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[libav.git] / doc / general.texi
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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
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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.
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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
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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
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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
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45 @tab 4X Technologies format, used in some games.
46@item ADTS AAC audio @tab X @tab X
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47@item American Laser Games MM @tab @tab X
48 @tab Multimedia format used in games like Mad Dog McCree.
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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.
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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.
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65@item CRYO APC @tab @tab X
66 @tab Audio format used in some games by CRYO Interactive Entertainment.
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67@item DV @tab X @tab X
68@item DXA @tab @tab X
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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
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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.
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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.
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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.
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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.
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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.
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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
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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.
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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.
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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 '
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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.
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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
82ced5a9 221@item Dirac @tab E @tab E
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
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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
42b30357 233@item Electronic Arts TGQ @tab @tab X
d66d8b83 234@item FFmpeg Video 1 @tab X @tab X
d698c5d3 235 @tab experimental lossless codec (fourcc: FFV1)
d66d8b83 236@item Flash Screen Video @tab X @tab X
d698c5d3 237 @tab fourcc: FSV1
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238@item FLIC video @tab @tab X
239@item FLV @tab X @tab X
d698c5d3 240 @tab Sorenson H.263 used in Flash
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241@item Fraps FPS1 @tab @tab X
242@item H.261 @tab X @tab X
243@item H.263(+) @tab X @tab X
d698c5d3 244 @tab also known as RealVideo 1.0
82ced5a9 245@item H.264 @tab E @tab X
360f980b 246 @tab encoding supported through external library libx264
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247@item HuffYUV @tab X @tab X
248@item IBM Ultimotion @tab @tab X
d698c5d3 249 @tab fourcc: ULTI
bac4c85c 250@item id Cinematic video @tab @tab X
d698c5d3 251 @tab Used in Quake II.
d66d8b83 252@item id RoQ @tab X @tab X
d698c5d3 253 @tab Used in Quake III, Jedi Knight 2, other computer games.
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254@item Intel Indeo 3 @tab @tab X
255@item Interplay Video @tab @tab X
d698c5d3 256 @tab Used in Interplay .MVE files.
d66d8b83 257@item JPEG-LS @tab X @tab X
d698c5d3 258 @tab fourcc: MJLS, lossless and near-lossless is supported.
d66d8b83 259@item KMVC @tab @tab X
d698c5d3 260 @tab Codec used in Worms games.
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261@item LOCO @tab @tab X
262@item lossless MJPEG @tab X @tab X
263@item Microsoft RLE @tab @tab X
264@item Microsoft Video-1 @tab @tab X
265@item Mimic @tab @tab X
d698c5d3 266 @tab Used in MSN Messenger Webcam streams.
d66d8b83 267@item Miro VideoXL @tab @tab X
d698c5d3 268 @tab fourcc: VIXL
d66d8b83 269@item MJPEG @tab X @tab X
822cc8f7 270@item Motion Pixels Video @tab @tab X
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271@item MPEG-1 @tab X @tab X
272@item MPEG-2 @tab X @tab X
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273@item MPEG-4 @tab X @tab X
274@item MSMPEG4 V1 @tab X @tab X
275@item MSMPEG4 V2 @tab X @tab X
276@item MSMPEG4 V3 @tab X @tab X
d66d8b83 277@item MSZH @tab @tab X
d698c5d3 278 @tab Part of LCL
d66d8b83 279@item On2 VP3 @tab @tab X
d698c5d3 280 @tab still experimental
d66d8b83 281@item On2 VP5 @tab @tab X
d698c5d3 282 @tab fourcc: VP50
d66d8b83 283@item On2 VP6 @tab @tab X
d698c5d3 284 @tab fourcc: VP60,VP61,VP62
d66d8b83 285@item planar RGB @tab @tab X
d698c5d3 286 @tab fourcc: 8BPS
d66d8b83 287@item QPEG @tab @tab X
d698c5d3 288 @tab fourccs: QPEG, Q1.0, Q1.1
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289@item RealVideo 1.0 @tab X @tab X
290@item RealVideo 2.0 @tab X @tab X
11c0f9ec 291@item RealVideo 4.0 @tab @tab X
d66d8b83 292@item Renderware TXD @tab @tab X
d698c5d3 293 @tab Texture dictionaries used by the Renderware Engine.
d66d8b83 294@item RTjpeg @tab @tab X
d698c5d3 295 @tab Video encoding used in NuppelVideo files.
bac4c85c 296@item Smacker video @tab @tab X
d698c5d3 297 @tab Video encoding used in Smacker.
