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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
d66d8b83 291@item Renderware TXD @tab @tab X
d698c5d3 292 @tab Texture dictionaries used by the Renderware Engine.
d66d8b83 293@item RTjpeg @tab @tab X
d698c5d3 294 @tab Video encoding used in NuppelVideo files.
bac4c85c 295@item Smacker video @tab @tab X
d698c5d3 296 @tab Video encoding used in Smacker.
d66d8b83 297@item Snow @tab X @tab X
d698c5d3 298 @tab experimental wavelet codec (fourcc: SNOW)
831ec935 299@item Sony PlayStation MDEC @tab @tab X
d66d8b83 300@item Sorenson Video 1 @tab X @tab X
d698c5d3 301 @tab fourcc: SVQ1
d66d8b83 302@item Sorenson Video 3 @tab @tab X
d698c5d3 303 @tab fourcc: SVQ3
d66d8b83 304@item Sunplus MJPEG @tab @tab X
d698c5d3 305 @tab fourcc: SP5X
d66d8b83 306@item TechSmith Camtasia @tab @tab X
d698c5d3 307 @tab fourcc: TSCC
82ced5a9 308@item Theora @tab E @tab X
360f980b 309 @tab encoding supported through external library libtheora
d66d8b83 310@item THP @tab @tab X
d698c5d3 311 @tab Used on the Nintendo GameCube.
bac4c85c 312@item Tiertex Seq video @tab @tab X
d698c5d3 313 @tab Codec used in DOS CD-ROM FlashBack game.
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314@item VC-1 @tab @tab X
315@item VMD Video @tab @tab X
d698c5d3 316 @tab Used in Sierra VMD files.
d66d8b83 317@item VMware Video @tab @tab X
d698c5d3 318 @tab Codec used in videos captured by VMware.
d0e1cd3d 319@item Westwood VQA @tab @tab X
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320@item Winnov WNV1 @tab @tab X
321@item WMV7 @tab X @tab X
322@item WMV8 @tab X @tab X
323@item WMV9 @tab @tab X
d698c5d3 324 @tab not completely working
d66d8b83 325@item Xan/WC3 @tab @tab X
d698c5d3 326 @tab Used in Wing Commander III .MVE files.
d66d8b83 327@item ZLIB @tab X @tab X
d698c5d3 328 @tab part of LCL, encoder experimental
d66d8b83 329@item ZMBV @tab X @tab X
d698c5d3 330 @tab Encoder works only in PAL8.
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331@end multitable
332
333@code{X} means that encoding (resp. decoding) is supported.
334
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335@code{E} means that support is provided through an external library.
336
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337@section Audio Codecs
338
485ec4f1 339@multitable @columnfractions .4 .1 .1 .4
b3de4544 340@item Name @tab Encoding @tab Decoding @tab Comments
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341@item 4X IMA ADPCM @tab @tab X
342@item 8SVX audio @tab @tab X
82ced5a9 343@item AAC @tab E @tab X
360f980b 344 @tab encoding supported through external library libfaac
16d81b27 345@item AC-3 @tab IX @tab IX
82ced5a9 346@item AMR-NB @tab E @tab E
360f980b 347 @tab supported through external library libamrnb
82ced5a9 348@item AMR-WB @tab E @tab E
360f980b 349 @tab supported through external library libamrwb
16d81b27 350@item AMV IMA ADPCM @tab @tab X
d698c5d3 351 @tab Used in AMV files
833e90dd 352@item Apple lossless audio @tab X @tab X
d698c5d3 353 @tab QuickTime fourcc 'alac'
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354@item Apple MACE 3 @tab @tab X
355@item Apple MACE 6 @tab @tab X
356@item ATRAC 3 @tab @tab X
357@item CD-ROM XA ADPCM @tab @tab X
bac4c85c 358@item Cin audio @tab @tab X
d698c5d3 359 @tab Codec used in Delphine Software International games.
16d81b27 360@item Creative ADPCM @tab @tab X
d698c5d3 361 @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
16d81b27 362@item CRI ADX ADPCM @tab X @tab X
d698c5d3 363 @tab Used in Sega Dreamcast games.
