cosmetics: Uniformize external library comments.
[libav.git] / doc / general.texi
CommitLineData
d0e1cd3d
DB
1\input texinfo @c -*- texinfo -*-
2
3@settitle General Documentation
4@titlepage
5@sp 7
6@center @titlefont{General Documentation}
7@sp 3
8@end titlepage
9
10
11@chapter external libraries
12
13FFmpeg can be hooked up with a number of external libraries to add support
14for more formats. None of them are used by default, their use has to be
15explicitly requested by passing the appropriate flags to @file{./configure}.
16
17@section AMR
18
50e4d833
DB
19AMR comes in two different flavors, wideband and narrowband. FFmpeg can make
20use of the AMR wideband (floating-point mode) and the AMR narrowband
21(floating-point mode) reference decoders and encoders.
d0e1cd3d
DB
22
23Go to @url{http://www.penguin.cz/~utx/amr} and follow the instructions for
24installing the libraries. Then pass @code{--enable-libamr-nb} and/or
25@code{--enable-libamr-wb} to configure to enable the libraries.
26
68e7d442
DB
27Note that libamr is copyrighted without any sort of license grant. This means
28that you can use it if you legally obtained it but you are not allowed to
29redistribute it in any way. @strong{Any FFmpeg binaries with libamr support
30you create are non-free and unredistributable!}
31
d0e1cd3d
DB
32
33@chapter Supported File Formats and Codecs
34
35You can use the @code{-formats} option to have an exhaustive list.
36
37@section File Formats
38
39FFmpeg supports the following file formats through the @code{libavformat}
40library:
41
42@multitable @columnfractions .4 .1 .1 .4
b3de4544 43@item Name @tab Encoding @tab Decoding @tab Comments
64c2f20a 44@item 4xm @tab @tab X
c6b2dc34
DB
45 @tab 4X Technologies format, used in some games.
46@item ADTS AAC audio @tab X @tab X
64c2f20a
DB
47@item American Laser Games MM @tab @tab X
48 @tab Multimedia format used in games like Mad Dog McCree.
c6b2dc34
DB
49@item ASF @tab X @tab X
50@item AVI @tab X @tab X
51@item AVM2 (Flash 9) @tab X @tab X
d698c5d3 52 @tab Only embedded audio is decoded.
c6b2dc34 53@item AVS @tab @tab X
d698c5d3 54 @tab Multimedia format used by the Creature Shock game.
c6b2dc34 55@item Bethsoft VID @tab @tab X
d698c5d3 56 @tab Used in some games from Bethesda Softworks.
64c2f20a
DB
57@item BFI @tab @tab X
58 @tab Brute Force & Ignorance, used in Flash Traffic: City of Angels.
c6b2dc34 59@item C93 @tab @tab X
d698c5d3 60 @tab Used in the game Cyberia from Interplay.
c6b2dc34 61@item CIN @tab @tab X
d698c5d3 62 @tab Multimedia format used by Delphine Software games.
c6b2dc34 63@item Creative VOC @tab X @tab X
d698c5d3 64 @tab Created for the Sound Blaster Pro.
64c2f20a
DB
65@item CRYO APC @tab @tab X
66 @tab Audio format used in some games by CRYO Interactive Entertainment.
c6b2dc34
DB
67@item DV @tab X @tab X
68@item DXA @tab @tab X
d698c5d3
DB
69 @tab This format is used in the non-Windows version of the Feeble Files
70 game and different game cutscenes repacked for use with ScummVM.
c6b2dc34 71@item Electronic Arts Multimedia @tab @tab X
d698c5d3 72 @tab Used in various EA games; files have extensions like WVE and UV2.
c6b2dc34 73@item FLIC @tab @tab X
d698c5d3 74 @tab .fli/.flc files
c6b2dc34 75@item FLV @tab X @tab X
d698c5d3 76 @tab Macromedia Flash video files
c6b2dc34 77@item GXF @tab X @tab X
d698c5d3 78 @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley
64c2f20a 79 playout servers.
76ec3939 80@item id Cinematic @tab @tab X
d698c5d3 81 @tab Used in Quake II.
76ec3939 82@item id RoQ @tab X @tab X
d698c5d3 83 @tab Used in Quake III, Jedi Knight 2, other computer games.
c6b2dc34 84@item IFF @tab @tab X
d698c5d3 85 @tab Interchange File Format
c6b2dc34 86@item Interplay MVE @tab @tab X
d698c5d3 87 @tab Format used in various Interplay computer games.
c6b2dc34 88@item LMLM4 @tab @tab X
d698c5d3 89 @tab Used by Linux Media Labs MPEG-4 PCI boards
64c2f20a 90@item Matroska @tab X @tab X
c6b2dc34 91@item MAXIS EA XA @tab @tab X
d698c5d3 92 @tab Used in Sim City 3000; file extension .xa.
64c2f20a 93@item Monkey's Audio @tab @tab X
822cc8f7 94@item Motion Pixels MVI @tab @tab X
64c2f20a 95@item MOV/QuickTime @tab X @tab X
c6b2dc34
DB
96@item MPEG audio @tab X @tab X
97@item MPEG-1 systems @tab X @tab X
d698c5d3 98 @tab muxed audio and video
c6b2dc34 99@item MPEG-2 PS @tab X @tab X
d698c5d3 100 @tab also known as @code{VOB} file
c6b2dc34 101@item MPEG-2 TS @tab @tab X
d698c5d3 102 @tab also known as DVB Transport Stream
c6b2dc34 103@item MPEG-4 @tab X @tab X
d698c5d3 104 @tab MPEG-4 is a variant of QuickTime.
bac4c85c 105@item MSN TCP webcam @tab @tab X
d698c5d3 106 @tab Used by MSN Messenger webcam streams.
bb68b69d 107@item MXF @tab X @tab X
d698c5d3 108 @tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
64c2f20a 109@item Nullsoft Video @tab @tab X
c6b2dc34 110@item NUT @tab X @tab X
d698c5d3 111 @tab NUT Open Container Format
c6b2dc34 112@item OMA @tab @tab X
d698c5d3 113 @tab Audio format used in Sony Sonic Stage and Sony Vegas.
64c2f20a 114@item PlayStation STR @tab @tab X
c6b2dc34 115@item PVA @tab @tab X
d698c5d3 116 @tab Used by TechnoTrend DVB PCI boards.