d66d8b83 298@item Snow @tab X @tab X
d698c5d3 299 @tab experimental wavelet codec (fourcc: SNOW)
831ec935 300@item Sony PlayStation MDEC @tab @tab X
d66d8b83 301@item Sorenson Video 1 @tab X @tab X
d698c5d3 302 @tab fourcc: SVQ1
d66d8b83 303@item Sorenson Video 3 @tab @tab X
d698c5d3 304 @tab fourcc: SVQ3
d66d8b83 305@item Sunplus MJPEG @tab @tab X
d698c5d3 306 @tab fourcc: SP5X
d66d8b83 307@item TechSmith Camtasia @tab @tab X
d698c5d3 308 @tab fourcc: TSCC
82ced5a9 309@item Theora @tab E @tab X
360f980b 310 @tab encoding supported through external library libtheora
d66d8b83 311@item THP @tab @tab X
d698c5d3 312 @tab Used on the Nintendo GameCube.
bac4c85c 313@item Tiertex Seq video @tab @tab X
d698c5d3 314 @tab Codec used in DOS CD-ROM FlashBack game.
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315@item VC-1 @tab @tab X
316@item VMD Video @tab @tab X
d698c5d3 317 @tab Used in Sierra VMD files.
d66d8b83 318@item VMware Video @tab @tab X
d698c5d3 319 @tab Codec used in videos captured by VMware.
d0e1cd3d 320@item Westwood VQA @tab @tab X
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321@item Winnov WNV1 @tab @tab X
322@item WMV7 @tab X @tab X
323@item WMV8 @tab X @tab X
324@item WMV9 @tab @tab X
d698c5d3 325 @tab not completely working
d66d8b83 326@item Xan/WC3 @tab @tab X
d698c5d3 327 @tab Used in Wing Commander III .MVE files.
d66d8b83 328@item ZLIB @tab X @tab X
d698c5d3 329 @tab part of LCL, encoder experimental
d66d8b83 330@item ZMBV @tab X @tab X
d698c5d3 331 @tab Encoder works only in PAL8.
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332@end multitable
333
334@code{X} means that encoding (resp. decoding) is supported.
335
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336@code{E} means that support is provided through an external library.
337
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338@section Audio Codecs
339
485ec4f1 340@multitable @columnfractions .4 .1 .1 .4
b3de4544 341@item Name @tab Encoding @tab Decoding @tab Comments
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342@item 4X IMA ADPCM @tab @tab X
343@item 8SVX audio @tab @tab X
82ced5a9 344@item AAC @tab E @tab X
360f980b 345 @tab encoding supported through external library libfaac
16d81b27 346@item AC-3 @tab IX @tab IX
82ced5a9 347@item AMR-NB @tab E @tab E
360f980b 348 @tab supported through external library libamrnb
82ced5a9 349@item AMR-WB @tab E @tab E
360f980b 350 @tab supported through external library libamrwb
16d81b27 351@item AMV IMA ADPCM @tab @tab X
d698c5d3 352 @tab Used in AMV files
833e90dd 353@item Apple lossless audio @tab X @tab X
d698c5d3 354 @tab QuickTime fourcc 'alac'
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355@item Apple MACE 3 @tab @tab X
356@item Apple MACE 6 @tab @tab X
357@item ATRAC 3 @tab @tab X
358@item CD-ROM XA ADPCM @tab @tab X
bac4c85c 359@item Cin audio @tab @tab X
d698c5d3 360 @tab Codec used in Delphine Software International games.
16d81b27 361@item Creative ADPCM @tab @tab X
d698c5d3 362 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
16d81b27 363@item CRI ADX ADPCM @tab X @tab X
d698c5d3 364 @tab Used in Sega Dreamcast games.
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365@item DSP Group TrueSpeech @tab @tab X
366@item DTS Coherent Audio @tab @tab X
367@item Duck DK3 IMA ADPCM @tab @tab X
d698c5d3 368 @tab Used in some Sega Saturn console games.
16d81b27 369@item Duck DK4 IMA ADPCM @tab @tab X
d698c5d3 370 @tab Used in some Sega Saturn console games.
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371@item DV audio @tab @tab X
372@item Electronic Arts ADPCM @tab @tab X
d698c5d3 373 @tab Used in various EA titles.
44723c84 374@item Enhanced AC-3 @tab @tab X
9a584db4 375@item FLAC lossless audio @tab IX @tab X
16d81b27 376@item G.726 ADPCM @tab X @tab X
82ced5a9 377@item GSM @tab E @tab E
3f33271a 378 @tab supported through external library libgsm
82ced5a9 379@item GSM_MS @tab E @tab E
3f33271a 380 @tab supported through external library libgsm
16d81b27 381@item id RoQ DPCM @tab X @tab X
d698c5d3 382 @tab Used in Quake III, Jedi Knight 2, other computer games.