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364@item DSP Group TrueSpeech @tab @tab X
365@item DTS Coherent Audio @tab @tab X
366@item Duck DK3 IMA ADPCM @tab @tab X
d698c5d3 367 @tab Used in some Sega Saturn console games.
16d81b27 368@item Duck DK4 IMA ADPCM @tab @tab X
d698c5d3 369 @tab Used in some Sega Saturn console games.
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370@item DV audio @tab @tab X
371@item Electronic Arts ADPCM @tab @tab X
d698c5d3 372 @tab Used in various EA titles.
44723c84 373@item Enhanced AC-3 @tab @tab X
9a584db4 374@item FLAC lossless audio @tab IX @tab X
16d81b27 375@item G.726 ADPCM @tab X @tab X
82ced5a9 376@item GSM @tab E @tab E
3f33271a 377 @tab supported through external library libgsm
82ced5a9 378@item GSM_MS @tab E @tab E
3f33271a 379 @tab supported through external library libgsm
16d81b27 380@item id RoQ DPCM @tab X @tab X
d698c5d3 381 @tab Used in Quake III, Jedi Knight 2, other computer games.
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382@item Intel Music Coder @tab @tab X
383@item Interplay MVE DPCM @tab @tab X
d698c5d3 384 @tab Used in various Interplay computer games.
16d81b27 385@item MAXIS EA ADPCM @tab @tab X
d698c5d3 386 @tab Used in Sim City 3000.
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387@item Microsoft ADPCM @tab X @tab X
388@item MLP/TrueHD @tab @tab X
d698c5d3 389 @tab Used in DVD-Audio and Blu-Ray discs.
16d81b27 390@item Monkey's Audio @tab @tab X
d698c5d3 391 @tab Only versions 3.97-3.99 are supported.
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392@item MPEG audio layer 3 @tab E @tab IX
393 @tab encoding supported through external library LAME
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394@item MPEG audio layer 2 @tab IX @tab IX
395@item MS IMA ADPCM @tab X @tab X
396@item Musepack @tab @tab X
d698c5d3 397 @tab SV7 and SV8 are supported.
755ba886 398@item Nellymoser ASAO @tab X @tab X
16d81b27 399@item Qdesign QDM2 @tab @tab X
d698c5d3 400 @tab There are still some distortions.
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401@item QT IMA ADPCM @tab X @tab X
402@item RA144 @tab @tab X
d698c5d3 403 @tab Real 14400 bit/s codec
16d81b27 404@item RA288 @tab @tab X
d698c5d3 405 @tab Real 28800 bit/s codec
575a5bf2 406@item RADnet @tab IX @tab IX
a692130f 407 @tab Real low bitrate AC-3 codec
16d81b27 408@item Real COOK @tab @tab X
d698c5d3 409 @tab All versions except 5.1 are supported.
bac4c85c 410@item Shorten @tab @tab X
16d81b27 411@item Sierra Online DPCM @tab @tab X
d698c5d3 412 @tab Used in Sierra Online game audio files.
bac4c85c 413@item Smacker audio @tab @tab X
16d81b27 414@item SMJPEG IMA ADPCM @tab @tab X
d698c5d3 415 @tab Used in certain Loki game ports.
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416@item Sonic @tab X @tab X
417 @tab experimental codec
418@item Sonic lossless @tab X @tab X
419 @tab experimental codec
82ced5a9 420@item Speex @tab @tab E
360f980b 421 @tab supported through external library libspeex
16d81b27 422@item THP ADPCM @tab @tab X
d698c5d3 423 @tab Used on the Nintendo GameCube.
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424@item True Audio (TTA) @tab @tab X
425@item Vorbis @tab X @tab X
bac4c85c 426@item WavPack @tab @tab X
16d81b27 427@item Westwood Studios IMA ADPCM @tab @tab X
d698c5d3 428 @tab Used in Westwood Studios games like Command and Conquer.
bac4c85c 429@item WMA v1/v2 @tab X @tab X
16d81b27 430@item Xan DPCM @tab @tab X
d698c5d3 431 @tab Used in Origin's Wing Commander IV AVI files.
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432@end multitable
433
434@code{X} means that encoding (resp. decoding) is supported.
435
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436@code{E} means that support is provided through an external library.
