in various Interplay computer games.
100 @item LMLM4 @tab @tab X
101 @tab Used by Linux Media Labs MPEG-4 PCI boards
102 @item Matroska @tab X @tab X
103 @item Matroska audio @tab X @tab
104 @item MAXIS XA @tab @tab X
105 @tab Used in Sim City 3000; file extension .xa.
106 @item Monkey's Audio @tab @tab X
107 @item Motion Pixels MVI @tab @tab X
108 @item MOV/QuickTime/MP4 @tab X @tab X
109 @tab 3GP, 3GP2, PSP, iPod variants supported
110 @item MP2 @tab X @tab X
111 @item MP3 @tab X @tab X
112 @item MPEG-1 System @tab X @tab X
113 @tab muxed audio and video, VCD format supported
114 @item MPEG-PS (program stream) @tab X @tab X
115 @tab also known as @code{VOB} file, SVCD and DVD format supported
116 @item MPEG-TS (transport stream) @tab X @tab X
117 @tab also known as DVB Transport Stream
118 @item MPEG-4 @tab X @tab X
119 @tab MPEG-4 is a variant of QuickTime.
120 @item MIME multipart JPEG @tab X @tab
121 @item MSN TCP webcam @tab @tab X
122 @tab Used by MSN Messenger webcam streams.
123 @item MTV @tab @tab X
124 @item Musepack @tab @tab X
125 @item Musepack SV8 @tab @tab X
126 @item Material eXchange Format (MXF) @tab X @tab X
127 @tab SMPTE 377M, used by D-Cinema, broadcast industry.
128 @item Material eXchange Format (MXF), D-10 Mapping @tab X @tab X
129 @tab SMPTE 386M, D-10/IMX Mapping.
130 @item NC camera feed @tab @tab X
131 @tab NC (AVIP NC4600) camera streams
132 @item NTT TwinVQ (VQF) @tab @tab X
133 @tab Nippon Telegraph and Telephone Corporation TwinVQ.
134 @item Nullsoft Streaming Video @tab @tab X
135 @item NuppelVideo @tab @tab X
136 @item NUT @tab X @tab X
137 @tab NUT Open Container Format
138 @item Ogg @tab X @tab X
139 @item TechnoTrend PVA @tab @tab X
140 @tab Used by TechnoTrend DVB PCI boards.
141 @item raw ADTS (AAC) @tab X @tab X
142 @item raw AC-3 @tab X @tab X
143 @item raw Chinese AVS video @tab @tab X
144 @item raw CRI ADX @tab X @tab X
145 @item raw Dirac @tab X @tab X
146 @item raw DNxHD @tab X @tab X
147 @item raw DTS @tab X @tab X
148 @item raw E-AC-3 @tab X @tab X
149 @item raw FLAC @tab X @tab X
150 @item raw GSM @tab @tab X
151 @item raw H.261 @tab X @tab X
152 @item raw H.263 @tab X @tab X
153 @item raw H.264 @tab X @tab X
154 @item raw Ingenient MJPEG @tab @tab X
155 @item raw MJPEG @tab X @tab X
156 @item raw MLP @tab @tab X
157 @item raw MPEG @tab @tab X
158 @item raw MPEG-1 @tab @tab X
159 @item raw MPEG-2 @tab @tab X
160 @item raw MPEG-4 @tab X @tab X
161 @item raw NULL @tab X @tab
162 @item raw video @tab X @tab X
163 @item raw id RoQ @tab X @tab
164 @item raw Shorten @tab @tab X
165 @item raw TrueHD @tab X @tab X
166 @item raw VC-1 @tab @tab X
167 @item raw PCM A-law @tab X @tab X
168 @item raw PCM mu-law @tab X @tab X
169 @item raw PCM signed 8 bit @tab X @tab X
170 @item raw PCM signed 16 bit big-endian @tab X @tab X
171 @item raw PCM signed 16 bit little-endian @tab X @tab X
172 @item raw PCM signed 24 bit big-endian @tab X @tab X
173 @item raw PCM signed 24 bit little-endian @tab X @tab X
174 @item raw PCM signed 32 bit big-endian @tab X @tab X
175 @item raw PCM signed 32 bit little-endian @tab X @tab X
176 @item raw PCM unsigned 8 bit @tab X @tab X
177 @item raw PCM unsigned 16 bit big-endian @tab X @tab X
178 @item raw PCM unsigned 16 bit little-endian @tab X @tab X
179 @item raw PCM unsigned 24 bit big-endian @tab X @tab X
180 @item raw PCM unsigned 24 bit little-endian @tab X @tab X
181 @item raw PCM unsigned 32 bit big-endian @tab X @tab X
182 @item raw PCM unsigned 32 bit little-endian @tab X @tab X
183 @item raw PCM floating-point 32 bit big-endian @tab X @tab X
184 @item raw PCM floating-point 32 bit little-endian @tab X @tab X
185 @item raw PCM floating-point 64 bit big-endian @tab X @tab X
186 @item raw PCM floating-point 64 bit little-endian @tab X @tab X
187 @item RDT @tab @tab X
188 @item REDCODE R3D @tab @tab X
189 @tab File format used by RED Digital cameras, contains JPEG 2000 frames and PCM audio.
190 @item RealMedia @tab X @tab X
191 @item Redirector @tab @tab X
192 @item Renderware TeXture Dictionary @tab @tab X
193 @item RL2 @tab @tab X
194 @tab Audio and video format used in some games by Entertainment Software Partners.
195 @item RPL/ARMovie @tab @tab X
196 @item RTP @tab @tab X
197 @item RTSP @tab @tab X
198 @item SDP @tab @tab X
199 @item Sega FILM/CPK @tab @tab X
200 @tab Used in many Sega Saturn console games.
201 @item Sierra SOL @tab @tab X
202 @tab .sol files used in Sierra Online games.
203 @item Sierra VMD @tab @tab X
204 @tab Used in Sierra CD-ROM games.
205 @item Smacker @tab @tab X
206 @tab Multimedia format used by many games.
207 @item Sony OpenMG (OMA) @tab @tab X
208 @tab Audio format used in Sony Sonic Stage and Sony Vegas.
209 @item Sony PlayStation STR @tab @tab X
210 @item SUN AU format @tab X @tab X
211 @item THP @tab @tab X
212 @tab Used on the Nintendo GameCube.
213 @item Tiertex Limited SEQ @tab @tab X
214 @tab Tiertex .seq files used in the DOS CD-ROM version of the game Flashback.
215 @item True Audio @tab @tab X
216 @item VC-1 test bitstream @tab X @tab X
217 @item WAV @tab X @tab X
218 @item WavPack @tab @tab X
219 @item Wing Commander III movie @tab @tab X
220 @tab Multimedia format used in Origin's Wing Commander III computer game.
