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
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 (libamr) as well as
22the OpenCORE libraries for AMR-NB decoding/encoding and AMR-WB decoding.
23
24@subsection OpenCORE
25
26Go to @url{http://gitorious.org/opencore-amr/} and follow the instructions for
27installing the libraries. Then pass @code{--enable-libopencore-amrnb} and/or
28@code{--enable-libopencore-amrwb} to configure to enable the libraries.
29
30Note that OpenCORE is under the Apache License 2.0 (see
31@url{http://www.apache.org/licenses/LICENSE-2.0} for details), which is
32incompatible with the LGPL version 2.1 and GPL version 2. You have to
33upgrade FFmpeg's license to LGPL version 3 (or if you have enabled
34GPL components, GPL version 3) to use it.
35
36@subsection libamr
37
38Go to @url{http://www.penguin.cz/~utx/amr} and follow the instructions for
39installing the libraries. Then pass @code{--enable-libamr-nb} and/or
40@code{--enable-libamr-wb} to configure to enable the libraries.
41
42Note that libamr is copyrighted without any sort of license grant. This means
43that you can use it if you legally obtained it but you are not allowed to
44redistribute it in any way. @strong{Any FFmpeg binaries with libamr support
45you create are non-free and unredistributable!}
46
47
48@chapter Supported File Formats and Codecs
49
50You can use the @code{-formats} option to have an exhaustive list.
51
52@section File Formats
53
54FFmpeg supports the following file formats through the @code{libavformat}
55library:
56
57@multitable @columnfractions .4 .1 .1 .4
58@item Name @tab Encoding @tab Decoding @tab Comments
59@item 4xm                       @tab   @tab X
60    @tab 4X Technologies format, used in some games.
61@item Audio IFF (AIFF)          @tab X @tab X
62@item American Laser Games MM   @tab   @tab X
63    @tab Multimedia format used in games like Mad Dog McCree.
64@item 3GPP AMR                  @tab X @tab X
65@item ASF                       @tab X @tab X
66@item AVI                       @tab X @tab X
67@item AVISynth                  @tab   @tab X
68@item AVS                       @tab   @tab X
69    @tab Multimedia format used by the Creature Shock game.
70@item Beam Software SIFF        @tab   @tab X
71    @tab Audio and video format used in some games by Beam Software.
72@item Bethesda Softworks VID    @tab   @tab X
73    @tab Used in some games from Bethesda Softworks.
74@item Brute Force & Ignorance   @tab   @tab X
75    @tab Used in the game Flash Traffic: City of Angels.
76@item Interplay C93             @tab   @tab X
77    @tab Used in the game Cyberia from Interplay.
78@item Delphine Software International CIN @tab   @tab X
79    @tab Multimedia format used by Delphine Software games.
80@item CRC testing format        @tab X @tab
81@item Creative Voice            @tab X @tab X
82    @tab Created for the Sound Blaster Pro.
83@item CRYO APC                  @tab   @tab X
84    @tab Audio format used in some games by CRYO Interactive Entertainment.
85@item D-Cinema audio            @tab X @tab X
86@item DV video                  @tab X @tab X
87@item DXA                       @tab   @tab X
88    @tab This format is used in the non-Windows version of the Feeble Files
89         game and different game cutscenes repacked for use with ScummVM.
90@item Electronic Arts cdata  @tab    @tab X
91@item Electronic Arts Multimedia  @tab    @tab X
92    @tab Used in various EA games; files have extensions like WVE and UV2.
93@item FFM (FFserver live feed)  @tab X @tab X
94@item Flash (SWF)               @tab X @tab X
95@item Flash 9 (AVM2)            @tab X @tab X
96    @tab Only embedded audio is decoded.
97@item FLI/FLC/FLX animation     @tab   @tab X
98    @tab .fli/.flc files
99@item Flash Video (FLV)         @tab   @tab X
100    @tab Macromedia Flash video files
101@item framecrc testing format   @tab X @tab
102@item FunCom ISS                @tab   @tab X
103    @tab Audio format used in various games from FunCom like The Longest Journey.
104@item GIF Animation             @tab X @tab
105@item GXF                       @tab X @tab X
106    @tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley
107         playout servers.