437
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438@code{I} means that an integer-only version is available, too (ensures high
439performance on systems without hardware floating point support).
440
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441@section Subtitle Formats
442
485ec4f1 443@multitable @columnfractions .4 .1 .1 .1 .1 .1
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444@item Name @tab Muxing @tab Demuxing @tab Encoding @tab Decoding @tab Rendering
445@item ASS/SSA @tab X @tab X
446@item DVB @tab X @tab X @tab X @tab X @tab X
447@item DVD @tab X @tab X @tab X @tab X @tab X
448@end multitable
449
450@code{X} means that the feature is supported.
451
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452@chapter Platform Specific information
453
454@section BSD
455
456BSD make will not build FFmpeg, you need to install and use GNU Make
457(@file{gmake}).
458
459@section Windows
460
46a845d0 461To get help and instructions for building FFmpeg under Windows, check out
d0e1cd3d 462the FFmpeg Windows Help Forum at
ab5ce4ae 463@url{http://ffmpeg.arrozcru.org/}.
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464
465@subsection Native Windows compilation
466
c1989552 467FFmpeg can be built to run natively on Windows using the MinGW tools. Install
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468the latest versions of MSYS and MinGW from @url{http://www.mingw.org/}.
469You can find detailed installation
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470instructions in the download section and the FAQ.
471
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472FFmpeg does not build out-of-the-box with the packages the automated MinGW
473installer provides. It also requires coreutils to be installed and many other
474packages updated to the latest version. The minimum version for some packages
475are listed below:
476
477@itemize
478@item bash 3.1
479@item msys-make 3.81-2 (note: not mingw32-make)
480@item w32api 3.12
481@item mingw-runtime 3.15
482@end itemize
483
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484You will also need to pass @code{-fno-common} to the compiler to work around
485a GCC bug (see @url{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37216}).
486
c1989552 487Within the MSYS shell, configure and make with:
d0e1cd3d 488
c1989552 489@example
0f898714 490./configure --enable-memalign-hack --extra-cflags=-fno-common
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491make
492make install
493@end example
d0e1cd3d 494
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495This will install @file{ffmpeg.exe} along with many other development files
496to @file{/usr/local}. You may specify another install path using the
497@code{--prefix} option in @file{configure}.
d0e1cd3d 498
c1989552 499Notes:
d0e1cd3d 500
c1989552 501@itemize
d0e1cd3d 502
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503@item In order to compile vhooks, you must have a POSIX-compliant libdl in
504your MinGW system. Get dlfcn-win32 from
505@url{http://code.google.com/p/dlfcn-win32}.
d0e1cd3d 506
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507@item In order to compile FFplay, you must have the MinGW development library
508of SDL. Get it from @url{http://www.libsdl.org}.
509Edit the @file{bin/sdl-config} script so that it points to the correct prefix
510where SDL was installed. Verify that @file{sdl-config} can be launched from
511the MSYS command line.
d0e1cd3d 512
d0e1cd3d 513@item By using @code{./configure --enable-shared} when configuring FFmpeg,
c1989552 514you can build libavutil, libavcodec and libavformat as DLLs.
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515
516@end itemize
517
c1989552 518@subsection Microsoft Visual C++ compatibility
d0e1cd3d 519
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520As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
521want to use the libav* libraries in your own applications, you can still
522compile those applications using MSVC++. But the libav* libraries you link
523to @emph{must} be built with MinGW. However, you will not be able to debug
524inside the libav* libraries, since MSVC++ does not recognize the debug
525symbols generated by GCC.
526We strongly recommend you to move over from MSVC++ to MinGW tools.
d0e1cd3d 527
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528This description of how to use the FFmpeg libraries with MSVC++ is based on
529Microsoft Visual C++ 2005 Express Edition. If you have a different version,
530you might have to modify the procedures slightly.
d0e1cd3d 531
c1989552 532@subsubsection Using static libraries
d0e1cd3d 533
c1989552 534Assuming you have just built and installed FFmpeg in @file{/usr/local}.
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535
536@enumerate
537
538@item Create a new console application ("File / New / Project") and then
539select "Win32 Console Application". On the appropriate page of the
540Application Wizard, uncheck the "Precompiled headers" option.