221 @item Westwood Studios audio @tab @tab X
222 @tab Multimedia format used in Westwood Studios games.
223 @item Westwood Studios VQA @tab @tab X
224 @tab Multimedia format used in Westwood Studios games.
225 @item YUV4MPEG pipe @tab X @tab X
226 @end multitable
228 @code{X} means that encoding (resp. decoding) is supported.
230 @section Image Formats
232 FFmpeg can read and write images for each frame of a video sequence. The
233 following image formats are supported:
235 @multitable @columnfractions .4 .1 .1 .4
236 @item Name @tab Encoding @tab Decoding @tab Comments
237 @item .Y.U.V @tab X @tab X
238 @tab one raw file per component
239 @item animated GIF @tab X @tab X
240 @tab Only uncompressed GIFs are generated.
241 @item BMP @tab X @tab X
242 @tab Microsoft BMP image
243 @item JPEG @tab X @tab X
244 @tab Progressive JPEG is not supported.
245 @item JPEG 2000 @tab @tab E
246 @tab decoding supported through external library libopenjpeg
247 @item JPEG-LS @tab X @tab X
248 @item LJPEG @tab X @tab
249 @tab Lossless JPEG
250 @item PAM @tab X @tab X
251 @tab PAM is a PNM extension with alpha support.
252 @item PBM @tab X @tab X
253 @tab Portable BitMap image
254 @item PCX @tab X @tab X
255 @tab PC Paintbrush
256 @item PGM @tab X @tab X
257 @tab Portable GrayMap image
258 @item PGMYUV @tab X @tab X
259 @tab PGM with U and V components in YUV 4:2:0
260 @item PNG @tab X @tab X
261 @tab 2/4 bpp not supported yet
262 @item PPM @tab X @tab X
263 @tab Portable PixelMap image
264 @item PTX @tab @tab X
265 @tab V.Flash PTX format
266 @item SGI @tab X @tab X
267 @tab SGI RGB image format
268 @item Sun Rasterfile @tab @tab X
269 @tab Sun RAS image format
270 @item TIFF @tab X @tab X
271 @tab YUV, JPEG and some extension is not supported yet.
272 @item Truevision Targa @tab X @tab X
273 @tab Targa (.TGA) image format
274 @end multitable
276 @code{X} means that encoding (resp. decoding) is supported.
278 @code{E} means that support is provided through an external library.
280 @section Video Codecs
282 @multitable @columnfractions .4 .1 .1 .4
283 @item Name @tab Encoding @tab Decoding @tab Comments
284 @item 4X Movie @tab @tab X
285 @tab Used in certain computer games.
286 @item 8SVX exponential @tab @tab X
287 @item 8SVX fibonacci @tab @tab X
288 @item American Laser Games MM @tab @tab X
289 @tab Used in games like Mad Dog McCree.
290 @item AMV Video @tab @tab X
291 @tab Used in Chinese MP3 players.
292 @item Apple MJPEG-B @tab @tab X
293 @item Apple QuickDraw @tab @tab X
294 @tab fourcc: qdrw
295 @item Asus v1 @tab X @tab X
296 @tab fourcc: ASV1
297 @item Asus v2 @tab X @tab X
298 @tab fourcc: ASV2
299 @item ATI VCR1 @tab @tab X
300 @tab fourcc: VCR1
301 @item ATI VCR2 @tab @tab X
302 @tab fourcc: VCR2
303 @item Autodesk Animator Flic video @tab @tab X
304 @item Autodesk RLE @tab @tab X
305 @tab fourcc: AASC
306 @item AVS (Audio Video Standard) video @tab @tab X
307 @tab Video encoding used by the Creature Shock game.
308 @item Beam Software VB @tab @tab X
309 @item Bethesda VID video @tab @tab X
310 @tab Used in some games from Bethesda Softworks.
311 @item Brute Force & Ignorance @tab @tab X
312 @tab Used in the game Flash Traffic: City of Angels.
313 @item C93 video @tab @tab X
314 @tab Codec used in Cyberia game.
315 @item CamStudio @tab @tab X
316 @tab fourcc: CSCD
317 @item Chinese AVS video @tab @tab X
318 @tab AVS1-P2, JiZhun profile
319 @item Delphine Software International CIN video @tab @tab X
320 @tab Codec used in Delphine Software International games.
321 @item Cinepak @tab @tab X
322 @item Cirrus Logic AccuPak @tab @tab X
323 @tab fourcc: CLJR
324 @item Creative YUV (CYUV) @tab @tab X
325 @item Dirac @tab E @tab E
326 @tab supported through external libdirac/libschroedinger libraries
327 @item DNxHD @tab X @tab X
328 @tab aka SMPTE VC3
329 @item Duck TrueMotion 1.0 @tab @tab X
330 @tab fourcc: DUCK
331 @item Duck TrueMotion 2.0 @tab @tab X
332 @tab fourcc: TM20
333 @item DV (Digital Video) @tab X @tab X
334 @item Feeble Files/ScummVM DXA @tab @tab X
335 @tab Codec originally used in Feeble Files game.
336 @item Electronic Arts CMV video @tab @tab X
337 @tab Used in NHL 95 game.
338 @item Electronic Arts TGV video @tab @tab X
339 @item Electronic Arts TGQ video @tab @tab X
340 @item Electronic Arts TQI video @tab @tab X
341 @item Escape 124 @tab @tab X
342 @item FFmpeg codec #1 @tab X @tab X
343 @tab experimental lossless codec (fourcc: FFV1)
344 @item Flash Screen Video v1 @tab X @tab X
345 @tab fourcc: FSV1
346 @item Flash Video (FLV) @tab X @tab X
347 @tab Sorenson H.263 used in Flash
348 @item Fraps @tab @tab X
349 @item H.261 @tab X @tab X
350 @item H.263 / H.263-1996 @tab X @tab X
351 @item H.263+ / H.263-1998 / H.263 version 2 @tab X @tab X
352 @item H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 @tab E @tab X
353 @tab encoding supported through external library libx264
354 @item H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (VDPAU acceleration) @tab E @tab X
355 @item HuffYUV @tab X @tab X
356 @item HuffYUV FFmpeg variant @tab X @tab X
357 @item IBM Ultimotion @tab @tab X
358 @tab fourcc: ULTI
359 @item id Cinematic video @tab @tab X
360 @tab Used in Quake II.
361 @item id RoQ video @tab X @tab X
362 @tab Used in Quake III, Jedi Knight 2, other computer games.
363 @item Intel H.263 @tab @tab X
364 @item Intel Indeo 2 @tab @tab X
365 @item Intel Indeo 3 @tab @tab X
366 @item Interplay C93 @tab @tab X
367 @tab Used in the game Cyberia from Interplay.