108@item id Quake II CIN video     @tab   @tab X
109@item id RoQ                    @tab X @tab X
110    @tab Used in Quake III, Jedi Knight 2, other computer games.
111@item IFF                       @tab   @tab X
112    @tab Interchange File Format
113@item Interplay MVE             @tab   @tab X
114    @tab Format used in various Interplay computer games.
115@item LMLM4                     @tab   @tab X
116    @tab Used by Linux Media Labs MPEG-4 PCI boards
117@item Matroska                  @tab X @tab X
118@item Matroska audio            @tab X @tab
119@item MAXIS XA                  @tab   @tab X
120    @tab Used in Sim City 3000; file extension .xa.
121@item Monkey's Audio            @tab   @tab X
122@item Motion Pixels MVI         @tab   @tab X
123@item MOV/QuickTime/MP4         @tab X @tab X
124    @tab 3GP, 3GP2, PSP, iPod variants supported
125@item MP2                       @tab X @tab X
126@item MP3                       @tab X @tab X
127@item MPEG-1 System             @tab X @tab X
128    @tab muxed audio and video, VCD format supported
129@item MPEG-PS (program stream)  @tab X @tab X
130    @tab also known as @code{VOB} file, SVCD and DVD format supported
131@item MPEG-TS (transport stream) @tab X @tab X
132    @tab also known as DVB Transport Stream
133@item MPEG-4                    @tab X @tab X
134    @tab MPEG-4 is a variant of QuickTime.
135@item MIME multipart JPEG       @tab X @tab
136@item MSN TCP webcam            @tab   @tab X
137    @tab Used by MSN Messenger webcam streams.
138@item MTV                       @tab   @tab X
139@item Musepack                  @tab   @tab X
140@item Musepack SV8              @tab   @tab X
141@item Material eXchange Format (MXF) @tab X @tab X
142    @tab SMPTE 377M, used by D-Cinema, broadcast industry.
143@item Material eXchange Format (MXF), D-10 Mapping @tab X @tab X
144    @tab SMPTE 386M, D-10/IMX Mapping.
145@item NC camera feed            @tab   @tab X
146    @tab NC (AVIP NC4600) camera streams
147@item Nullsoft Streaming Video  @tab   @tab X
148@item NuppelVideo               @tab   @tab X
149@item NUT                       @tab X @tab X
150    @tab NUT Open Container Format
151@item Ogg                       @tab X @tab X
152@item TechnoTrend PVA           @tab   @tab X
153    @tab Used by TechnoTrend DVB PCI boards.
154@item raw ADTS (AAC)            @tab X @tab X
155@item raw AC-3                  @tab X @tab X
156@item raw Chinese AVS video     @tab   @tab X
157@item raw CRI ADX               @tab X @tab X
158@item raw Dirac                 @tab X @tab X
159@item raw DNxHD                 @tab X @tab X
160@item raw DTS                   @tab X @tab X
161@item raw E-AC-3                @tab X @tab X
162@item raw FLAC                  @tab X @tab X
163@item raw GSM                   @tab   @tab X
164@item raw H.261                 @tab X @tab X
165@item raw H.263                 @tab X @tab X
166@item raw H.264                 @tab X @tab X
167@item raw Ingenient MJPEG       @tab   @tab X
168@item raw MJPEG                 @tab X @tab X
169@item raw MLP                   @tab   @tab X
170@item raw MPEG                  @tab   @tab X
171@item raw MPEG-1                @tab   @tab X
172@item raw MPEG-2                @tab   @tab X
173@item raw MPEG-4                @tab X @tab X
174@item raw NULL                  @tab X @tab
175@item raw video                 @tab X @tab X
176@item raw id RoQ                @tab X @tab
177@item raw Shorten               @tab   @tab X
178@item raw VC-1                  @tab   @tab X
179@item raw PCM A-law             @tab X @tab X
180@item raw PCM mu-law            @tab X @tab X
181@item raw PCM signed 8 bit      @tab X @tab X
182@item raw PCM signed 16 bit big-endian  @tab X @tab X
183@item raw PCM signed 16 bit little-endian  @tab X @tab X
184@item raw PCM signed 24 bit big-endian  @tab X @tab X
185@item raw PCM signed 24 bit little-endian  @tab X @tab X
186@item raw PCM signed 32 bit big-endian  @tab X @tab X
187@item raw PCM signed 32 bit little-endian  @tab X @tab X
188@item raw PCM unsigned 8 bit    @tab X @tab X
189@item raw PCM unsigned 16 bit big-endian  @tab X @tab X
190@item raw PCM unsigned 16 bit little-endian  @tab X @tab X
191@item raw PCM unsigned 24 bit big-endian  @tab X @tab X
192@item raw PCM unsigned 24 bit little-endian  @tab X @tab X
193@item raw PCM unsigned 32 bit big-endian  @tab X @tab X
194@item raw PCM unsigned 32 bit little-endian  @tab X @tab X
195@item raw PCM floating-point 32 bit big-endian  @tab X @tab X
196@item raw PCM floating-point 32 bit little-endian  @tab X @tab X
197@item raw PCM floating-point 64 bit big-endian  @tab X @tab X
198@item raw PCM floating-point 64 bit little-endian  @tab X @tab X
199@item RDT                       @tab   @tab X
200@item REDCODE R3D               @tab   @tab X
201    @tab File format used by RED Digital cameras, contains JPEG 2000 frames and PCM audio.