541
542@item Write the source code for your application, or, for testing, just
543copy the code from an existing sample application into the source file
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544that MSVC++ has already created for you. For example, you can copy
545@file{output_example.c} from the FFmpeg distribution.
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546
547@item Open the "Project / Properties" dialog box. In the "Configuration"
548combo box, select "All Configurations" so that the changes you make will
549affect both debug and release builds. In the tree view on the left hand
550side, select "C/C++ / General", then edit the "Additional Include
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551Directories" setting to contain the path where the FFmpeg includes were
552installed (i.e. @file{c:\msys\1.0\local\include}).
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553Do not add MinGW's include directory here, or the include files will
554conflict with MSVC's.
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555
556@item Still in the "Project / Properties" dialog box, select
557"Linker / General" from the tree view and edit the
558"Additional Library Directories" setting to contain the @file{lib}
559directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
560the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
561and the directory where MinGW's GCC libs are installed
562(i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
563"Linker / Input" from the tree view, and add the files @file{libavformat.a},
564@file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
565@file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
566to the end of "Additional Dependencies".
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567
568@item Now, select "C/C++ / Code Generation" from the tree view. Select
569"Debug" in the "Configuration" combo box. Make sure that "Runtime
570Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
571the "Configuration" combo box and make sure that "Runtime Library" is
572set to "Multi-threaded DLL".
573
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574@item Click "OK" to close the "Project / Properties" dialog box.
575
576@item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
577Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
578and install it in MSVC++'s include directory
579(i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
580
581@item MSVC++ also does not understand the @code{inline} keyword used by
582FFmpeg, so you must add this line before @code{#include}ing libav*:
583@example
584#define inline _inline
585@end example
586
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587@item Build your application, everything should work.
588
589@end enumerate
590
591@subsubsection Using shared libraries
592
593This is how to create DLL and LIB files that are compatible with MSVC++:
594
595@enumerate
596
597@item Add a call to @file{vcvars32.bat} (which sets up the environment
598variables for the Visual C++ tools) as the first line of @file{msys.bat}.
599The standard location for @file{vcvars32.bat} is
600@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
601and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
602If this corresponds to your setup, add the following line as the first line
603of @file{msys.bat}:
604
605@example
606call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
607@end example
608
609Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
610and run @file{c:\msys\1.0\msys.bat} from there.
611
612@item Within the MSYS shell, run @code{lib.exe}. If you get a help message
613from @file{Microsoft (R) Library Manager}, this means your environment
614variables are set up correctly, the @file{Microsoft (R) Library Manager}
615is on the path and will be used by FFmpeg to create
616MSVC++-compatible import libraries.
617
618@item Build FFmpeg with
619
620@example
621./configure --enable-shared --enable-memalign-hack
622make
623make install
624@end example
625
626Your install path (@file{/usr/local/} by default) should now have the
627necessary DLL and LIB files under the @file{bin} directory.
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628
629@end enumerate
630
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631To use those files with MSVC++, do the same as you would do with
632the static libraries, as described above. But in Step 4,
633you should only need to add the directory where the LIB files are installed
634(i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
635installed in the @file{bin} directory. And instead of adding @file{libxx.a}
636files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
637@file{avutil.lib}. There should be no need for @file{libmingwex.a},
638@file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
639statically linked into the DLLs. The @file{bin} directory contains a bunch
640of DLL files, but the ones that are actually used to run your application
641are the ones with a major version number in their filenames
642(i.e. @file{avcodec-51.dll}).
643
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644@subsection Cross compilation for Windows with Linux
645
646You must use the MinGW cross compilation tools available at
647@url{http://www.mingw.org/}.
648
649Then configure FFmpeg with the following options:
650@example
651./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
652@end example
653(you can change the cross-prefix according to the prefix chosen for the
654MinGW tools).
655
656Then you can easily test FFmpeg with Wine
657(@url{http://www.winehq.com/}).
658
659@subsection Compilation under Cygwin
660
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661The main issue with Cygwin is that newlib, its C library, does not
662contain llrint(). However, it is possible to leverage the
663implementation in MinGW.