368 @item Interplay MVE video @tab @tab X
369 @tab Used in Interplay .MVE files.
370 @item Karl Morton's video codec @tab @tab X
371 @tab Codec used in Worms games.
372 @item LCL (LossLess Codec Library) MSZH @tab @tab X
373 @item LCL (LossLess Codec Library) ZLIB @tab E @tab E
374 @item LOCO @tab @tab X
375 @item lossless MJPEG @tab X @tab X
376 @item Microsoft RLE @tab @tab X
377 @item Microsoft Video 1 @tab @tab X
378 @item Mimic @tab @tab X
379 @tab Used in MSN Messenger Webcam streams.
380 @item Miro VideoXL @tab @tab X
381 @tab fourcc: VIXL
382 @item MJPEG (Motion JPEG) @tab X @tab X
383 @item Motion Pixels video @tab @tab X
384 @item MPEG-1 video @tab X @tab X
385 @item MPEG-1/2 video XvMC (X-Video Motion Compensation) @tab @tab X
386 @item MPEG-1/2 video (VDPAU acceleration) @tab @tab X
387 @item MPEG-2 video @tab X @tab X
388 @item MPEG-4 part 2 @tab X @tab X
389 @ libxvidcore can be used alternatively for encoding.
390 @item MPEG-4 part 2 Microsoft variant version 1 @tab X @tab X
391 @item MPEG-4 part 2 Microsoft variant version 2 @tab X @tab X
392 @item MPEG-4 part 2 Microsoft variant version 3 @tab X @tab X
393 @item Nintendo Gamecube THP video @tab @tab X
394 @item NuppelVideo/RTjpeg @tab @tab X
395 @tab Video encoding used in NuppelVideo files.
396 @item On2 VP3 @tab @tab X
397 @tab still experimental
398 @item On2 VP5 @tab @tab X
399 @tab fourcc: VP50
400 @item On2 VP6 @tab @tab X
401 @tab fourcc: VP60,VP61,VP62
402 @item planar RGB @tab @tab X
403 @tab fourcc: 8BPS
404 @item Q-team QPEG @tab @tab X
405 @tab fourccs: QPEG, Q1.0, Q1.1
406 @item QuickTime 8BPS video @tab @tab X
407 @item QuickTime Animation (RLE) video @tab X @tab X
408 @tab fourcc: 'rle '
409 @item QuickTime Graphics (SMC) @tab @tab X
410 @tab fourcc: 'smc '
411 @item QuickTime video (RPZA) @tab @tab X
412 @tab fourcc: rpza
413 @item Raw Video @tab X @tab X
414 @item RealVideo 1.0 @tab X @tab X
415 @item RealVideo 2.0 @tab X @tab X
416 @item RealVideo 3.0 @tab @tab X
417 @tab still far from ideal
418 @item RealVideo 4.0 @tab @tab X
419 @item Renderware TXD (TeXture Dictionary) @tab @tab X
420 @tab Texture dictionaries used by the Renderware Engine.
421 @item RL2 video @tab @tab X
422 @tab used in some games by Entertainment Software Partners
423 @item Sierra VMD video @tab @tab X
424 @tab Used in Sierra VMD files.
425 @item Smacker video @tab @tab X
426 @tab Video encoding used in Smacker.
427 @item SMPTE VC-1 @tab @tab X
428 @item Snow @tab X @tab X
429 @tab experimental wavelet codec (fourcc: SNOW)
430 @item Sony PlayStation MDEC (Motion DECoder) @tab @tab X
431 @item Sorenson Vector Quantizer 1 @tab X @tab X
432 @tab fourcc: SVQ1
433 @item Sorenson Vector Quantizer 3 @tab @tab X
434 @tab fourcc: SVQ3
435 @item Sunplus JPEG (SP5X) @tab @tab X
436 @tab fourcc: SP5X
437 @item TechSmith Screen Capture Codec @tab @tab X
438 @tab fourcc: TSCC
439 @item Theora @tab E @tab X
440 @tab encoding supported through external library libtheora
441 @item Tiertex Limited SEQ video @tab @tab X
442 @tab Codec used in DOS CD-ROM FlashBack game.
443 @item VMware Screen Codec / VMware Video @tab @tab X
444 @tab Codec used in videos captured by VMware.
445 @item Westwood Studios VQA (Vector Quantized Animation) video @tab @tab X
446 @item Windows Media Video 7 @tab X @tab X
447 @item Windows Media Video 8 @tab X @tab X
448 @item Windows Media Video 9 @tab @tab X
449 @tab not completely working
450 @item Wing Commander III / Xan @tab @tab X
451 @tab Used in Wing Commander III .MVE files.
452 @item Winnov WNV1 @tab @tab X
453 @item WMV7 @tab X @tab X
454 @item YAMAHA SMAF @tab X @tab X
455 @item ZLIB @tab X @tab X
456 @tab part of LCL, encoder experimental
457 @item Zip Motion Blocks Video @tab X @tab X
458 @tab Encoder works only in PAL8.
459 @end multitable
461 @code{X} means that encoding (resp. decoding) is supported.
463 @code{E} means that support is provided through an external library.
465 @section Audio Codecs
467 @multitable @columnfractions .4 .1 .1 .4
468 @item Name @tab Encoding @tab Decoding @tab Comments
469 @item 8SVX audio @tab @tab X
470 @item AAC @tab E @tab X
471 @tab encoding supported through external library libfaac
472 @item AC-3 @tab IX @tab X
473 @item ADPCM 4X Movie @tab @tab X
474 @item ADPCM CDROM XA @tab @tab X
475 @item ADPCM Creative Technology @tab @tab X
476 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
477 @item ADPCM Electronic Arts @tab @tab X
478 @tab Used in various EA titles.
479 @item ADPCM Electronic Arts Maxis CDROM XS @tab @tab X
480 @tab Used in Sim City 3000.
481 @item ADPCM Electronic Arts R1 @tab @tab X
482 @item ADPCM Electronic Arts R2 @tab @tab X
483 @item ADPCM Electronic Arts R3 @tab @tab X
484 @item ADPCM Electronic Arts XAS @tab @tab X
485 @item ADPCM G.726 @tab X @tab X
486 @item ADPCM IMA AMV @tab @tab X
487 @tab Used in AMV files
488 @item ADPCM IMA Electronic Arts EACS @tab @tab X
489 @item ADPCM IMA Electronic Arts SEAD @tab @tab X
490 @item ADPCM IMA Funcom @tab @tab X
491 @item ADPCM IMA QuickTime @tab X @tab X
492 @item ADPCM IMA Loki SDL MJPEG @tab @tab X
493 @item ADPCM IMA WAV @tab X @tab X
494 @item ADPCM IMA Westwood @tab @tab X
495 @item ADPCM ISS IMA @tab @tab X
496 @tab Used in FunCom games.