76ec3939
DB
117@item raw AC-3 @tab X @tab X
118@item raw CRI ADX audio @tab X @tab X
119@item raw MJPEG @tab X @tab X
120@item raw MPEG video @tab X @tab X
121@item raw MPEG-4 video @tab X @tab X
eb6fc557 122@item raw PCM 8/16/32 bits, 32/64-bit floating point, mu-law/A-law @tab X @tab X
76ec3939 123@item raw Shorten audio @tab @tab X
64c2f20a 124@item RealMedia @tab X @tab X
c6b2dc34 125@item RL2 @tab @tab X
d698c5d3 126 @tab Audio and video format used in some games by Entertainment Software Partners.
c6b2dc34 127@item Sega FILM/CPK @tab @tab X
d698c5d3 128 @tab Used in many Sega Saturn console games.
64c2f20a
DB
129@item SEQ @tab @tab X
130 @tab Tiertex .seq files used in the DOS CD-ROM version of the game Flashback.
c6b2dc34 131@item Sierra Online @tab @tab X
d698c5d3 132 @tab .sol files used in Sierra Online games.
c6b2dc34 133@item Sierra VMD @tab @tab X
d698c5d3 134 @tab Used in Sierra CD-ROM games.
64c2f20a
DB
135@item SIFF @tab @tab X
136 @tab Audio and video format used in some games by Beam Software.
c6b2dc34 137@item Smacker @tab @tab X
d698c5d3 138 @tab Multimedia format used by many games.
64c2f20a 139@item SUN AU format @tab X @tab X
c6b2dc34 140@item THP @tab @tab X
d698c5d3 141 @tab Used on the Nintendo GameCube.
c6b2dc34
DB
142@item WAV @tab X @tab X
143@item WC3 Movie @tab @tab X
d698c5d3 144 @tab Multimedia format used in Origin's Wing Commander III computer game.
c6b2dc34 145@item Westwood Studios VQA/AUD @tab @tab X
d698c5d3 146 @tab Multimedia formats used in Westwood Studios games.
d0e1cd3d
DB
147@end multitable
148
149@code{X} means that encoding (resp. decoding) is supported.
150
151@section Image Formats
152
153FFmpeg can read and write images for each frame of a video sequence. The
154following image formats are supported:
155
156@multitable @columnfractions .4 .1 .1 .4
b3de4544 157@item Name @tab Encoding @tab Decoding @tab Comments
64c2f20a 158@item .Y.U.V @tab X @tab X @tab one raw file per component
3d172fb5
DB
159@item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
160@item JPEG @tab X @tab X @tab Progressive JPEG is not supported.
d0e1cd3d 161@item PAM @tab X @tab X @tab PAM is a PNM extension with alpha support.
3d172fb5
DB
162@item PCX @tab @tab X @tab PC Paintbrush
163@item PGM, PPM @tab X @tab X
d0e1cd3d 164@item PGMYUV @tab X @tab X @tab PGM with U and V components in YUV 4:2:0
0a91f4ee 165@item PNG @tab X @tab X @tab 2/4 bpp not supported yet
d0e1cd3d 166@item PTX @tab @tab X @tab V.Flash PTX format
d1928ac1 167@item RAS @tab @tab X @tab Sun Rasterfile
3d172fb5 168@item SGI @tab X @tab X @tab SGI RGB image format
3d172fb5 169@item Targa @tab @tab X @tab Targa (.TGA) image format
64c2f20a 170@item TIFF @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
d0e1cd3d
DB
171@end multitable
172
173@code{X} means that encoding (resp. decoding) is supported.
174
175@section Video Codecs
176
177@multitable @columnfractions .4 .1 .1 .4
b3de4544 178@item Name @tab Encoding @tab Decoding @tab Comments
d66d8b83 179@item 4X Video @tab @tab X
d698c5d3 180 @tab Used in certain computer games.
d66d8b83 181@item American Laser Games Video @tab @tab X
d698c5d3 182 @tab Used in games like Mad Dog McCree.
d66d8b83 183@item AMV @tab @tab X
d698c5d3 184 @tab Used in Chinese MP3 players.
d66d8b83 185@item Apple Animation @tab X @tab X
d698c5d3 186 @tab fourcc: 'rle '
d66d8b83 187@item Apple Graphics @tab @tab X
d698c5d3 188 @tab fourcc: 'smc '
d66d8b83
DB
189@item Apple MJPEG-B @tab @tab X
190@item Apple QuickDraw @tab @tab X
d698c5d3 191 @tab fourcc: qdrw
d66d8b83 192@item Apple Video @tab @tab X
d698c5d3 193 @tab fourcc: rpza
d66d8b83 194@item Asus v1 @tab X @tab X
d698c5d3 195 @tab fourcc: ASV1
d66d8b83 196@item Asus v2 @tab X @tab X
d698c5d3 197 @tab fourcc: ASV2
d66d8b83 198@item ATI VCR1 @tab @tab X
d698c5d3 199 @tab fourcc: VCR1
d66d8b83 200@item ATI VCR2 @tab @tab X
d698c5d3 201 @tab fourcc: VCR2
d66d8b83 202@item Autodesk RLE @tab @tab X
d698c5d3 203 @tab fourcc: AASC
d66d8b83 204@item AVID DNxHD @tab X @tab X
d698c5d3 205 @tab aka SMPTE VC3
bac4c85c 206@item AVS video @tab @tab X
d698c5d3 207 @tab Video encoding used by the Creature Shock game.
d66d8b83 208@item Bethsoft VID @tab @tab X
d698c5d3 209 @tab Used in some games from Bethesda Softworks.
bac4c85c 210@item C93 video @tab @tab X
d698c5d3 211 @tab Codec used in Cyberia game.
d66d8b83 212@item CamStudio @tab @tab X
d698c5d3 213 @tab fourcc: CSCD
bac4c85c 214@item Cin video @tab @tab X
d698c5d3 215 @tab Codec used in Delphine Software games.