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383@item Intel Music Coder @tab @tab X
384@item Interplay MVE DPCM @tab @tab X
d698c5d3 385 @tab Used in various Interplay computer games.
16d81b27 386@item MAXIS EA ADPCM @tab @tab X
d698c5d3 387 @tab Used in Sim City 3000.
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388@item Microsoft ADPCM @tab X @tab X
389@item MLP/TrueHD @tab @tab X
d698c5d3 390 @tab Used in DVD-Audio and Blu-Ray discs.
16d81b27 391@item Monkey's Audio @tab @tab X
d698c5d3 392 @tab Only versions 3.97-3.99 are supported.
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393@item MPEG audio layer 3 @tab E @tab IX
394 @tab encoding supported through external library LAME
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395@item MPEG audio layer 2 @tab IX @tab IX
396@item MS IMA ADPCM @tab X @tab X
397@item Musepack @tab @tab X
d698c5d3 398 @tab SV7 and SV8 are supported.
755ba886 399@item Nellymoser ASAO @tab X @tab X
73b458e3 400@item QCELP / PureVoice @tab @tab X
16d81b27 401@item Qdesign QDM2 @tab @tab X
d698c5d3 402 @tab There are still some distortions.
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403@item QT IMA ADPCM @tab X @tab X
404@item RA144 @tab @tab X
d698c5d3 405 @tab Real 14400 bit/s codec
16d81b27 406@item RA288 @tab @tab X
d698c5d3 407 @tab Real 28800 bit/s codec
575a5bf2 408@item RADnet @tab IX @tab IX
a692130f 409 @tab Real low bitrate AC-3 codec
16d81b27 410@item Real COOK @tab @tab X
d698c5d3 411 @tab All versions except 5.1 are supported.
bac4c85c 412@item Shorten @tab @tab X
16d81b27 413@item Sierra Online DPCM @tab @tab X
d698c5d3 414 @tab Used in Sierra Online game audio files.
bac4c85c 415@item Smacker audio @tab @tab X
16d81b27 416@item SMJPEG IMA ADPCM @tab @tab X
d698c5d3 417 @tab Used in certain Loki game ports.
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418@item Sonic @tab X @tab X
419 @tab experimental codec
420@item Sonic lossless @tab X @tab X
421 @tab experimental codec
82ced5a9 422@item Speex @tab @tab E
360f980b 423 @tab supported through external library libspeex
16d81b27 424@item THP ADPCM @tab @tab X
d698c5d3 425 @tab Used on the Nintendo GameCube.
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426@item True Audio (TTA) @tab @tab X
427@item Vorbis @tab X @tab X
bac4c85c 428@item WavPack @tab @tab X
16d81b27 429@item Westwood Studios IMA ADPCM @tab @tab X
d698c5d3 430 @tab Used in Westwood Studios games like Command and Conquer.
bac4c85c 431@item WMA v1/v2 @tab X @tab X
16d81b27 432@item Xan DPCM @tab @tab X
d698c5d3 433 @tab Used in Origin's Wing Commander IV AVI files.
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434@end multitable
435
436@code{X} means that encoding (resp. decoding) is supported.
437
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438@code{E} means that support is provided through an external library.
439
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440@code{I} means that an integer-only version is available, too (ensures high
441performance on systems without hardware floating point support).
442
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443@section Subtitle Formats
444
485ec4f1 445@multitable @columnfractions .4 .1 .1 .1 .1 .1
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446@item Name @tab Muxing @tab Demuxing @tab Encoding @tab Decoding @tab Rendering
447@item ASS/SSA @tab X @tab X
448@item DVB @tab X @tab X @tab X @tab X @tab X
449@item DVD @tab X @tab X @tab X @tab X @tab X
450@end multitable
451
452@code{X} means that the feature is supported.
453
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454@chapter Platform Specific information
455
456@section BSD
457
458BSD make will not build FFmpeg, you need to install and use GNU Make
459(@file{gmake}).
460
461@section Windows
462
46a845d0 463To get help and instructions for building FFmpeg under Windows, check out
d0e1cd3d 464the FFmpeg Windows Help Forum at
ab5ce4ae 465@url{http://ffmpeg.arrozcru.org/}.
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466
467@subsection Native Windows compilation
468
c1989552 469FFmpeg can be built to run natively on Windows using the MinGW tools. Install
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470the latest versions of MSYS and MinGW from @url{http://www.mingw.org/}.
471You can find detailed installation
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472instructions in the download section and the FAQ.