497 @item ADPCM IMA Duck DK3 @tab @tab X
498 @tab Used in some Sega Saturn console games.
499 @item ADPCM IMA Duck DK4 @tab @tab X
500 @tab Used in some Sega Saturn console games.
501 @item ADPCM Microsoft @tab X @tab X
502 @item ADPCM MS IMA @tab X @tab X
503 @item ADPCM Nintendo Gamecube THP @tab @tab X
504 @item ADPCM QT IMA @tab X @tab X
505 @item ADPCM SEGA CRI ADX @tab X @tab X
506 @tab Used in Sega Dreamcast games.
507 @item ADPCM Shockwave Flash @tab X @tab X
508 @item ADPCM SMJPEG IMA @tab @tab X
509 @tab Used in certain Loki game ports.
510 @item ADPCM Sound Blaster Pro 2-bit @tab @tab X
511 @item ADPCM Sound Blaster Pro 2.6-bit @tab @tab X
512 @item ADPCM Sound Blaster Pro 4-bit @tab @tab X
513 @item ADPCM Westwood Studios IMA @tab @tab X
514 @tab Used in Westwood Studios games like Command and Conquer.
515 @item ADPCM Yamaha @tab X @tab X
516 @item AMR-NB @tab E @tab E
517 @tab supported through external library libamrnb
518 @item AMR-WB @tab E @tab E
519 @tab supported through external library libamrwb
520 @item Apple lossless audio @tab X @tab X
521 @tab QuickTime fourcc 'alac'
522 @item Atrac 3 @tab @tab X
523 @item Delphine Software International CIN audio @tab @tab X
524 @tab Codec used in Delphine Software International games.
525 @item COOK @tab @tab X
526 @tab All versions except 5.1 are supported.
527 @item DCA (DTS Coherent Acoustics) @tab @tab X
528 @item DPCM id RoQ @tab X @tab X
529 @tab Used in Quake III, Jedi Knight 2, other computer games.
530 @item DPCM Interplay @tab @tab X
531 @tab Used in various Interplay computer games.
532 @item DPCM Sierra Online @tab @tab X
533 @tab Used in Sierra Online game audio files.
534 @item DPCM Sol @tab @tab X
535 @item DPCM Xan @tab @tab X
536 @item DSP Group TrueSpeech @tab @tab X
537 @item DV audio @tab @tab X
538 @item Enhanced AC-3 @tab @tab X
539 @item FLAC (Free Lossless Audio Codec) @tab X @tab IX
540 @item G.729 @tab @tab X
541 @item GSM @tab E @tab E
542 @tab supported through external library libgsm
543 @item GSM Microsoft variant @tab E @tab E
544 @tab supported through external library libgsm
545 @item IMC (Intel Music Coder) @tab @tab X
546 @item MACE (Macintosh Audio Compression/Expansion) 3:1 @tab @tab X
547 @item MACE (Macintosh Audio Compression/Expansion) 6:1 @tab @tab X
548 @item MLP (Meridian Lossless Packing) @tab @tab X
549 @tab Used in DVD-Audio discs.
550 @item Monkey's Audio @tab @tab X
551 @tab Only versions 3.97-3.99 are supported.
552 @item MP1 (MPEG audio layer 1) @tab @tab IX
553 @item MP2 (MPEG audio layer 2) @tab IX @tab IX
554 @item MP3 (MPEG audio layer 3) @tab E @tab IX
555 @tab encoding supported through external library LAME, ADU MP3 and MP3onMP4 also supported
556 @item Musepack SV7 @tab @tab X
557 @item Musepack SV8 @tab @tab X
558 @item Nellymoser Asao @tab X @tab X
559 @item PCM A-law @tab X @tab X
560 @item PCM mu-law @tab X @tab X
561 @item PCM 16-bit little-endian planar @tab @tab X
562 @item PCM 32-bit floating point big-endian @tab X @tab X
563 @item PCM 32-bit floating point little-endian @tab X @tab X
564 @item PCM 64-bit floating point big-endian @tab X @tab X
565 @item PCM 64-bit floating point little-endian @tab X @tab X
566 @item PCM D-Cinema audio signed 24-bit @tab X @tab X
567 @item PCM signed 8-bit @tab X @tab X
568 @item PCM signed 16-bit big-endian @tab X @tab X
569 @item PCM signed 16-bit little-endian @tab X @tab X
570 @item PCM signed 24-bit big-endian @tab X @tab X
571 @item PCM signed 24-bit little-endian @tab X @tab X
572 @item PCM signed 32-bit big-endian @tab X @tab X
573 @item PCM signed 32-bit little-endian @tab X @tab X
574 @item PCM unsigned 8-bit @tab X @tab X
575 @item PCM unsigned 16-bit big-endian @tab X @tab X
576 @item PCM unsigned 16-bit little-endian @tab X @tab X
577 @item PCM unsigned 24-bit big-endian @tab X @tab X
578 @item PCM unsigned 24-bit little-endian @tab X @tab X
579 @item PCM unsigned 32-bit big-endian @tab X @tab X
580 @item PCM unsigned 32-bit little-endian @tab X @tab X
581 @item PCM Zork @tab X @tab X
582 @item QCELP / PureVoice @tab @tab X
583 @item QDesign Music Codec 2 @tab @tab X
584 @tab There are still some distortions.
585 @item RealAudio 1.0 (14.4K) @tab @tab X
586 @tab Real 14400 bit/s codec
587 @item RealAudio 2.0 (28.8K) @tab @tab X
588 @tab Real 28800 bit/s codec
589 @item RealAudio 3.0 (dnet) @tab IX @tab X
590 @tab Real low bitrate AC-3 codec
591 @item Shorten @tab @tab X
592 @item Sierra VMD audio @tab @tab X
593 @tab Used in Sierra VMD files.
594 @item Smacker audio @tab @tab X
595 @item Sonic @tab X @tab X
596 @tab experimental codec
597 @item Sonic lossless @tab X @tab X
598 @tab experimental codec
599 @item Speex @tab @tab E
600 @tab supported through external library libspeex
601 @item True Audio (TTA) @tab @tab X
602 @item TrueHD @tab @tab X
603 @tab Used in HD-DVD and Blu-Ray discs.
604 @item Vorbis @tab E @tab X
605 @ A native but very primitive encoder exists.
606 @item WavPack @tab @tab X
607 @item Westwood Audio (SND1) @tab @tab X
608 @item Windows Media Audio 1 @tab X @tab X
609 @item Windows Media Audio 2 @tab X @tab X
610 @tab Used in Origin's Wing Commander IV AVI files.