d66d8b83
DB
216@item Cinepak @tab @tab X
217@item Cirrus Logic AccuPak @tab @tab X
d698c5d3 218 @tab fourcc: CLJR
d66d8b83 219@item Creative YUV @tab @tab X
d698c5d3 220 @tab fourcc: CYUV
5c5a6dfe 221@item Dirac @tab X @tab X
360f980b 222 @tab supported through external libdirac/libschroedinger libraries
d66d8b83 223@item Duck TrueMotion v1 @tab @tab X
d698c5d3 224 @tab fourcc: DUCK
d66d8b83 225@item Duck TrueMotion v2 @tab @tab X
d698c5d3 226 @tab fourcc: TM20
d66d8b83
DB
227@item DV @tab X @tab X
228@item DXA Video @tab @tab X
d698c5d3 229 @tab Codec originally used in Feeble Files game.
d66d8b83 230@item Electronic Arts CMV @tab @tab X
d698c5d3 231 @tab Used in NHL 95 game.
cfc78718 232@item Electronic Arts TGV @tab @tab X
d66d8b83 233@item FFmpeg Video 1 @tab X @tab X
d698c5d3 234 @tab experimental lossless codec (fourcc: FFV1)
d66d8b83 235@item Flash Screen Video @tab X @tab X
d698c5d3 236 @tab fourcc: FSV1
d66d8b83
DB
237@item FLIC video @tab @tab X
238@item FLV @tab X @tab X
d698c5d3 239 @tab Sorenson H.263 used in Flash
d66d8b83
DB
240@item Fraps FPS1 @tab @tab X
241@item H.261 @tab X @tab X
242@item H.263(+) @tab X @tab X
d698c5d3 243 @tab also known as RealVideo 1.0
d66d8b83 244@item H.264 @tab @tab X
360f980b 245 @tab encoding supported through external library libx264
d66d8b83
DB
246@item HuffYUV @tab X @tab X
247@item IBM Ultimotion @tab @tab X
d698c5d3 248 @tab fourcc: ULTI
bac4c85c 249@item id Cinematic video @tab @tab X
d698c5d3 250 @tab Used in Quake II.
d66d8b83 251@item id RoQ @tab X @tab X
d698c5d3 252 @tab Used in Quake III, Jedi Knight 2, other computer games.
d66d8b83
DB
253@item Intel Indeo 3 @tab @tab X
254@item Interplay Video @tab @tab X
d698c5d3 255 @tab Used in Interplay .MVE files.
d66d8b83 256@item JPEG-LS @tab X @tab X
d698c5d3 257 @tab fourcc: MJLS, lossless and near-lossless is supported.
d66d8b83 258@item KMVC @tab @tab X
d698c5d3 259 @tab Codec used in Worms games.
d66d8b83
DB
260@item LOCO @tab @tab X
261@item lossless MJPEG @tab X @tab X
262@item Microsoft RLE @tab @tab X
263@item Microsoft Video-1 @tab @tab X
264@item Mimic @tab @tab X
d698c5d3 265 @tab Used in MSN Messenger Webcam streams.
d66d8b83 266@item Miro VideoXL @tab @tab X
d698c5d3 267 @tab fourcc: VIXL
d66d8b83 268@item MJPEG @tab X @tab X
822cc8f7 269@item Motion Pixels Video @tab @tab X
bac4c85c
DB
270@item MPEG-1 @tab X @tab X
271@item MPEG-2 @tab X @tab X
d0e1cd3d
DB
272@item MPEG-4 @tab X @tab X
273@item MSMPEG4 V1 @tab X @tab X
274@item MSMPEG4 V2 @tab X @tab X
275@item MSMPEG4 V3 @tab X @tab X
d66d8b83 276@item MSZH @tab @tab X
d698c5d3 277 @tab Part of LCL
d66d8b83 278@item On2 VP3 @tab @tab X
d698c5d3 279 @tab still experimental
d66d8b83 280@item On2 VP5 @tab @tab X
d698c5d3 281 @tab fourcc: VP50
d66d8b83 282@item On2 VP6 @tab @tab X
d698c5d3 283 @tab fourcc: VP60,VP61,VP62
d66d8b83 284@item planar RGB @tab @tab X
d698c5d3 285 @tab fourcc: 8BPS
d66d8b83 286@item QPEG @tab @tab X
d698c5d3 287 @tab fourccs: QPEG, Q1.0, Q1.1
d0e1cd3d
DB
288@item RealVideo 1.0 @tab X @tab X
289@item RealVideo 2.0 @tab X @tab X
d66d8b83 290@item Renderware TXD @tab @tab X
d698c5d3 291 @tab Texture dictionaries used by the Renderware Engine.
d66d8b83 292@item RTjpeg @tab @tab X
d698c5d3 293 @tab Video encoding used in NuppelVideo files.
bac4c85c 294@item Smacker video @tab @tab X
d698c5d3 295 @tab Video encoding used in Smacker.
d66d8b83 296@item Snow @tab X @tab X
d698c5d3 297 @tab experimental wavelet codec (fourcc: SNOW)
831ec935 298@item Sony PlayStation MDEC @tab @tab X
d66d8b83 299@item Sorenson Video 1 @tab X @tab X
d698c5d3 300 @tab fourcc: SVQ1
d66d8b83 301@item Sorenson Video 3 @tab @tab X
d698c5d3 302 @tab fourcc: SVQ3
d66d8b83 303@item Sunplus MJPEG @tab @tab X
d698c5d3 304 @tab fourcc: SP5X
d66d8b83 305@item TechSmith Camtasia @tab @tab X
d698c5d3 306 @tab fourcc: TSCC
d66d8b83 307@item Theora @tab X @tab X
360f980b 308 @tab encoding supported through external library libtheora
d66d8b83 309@item THP @tab @tab X
d698c5d3 310 @tab Used on the Nintendo GameCube.
bac4c85c 311@item Tiertex Seq video @tab @tab X
d698c5d3 312 @tab Codec used in DOS CD-ROM FlashBack game.
d66d8b83
DB
313@item VC-1 @tab @tab X
314@item VMD Video @tab @tab X
d698c5d3 315 @tab Used in Sierra VMD files.
d66d8b83 316@item VMware Video @tab @tab X
d698c5d3 317 @tab Codec used in videos captured by VMware.
d0e1cd3d 318@item Westwood VQA @tab @tab X
d66d8b83
DB
319@item Winnov WNV1 @tab @tab X
320@item WMV7 @tab X @tab X
321@item WMV8 @tab X @tab X
322@item WMV9 @tab @tab X
d698c5d3 323 @tab not completely working
d66d8b83 324@item Xan/WC3 @tab @tab X
d698c5d3 325 @tab Used in Wing Commander III .MVE files.
d66d8b83 326@item ZLIB @tab X @tab X
d698c5d3 327 @tab part of LCL, encoder experimental
d66d8b83 328@item ZMBV @tab X @tab X
d698c5d3 329 @tab Encoder works only in PAL8.
d0e1cd3d
DB
330@end multitable
331
332@code{X} means that encoding (resp. decoding) is supported.