473
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474FFmpeg does not build out-of-the-box with the packages the automated MinGW
475installer provides. It also requires coreutils to be installed and many other
476packages updated to the latest version. The minimum version for some packages
477are listed below:
478
479@itemize
480@item bash 3.1
481@item msys-make 3.81-2 (note: not mingw32-make)
2014b51c 482@item w32api 3.13
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483@item mingw-runtime 3.15
484@end itemize
485
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486You will also need to pass @code{-fno-common} to the compiler to work around
487a GCC bug (see @url{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37216}).
488
c1989552 489Within the MSYS shell, configure and make with:
d0e1cd3d 490
c1989552 491@example
0f898714 492./configure --enable-memalign-hack --extra-cflags=-fno-common
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493make
494make install
495@end example
d0e1cd3d 496
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497This will install @file{ffmpeg.exe} along with many other development files
498to @file{/usr/local}. You may specify another install path using the
499@code{--prefix} option in @file{configure}.
d0e1cd3d 500
c1989552 501Notes:
d0e1cd3d 502
c1989552 503@itemize
d0e1cd3d 504
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505@item In order to compile vhooks, you must have a POSIX-compliant libdl in
506your MinGW system. Get dlfcn-win32 from
507@url{http://code.google.com/p/dlfcn-win32}.
d0e1cd3d 508
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509@item In order to compile FFplay, you must have the MinGW development library
510of SDL. Get it from @url{http://www.libsdl.org}.
511Edit the @file{bin/sdl-config} script so that it points to the correct prefix
512where SDL was installed. Verify that @file{sdl-config} can be launched from
513the MSYS command line.
d0e1cd3d 514
d0e1cd3d 515@item By using @code{./configure --enable-shared} when configuring FFmpeg,
c1989552 516you can build libavutil, libavcodec and libavformat as DLLs.
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517
518@end itemize
519
c1989552 520@subsection Microsoft Visual C++ compatibility
d0e1cd3d 521
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522As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
523want to use the libav* libraries in your own applications, you can still
524compile those applications using MSVC++. But the libav* libraries you link
525to @emph{must} be built with MinGW. However, you will not be able to debug
526inside the libav* libraries, since MSVC++ does not recognize the debug
527symbols generated by GCC.
528We strongly recommend you to move over from MSVC++ to MinGW tools.
d0e1cd3d 529
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530This description of how to use the FFmpeg libraries with MSVC++ is based on
531Microsoft Visual C++ 2005 Express Edition. If you have a different version,
532you might have to modify the procedures slightly.
d0e1cd3d 533
c1989552 534@subsubsection Using static libraries
d0e1cd3d 535
c1989552 536Assuming you have just built and installed FFmpeg in @file{/usr/local}.
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537
538@enumerate
539
540@item Create a new console application ("File / New / Project") and then
541select "Win32 Console Application". On the appropriate page of the
542Application Wizard, uncheck the "Precompiled headers" option.
543
544@item Write the source code for your application, or, for testing, just
545copy the code from an existing sample application into the source file
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546that MSVC++ has already created for you. For example, you can copy
547@file{output_example.c} from the FFmpeg distribution.
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548
549@item Open the "Project / Properties" dialog box. In the "Configuration"
550combo box, select "All Configurations" so that the changes you make will
551affect both debug and release builds. In the tree view on the left hand
552side, select "C/C++ / General", then edit the "Additional Include
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553Directories" setting to contain the path where the FFmpeg includes were
554installed (i.e. @file{c:\msys\1.0\local\include}).
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555Do not add MinGW's include directory here, or the include files will
556conflict with MSVC's.
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557
558@item Still in the "Project / Properties" dialog box, select
559"Linker / General" from the tree view and edit the
560"Additional Library Directories" setting to contain the @file{lib}
561directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
562the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
563and the directory where MinGW's GCC libs are installed
564(i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
565"Linker / Input" from the tree view, and add the files @file{libavformat.a},
566@file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
567@file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
568to the end of "Additional Dependencies".
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569
570@item Now, select "C/C++ / Code Generation" from the tree view. Select
571"Debug" in the "Configuration" combo box. Make sure that "Runtime
572Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
573the "Configuration" combo box and make sure that "Runtime Library" is
574set to "Multi-threaded DLL".
575
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576@item Click "OK" to close the "Project / Properties" dialog box.
577
578@item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
579Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
580and install it in MSVC++'s include directory
581(i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
582
583@item MSVC++ also does not understand the @code{inline} keyword used by
584FFmpeg, so you must add this line before @code{#include}ing libav*:
585@example
586#define inline _inline
587@end example
588
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589@item Build your application, everything should work.
590
591@end enumerate
592
593@subsubsection Using shared libraries
594
595This is how to create DLL and LIB files that are compatible with MSVC++:
596
597@enumerate
598
599@item Add a call to @file{vcvars32.bat} (which sets up the environment
600variables for the Visual C++ tools) as the first line of @file{msys.bat}.