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664
665Just install your Cygwin with all the "Base" packages, plus the
666following "Devel" ones:
667@example
29c3d42b 668binutils, gcc-core, make, subversion, mingw-runtime
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669@end example
670
671Do not install binutils-20060709-1 (they are buggy on shared builds);
672use binutils-20050610-1 instead.
673
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674Then create a small library that just contains llrint():
675
676@example
677ar x /usr/lib/mingw/libmingwex.a llrint.o
678ar cq /usr/local/lib/libllrint.a llrint.o
679@end example
680
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681Then run
682
683@example
29c3d42b 684./configure --enable-static --disable-shared --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
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685@end example
686
687to make a static build or
688
689@example
29c3d42b 690./configure --enable-shared --disable-static --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
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691@end example
692
693to build shared libraries.
694
695If you want to build FFmpeg with additional libraries, download Cygwin
696"Devel" packages for Ogg and Vorbis from any Cygwin packages repository
697and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
698(@url{http://cygwinports.dotsrc.org/}).
699
700@subsection Crosscompilation for Windows under Cygwin
701
702With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
703
704Just install your Cygwin as explained before, plus these additional
705"Devel" packages:
706@example
707gcc-mingw-core, mingw-runtime, mingw-zlib
708@end example
709
710and add some special flags to your configure invocation.
711
712For a static build run
713@example
714./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
715@end example
716
717and for a build with shared libraries
718@example
719./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
720@end example
721
722@section BeOS
723
5f757b85 724BeOS support is broken in mysterious ways.
d0e1cd3d 725
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726@section OS/2
727
728For information about compiling FFmpeg on OS/2 see
729@url{http://www.edm2.com/index.php/FFmpeg}.
730
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731@chapter Developers Guide
732
733@section API
734@itemize @bullet
735@item libavcodec is the library containing the codecs (both encoding and
736decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
737
738@item libavformat is the library containing the file format handling (mux and
739demux code for several formats). Look at @file{ffplay.c} to use it in a
740player. See @file{output_example.c} to use it to generate audio or video
741streams.
742
743@end itemize
744
745@section Integrating libavcodec or libavformat in your program
746
747You can integrate all the source code of the libraries to link them
748statically to avoid any version problem. All you need is to provide a
749'config.mak' and a 'config.h' in the parent directory. See the defines
750generated by ./configure to understand what is needed.
751
752You can use libavcodec or libavformat in your commercial program, but
753@emph{any patch you make must be published}. The best way to proceed is
754to send your patches to the FFmpeg mailing list.
755
756@node Coding Rules
757@section Coding Rules
758
759FFmpeg is programmed in the ISO C90 language with a few additional
760features from ISO C99, namely:
761@itemize @bullet
762@item
763the @samp{inline} keyword;
764@item
765@samp{//} comments;
766@item
767designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
768@item
769compound literals (@samp{x = (struct s) @{ 17, 23 @};})
770@end itemize
771
772These features are supported by all compilers we care about, so we will not
773accept patches to remove their use unless they absolutely do not impair
774clarity and performance.
775
776All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
777compiles with several other compilers, such as the Compaq ccc compiler
778or Sun Studio 9, and we would like to keep it that way unless it would
779be exceedingly involved. To ensure compatibility, please do not use any
780additional C99 features or GCC extensions. Especially watch out for:
781@itemize @bullet
782@item
783mixing statements and declarations;
784@item
785@samp{long long} (use @samp{int64_t} instead);
786@item
787@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
788@item
789GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
790@end itemize
791
792Indent size is 4.
793The presentation is the one specified by 'indent -i4 -kr -nut'.
794The TAB character is forbidden outside of Makefiles as is any
795form of trailing whitespace. Commits containing either will be
796rejected by the Subversion repository.
797
798The main priority in FFmpeg is simplicity and small code size in order to
799minimize the bug count.
800
801Comments: Use the JavaDoc/Doxygen
802format (see examples below) so that code documentation
803can be generated automatically. All nontrivial functions should have a comment
804above them explaining what the function does, even if it is just one sentence.
805All structures and their member variables should be documented, too.
806@example
807/**
808 * @@file mpeg.c
809 * MPEG codec.
810 * @@author ...
811 */
812
813/**
814 * Summary sentence.