611 @end multitable
613 @code{X} means that encoding (resp. decoding) is supported.
615 @code{E} means that support is provided through an external library.
617 @code{I} means that an integer-only version is available, too (ensures high
618 performance on systems without hardware floating point support).
620 @section Subtitle Formats
622 @multitable @columnfractions .4 .1 .1 .1 .1
623 @item Name @tab Muxing @tab Demuxing @tab Encoding @tab Decoding
624 @item SSA/ASS @tab X @tab X
625 @item DVB @tab X @tab X @tab X @tab X
626 @item DVD @tab X @tab X @tab X @tab X
627 @item XSUB @tab @tab @tab @tab X
628 @end multitable
630 @code{X} means that the feature is supported.
632 @section Network Protocols
634 @multitable @columnfractions .4 .1
635 @item Name @tab Support
636 @item file @tab X
637 @item Gopher @tab X
638 @item HTTP @tab X
639 @item pipe @tab X
640 @item RTP @tab X
641 @item TCP @tab X
642 @item UDP @tab X
643 @end multitable
645 @code{X} means that the protocol is supported.
648 @section Input/Output Devices
650 @multitable @columnfractions .4 .1 .1
651 @item Name @tab Input @tab Output
652 @item ALSA @tab X @tab X
653 @item BEOS audio @tab X @tab X
654 @item BKTR @tab X @tab
655 @item DV1394 @tab X @tab
656 @item LIBDC1394 @tab X @tab
657 @item OSS @tab X @tab X
658 @item Video4Linux @tab X @tab
659 @item Video4Linux2 @tab X @tab
660 @item VfW capture @tab X @tab
661 @item X11 grabbing @tab X @tab
662 @end multitable
664 @code{X} means that input/output is supported.
667 @chapter Platform Specific information
669 @section BSD
671 BSD make will not build FFmpeg, you need to install and use GNU Make
672 (@file{gmake}).
674 @section Windows
676 To get help and instructions for building FFmpeg under Windows, check out
677 the FFmpeg Windows Help Forum at
678 @url{http://ffmpeg.arrozcru.org/}.
680 @subsection Native Windows compilation
682 FFmpeg can be built to run natively on Windows using the MinGW tools. Install
683 the latest versions of MSYS and MinGW from @url{http://www.mingw.org/}.
684 You can find detailed installation
685 instructions in the download section and the FAQ.
687 FFmpeg does not build out-of-the-box with the packages the automated MinGW
688 installer provides. It also requires coreutils to be installed and many other
689 packages updated to the latest version. The minimum version for some packages
690 are listed below:
692 @itemize
693 @item bash 3.1
694 @item msys-make 3.81-2 (note: not mingw32-make)
695 @item w32api 3.13
696 @item mingw-runtime 3.15
697 @end itemize
699 You will also need to pass @code{-fno-common} to the compiler to work around
700 a GCC bug (see @url{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37216}).
702 Within the MSYS shell, configure and make with:
704 @example
705 ./configure --enable-memalign-hack --extra-cflags=-fno-common
706 make
707 make install
708 @end example
710 This will install @file{ffmpeg.exe} along with many other development files
711 to @file{/usr/local}. You may specify another install path using the
712 @code{--prefix} option in @file{configure}.
714 Notes:
716 @itemize
718 @item In order to compile FFplay, you must have the MinGW development library
719 of SDL. Get it from @url{http://www.libsdl.org}.
720 Edit the @file{bin/sdl-config} script so that it points to the correct prefix
721 where SDL was installed. Verify that @file{sdl-config} can be launched from
722 the MSYS command line.
724 @item By using @code{./configure --enable-shared} when configuring FFmpeg,
725 you can build libavutil, libavcodec and libavformat as DLLs.
727 @end itemize
729 @subsection Microsoft Visual C++ compatibility
731 As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
732 want to use the libav* libraries in your own applications, you can still
733 compile those applications using MSVC++. But the libav* libraries you link
734 to @emph{must} be built with MinGW. However, you will not be able to debug
735 inside the libav* libraries, since MSVC++ does not recognize the debug
736 symbols generated by GCC.
737 We strongly recommend you to move over from MSVC++ to MinGW tools.
739 This description of how to use the FFmpeg libraries with MSVC++ is based on
740 Microsoft Visual C++ 2005 Express Edition. If you have a different version,
741 you might have to modify the procedures slightly.
743 @subsubsection Using static libraries
745 Assuming you have just built and installed FFmpeg in @file{/usr/local}.
747 @enumerate
749 @item Create a new console application ("File / New / Project") and then
750 select "Win32 Console Application". On the appropriate page of the
751 Application Wizard, uncheck the "Precompiled headers" option.
753 @item Write the source code for your application, or, for testing, just
754 copy the code from an existing sample application into the source file
755 that MSVC++ has already created for you. For example, you can copy
756 @file{libavformat/output-example.c} from the FFmpeg distribution.
758 @item Open the "Project / Properties" dialog box. In the "Configuration"
759 combo box, select "All Configurations" so that the changes you make will
760 affect both debug and release builds. In the tree view on the left hand
761 side, select "C/C++ / General", then edit the "Additional Include
762 Directories" setting to contain the path where the FFmpeg includes were
763 installed (i.e. @file{c:\msys\1.0\local\include}).
764 Do not add MinGW's include directory here, or the include files will
765 conflict with MSVC's.
767 @item Still in the "Project / Properties" dialog box, select
768 "Linker / General" from the tree view and edit the
769 "Additional Library Directories" setting to contain the @file{lib}
770 directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
771 the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
772 and the directory where MinGW's GCC libs are installed
773 (i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
774 "Linker / Input" from the tree view, and add the files @file{libavformat.a},
775 @file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
776 @file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
777 to the end of "Additional Dependencies".
779 @item Now, select "C/C++ / Code Generation" from the tree view. Select
780 "Debug" in the "Configuration" combo box. Make sure that "Runtime
781 Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
782 the "Configuration" combo box and make sure that "Runtime Library" is
783 set to "Multi-threaded DLL".
785 @item Click "OK" to close the "Project / Properties" dialog box.
787 @item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
788 Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
789 and install it in MSVC++'s include directory
790 (i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
792 @item MSVC++ also does not understand the @code{inline} keyword used by
793 FFmpeg, so you must add this line before @code{#include}ing libav*:
794 @example
795 #define inline _inline
796 @end example
798 @item Build your application, everything should work.
800 @end enumerate
802 @subsubsection Using shared libraries
804 This is how to create DLL and LIB files that are compatible with MSVC++:
806 @enumerate
808 @item Add a call to @file{vcvars32.bat} (which sets up the environment
809 variables for the Visual C++ tools) as the first line of @file{msys.bat}.