202@item RealMedia                 @tab X @tab X
203@item Redirector                @tab   @tab X
204@item Renderware TeXture Dictionary @tab   @tab X
205@item RL2                       @tab   @tab X
206    @tab Audio and video format used in some games by Entertainment Software Partners.
207@item RPL/ARMovie               @tab   @tab X
208@item RTP                       @tab   @tab X
209@item RTSP                      @tab   @tab X
210@item SDP                       @tab   @tab X
211@item Sega FILM/CPK             @tab   @tab X
212    @tab Used in many Sega Saturn console games.
213@item Sierra SOL                @tab   @tab X
214    @tab .sol files used in Sierra Online games.
215@item Sierra VMD                @tab   @tab X
216    @tab Used in Sierra CD-ROM games.
217@item Smacker                   @tab   @tab X
218    @tab Multimedia format used by many games.
219@item Sony OpenMG (OMA)         @tab   @tab X
220    @tab Audio format used in Sony Sonic Stage and Sony Vegas.
221@item Sony PlayStation STR      @tab   @tab X
222@item SUN AU format             @tab X @tab X
223@item THP                       @tab   @tab X
224    @tab Used on the Nintendo GameCube.
225@item Tiertex Limited SEQ       @tab   @tab X
226    @tab Tiertex .seq files used in the DOS CD-ROM version of the game Flashback.
227@item True Audio                @tab   @tab X
228@item VC-1 test bitstream       @tab X @tab X
229@item WAV                       @tab X @tab X
230@item WavPack                   @tab   @tab X
231@item Wing Commander III movie  @tab   @tab X
232    @tab Multimedia format used in Origin's Wing Commander III computer game.
233@item Westwood Studios audio    @tab   @tab X
234    @tab Multimedia format used in Westwood Studios games.
235@item Westwood Studios VQA      @tab   @tab X
236    @tab Multimedia format used in Westwood Studios games.
237@item YUV4MPEG pipe             @tab X @tab X
238@end multitable
239
240@code{X} means that encoding (resp. decoding) is supported.
241
242@section Image Formats
243
244FFmpeg can read and write images for each frame of a video sequence. The
245following image formats are supported:
246
247@multitable @columnfractions .4 .1 .1 .4
248@item Name @tab Encoding @tab Decoding @tab Comments
249@item .Y.U.V       @tab X @tab X
250    @tab one raw file per component
251@item animated GIF @tab X @tab X
252    @tab Only uncompressed GIFs are generated.
253@item BMP          @tab X @tab X
254    @tab Microsoft BMP image
255@item JPEG         @tab X @tab X
256    @tab Progressive JPEG is not supported.
257@item JPEG 2000    @tab   @tab E
258    @tab decoding supported through external library libopenjpeg
259@item JPEG-LS      @tab X @tab X
260@item LJPEG        @tab X @tab
261    @tab Lossless JPEG
262@item PAM          @tab X @tab X
263    @tab PAM is a PNM extension with alpha support.