815 * more text ...
816 * ...
817 */
818typedef struct Foobar@{
819 int var1; /**< var1 description */
820 int var2; ///< var2 description
821 /** var3 description */
822 int var3;
823@} Foobar;
824
825/**
826 * Summary sentence.
827 * more text ...
828 * ...
829 * @@param my_parameter description of my_parameter
830 * @@return return value description
831 */
832int myfunc(int my_parameter)
833...
834@end example
835
836fprintf and printf are forbidden in libavformat and libavcodec,
837please use av_log() instead.
838
839Casts should be used only when necessary. Unneeded parentheses
840should also be avoided if they don't make the code easier to understand.
841
842@section Development Policy
843
844@enumerate
845@item
846 Contributions should be licensed under the LGPL 2.1, including an
847 "or any later version" clause, or the MIT license. GPL 2 including
848 an "or any later version" clause is also acceptable, but LGPL is
849 preferred.
850@item
851 You must not commit code which breaks FFmpeg! (Meaning unfinished but
852 enabled code which breaks compilation or compiles but does not work or
853 breaks the regression tests)
854 You can commit unfinished stuff (for testing etc), but it must be disabled
855 (#ifdef etc) by default so it does not interfere with other developers'
856 work.
857@item
858 You do not have to over-test things. If it works for you, and you think it
859 should work for others, then commit. If your code has problems
860 (portability, triggers compiler bugs, unusual environment etc) they will be
861 reported and eventually fixed.
862@item
863 Do not commit unrelated changes together, split them into self-contained
864 pieces. Also do not forget that if part B depends on part A, but A does not
865 depend on B, then A can and should be committed first and separate from B.
866 Keeping changes well split into self-contained parts makes reviewing and
867 understanding them on the commit log mailing list easier. This also helps
868 in case of debugging later on.
869 Also if you have doubts about splitting or not splitting, do not hesitate to
870 ask/discuss it on the developer mailing list.
871@item
872 Do not change behavior of the program (renaming options etc) without
873 first discussing it on the ffmpeg-devel mailing list. Do not remove
874 functionality from the code. Just improve!
875
876 Note: Redundant code can be removed.
877@item
878 Do not commit changes to the build system (Makefiles, configure script)
879 which change behavior, defaults etc, without asking first. The same
880 applies to compiler warning fixes, trivial looking fixes and to code
881 maintained by other developers. We usually have a reason for doing things
882 the way we do. Send your changes as patches to the ffmpeg-devel mailing
883 list, and if the code maintainers say OK, you may commit. This does not
884 apply to files you wrote and/or maintain.
885@item
886 We refuse source indentation and other cosmetic changes if they are mixed
887 with functional changes, such commits will be rejected and removed. Every
888 developer has his own indentation style, you should not change it. Of course
889 if you (re)write something, you can use your own style, even though we would
890 prefer if the indentation throughout FFmpeg was consistent (Many projects
891 force a given indentation style - we do not.). If you really need to make
892 indentation changes (try to avoid this), separate them strictly from real
893 changes.
894
895 NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
896 then either do NOT change the indentation of the inner part within (do not
897 move it to the right)! or do so in a separate commit
898@item
899 Always fill out the commit log message. Describe in a few lines what you
900 changed and why. You can refer to mailing list postings if you fix a
901 particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
902@item
903 If you apply a patch by someone else, include the name and email address in
904 the log message. Since the ffmpeg-cvslog mailing list is publicly
905 archived you should add some SPAM protection to the email address. Send an
906 answer to ffmpeg-devel (or wherever you got the patch from) saying that
907 you applied the patch.
908@item
909 When applying patches that have been discussed (at length) on the mailing
910 list, reference the thread in the log message.
911@item
912 Do NOT commit to code actively maintained by others without permission.
913 Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
914 timeframe (12h for build failures and security fixes, 3 days small changes,
915 1 week for big patches) then commit your patch if you think it is OK.
916 Also note, the maintainer can simply ask for more time to review!
917@item
918 Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
919 are sent there and reviewed by all the other developers. Bugs and possible
920 improvements or general questions regarding commits are discussed there. We
921 expect you to react if problems with your code are uncovered.