601The standard location for @file{vcvars32.bat} is
602@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
603and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
604If this corresponds to your setup, add the following line as the first line
605of @file{msys.bat}:
606
607@example
608call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
609@end example
610
611Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
612and run @file{c:\msys\1.0\msys.bat} from there.
613
614@item Within the MSYS shell, run @code{lib.exe}. If you get a help message
615from @file{Microsoft (R) Library Manager}, this means your environment
616variables are set up correctly, the @file{Microsoft (R) Library Manager}
617is on the path and will be used by FFmpeg to create
618MSVC++-compatible import libraries.
619
620@item Build FFmpeg with
621
622@example
623./configure --enable-shared --enable-memalign-hack
624make
625make install
626@end example
627
628Your install path (@file{/usr/local/} by default) should now have the
629necessary DLL and LIB files under the @file{bin} directory.
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630
631@end enumerate
632
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633To use those files with MSVC++, do the same as you would do with
634the static libraries, as described above. But in Step 4,
635you should only need to add the directory where the LIB files are installed
636(i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
637installed in the @file{bin} directory. And instead of adding @file{libxx.a}
638files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
639@file{avutil.lib}. There should be no need for @file{libmingwex.a},
640@file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
641statically linked into the DLLs. The @file{bin} directory contains a bunch
642of DLL files, but the ones that are actually used to run your application
643are the ones with a major version number in their filenames
644(i.e. @file{avcodec-51.dll}).
645
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646@subsection Cross compilation for Windows with Linux
647
648You must use the MinGW cross compilation tools available at
649@url{http://www.mingw.org/}.
650
651Then configure FFmpeg with the following options:
652@example
653./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
654@end example
655(you can change the cross-prefix according to the prefix chosen for the
656MinGW tools).
657
658Then you can easily test FFmpeg with Wine
659(@url{http://www.winehq.com/}).
660
661@subsection Compilation under Cygwin
662
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663The main issue with Cygwin is that newlib, its C library, does not
664contain llrint(). However, it is possible to leverage the
665implementation in MinGW.
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666
667Just install your Cygwin with all the "Base" packages, plus the
668following "Devel" ones:
669@example
29c3d42b 670binutils, gcc-core, make, subversion, mingw-runtime
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671@end example
672
673Do not install binutils-20060709-1 (they are buggy on shared builds);
674use binutils-20050610-1 instead.
675
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676Then create a small library that just contains llrint():
677
678@example
679ar x /usr/lib/mingw/libmingwex.a llrint.o
680ar cq /usr/local/lib/libllrint.a llrint.o
681@end example
682
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683Then run
684
685@example
29c3d42b 686./configure --enable-static --disable-shared --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
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687@end example
688
689to make a static build or
690
691@example
29c3d42b 692./configure --enable-shared --disable-static --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
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693@end example
694
695to build shared libraries.
696
697If you want to build FFmpeg with additional libraries, download Cygwin
698"Devel" packages for Ogg and Vorbis from any Cygwin packages repository
699and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
700(@url{http://cygwinports.dotsrc.org/}).
701
702@subsection Crosscompilation for Windows under Cygwin
703
704With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
705
706Just install your Cygwin as explained before, plus these additional
707"Devel" packages:
708@example
709gcc-mingw-core, mingw-runtime, mingw-zlib
710@end example
711
712and add some special flags to your configure invocation.
713
714For a static build run
715@example
716./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
717@end example
718
719and for a build with shared libraries
720@example
721./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
722@end example
723
724@section BeOS
725
5f757b85 726BeOS support is broken in mysterious ways.
d0e1cd3d 727
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728@section OS/2
729
730For information about compiling FFmpeg on OS/2 see
731@url{http://www.edm2.com/index.php/FFmpeg}.
732
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733@chapter Developers Guide
734
735@section API
736@itemize @bullet
737@item libavcodec is the library containing the codecs (both encoding and
738decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
739
740@item libavformat is the library containing the file format handling (mux and
741demux code for several formats). Look at @file{ffplay.c} to use it in a
742player. See @file{output_example.c} to use it to generate audio or video
743streams.
744
745@end itemize
746
747@section Integrating libavcodec or libavformat in your program
748
749You can integrate all the source code of the libraries to link them
750statically to avoid any version problem. All you need is to provide a
751'config.mak' and a 'config.h' in the parent directory. See the defines
752generated by ./configure to understand what is needed.
753
754You can use libavcodec or libavformat in your commercial program, but
755@emph{any patch you make must be published}. The best way to proceed is
756to send your patches to the FFmpeg mailing list.