333
334@section Audio Codecs
335
336@multitable @columnfractions .4 .1 .1 .1 .7
b3de4544 337@item Name @tab Encoding @tab Decoding @tab Comments
16d81b27
DB
338@item 4X IMA ADPCM @tab @tab X
339@item 8SVX audio @tab @tab X
340@item AAC @tab X @tab X
360f980b 341 @tab encoding supported through external library libfaac
16d81b27 342@item AC-3 @tab IX @tab IX
16d81b27 343@item AMR-NB @tab X @tab X
360f980b 344 @tab supported through external library libamrnb
16d81b27 345@item AMR-WB @tab X @tab X
360f980b 346 @tab supported through external library libamrwb
16d81b27 347@item AMV IMA ADPCM @tab @tab X
d698c5d3 348 @tab Used in AMV files
833e90dd 349@item Apple lossless audio @tab X @tab X
d698c5d3 350 @tab QuickTime fourcc 'alac'
16d81b27
DB
351@item Apple MACE 3 @tab @tab X
352@item Apple MACE 6 @tab @tab X
353@item ATRAC 3 @tab @tab X
354@item CD-ROM XA ADPCM @tab @tab X
bac4c85c 355@item Cin audio @tab @tab X
d698c5d3 356 @tab Codec used in Delphine Software International games.
16d81b27 357@item Creative ADPCM @tab @tab X
d698c5d3 358 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
16d81b27 359@item CRI ADX ADPCM @tab X @tab X
d698c5d3 360 @tab Used in Sega Dreamcast games.
16d81b27
DB
361@item DSP Group TrueSpeech @tab @tab X
362@item DTS Coherent Audio @tab @tab X
363@item Duck DK3 IMA ADPCM @tab @tab X
d698c5d3 364 @tab Used in some Sega Saturn console games.
16d81b27 365@item Duck DK4 IMA ADPCM @tab @tab X
d698c5d3 366 @tab Used in some Sega Saturn console games.
16d81b27
DB
367@item DV audio @tab @tab X
368@item Electronic Arts ADPCM @tab @tab X
d698c5d3 369 @tab Used in various EA titles.
44723c84 370@item Enhanced AC-3 @tab @tab X
9a584db4 371@item FLAC lossless audio @tab IX @tab X
16d81b27
DB
372@item G.726 ADPCM @tab X @tab X
373@item id RoQ DPCM @tab X @tab X
d698c5d3 374 @tab Used in Quake III, Jedi Knight 2, other computer games.
16d81b27
DB
375@item Intel Music Coder @tab @tab X
376@item Interplay MVE DPCM @tab @tab X
d698c5d3 377 @tab Used in various Interplay computer games.
16d81b27 378@item MAXIS EA ADPCM @tab @tab X
d698c5d3 379 @tab Used in Sim City 3000.
16d81b27
DB
380@item Microsoft ADPCM @tab X @tab X
381@item MLP/TrueHD @tab @tab X
d698c5d3 382 @tab Used in DVD-Audio and Blu-Ray discs.
16d81b27 383@item Monkey's Audio @tab @tab X
d698c5d3 384 @tab Only versions 3.97-3.99 are supported.
16d81b27 385@item MPEG audio layer 1/3 @tab X @tab IX
360f980b 386 @tab MP3 encoding supported through external library LAME
16d81b27
DB
387@item MPEG audio layer 2 @tab IX @tab IX
388@item MS IMA ADPCM @tab X @tab X
389@item Musepack @tab @tab X
d698c5d3 390 @tab SV7 and SV8 are supported.
755ba886 391@item Nellymoser ASAO @tab X @tab X
16d81b27 392@item Qdesign QDM2 @tab @tab X
d698c5d3 393 @tab There are still some distortions.
16d81b27
DB
394@item QT IMA ADPCM @tab X @tab X
395@item RA144 @tab @tab X
d698c5d3 396 @tab Real 14400 bit/s codec
16d81b27 397@item RA288 @tab @tab X
d698c5d3 398 @tab Real 28800 bit/s codec
575a5bf2 399@item RADnet @tab IX @tab IX
a692130f 400 @tab Real low bitrate AC-3 codec
16d81b27 401@item Real COOK @tab @tab X
d698c5d3 402 @tab All versions except 5.1 are supported.
bac4c85c 403@item Shorten @tab @tab X
16d81b27 404@item Sierra Online DPCM @tab @tab X
d698c5d3 405 @tab Used in Sierra Online game audio files.
bac4c85c 406@item Smacker audio @tab @tab X
16d81b27 407@item SMJPEG IMA ADPCM @tab @tab X
d698c5d3 408 @tab Used in certain Loki game ports.
e6fa1ca5
JR
409@item Sonic @tab X @tab X
410 @tab experimental codec
411@item Sonic lossless @tab X @tab X
412 @tab experimental codec
f6958006 413@item Speex @tab @tab X
360f980b 414 @tab supported through external library libspeex
16d81b27 415@item THP ADPCM @tab @tab X
d698c5d3 416 @tab Used on the Nintendo GameCube.
16d81b27
DB
417@item True Audio (TTA) @tab @tab X
418@item Vorbis @tab X @tab X
bac4c85c 419@item WavPack @tab @tab X
16d81b27 420@item Westwood Studios IMA ADPCM @tab @tab X
d698c5d3 421 @tab Used in Westwood Studios games like Command and Conquer.
bac4c85c 422@item WMA v1/v2 @tab X @tab X
16d81b27 423@item Xan DPCM @tab @tab X
d698c5d3 424 @tab Used in Origin's Wing Commander IV AVI files.
d0e1cd3d
DB
425@end multitable
426
427@code{X} means that encoding (resp. decoding) is supported.
428
429@code{I} means that an integer-only version is available, too (ensures high
430performance on systems without hardware floating point support).