922@item
923 Update the documentation if you change behavior or add features. If you are
924 unsure how best to do this, send a patch to ffmpeg-devel, the documentation
925 maintainer(s) will review and commit your stuff.
926@item
927 Try to keep important discussions and requests (also) on the public
928 developer mailing list, so that all developers can benefit from them.
929@item
930 Never write to unallocated memory, never write over the end of arrays,
931 always check values read from some untrusted source before using them
932 as array index or other risky things.
933@item
934 Remember to check if you need to bump versions for the specific libav
935 parts (libavutil, libavcodec, libavformat) you are changing. You need
b98052d5 936 to change the version integer.
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937 Incrementing the first component means no backward compatibility to
938 previous versions (e.g. removal of a function from the public API).
939 Incrementing the second component means backward compatible change
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940 (e.g. addition of a function to the public API or extension of an
941 existing data structure).
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942 Incrementing the third component means a noteworthy binary compatible
943 change (e.g. encoder bug fix that matters for the decoder).
944@item
53407b64 945 Compiler warnings indicate potential bugs or code with bad style. If a type of
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946 warning always points to correct and clean code, that warning should
947 be disabled, not the code changed.
948 Thus the remaining warnings can either be bugs or correct code.
beaa4a91 949 If it is a bug, the bug has to be fixed. If it is not, the code should
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950 be changed to not generate a warning unless that causes a slowdown
951 or obfuscates the code.
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952@item
953 If you add a new file, give it a proper license header. Do not copy and
954 paste it from a random place, use an existing file as template.
955@end enumerate
956
957We think our rules are not too hard. If you have comments, contact us.
958
959Note, these rules are mostly borrowed from the MPlayer project.
960
961@section Submitting patches
962
963First, (@pxref{Coding Rules}) above if you did not yet.
964
965When you submit your patch, try to send a unified diff (diff '-up'
966option). We cannot read other diffs :-)
967
968Also please do not submit a patch which contains several unrelated changes.
969Split it into separate, self-contained pieces. This does not mean splitting
970file by file. Instead, make the patch as small as possible while still
971keeping it as a logical unit that contains an individual change, even
972if it spans multiple files. This makes reviewing your patches much easier
973for us and greatly increases your chances of getting your patch applied.
974
975Run the regression tests before submitting a patch so that you can
976verify that there are no big problems.
977
978Patches should be posted as base64 encoded attachments (or any other
979encoding which ensures that the patch will not be trashed during
980transmission) to the ffmpeg-devel mailing list, see
981@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
982
983It also helps quite a bit if you tell us what the patch does (for example
984'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
985and has no lrint()')
986
987Also please if you send several patches, send each patch as a separate mail,
988do not attach several unrelated patches to the same mail.
989
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990@section New codecs or formats checklist
991
992@enumerate
993@item
994 Did you use av_cold for codec initialization and close functions?
995@item
996 Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
997 AVInputFormat/AVOutputFormat struct?
998@item
999 Did you bump the minor version number in @file{avcodec.h} or
1000 @file{avformat.h}?
1001@item
1002 Did you register it in @file{allcodecs.c} or @file{allformats.c}?
1003@item
1004 Did you add the CodecID to @file{avcodec.h}?
1005@item
1006 If it has a fourcc, did you add it to @file{libavformat/riff.c},
1007 even if it is only a decoder?
1008@item
1009 Did you add a rule to compile the appropriate files in the Makefile?
1010 Remember to do this even if you're just adding a format to a file that is
1011 already being compiled by some other rule, like a raw demuxer.
1012@item
1013 Did you add an entry to the table of supported formats or codecs in the
1014 documentation?
1015@item
1016 Did you add an entry in the Changelog?
1017@item
1018 If it depends on a parser or a library, did you add that dependency in
1019 configure?
1020@item
1021 Did you "svn add" the appropriate files before commiting?
1022@end enumerate
1023
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1024@section patch submission checklist
1025
1026@enumerate
1027@item
1028 Do the regression tests pass with the patch applied?
1029@item
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1030 Does @code{make checkheaders} pass with the patch applied?