757
758@node Coding Rules
759@section Coding Rules
760
761FFmpeg is programmed in the ISO C90 language with a few additional
762features from ISO C99, namely:
763@itemize @bullet
764@item
765the @samp{inline} keyword;
766@item
767@samp{//} comments;
768@item
769designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
770@item
771compound literals (@samp{x = (struct s) @{ 17, 23 @};})
772@end itemize
773
774These features are supported by all compilers we care about, so we will not
775accept patches to remove their use unless they absolutely do not impair
776clarity and performance.
777
778All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
779compiles with several other compilers, such as the Compaq ccc compiler
780or Sun Studio 9, and we would like to keep it that way unless it would
781be exceedingly involved. To ensure compatibility, please do not use any
782additional C99 features or GCC extensions. Especially watch out for:
783@itemize @bullet
784@item
785mixing statements and declarations;
786@item
787@samp{long long} (use @samp{int64_t} instead);
788@item
789@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
790@item
791GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
792@end itemize
793
794Indent size is 4.
795The presentation is the one specified by 'indent -i4 -kr -nut'.
796The TAB character is forbidden outside of Makefiles as is any
797form of trailing whitespace. Commits containing either will be
798rejected by the Subversion repository.
799
800The main priority in FFmpeg is simplicity and small code size in order to
801minimize the bug count.
802
803Comments: Use the JavaDoc/Doxygen
804format (see examples below) so that code documentation
805can be generated automatically. All nontrivial functions should have a comment
806above them explaining what the function does, even if it is just one sentence.
807All structures and their member variables should be documented, too.
808@example
809/**
810 * @@file mpeg.c
811 * MPEG codec.
812 * @@author ...
813 */
814
815/**
816 * Summary sentence.
817 * more text ...
818 * ...
819 */
820typedef struct Foobar@{
821 int var1; /**< var1 description */
822 int var2; ///< var2 description
823 /** var3 description */
824 int var3;
825@} Foobar;
826
827/**
828 * Summary sentence.
829 * more text ...
830 * ...
831 * @@param my_parameter description of my_parameter
832 * @@return return value description
833 */
834int myfunc(int my_parameter)
835...
836@end example
837
838fprintf and printf are forbidden in libavformat and libavcodec,
839please use av_log() instead.
840
841Casts should be used only when necessary. Unneeded parentheses
842should also be avoided if they don't make the code easier to understand.
843
844@section Development Policy
845
846@enumerate
847@item
848 Contributions should be licensed under the LGPL 2.1, including an
849 "or any later version" clause, or the MIT license. GPL 2 including
850 an "or any later version" clause is also acceptable, but LGPL is
851 preferred.
852@item
853 You must not commit code which breaks FFmpeg! (Meaning unfinished but
854 enabled code which breaks compilation or compiles but does not work or
855 breaks the regression tests)
856 You can commit unfinished stuff (for testing etc), but it must be disabled
857 (#ifdef etc) by default so it does not interfere with other developers'
858 work.
859@item
860 You do not have to over-test things. If it works for you, and you think it
861 should work for others, then commit. If your code has problems
862 (portability, triggers compiler bugs, unusual environment etc) they will be
863 reported and eventually fixed.
864@item
865 Do not commit unrelated changes together, split them into self-contained
866 pieces. Also do not forget that if part B depends on part A, but A does not
867 depend on B, then A can and should be committed first and separate from B.
868 Keeping changes well split into self-contained parts makes reviewing and
869 understanding them on the commit log mailing list easier. This also helps
870 in case of debugging later on.
871 Also if you have doubts about splitting or not splitting, do not hesitate to
872 ask/discuss it on the developer mailing list.
873@item
874 Do not change behavior of the program (renaming options etc) without
875 first discussing it on the ffmpeg-devel mailing list. Do not remove
876 functionality from the code. Just improve!
877
878 Note: Redundant code can be removed.
879@item
880 Do not commit changes to the build system (Makefiles, configure script)
881 which change behavior, defaults etc, without asking first. The same
882 applies to compiler warning fixes, trivial looking fixes and to code
883 maintained by other developers. We usually have a reason for doing things
884 the way we do. Send your changes as patches to the ffmpeg-devel mailing
885 list, and if the code maintainers say OK, you may commit. This does not
886 apply to files you wrote and/or maintain.
887@item
888 We refuse source indentation and other cosmetic changes if they are mixed
889 with functional changes, such commits will be rejected and removed. Every
890 developer has his own indentation style, you should not change it. Of course
891 if you (re)write something, you can use your own style, even though we would
892 prefer if the indentation throughout FFmpeg was consistent (Many projects
893 force a given indentation style - we do not.). If you really need to make
894 indentation changes (try to avoid this), separate them strictly from real
895 changes.