431
432@chapter Platform Specific information
433
434@section BSD
435
436BSD make will not build FFmpeg, you need to install and use GNU Make
437(@file{gmake}).
438
439@section Windows
440
46a845d0 441To get help and instructions for building FFmpeg under Windows, check out
d0e1cd3d 442the FFmpeg Windows Help Forum at
ab5ce4ae 443@url{http://ffmpeg.arrozcru.org/}.
d0e1cd3d
DB
444
445@subsection Native Windows compilation
446
c1989552 447FFmpeg can be built to run natively on Windows using the MinGW tools. Install
126cadc7
RP
448the latest versions of MSYS and MinGW from @url{http://www.mingw.org/}.
449You can find detailed installation
d0e1cd3d
DB
450instructions in the download section and the FAQ.
451
126cadc7
RP
452FFmpeg does not build out-of-the-box with the packages the automated MinGW
453installer provides. It also requires coreutils to be installed and many other
454packages updated to the latest version. The minimum version for some packages
455are listed below:
456
457@itemize
458@item bash 3.1
459@item msys-make 3.81-2 (note: not mingw32-make)
460@item w32api 3.12
461@item mingw-runtime 3.15
462@end itemize
463
0f898714
DB
464You will also need to pass @code{-fno-common} to the compiler to work around
465a GCC bug (see @url{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37216}).
466
c1989552 467Within the MSYS shell, configure and make with:
d0e1cd3d 468
c1989552 469@example
0f898714 470./configure --enable-memalign-hack --extra-cflags=-fno-common
c1989552
RP
471make
472make install
473@end example
d0e1cd3d 474
c1989552
RP
475This will install @file{ffmpeg.exe} along with many other development files
476to @file{/usr/local}. You may specify another install path using the
477@code{--prefix} option in @file{configure}.
d0e1cd3d 478
c1989552 479Notes:
d0e1cd3d 480
c1989552 481@itemize
d0e1cd3d 482
c1989552
RP
483@item In order to compile vhooks, you must have a POSIX-compliant libdl in
484your MinGW system. Get dlfcn-win32 from
485@url{http://code.google.com/p/dlfcn-win32}.
d0e1cd3d 486
c1989552
RP
487@item In order to compile FFplay, you must have the MinGW development library
488of SDL. Get it from @url{http://www.libsdl.org}.
489Edit the @file{bin/sdl-config} script so that it points to the correct prefix
490where SDL was installed. Verify that @file{sdl-config} can be launched from
491the MSYS command line.
d0e1cd3d 492
d0e1cd3d 493@item By using @code{./configure --enable-shared} when configuring FFmpeg,
c1989552 494you can build libavutil, libavcodec and libavformat as DLLs.
d0e1cd3d
DB
495
496@end itemize
497
c1989552 498@subsection Microsoft Visual C++ compatibility
d0e1cd3d 499
c1989552
RP
500As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
501want to use the libav* libraries in your own applications, you can still
502compile those applications using MSVC++. But the libav* libraries you link
503to @emph{must} be built with MinGW. However, you will not be able to debug
504inside the libav* libraries, since MSVC++ does not recognize the debug
505symbols generated by GCC.
506We strongly recommend you to move over from MSVC++ to MinGW tools.
d0e1cd3d 507
c1989552
RP
508This description of how to use the FFmpeg libraries with MSVC++ is based on
509Microsoft Visual C++ 2005 Express Edition. If you have a different version,
510you might have to modify the procedures slightly.
d0e1cd3d 511
c1989552 512@subsubsection Using static libraries
d0e1cd3d 513
c1989552 514Assuming you have just built and installed FFmpeg in @file{/usr/local}.
d0e1cd3d
DB
515
516@enumerate
517
518@item Create a new console application ("File / New / Project") and then
519select "Win32 Console Application". On the appropriate page of the
520Application Wizard, uncheck the "Precompiled headers" option.
521
522@item Write the source code for your application, or, for testing, just
523copy the code from an existing sample application into the source file
c1989552
RP
524that MSVC++ has already created for you. For example, you can copy
525@file{output_example.c} from the FFmpeg distribution.
d0e1cd3d
DB
526
527@item Open the "Project / Properties" dialog box. In the "Configuration"
528combo box, select "All Configurations" so that the changes you make will
529affect both debug and release builds. In the tree view on the left hand
530side, select "C/C++ / General", then edit the "Additional Include
c1989552
RP
531Directories" setting to contain the path where the FFmpeg includes were
532installed (i.e. @file{c:\msys\1.0\local\include}).
f010d377
RP
533Do not add MinGW's include directory here, or the include files will
534conflict with MSVC's.
c1989552
RP
535
536@item Still in the "Project / Properties" dialog box, select
537"Linker / General" from the tree view and edit the
538"Additional Library Directories" setting to contain the @file{lib}
539directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
540the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
541and the directory where MinGW's GCC libs are installed
542(i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
543"Linker / Input" from the tree view, and add the files @file{libavformat.a},
544@file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
545@file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
546to the end of "Additional Dependencies".
d0e1cd3d
DB
547
548@item Now, select "C/C++ / Code Generation" from the tree view. Select
549"Debug" in the "Configuration" combo box. Make sure that "Runtime
550Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
551the "Configuration" combo box and make sure that "Runtime Library" is
552set to "Multi-threaded DLL".
553
c1989552
RP
554@item Click "OK" to close the "Project / Properties" dialog box.
555
556@item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
557Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
558and install it in MSVC++'s include directory
559(i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
560
561@item MSVC++ also does not understand the @code{inline} keyword used by
562FFmpeg, so you must add this line before @code{#include}ing libav*:
563@example
564#define inline _inline
565@end example
566
c1989552
RP
567@item Build your application, everything should work.
568
569@end enumerate
570
571@subsubsection Using shared libraries
572
573This is how to create DLL and LIB files that are compatible with MSVC++:
574
575@enumerate
576
577@item Add a call to @file{vcvars32.bat} (which sets up the environment
578variables for the Visual C++ tools) as the first line of @file{msys.bat}.
579The standard location for @file{vcvars32.bat} is
580@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
581and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
582If this corresponds to your setup, add the following line as the first line
583of @file{msys.bat}:
584
585@example
586call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
587@end example
588
589Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
590and run @file{c:\msys\1.0\msys.bat} from there.