264@item PBM          @tab X @tab X
265    @tab Portable BitMap image
266@item PCX          @tab   @tab X
267    @tab PC Paintbrush
268@item PGM          @tab X @tab X
269    @tab Portable GrayMap image
270@item PGMYUV       @tab X @tab X
271    @tab PGM with U and V components in YUV 4:2:0
272@item PNG          @tab X @tab X
273    @tab 2/4 bpp not supported yet
274@item PPM          @tab X @tab X
275    @tab Portable PixelMap image
276@item PTX          @tab   @tab X
277    @tab V.Flash PTX format
278@item SGI          @tab X @tab X
279    @tab SGI RGB image format
280@item Sun Rasterfile  @tab   @tab X
281    @tab Sun RAS image format
282@item TIFF         @tab X @tab X
283    @tab YUV, JPEG and some extension is not supported yet.
284@item Truevision Targa  @tab X @tab X
285    @tab Targa (.TGA) image format
286@end multitable
287
288@code{X} means that encoding (resp. decoding) is supported.
289
290@code{E} means that support is provided through an external library.
291
292@section Video Codecs
293
294@multitable @columnfractions .4 .1 .1 .4
295@item Name @tab Encoding @tab Decoding @tab Comments
296@item 4X Movie               @tab     @tab  X
297    @tab Used in certain computer games.
298@item 8SVX exponential       @tab     @tab  X
299@item 8SVX fibonacci         @tab     @tab  X
300@item American Laser Games MM  @tab    @tab X
301    @tab Used in games like Mad Dog McCree.
302@item AMV Video              @tab     @tab  X
303    @tab Used in Chinese MP3 players.
304@item Apple MJPEG-B          @tab     @tab  X
305@item Apple QuickDraw        @tab     @tab  X
306    @tab fourcc: qdrw
307@item Asus v1                @tab  X  @tab  X
308    @tab fourcc: ASV1
309@item Asus v2                @tab  X  @tab  X
310    @tab fourcc: ASV2
311@item ATI VCR1               @tab     @tab  X
312    @tab fourcc: VCR1
313@item ATI VCR2               @tab     @tab  X
314    @tab fourcc: VCR2
315@item Autodesk Animator Flic video  @tab     @tab  X
316@item Autodesk RLE           @tab     @tab  X
317    @tab fourcc: AASC
318@item AVS (Audio Video Standard) video  @tab     @tab  X
319    @tab Video encoding used by the Creature Shock game.
320@item Beam Software VB       @tab     @tab  X
321@item Bethesda VID video     @tab     @tab  X
322    @tab Used in some games from Bethesda Softworks.
323@item Brute Force & Ignorance   @tab   @tab X
324    @tab Used in the game Flash Traffic: City of Angels.
325@item C93 video              @tab     @tab  X
326    @tab Codec used in Cyberia game.
327@item CamStudio              @tab     @tab  X
328    @tab fourcc: CSCD
329@item Chinese AVS video      @tab     @tab  X
330    @tab AVS1-P2, JiZhun profile
331@item Delphine Software International CIN video  @tab     @tab  X
332    @tab Codec used in Delphine Software International games.
333@item Cinepak                @tab     @tab  X
334@item Cirrus Logic AccuPak   @tab     @tab  X
335    @tab fourcc: CLJR
336@item Creative YUV (CYUV)    @tab     @tab  X
337@item Dirac                  @tab  E  @tab  E
338    @tab supported through external libdirac/libschroedinger libraries
339@item DNxHD                  @tab   X @tab  X
340    @tab aka SMPTE VC3
341@item Duck TrueMotion 1.0   @tab     @tab  X
342    @tab fourcc: DUCK
343@item Duck TrueMotion 2.0    @tab     @tab  X
344    @tab fourcc: TM20
345@item DV (Digital Video)     @tab  X  @tab  X
346@item Feeble Files/ScummVM DXA  @tab     @tab  X
347    @tab Codec originally used in Feeble Files game.
348@item Electronic Arts CMV video  @tab     @tab  X
349    @tab Used in NHL 95 game.