810 The standard location for @file{vcvars32.bat} is
811 @file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
812 and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
813 If this corresponds to your setup, add the following line as the first line
814 of @file{msys.bat}:
816 @example
817 call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
818 @end example
820 Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
821 and run @file{c:\msys\1.0\msys.bat} from there.
823 @item Within the MSYS shell, run @code{lib.exe}. If you get a help message
824 from @file{Microsoft (R) Library Manager}, this means your environment
825 variables are set up correctly, the @file{Microsoft (R) Library Manager}
826 is on the path and will be used by FFmpeg to create
827 MSVC++-compatible import libraries.
829 @item Build FFmpeg with
831 @example
832 ./configure --enable-shared --enable-memalign-hack
833 make
834 make install
835 @end example
837 Your install path (@file{/usr/local/} by default) should now have the
838 necessary DLL and LIB files under the @file{bin} directory.
840 @end enumerate
842 To use those files with MSVC++, do the same as you would do with
843 the static libraries, as described above. But in Step 4,
844 you should only need to add the directory where the LIB files are installed
845 (i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
846 installed in the @file{bin} directory. And instead of adding @file{libxx.a}
847 files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
848 @file{avutil.lib}. There should be no need for @file{libmingwex.a},
849 @file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
850 statically linked into the DLLs. The @file{bin} directory contains a bunch
851 of DLL files, but the ones that are actually used to run your application
852 are the ones with a major version number in their filenames
853 (i.e. @file{avcodec-51.dll}).
855 @subsection Cross compilation for Windows with Linux
857 You must use the MinGW cross compilation tools available at
858 @url{http://www.mingw.org/}.
860 Then configure FFmpeg with the following options:
861 @example
862 ./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
863 @end example
864 (you can change the cross-prefix according to the prefix chosen for the
865 MinGW tools).
867 Then you can easily test FFmpeg with Wine
868 (@url{http://www.winehq.com/}).
870 @subsection Compilation under Cygwin
872 The main issue with the 1.5.x Cygwin versions is that newlib, its C library,
873 does not contain llrint(). You need to upgrade to the unstable 1.7.x versions,
874 or leverage the implementation in MinGW (as explained below).
876 Just install your Cygwin with all the "Base" packages, plus the
877 following "Devel" ones:
878 @example
879 binutils, gcc-core, make, subversion, mingw-runtime, diffutils
880 @end example
882 The experimental gcc4 package is still buggy, hence please
883 use the official gcc 3.4.4 or a 4.2.x compiled from source by yourself.
885 Install the current binutils-20080624-2 as they work fine (the old
886 binutils-20060709-1 proved buggy on shared builds).
888 Then create a small library that just contains llrint():
890 @example
891 ar x /usr/lib/mingw/libmingwex.a llrint.o
892 ar cq /usr/local/lib/libllrint.a llrint.o
893 @end example
895 Then run
897 @example
898 ./configure --enable-static --disable-shared --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
899 @end example
901 to make a static build or
903 @example
904 ./configure --enable-shared --disable-static --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
905 @end example
907 to build shared libraries.
909 If you want to build FFmpeg with additional libraries, download Cygwin
910 "Devel" packages for Ogg and Vorbis from any Cygwin packages repository:
911 @example
912 libogg-devel, libvorbis-devel
913 @end example
915 These library packages are only available from Cygwin Ports
916 (@url{http://sourceware.org/cygwinports/}) :
918 @example
919 yasm, libSDL-devel, libdirac-devel, libfaac-devel, libfaad-devel, libgsm-devel,
920 libmp3lame-devel, libschroedinger1.0-devel, speex-devel, libtheora-devel,
921 libxvidcore-devel
922 @end example
924 The recommendation for libnut and x264 is to build them from source by
925 yourself, as they evolve too quickly for Cygwin Ports to be up to date.
927 Cygwin 1.7.x has IPv6 support. You can add IPv6 to Cygwin 1.5.x by means
928 of the @code{libgetaddrinfo-devel} package, available at Cygwin Ports.
930 @subsection Crosscompilation for Windows under Cygwin
932 With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
934 Just install your Cygwin as explained before, plus these additional
935 "Devel" packages:
936 @example
937 gcc-mingw-core, mingw-runtime, mingw-zlib
938 @end example
940 and add some special flags to your configure invocation.
942 For a static build run
943 @example
944 ./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
945 @end example
947 and for a build with shared libraries
948 @example
949 ./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
950 @end example
952 @section BeOS
954 BeOS support is broken in mysterious ways.
956 @section OS/2
958 For information about compiling FFmpeg on OS/2 see
959 @url{http://www.edm2.com/index.php/FFmpeg}.
961 @chapter Developers Guide
963 @section API
964 @itemize @bullet
965 @item libavcodec is the library containing the codecs (both encoding and
966 decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
968 @item libavformat is the library containing the file format handling (mux and
969 demux code for several formats). Look at @file{ffplay.c} to use it in a
970 player. See @file{libavformat/output-example.c} to use it to generate
971 audio or video streams.
973 @end itemize
975 @section Integrating libavcodec or libavformat in your program
977 You can integrate all the source code of the libraries to link them
978 statically to avoid any version problem. All you need is to provide a
979 'config.mak' and a 'config.h' in the parent directory. See the defines
980 generated by ./configure to understand what is needed.
982 You can use libavcodec or libavformat in your commercial program, but
983 @emph{any patch you make must be published}. The best way to proceed is
984 to send your patches to the FFmpeg mailing list.
986 @node Coding Rules
987 @section Coding Rules
989 FFmpeg is programmed in the ISO C90 language with a few additional
990 features from ISO C99, namely:
991 @itemize @bullet
992 @item
993 the @samp{inline} keyword;
994 @item
995 @samp{//} comments;
996 @item
997 designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
998 @item
999 compound literals (@samp{x = (struct s) @{ 17, 23 @};})
1000 @end itemize
1002 These features are supported by all compilers we care about, so we will not
1003 accept patches to remove their use unless they absolutely do not impair
1004 clarity and performance.
1006 All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
1007 compiles with several other compilers, such as the Compaq ccc compiler
1008 or Sun Studio 9, and we would like to keep it that way unless it would
1009 be exceedingly involved. To ensure compatibility, please do not use any
1010 additional C99 features or GCC extensions. Especially watch out for:
1011 @itemize @bullet
1012 @item
1013 mixing statements and declarations;
1014 @item
1015 @samp{long long} (use @samp{int64_t} instead);
1016 @item
1017 @samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
1018 @item
1019 GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
1020 @end itemize
1022 Indent size is 4.
1023 The presentation is the one specified by 'indent -i4 -kr -nut'.
1024 The TAB character is forbidden outside of Makefiles as is any
1025 form of trailing whitespace. Commits containing either will be
1026 rejected by the Subversion repository.