591
592@item Within the MSYS shell, run @code{lib.exe}. If you get a help message
593from @file{Microsoft (R) Library Manager}, this means your environment
594variables are set up correctly, the @file{Microsoft (R) Library Manager}
595is on the path and will be used by FFmpeg to create
596MSVC++-compatible import libraries.
597
598@item Build FFmpeg with
599
600@example
601./configure --enable-shared --enable-memalign-hack
602make
603make install
604@end example
605
606Your install path (@file{/usr/local/} by default) should now have the
607necessary DLL and LIB files under the @file{bin} directory.
d0e1cd3d
DB
608
609@end enumerate
610
c1989552
RP
611To use those files with MSVC++, do the same as you would do with
612the static libraries, as described above. But in Step 4,
613you should only need to add the directory where the LIB files are installed
614(i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
615installed in the @file{bin} directory. And instead of adding @file{libxx.a}
616files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
617@file{avutil.lib}. There should be no need for @file{libmingwex.a},
618@file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
619statically linked into the DLLs. The @file{bin} directory contains a bunch
620of DLL files, but the ones that are actually used to run your application
621are the ones with a major version number in their filenames
622(i.e. @file{avcodec-51.dll}).
623
d0e1cd3d
DB
624@subsection Cross compilation for Windows with Linux
625
626You must use the MinGW cross compilation tools available at
627@url{http://www.mingw.org/}.
628
629Then configure FFmpeg with the following options:
630@example
631./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
632@end example
633(you can change the cross-prefix according to the prefix chosen for the
634MinGW tools).
635
636Then you can easily test FFmpeg with Wine
637(@url{http://www.winehq.com/}).
638
639@subsection Compilation under Cygwin
640
29c3d42b
VP
641The main issue with Cygwin is that newlib, its C library, does not
642contain llrint(). However, it is possible to leverage the
643implementation in MinGW.
d0e1cd3d
DB
644
645Just install your Cygwin with all the "Base" packages, plus the
646following "Devel" ones:
647@example
29c3d42b 648binutils, gcc-core, make, subversion, mingw-runtime
d0e1cd3d
DB
649@end example
650
651Do not install binutils-20060709-1 (they are buggy on shared builds);
652use binutils-20050610-1 instead.
653
29c3d42b
VP
654Then create a small library that just contains llrint():
655
656@example
657ar x /usr/lib/mingw/libmingwex.a llrint.o
658ar cq /usr/local/lib/libllrint.a llrint.o
659@end example
660
d0e1cd3d
DB
661Then run
662
663@example
29c3d42b 664./configure --enable-static --disable-shared --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
d0e1cd3d
DB
665@end example
666
667to make a static build or
668
669@example
29c3d42b 670./configure --enable-shared --disable-static --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
d0e1cd3d
DB
671@end example
672
673to build shared libraries.
674
675If you want to build FFmpeg with additional libraries, download Cygwin
676"Devel" packages for Ogg and Vorbis from any Cygwin packages repository
677and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
678(@url{http://cygwinports.dotsrc.org/}).
679
680@subsection Crosscompilation for Windows under Cygwin
681
682With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
683
684Just install your Cygwin as explained before, plus these additional
685"Devel" packages:
686@example
687gcc-mingw-core, mingw-runtime, mingw-zlib
688@end example
689
690and add some special flags to your configure invocation.
691
692For a static build run
693@example
694./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
695@end example
696
697and for a build with shared libraries
698@example
699./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
700@end example
701
702@section BeOS
703
5f757b85 704BeOS support is broken in mysterious ways.
d0e1cd3d 705
25b92a79
DY
706@section OS/2
707
708For information about compiling FFmpeg on OS/2 see
709@url{http://www.edm2.com/index.php/FFmpeg}.
710
d0e1cd3d
DB
711@chapter Developers Guide
712
713@section API
714@itemize @bullet
715@item libavcodec is the library containing the codecs (both encoding and
716decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
717
718@item libavformat is the library containing the file format handling (mux and
719demux code for several formats). Look at @file{ffplay.c} to use it in a
720player. See @file{output_example.c} to use it to generate audio or video
721streams.
722
723@end itemize
724
725@section Integrating libavcodec or libavformat in your program
726
727You can integrate all the source code of the libraries to link them
728statically to avoid any version problem. All you need is to provide a
729'config.mak' and a 'config.h' in the parent directory. See the defines
730generated by ./configure to understand what is needed.
731
732You can use libavcodec or libavformat in your commercial program, but
733@emph{any patch you make must be published}. The best way to proceed is
734to send your patches to the FFmpeg mailing list.
735
736@node Coding Rules
737@section Coding Rules
738
739FFmpeg is programmed in the ISO C90 language with a few additional
740features from ISO C99, namely:
741@itemize @bullet
742@item
743the @samp{inline} keyword;
744@item
745@samp{//} comments;
746@item
747designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
748@item
749compound literals (@samp{x = (struct s) @{ 17, 23 @};})
750@end itemize
751
752These features are supported by all compilers we care about, so we will not
753accept patches to remove their use unless they absolutely do not impair
754clarity and performance.
755
756All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
757compiles with several other compilers, such as the Compaq ccc compiler
758or Sun Studio 9, and we would like to keep it that way unless it would
759be exceedingly involved. To ensure compatibility, please do not use any
760additional C99 features or GCC extensions. Especially watch out for:
761@itemize @bullet
762@item
763mixing statements and declarations;
764@item
765@samp{long long} (use @samp{int64_t} instead);
766@item
767@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
768@item
769GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
770@end itemize
771
772Indent size is 4.
773The presentation is the one specified by 'indent -i4 -kr -nut'.
774The TAB character is forbidden outside of Makefiles as is any
775form of trailing whitespace. Commits containing either will be
776rejected by the Subversion repository.
777
778The main priority in FFmpeg is simplicity and small code size in order to
779minimize the bug count.
780
781Comments: Use the JavaDoc/Doxygen
782format (see examples below) so that code documentation
783can be generated automatically. All nontrivial functions should have a comment
784above them explaining what the function does, even if it is just one sentence.
785All structures and their member variables should be documented, too.
786@example
787/**
788 * @@file mpeg.c
789 * MPEG codec.
790 * @@author ...
791 */
792
793/**
794 * Summary sentence.