350@item Electronic Arts TGV video  @tab     @tab  X
351@item Electronic Arts TGQ video  @tab     @tab  X
352@item Electronic Arts TQI video  @tab     @tab  X
353@item Escape 124             @tab     @tab  X
354@item FFmpeg codec #1        @tab  X  @tab  X
355    @tab experimental lossless codec (fourcc: FFV1)
356@item Flash Screen Video v1  @tab  X  @tab  X
357    @tab fourcc: FSV1
358@item Flash Video (FLV)      @tab  X  @tab  X
359    @tab Sorenson H.263 used in Flash
360@item Fraps                  @tab     @tab  X
361@item H.261                  @tab  X  @tab  X
362@item H.263 / H.263-1996     @tab  X  @tab  X
363@item H.263+ / H.263-1998 / H.263 version 2  @tab  X  @tab  X
364@item H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10  @tab  E  @tab  X
365    @tab encoding supported through external library libx264
366@item H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (VDPAU acceleration)  @tab  E  @tab  X
367@item HuffYUV                @tab  X  @tab  X
368@item HuffYUV FFmpeg variant @tab  X  @tab  X
369@item IBM Ultimotion         @tab     @tab  X
370    @tab fourcc: ULTI
371@item id Cinematic video     @tab     @tab  X
372    @tab Used in Quake II.
373@item id RoQ video           @tab  X  @tab  X
374    @tab Used in Quake III, Jedi Knight 2, other computer games.
375@item Intel H.263            @tab     @tab  X
376@item Intel Indeo 2          @tab     @tab  X
377@item Intel Indeo 3          @tab     @tab  X
378@item Interplay C93          @tab     @tab  X
379    @tab Used in the game Cyberia from Interplay.
380@item Interplay MVE video    @tab     @tab  X
381    @tab Used in Interplay .MVE files.
382@item Karl Morton's video codec  @tab     @tab  X
383    @tab Codec used in Worms games.
384@item LCL (LossLess Codec Library) MSZH  @tab     @tab  X
385@item LCL (LossLess Codec Library) ZLIB  @tab  E  @tab  E
386@item LOCO                   @tab     @tab  X
387@item lossless MJPEG         @tab  X  @tab  X
388@item Microsoft RLE          @tab     @tab  X
389@item Microsoft Video 1      @tab     @tab  X
390@item Mimic                  @tab     @tab  X
391    @tab Used in MSN Messenger Webcam streams.
392@item Miro VideoXL           @tab     @tab  X
393    @tab fourcc: VIXL
394@item MJPEG (Motion JPEG)    @tab  X  @tab  X
395@item Motion Pixels video    @tab     @tab  X
396@item MPEG-1 video           @tab  X  @tab  X
397@item MPEG-1/2 video XvMC (X-Video Motion Compensation)  @tab     @tab  X
398@item MPEG-1/2 video (VDPAU acceleration)  @tab     @tab  X
399@item MPEG-2 video           @tab  X  @tab  X
400@item MPEG-4 part 2          @tab  X  @tab  X
401    @ libxvidcore can be used alternatively for encoding.
402@item MPEG-4 part 2 Microsoft variant version 1  @tab  X  @tab  X
403@item MPEG-4 part 2 Microsoft variant version 2  @tab  X  @tab  X
404@item MPEG-4 part 2 Microsoft variant version 3  @tab  X  @tab  X
405@item Nintendo Gamecube THP video  @tab     @tab  X
406@item NuppelVideo/RTjpeg     @tab     @tab  X
407    @tab Video encoding used in NuppelVideo files.
408@item On2 VP3                @tab     @tab  X
409    @tab still experimental
410@item On2 VP5                @tab     @tab  X
411    @tab fourcc: VP50
412@item On2 VP6                @tab     @tab  X
413    @tab fourcc: VP60,VP61,VP62
414@item planar RGB             @tab     @tab  X
415    @tab fourcc: 8BPS
416@item Q-team QPEG            @tab     @tab  X
417    @tab fourccs: QPEG, Q1.0, Q1.1
418@item QuickTime 8BPS video   @tab     @tab  X
419@item QuickTime Animation (RLE) video  @tab  X  @tab  X
420    @tab fourcc: 'rle '
421@item QuickTime Graphics (SMC)  @tab     @tab  X
422    @tab fourcc: 'smc '
423@item QuickTime video (RPZA) @tab     @tab  X
424    @tab fourcc: rpza
425@item Raw Video              @tab  X  @tab  X
426@item RealVideo 1.0          @tab  X  @tab  X
427@item RealVideo 2.0          @tab  X  @tab  X
428@item RealVideo 3.0          @tab     @tab  X
429    @tab still far from ideal
430@item RealVideo 4.0          @tab     @tab  X
431@item Renderware TXD (TeXture Dictionary)  @tab     @tab  X
432    @tab Texture dictionaries used by the Renderware Engine.