896
897 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
898 then either do NOT change the indentation of the inner part within (do not
899 move it to the right)! or do so in a separate commit
900@item
901 Always fill out the commit log message. Describe in a few lines what you
902 changed and why. You can refer to mailing list postings if you fix a
903 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
904@item
905 If you apply a patch by someone else, include the name and email address in
906 the log message. Since the ffmpeg-cvslog mailing list is publicly
907 archived you should add some SPAM protection to the email address. Send an
908 answer to ffmpeg-devel (or wherever you got the patch from) saying that
909 you applied the patch.
910@item
911 When applying patches that have been discussed (at length) on the mailing
912 list, reference the thread in the log message.
913@item
914 Do NOT commit to code actively maintained by others without permission.
915 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
916 timeframe (12h for build failures and security fixes, 3 days small changes,
917 1 week for big patches) then commit your patch if you think it is OK.
918 Also note, the maintainer can simply ask for more time to review!
919@item
920 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
921 are sent there and reviewed by all the other developers. Bugs and possible
922 improvements or general questions regarding commits are discussed there. We
923 expect you to react if problems with your code are uncovered.
924@item
925 Update the documentation if you change behavior or add features. If you are
926 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
927 maintainer(s) will review and commit your stuff.
928@item
929 Try to keep important discussions and requests (also) on the public
930 developer mailing list, so that all developers can benefit from them.
931@item
932 Never write to unallocated memory, never write over the end of arrays,
933 always check values read from some untrusted source before using them
934 as array index or other risky things.
935@item
936 Remember to check if you need to bump versions for the specific libav
937 parts (libavutil, libavcodec, libavformat) you are changing. You need
b98052d5 938 to change the version integer.
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939 Incrementing the first component means no backward compatibility to
940 previous versions (e.g. removal of a function from the public API).
941 Incrementing the second component means backward compatible change
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942 (e.g. addition of a function to the public API or extension of an
943 existing data structure).
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944 Incrementing the third component means a noteworthy binary compatible
945 change (e.g. encoder bug fix that matters for the decoder).
946@item
53407b64 947 Compiler warnings indicate potential bugs or code with bad style. If a type of
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948 warning always points to correct and clean code, that warning should
949 be disabled, not the code changed.
950 Thus the remaining warnings can either be bugs or correct code.
beaa4a91 951 If it is a bug, the bug has to be fixed. If it is not, the code should
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952 be changed to not generate a warning unless that causes a slowdown
953 or obfuscates the code.
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954@item
955 If you add a new file, give it a proper license header. Do not copy and
956 paste it from a random place, use an existing file as template.
957@end enumerate
958
959We think our rules are not too hard. If you have comments, contact us.
960
961Note, these rules are mostly borrowed from the MPlayer project.
962
963@section Submitting patches
964
965First, (@pxref{Coding Rules}) above if you did not yet.
966
967When you submit your patch, try to send a unified diff (diff '-up'
968option). We cannot read other diffs :-)
969
970Also please do not submit a patch which contains several unrelated changes.
971Split it into separate, self-contained pieces. This does not mean splitting
972file by file. Instead, make the patch as small as possible while still
973keeping it as a logical unit that contains an individual change, even
974if it spans multiple files. This makes reviewing your patches much easier
975for us and greatly increases your chances of getting your patch applied.
976
977Run the regression tests before submitting a patch so that you can
978verify that there are no big problems.
979
980Patches should be posted as base64 encoded attachments (or any other
981encoding which ensures that the patch will not be trashed during
982transmission) to the ffmpeg-devel mailing list, see
983@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
984
985It also helps quite a bit if you tell us what the patch does (for example
986'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
987and has no lrint()')
988
989Also please if you send several patches, send each patch as a separate mail,
990do not attach several unrelated patches to the same mail.
991
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992@section New codecs or formats checklist
993
994@enumerate
995@item
996 Did you use av_cold for codec initialization and close functions?
997@item
998 Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
999 AVInputFormat/AVOutputFormat struct?
1000@item
1001 Did you bump the minor version number in @file{avcodec.h} or
1002 @file{avformat.h}?
1003@item
1004 Did you register it in @file{allcodecs.c} or @file{allformats.c}?
1005@item
1006 Did you add the CodecID to @file{avcodec.h}?
1007@item
1008 If it has a fourcc, did you add it to @file{libavformat/riff.c},
1009 even if it is only a decoder?
1010@item
1011 Did you add a rule to compile the appropriate files in the Makefile?
1012 Remember to do this even if you're just adding a format to a file that is
1013 already being compiled by some other rule, like a raw demuxer.