795 * more text ...
796 * ...
797 */
798typedef struct Foobar@{
799 int var1; /**< var1 description */
800 int var2; ///< var2 description
801 /** var3 description */
802 int var3;
803@} Foobar;
804
805/**
806 * Summary sentence.
807 * more text ...
808 * ...
809 * @@param my_parameter description of my_parameter
810 * @@return return value description
811 */
812int myfunc(int my_parameter)
813...
814@end example
815
816fprintf and printf are forbidden in libavformat and libavcodec,
817please use av_log() instead.
818
819Casts should be used only when necessary. Unneeded parentheses
820should also be avoided if they don't make the code easier to understand.
821
822@section Development Policy
823
824@enumerate
825@item
826 Contributions should be licensed under the LGPL 2.1, including an
827 "or any later version" clause, or the MIT license. GPL 2 including
828 an "or any later version" clause is also acceptable, but LGPL is
829 preferred.
830@item
831 You must not commit code which breaks FFmpeg! (Meaning unfinished but
832 enabled code which breaks compilation or compiles but does not work or
833 breaks the regression tests)
834 You can commit unfinished stuff (for testing etc), but it must be disabled
835 (#ifdef etc) by default so it does not interfere with other developers'
836 work.
837@item
838 You do not have to over-test things. If it works for you, and you think it
839 should work for others, then commit. If your code has problems
840 (portability, triggers compiler bugs, unusual environment etc) they will be
841 reported and eventually fixed.
842@item
843 Do not commit unrelated changes together, split them into self-contained
844 pieces. Also do not forget that if part B depends on part A, but A does not
845 depend on B, then A can and should be committed first and separate from B.
846 Keeping changes well split into self-contained parts makes reviewing and
847 understanding them on the commit log mailing list easier. This also helps
848 in case of debugging later on.
849 Also if you have doubts about splitting or not splitting, do not hesitate to
850 ask/discuss it on the developer mailing list.
851@item
852 Do not change behavior of the program (renaming options etc) without
853 first discussing it on the ffmpeg-devel mailing list. Do not remove
854 functionality from the code. Just improve!
855
856 Note: Redundant code can be removed.
857@item
858 Do not commit changes to the build system (Makefiles, configure script)
859 which change behavior, defaults etc, without asking first. The same
860 applies to compiler warning fixes, trivial looking fixes and to code
861 maintained by other developers. We usually have a reason for doing things
862 the way we do. Send your changes as patches to the ffmpeg-devel mailing
863 list, and if the code maintainers say OK, you may commit. This does not
864 apply to files you wrote and/or maintain.
865@item
866 We refuse source indentation and other cosmetic changes if they are mixed
867 with functional changes, such commits will be rejected and removed. Every
868 developer has his own indentation style, you should not change it. Of course
869 if you (re)write something, you can use your own style, even though we would
870 prefer if the indentation throughout FFmpeg was consistent (Many projects
871 force a given indentation style - we do not.). If you really need to make
872 indentation changes (try to avoid this), separate them strictly from real
873 changes.
874
875 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
876 then either do NOT change the indentation of the inner part within (do not
877 move it to the right)! or do so in a separate commit
878@item
879 Always fill out the commit log message. Describe in a few lines what you
880 changed and why. You can refer to mailing list postings if you fix a
881 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
882@item
883 If you apply a patch by someone else, include the name and email address in
884 the log message. Since the ffmpeg-cvslog mailing list is publicly
885 archived you should add some SPAM protection to the email address. Send an
886 answer to ffmpeg-devel (or wherever you got the patch from) saying that
887 you applied the patch.
888@item
889 When applying patches that have been discussed (at length) on the mailing
890 list, reference the thread in the log message.
891@item
892 Do NOT commit to code actively maintained by others without permission.
893 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
894 timeframe (12h for build failures and security fixes, 3 days small changes,
895 1 week for big patches) then commit your patch if you think it is OK.
896 Also note, the maintainer can simply ask for more time to review!
897@item
898 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
899 are sent there and reviewed by all the other developers. Bugs and possible
900 improvements or general questions regarding commits are discussed there. We
901 expect you to react if problems with your code are uncovered.
902@item
903 Update the documentation if you change behavior or add features. If you are
904 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
905 maintainer(s) will review and commit your stuff.
906@item
907 Try to keep important discussions and requests (also) on the public
908 developer mailing list, so that all developers can benefit from them.
909@item
910 Never write to unallocated memory, never write over the end of arrays,
911 always check values read from some untrusted source before using them
912 as array index or other risky things.
913@item
914 Remember to check if you need to bump versions for the specific libav
915 parts (libavutil, libavcodec, libavformat) you are changing. You need
b98052d5 916 to change the version integer.
d0e1cd3d
DB
917 Incrementing the first component means no backward compatibility to
918 previous versions (e.g. removal of a function from the public API).
919 Incrementing the second component means backward compatible change
b98052d5
PR
920 (e.g. addition of a function to the public API or extension of an
921 existing data structure).
d0e1cd3d
DB
922 Incrementing the third component means a noteworthy binary compatible
923 change (e.g. encoder bug fix that matters for the decoder).
924@item
53407b64 925 Compiler warnings indicate potential bugs or code with bad style. If a type of
9908c1a8
DB
926 warning always points to correct and clean code, that warning should
927 be disabled, not the code changed.
928 Thus the remaining warnings can either be bugs or correct code.
beaa4a91 929 If it is a bug, the bug has to be fixed. If it is not, the code should
9908c1a8
DB
930 be changed to not generate a warning unless that causes a slowdown
931 or obfuscates the code.
d0e1cd3d
DB
932@item
933 If you add a new file, give it a proper license header. Do not copy and
934 paste it from a random place, use an existing file as template.
935@end enumerate
936
937We think our rules are not too hard. If you have comments, contact us.
938
939Note, these rules are mostly borrowed from the MPlayer project.
940
941@section Submitting patches
942
943First, (@pxref{Coding Rules}) above if you did not yet.
944
945When you submit your patch, try to send a unified diff (diff '-up'
946option). We cannot read other diffs :-)
947
948Also please do not submit a patch which contains several unrelated changes.