1028 The main priority in FFmpeg is simplicity and small code size in order to
1029 minimize the bug count.
1031 Comments: Use the JavaDoc/Doxygen
1032 format (see examples below) so that code documentation
1033 can be generated automatically. All nontrivial functions should have a comment
1034 above them explaining what the function does, even if it is just one sentence.
1035 All structures and their member variables should be documented, too.
1036 @example
1037 /**
1038 * @@file mpeg.c
1039 * MPEG codec.
1040 * @@author ...
1041 */
1043 /**
1044 * Summary sentence.
1045 * more text ...
1046 * ...
1047 */
1048 typedef struct Foobar@{
1049 int var1; /**< var1 description */
1050 int var2; ///< var2 description
1051 /** var3 description */
1052 int var3;
1053 @} Foobar;
1055 /**
1056 * Summary sentence.
1057 * more text ...
1058 * ...
1059 * @@param my_parameter description of my_parameter
1060 * @@return return value description
1061 */
1062 int myfunc(int my_parameter)
1063 ...
1064 @end example
1066 fprintf and printf are forbidden in libavformat and libavcodec,
1067 please use av_log() instead.
1069 Casts should be used only when necessary. Unneeded parentheses
1070 should also be avoided if they don't make the code easier to understand.
1072 @section Development Policy
1074 @enumerate
1075 @item
1076 Contributions should be licensed under the LGPL 2.1, including an
1077 "or any later version" clause, or the MIT license. GPL 2 including
1078 an "or any later version" clause is also acceptable, but LGPL is
1079 preferred.
1080 @item
1081 You must not commit code which breaks FFmpeg! (Meaning unfinished but
1082 enabled code which breaks compilation or compiles but does not work or
1083 breaks the regression tests)
1084 You can commit unfinished stuff (for testing etc), but it must be disabled
1085 (#ifdef etc) by default so it does not interfere with other developers'
1086 work.
1087 @item
1088 You do not have to over-test things. If it works for you, and you think it
1089 should work for others, then commit. If your code has problems
1090 (portability, triggers compiler bugs, unusual environment etc) they will be
1091 reported and eventually fixed.
1092 @item
1093 Do not commit unrelated changes together, split them into self-contained
1094 pieces. Also do not forget that if part B depends on part A, but A does not
1095 depend on B, then A can and should be committed first and separate from B.
1096 Keeping changes well split into self-contained parts makes reviewing and
1097 understanding them on the commit log mailing list easier. This also helps
1098 in case of debugging later on.
1099 Also if you have doubts about splitting or not splitting, do not hesitate to
1100 ask/discuss it on the developer mailing list.
1101 @item
1102 Do not change behavior of the program (renaming options etc) without
1103 first discussing it on the ffmpeg-devel mailing list. Do not remove
1104 functionality from the code. Just improve!
1106 Note: Redundant code can be removed.
1107 @item
1108 Do not commit changes to the build system (Makefiles, configure script)
1109 which change behavior, defaults etc, without asking first. The same
1110 applies to compiler warning fixes, trivial looking fixes and to code
1111 maintained by other developers. We usually have a reason for doing things
1112 the way we do. Send your changes as patches to the ffmpeg-devel mailing
1113 list, and if the code maintainers say OK, you may commit. This does not
1114 apply to files you wrote and/or maintain.
1115 @item
1116 We refuse source indentation and other cosmetic changes if they are mixed
1117 with functional changes, such commits will be rejected and removed. Every
1118 developer has his own indentation style, you should not change it. Of course
1119 if you (re)write something, you can use your own style, even though we would
1120 prefer if the indentation throughout FFmpeg was consistent (Many projects
1121 force a given indentation style - we do not.). If you really need to make
1122 indentation changes (try to avoid this), separate them strictly from real
1123 changes.
1125 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
1126 then either do NOT change the indentation of the inner part within (do not
1127 move it to the right)! or do so in a separate commit
1128 @item
1129 Always fill out the commit log message. Describe in a few lines what you
1130 changed and why. You can refer to mailing list postings if you fix a
1131 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1132 @item
1133 If you apply a patch by someone else, include the name and email address in
1134 the log message. Since the ffmpeg-cvslog mailing list is publicly
1135 archived you should add some SPAM protection to the email address. Send an
1136 answer to ffmpeg-devel (or wherever you got the patch from) saying that
1137 you applied the patch.
1138 @item
1139 When applying patches that have been discussed (at length) on the mailing
1140 list, reference the thread in the log message.
1141 @item
1142 Do NOT commit to code actively maintained by others without permission.
1143 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
1144 timeframe (12h for build failures and security fixes, 3 days small changes,
1145 1 week for big patches) then commit your patch if you think it is OK.
1146 Also note, the maintainer can simply ask for more time to review!
1147 @item
1148 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
1149 are sent there and reviewed by all the other developers. Bugs and possible
1150 improvements or general questions regarding commits are discussed there. We
1151 expect you to react if problems with your code are uncovered.
1152 @item
1153 Update the documentation if you change behavior or add features. If you are
1154 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
1155 maintainer(s) will review and commit your stuff.
1156 @item
1157 Try to keep important discussions and requests (also) on the public
1158 developer mailing list, so that all developers can benefit from them.
1159 @item
1160 Never write to unallocated memory, never write over the end of arrays,
1161 always check values read from some untrusted source before using them
1162 as array index or other risky things.
1163 @item
1164 Remember to check if you need to bump versions for the specific libav
1165 parts (libavutil, libavcodec, libavformat) you are changing. You need
1166 to change the version integer.
1167 Incrementing the first component means no backward compatibility to
1168 previous versions (e.g. removal of a function from the public API).
1169 Incrementing the second component means backward compatible change
1170 (e.g. addition of a function to the public API or extension of an
1171 existing data structure).
1172 Incrementing the third component means a noteworthy binary compatible
1173 change (e.g. encoder bug fix that matters for the decoder).
1174 @item
1175 Compiler warnings indicate potential bugs or code with bad style. If a type of
1176 warning always points to correct and clean code, that warning should
1177 be disabled, not the code changed.
1178 Thus the remaining warnings can either be bugs or correct code.
1179 If it is a bug, the bug has to be fixed. If it is not, the code should
1180 be changed to not generate a warning unless that causes a slowdown
1181 or obfuscates the code.
1182 @item
1183 If you add a new file, give it a proper license header. Do not copy and
1184 paste it from a random place, use an existing file as template.