1031@item
d0e1cd3d
DB
1032 Is the patch a unified diff?
1033@item
1034 Is the patch against latest FFmpeg SVN?
1035@item
1036 Are you subscribed to ffmpeg-dev?
1037 (the list is subscribers only due to spam)
1038@item
1039 Have you checked that the changes are minimal, so that the same cannot be
1040 achieved with a smaller patch and/or simpler final code?
1041@item
1042 If the change is to speed critical code, did you benchmark it?
1043@item
1044 If you did any benchmarks, did you provide them in the mail?
1045@item
1046 Have you checked that the patch does not introduce buffer overflows or
1047 other security issues?
1048@item
63d247ea
DB
1049 Did you test your decoder or demuxer against damaged data? If no, see
1050 tools/trasher and the noise bitstream filter. Your decoder or demuxer
1051 should not crash or end in a (near) infinite loop when fed damaged data.
b885e0db 1052@item
d0e1cd3d
DB
1053 Is the patch created from the root of the source tree, so it can be
1054 applied with @code{patch -p0}?
1055@item
1056 Does the patch not mix functional and cosmetic changes?
1057@item
1058 Did you add tabs or trailing whitespace to the code? Both are forbidden.
1059@item
1060 Is the patch attached to the email you send?
1061@item
1062 Is the mime type of the patch correct? It should be text/x-diff or
1063 text/x-patch or at least text/plain and not application/octet-stream.
1064@item
1065 If the patch fixes a bug, did you provide a verbose analysis of the bug?
1066@item
1067 If the patch fixes a bug, did you provide enough information, including
1068 a sample, so the bug can be reproduced and the fix can be verified?
1069 Note please do not attach samples >100k to mails but rather provide a
1070 URL, you can upload to ftp://upload.mplayerhq.hu
1071@item
1072 Did you provide a verbose summary about what the patch does change?
1073@item
1074 Did you provide a verbose explanation why it changes things like it does?
1075@item
1076 Did you provide a verbose summary of the user visible advantages and
1077 disadvantages if the patch is applied?
1078@item
1079 Did you provide an example so we can verify the new feature added by the
1080 patch easily?
1081@item
1082 If you added a new file, did you insert a license header? It should be
1083 taken from FFmpeg, not randomly copied and pasted from somewhere else.
1084@item
1085 You should maintain alphabetical order in alphabetically ordered lists as
1086 long as doing so does not break API/ABI compatibility.
1087@item
1088 Lines with similar content should be aligned vertically when doing so
1089 improves readability.
1090@item
1091 Did you provide a suggestion for a clear commit log message?
1092@end enumerate
1093
1094@section Patch review process
1095
1096All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1097clear note that the patch is not for SVN.
1098Reviews and comments will be posted as replies to the patch on the
1099mailing list. The patch submitter then has to take care of every comment,
1100that can be by resubmitting a changed patch or by discussion. Resubmitted
1101patches will themselves be reviewed like any other patch. If at some point
1102a patch passes review with no comments then it is approved, that can for
1103simple and small patches happen immediately while large patches will generally
1104have to be changed and reviewed many times before they are approved.
1105After a patch is approved it will be committed to the repository.
1106
1107We will review all submitted patches, but sometimes we are quite busy so
1108especially for large patches this can take several weeks.
1109
1110When resubmitting patches, please do not make any significant changes
1111not related to the comments received during review. Such patches will
1112be rejected. Instead, submit significant changes or new features as
1113separate patches.
1114
1115@section Regression tests
1116
1117Before submitting a patch (or committing to the repository), you should at least
1118test that you did not break anything.
1119
1120The regression tests build a synthetic video stream and a synthetic
1121audio stream. These are then encoded and decoded with all codecs or
1122formats. The CRC (or MD5) of each generated file is recorded in a
1123result file. A 'diff' is launched to compare the reference results and
1124the result file.
1125
1126The regression tests then go on to test the FFserver code with a
1127limited set of streams. It is important that this step runs correctly
1128as well.
1129
1130Run 'make test' to test all the codecs and formats.
1131
1132Run 'make fulltest' to test all the codecs, formats and FFserver.
1133
1134[Of course, some patches may change the results of the regression tests. In
1135this case, the reference results of the regression tests shall be modified
1136accordingly].
1137
1138@bye