1014@item
1015 Did you add an entry to the table of supported formats or codecs in the
1016 documentation?
1017@item
1018 Did you add an entry in the Changelog?
1019@item
1020 If it depends on a parser or a library, did you add that dependency in
1021 configure?
1022@item
1023 Did you "svn add" the appropriate files before commiting?
1024@end enumerate
1025
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1026@section patch submission checklist
1027
1028@enumerate
1029@item
1030 Do the regression tests pass with the patch applied?
1031@item
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1032 Does @code{make checkheaders} pass with the patch applied?
1033@item
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1034 Is the patch a unified diff?
1035@item
1036 Is the patch against latest FFmpeg SVN?
1037@item
1038 Are you subscribed to ffmpeg-dev?
1039 (the list is subscribers only due to spam)
1040@item
1041 Have you checked that the changes are minimal, so that the same cannot be
1042 achieved with a smaller patch and/or simpler final code?
1043@item
1044 If the change is to speed critical code, did you benchmark it?
1045@item
1046 If you did any benchmarks, did you provide them in the mail?
1047@item
1048 Have you checked that the patch does not introduce buffer overflows or
1049 other security issues?
1050@item
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1051 Did you test your decoder or demuxer against damaged data? If no, see
1052 tools/trasher and the noise bitstream filter. Your decoder or demuxer
1053 should not crash or end in a (near) infinite loop when fed damaged data.
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1055 Is the patch created from the root of the source tree, so it can be
1056 applied with @code{patch -p0}?
1057@item
1058 Does the patch not mix functional and cosmetic changes?
1059@item
1060 Did you add tabs or trailing whitespace to the code? Both are forbidden.
1061@item
1062 Is the patch attached to the email you send?
1063@item
1064 Is the mime type of the patch correct? It should be text/x-diff or
1065 text/x-patch or at least text/plain and not application/octet-stream.
1066@item
1067 If the patch fixes a bug, did you provide a verbose analysis of the bug?
1068@item
1069 If the patch fixes a bug, did you provide enough information, including
1070 a sample, so the bug can be reproduced and the fix can be verified?
1071 Note please do not attach samples >100k to mails but rather provide a
1072 URL, you can upload to ftp://upload.mplayerhq.hu
1073@item
1074 Did you provide a verbose summary about what the patch does change?
1075@item
1076 Did you provide a verbose explanation why it changes things like it does?
1077@item
1078 Did you provide a verbose summary of the user visible advantages and
1079 disadvantages if the patch is applied?
1080@item
1081 Did you provide an example so we can verify the new feature added by the
1082 patch easily?
1083@item
1084 If you added a new file, did you insert a license header? It should be
1085 taken from FFmpeg, not randomly copied and pasted from somewhere else.
1086@item
1087 You should maintain alphabetical order in alphabetically ordered lists as
1088 long as doing so does not break API/ABI compatibility.
1089@item
1090 Lines with similar content should be aligned vertically when doing so
1091 improves readability.
1092@item
1093 Did you provide a suggestion for a clear commit log message?
1094@end enumerate
1095
1096@section Patch review process
1097
1098All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1099clear note that the patch is not for SVN.
1100Reviews and comments will be posted as replies to the patch on the
1101mailing list. The patch submitter then has to take care of every comment,
1102that can be by resubmitting a changed patch or by discussion. Resubmitted
1103patches will themselves be reviewed like any other patch. If at some point
1104a patch passes review with no comments then it is approved, that can for
1105simple and small patches happen immediately while large patches will generally
1106have to be changed and reviewed many times before they are approved.
1107After a patch is approved it will be committed to the repository.
1108
1109We will review all submitted patches, but sometimes we are quite busy so
1110especially for large patches this can take several weeks.
1111
1112When resubmitting patches, please do not make any significant changes
1113not related to the comments received during review. Such patches will
1114be rejected. Instead, submit significant changes or new features as
1115separate patches.
1116
1117@section Regression tests
1118
1119Before submitting a patch (or committing to the repository), you should at least
1120test that you did not break anything.
1121
1122The regression tests build a synthetic video stream and a synthetic
1123audio stream. These are then encoded and decoded with all codecs or
1124formats. The CRC (or MD5) of each generated file is recorded in a
1125result file. A 'diff' is launched to compare the reference results and
1126the result file.
1127
1128The regression tests then go on to test the FFserver code with a
1129limited set of streams. It is important that this step runs correctly
1130as well.
1131
1132Run 'make test' to test all the codecs and formats.
1133
1134Run 'make fulltest' to test all the codecs, formats and FFserver.
1135
1136[Of course, some patches may change the results of the regression tests. In
1137this case, the reference results of the regression tests shall be modified
1138accordingly].
1139
1140@bye