1185 @end enumerate
1187 We think our rules are not too hard. If you have comments, contact us.
1189 Note, these rules are mostly borrowed from the MPlayer project.
1191 @section Submitting patches
1193 First, (@pxref{Coding Rules}) above if you did not yet.
1195 When you submit your patch, try to send a unified diff (diff '-up'
1196 option). We cannot read other diffs :-)
1198 Also please do not submit a patch which contains several unrelated changes.
1199 Split it into separate, self-contained pieces. This does not mean splitting
1200 file by file. Instead, make the patch as small as possible while still
1201 keeping it as a logical unit that contains an individual change, even
1202 if it spans multiple files. This makes reviewing your patches much easier
1203 for us and greatly increases your chances of getting your patch applied.
1205 Run the regression tests before submitting a patch so that you can
1206 verify that there are no big problems.
1208 Patches should be posted as base64 encoded attachments (or any other
1209 encoding which ensures that the patch will not be trashed during
1210 transmission) to the ffmpeg-devel mailing list, see
1211 @url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
1213 It also helps quite a bit if you tell us what the patch does (for example
1214 'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
1215 and has no lrint()')
1217 Also please if you send several patches, send each patch as a separate mail,
1218 do not attach several unrelated patches to the same mail.
1220 @section New codecs or formats checklist
1222 @enumerate
1223 @item
1224 Did you use av_cold for codec initialization and close functions?
1225 @item
1226 Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
1227 AVInputFormat/AVOutputFormat struct?
1228 @item
1229 Did you bump the minor version number in @file{avcodec.h} or
1230 @file{avformat.h}?
1231 @item
1232 Did you register it in @file{allcodecs.c} or @file{allformats.c}?
1233 @item
1234 Did you add the CodecID to @file{avcodec.h}?
1235 @item
1236 If it has a fourcc, did you add it to @file{libavformat/riff.c},
1237 even if it is only a decoder?
1238 @item
1239 Did you add a rule to compile the appropriate files in the Makefile?
1240 Remember to do this even if you're just adding a format to a file that is
1241 already being compiled by some other rule, like a raw demuxer.
1242 @item
1243 Did you add an entry to the table of supported formats or codecs in the
1244 documentation?
1245 @item
1246 Did you add an entry in the Changelog?
1247 @item
1248 If it depends on a parser or a library, did you add that dependency in
1249 configure?
1250 @item
1251 Did you "svn add" the appropriate files before commiting?
1252 @end enumerate
1254 @section patch submission checklist
1256 @enumerate
1257 @item
1258 Do the regression tests pass with the patch applied?
1259 @item
1260 Does @code{make checkheaders} pass with the patch applied?
1261 @item
1262 Is the patch a unified diff?
1263 @item
1264 Is the patch against latest FFmpeg SVN?
1265 @item
1266 Are you subscribed to ffmpeg-dev?
1267 (the list is subscribers only due to spam)
1268 @item
1269 Have you checked that the changes are minimal, so that the same cannot be
1270 achieved with a smaller patch and/or simpler final code?
1271 @item
1272 If the change is to speed critical code, did you benchmark it?
1273 @item
1274 If you did any benchmarks, did you provide them in the mail?
1275 @item
1276 Have you checked that the patch does not introduce buffer overflows or
1277 other security issues?
1278 @item
1279 Did you test your decoder or demuxer against damaged data? If no, see
1280 tools/trasher and the noise bitstream filter. Your decoder or demuxer
1281 should not crash or end in a (near) infinite loop when fed damaged data.
1282 @item
1283 Is the patch created from the root of the source tree, so it can be
1284 applied with @code{patch -p0}?
1285 @item
1286 Does the patch not mix functional and cosmetic changes?
1287 @item
1288 Did you add tabs or trailing whitespace to the code? Both are forbidden.
1289 @item
1290 Is the patch attached to the email you send?
1291 @item
1292 Is the mime type of the patch correct? It should be text/x-diff or
1293 text/x-patch or at least text/plain and not application/octet-stream.
1294 @item
1295 If the patch fixes a bug, did you provide a verbose analysis of the bug?
1296 @item
1297 If the patch fixes a bug, did you provide enough information, including
1298 a sample, so the bug can be reproduced and the fix can be verified?
1299 Note please do not attach samples >100k to mails but rather provide a
1300 URL, you can upload to ftp://upload.ffmpeg.org
1301 @item
1302 Did you provide a verbose summary about what the patch does change?
1303 @item
1304 Did you provide a verbose explanation why it changes things like it does?
1305 @item
1306 Did you provide a verbose summary of the user visible advantages and
1307 disadvantages if the patch is applied?
1308 @item
1309 Did you provide an example so we can verify the new feature added by the
1310 patch easily?
1311 @item
1312 If you added a new file, did you insert a license header? It should be
1313 taken from FFmpeg, not randomly copied and pasted from somewhere else.
1314 @item
1315 You should maintain alphabetical order in alphabetically ordered lists as
1316 long as doing so does not break API/ABI compatibility.
1317 @item
1318 Lines with similar content should be aligned vertically when doing so
1319 improves readability.
1320 @item
1321 Did you provide a suggestion for a clear commit log message?
1322 @end enumerate
1324 @section Patch review process
1326 All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1327 clear note that the patch is not for SVN.
1328 Reviews and comments will be posted as replies to the patch on the
1329 mailing list. The patch submitter then has to take care of every comment,
1330 that can be by resubmitting a changed patch or by discussion. Resubmitted
1331 patches will themselves be reviewed like any other patch. If at some point
1332 a patch passes review with no comments then it is approved, that can for
1333 simple and small patches happen immediately while large patches will generally
1334 have to be changed and reviewed many times before they are approved.
1335 After a patch is approved it will be committed to the repository.
1337 We will review all submitted patches, but sometimes we are quite busy so
1338 especially for large patches this can take several weeks.
1340 When resubmitting patches, please do not make any significant changes
1341 not related to the comments received during review. Such patches will
1342 be rejected. Instead, submit significant changes or new features as
1343 separate patches.
1345 @section Regression tests
1347 Before submitting a patch (or committing to the repository), you should at least
1348 test that you did not break anything.
1350 The regression tests build a synthetic video stream and a synthetic
1351 audio stream. These are then encoded and decoded with all codecs or
1352 formats. The CRC (or MD5) of each generated file is recorded in a
1353 result file. A 'diff' is launched to compare the reference results and
1354 the result file.
1356 The regression tests then go on to test the FFserver code with a
1357 limited set of streams. It is important that this step runs correctly
1358 as well.
1360 Run 'make test' to test all the codecs and formats.
1362 Run 'make fulltest' to test all the codecs, formats and FFserver.
1364 [Of course, some patches may change the results of the regression tests. In
1365 this case, the reference results of the regression tests shall be modified
1366 accordingly].
1368 @bye