949Split it into separate, self-contained pieces. This does not mean splitting
950file by file. Instead, make the patch as small as possible while still
951keeping it as a logical unit that contains an individual change, even
952if it spans multiple files. This makes reviewing your patches much easier
953for us and greatly increases your chances of getting your patch applied.
954
955Run the regression tests before submitting a patch so that you can
956verify that there are no big problems.
957
958Patches should be posted as base64 encoded attachments (or any other
959encoding which ensures that the patch will not be trashed during
960transmission) to the ffmpeg-devel mailing list, see
961@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
962
963It also helps quite a bit if you tell us what the patch does (for example
964'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
965and has no lrint()')
966
967Also please if you send several patches, send each patch as a separate mail,
968do not attach several unrelated patches to the same mail.
969
28ce1839
RP
970@section New codecs or formats checklist
971
972@enumerate
973@item
974 Did you use av_cold for codec initialization and close functions?
975@item
976 Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
977 AVInputFormat/AVOutputFormat struct?
978@item
979 Did you bump the minor version number in @file{avcodec.h} or
980 @file{avformat.h}?
981@item
982 Did you register it in @file{allcodecs.c} or @file{allformats.c}?
983@item
984 Did you add the CodecID to @file{avcodec.h}?
985@item
986 If it has a fourcc, did you add it to @file{libavformat/riff.c},
987 even if it is only a decoder?
988@item
989 Did you add a rule to compile the appropriate files in the Makefile?
990 Remember to do this even if you're just adding a format to a file that is
991 already being compiled by some other rule, like a raw demuxer.
992@item
993 Did you add an entry to the table of supported formats or codecs in the
994 documentation?
995@item
996 Did you add an entry in the Changelog?
997@item
998 If it depends on a parser or a library, did you add that dependency in
999 configure?
1000@item
1001 Did you "svn add" the appropriate files before commiting?
1002@end enumerate
1003
d0e1cd3d
DB
1004@section patch submission checklist
1005
1006@enumerate
1007@item
1008 Do the regression tests pass with the patch applied?
1009@item
1010 Is the patch a unified diff?
1011@item
1012 Is the patch against latest FFmpeg SVN?
1013@item
1014 Are you subscribed to ffmpeg-dev?
1015 (the list is subscribers only due to spam)
1016@item
1017 Have you checked that the changes are minimal, so that the same cannot be
1018 achieved with a smaller patch and/or simpler final code?
1019@item
1020 If the change is to speed critical code, did you benchmark it?
1021@item
1022 If you did any benchmarks, did you provide them in the mail?
1023@item
1024 Have you checked that the patch does not introduce buffer overflows or
1025 other security issues?
1026@item
b885e0db
MN
1027 If you add a new demuxer or decoder, have you checked that it does not
1028 crash with damaged input (see tools/trasher)?
1029@item
d0e1cd3d
DB
1030 Is the patch created from the root of the source tree, so it can be
1031 applied with @code{patch -p0}?
1032@item
1033 Does the patch not mix functional and cosmetic changes?
1034@item
1035 Did you add tabs or trailing whitespace to the code? Both are forbidden.
1036@item
1037 Is the patch attached to the email you send?
1038@item
1039 Is the mime type of the patch correct? It should be text/x-diff or
1040 text/x-patch or at least text/plain and not application/octet-stream.
1041@item
1042 If the patch fixes a bug, did you provide a verbose analysis of the bug?
1043@item
1044 If the patch fixes a bug, did you provide enough information, including
1045 a sample, so the bug can be reproduced and the fix can be verified?
1046 Note please do not attach samples >100k to mails but rather provide a
1047 URL, you can upload to ftp://upload.mplayerhq.hu
1048@item
1049 Did you provide a verbose summary about what the patch does change?
1050@item
1051 Did you provide a verbose explanation why it changes things like it does?
1052@item
1053 Did you provide a verbose summary of the user visible advantages and
1054 disadvantages if the patch is applied?
1055@item
1056 Did you provide an example so we can verify the new feature added by the
1057 patch easily?
1058@item
1059 If you added a new file, did you insert a license header? It should be
1060 taken from FFmpeg, not randomly copied and pasted from somewhere else.
1061@item
1062 You should maintain alphabetical order in alphabetically ordered lists as
1063 long as doing so does not break API/ABI compatibility.
1064@item
1065 Lines with similar content should be aligned vertically when doing so
1066 improves readability.
1067@item
1068 Did you provide a suggestion for a clear commit log message?
27250d20
MN
1069@item
1070 Did you test your decoder or demuxer against damaged data? If no, see
1071 tools/trasher and the noise bitstream filter. Your decoder or demuxer
fe74278f 1072 should not crash or end in a (near) infinite loop when fed damaged data.
d0e1cd3d
DB
1073@end enumerate
1074
1075@section Patch review process
1076
1077All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1078clear note that the patch is not for SVN.
1079Reviews and comments will be posted as replies to the patch on the
1080mailing list. The patch submitter then has to take care of every comment,
1081that can be by resubmitting a changed patch or by discussion. Resubmitted
1082patches will themselves be reviewed like any other patch. If at some point
1083a patch passes review with no comments then it is approved, that can for
1084simple and small patches happen immediately while large patches will generally
1085have to be changed and reviewed many times before they are approved.
1086After a patch is approved it will be committed to the repository.
1087
1088We will review all submitted patches, but sometimes we are quite busy so
1089especially for large patches this can take several weeks.
1090
1091When resubmitting patches, please do not make any significant changes
1092not related to the comments received during review. Such patches will
1093be rejected. Instead, submit significant changes or new features as
1094separate patches.
1095
1096@section Regression tests
1097
1098Before submitting a patch (or committing to the repository), you should at least
1099test that you did not break anything.
1100
1101The regression tests build a synthetic video stream and a synthetic
1102audio stream. These are then encoded and decoded with all codecs or
1103formats. The CRC (or MD5) of each generated file is recorded in a
1104result file. A 'diff' is launched to compare the reference results and
1105the result file.
1106
1107The regression tests then go on to test the FFserver code with a
1108limited set of streams. It is important that this step runs correctly
1109as well.
1110
1111Run 'make test' to test all the codecs and formats.
1112
1113Run 'make fulltest' to test all the codecs, formats and FFserver.
1114
1115[Of course, some patches may change the results of the regression tests. In
1116this case, the reference results of the regression tests shall be modified
1117accordingly].
1118
1119@bye