433@item RL2 video              @tab     @tab  X
434    @tab used in some games by Entertainment Software Partners
435@item Sierra VMD video       @tab     @tab  X
436    @tab Used in Sierra VMD files.
437@item Smacker video          @tab     @tab  X
438    @tab Video encoding used in Smacker.
439@item SMPTE VC-1             @tab     @tab  X
440@item Snow                   @tab  X  @tab  X
441    @tab experimental wavelet codec (fourcc: SNOW)
442@item Sony PlayStation MDEC (Motion DECoder)  @tab     @tab  X
443@item Sorenson Vector Quantizer 1  @tab  X  @tab  X
444    @tab fourcc: SVQ1
445@item Sorenson Vector Quantizer 3  @tab     @tab  X
446    @tab fourcc: SVQ3
447@item Sunplus JPEG (SP5X)    @tab     @tab  X
448    @tab fourcc: SP5X
449@item TechSmith Screen Capture Codec  @tab     @tab  X
450    @tab fourcc: TSCC
451@item Theora                 @tab  E  @tab  X
452    @tab encoding supported through external library libtheora
453@item Tiertex Limited SEQ video  @tab     @tab  X
454    @tab Codec used in DOS CD-ROM FlashBack game.
455@item VMware Screen Codec / VMware Video  @tab     @tab  X
456    @tab Codec used in videos captured by VMware.
457@item Westwood Studios VQA (Vector Quantized Animation) video  @tab     @tab  X
458@item Windows Media Video 7  @tab  X  @tab  X
459@item Windows Media Video 8  @tab  X  @tab  X
460@item Windows Media Video 9  @tab     @tab  X
461    @tab not completely working
462@item Wing Commander III / Xan  @tab     @tab  X
463    @tab Used in Wing Commander III .MVE files.
464@item Winnov WNV1            @tab     @tab  X
465@item WMV7                   @tab  X  @tab  X
466@item YAMAHA SMAF            @tab  X  @tab  X
467@item ZLIB                   @tab  X  @tab  X
468    @tab part of LCL, encoder experimental
469@item Zip Motion Blocks Video  @tab   X @tab  X
470    @tab Encoder works only in PAL8.
471@end multitable
472
473@code{X} means that encoding (resp. decoding) is supported.
474
475@code{E} means that support is provided through an external library.
476
477@section Audio Codecs
478
479@multitable @columnfractions .4 .1 .1 .4
480@item Name @tab Encoding @tab Decoding @tab Comments
481@item 8SVX audio             @tab     @tab  X
482@item AAC                    @tab  E  @tab  X
483    @tab encoding supported through external library libfaac
484@item AC-3                   @tab IX  @tab  X
485@item ADPCM 4X Movie         @tab     @tab  X
486@item ADPCM CDROM XA         @tab     @tab  X
487@item ADPCM Creative Technology @tab     @tab  X
488    @tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
489@item ADPCM Electronic Arts  @tab     @tab  X
490    @tab Used in various EA titles.
491@item ADPCM Electronic Arts Maxis CDROM XS  @tab     @tab  X
492    @tab Used in Sim City 3000.
493@item ADPCM Electronic Arts R1  @tab     @tab  X
494@item ADPCM Electronic Arts R2  @tab     @tab  X
495@item ADPCM Electronic Arts R3  @tab     @tab  X
496@item ADPCM Electronic Arts XAS @tab     @tab  X
497@item ADPCM G.726            @tab  X  @tab  X
498@item ADPCM IMA AMV          @tab     @tab  X
499    @tab Used in AMV files
500@item ADPCM IMA Electronic Arts EACS  @tab     @tab  X
501@item ADPCM IMA Electronic Arts SEAD  @tab     @tab  X
502@item ADPCM IMA Funcom       @tab     @tab  X
503@item ADPCM IMA QuickTime    @tab  X  @tab  X
504@item ADPCM IMA Loki SDL MJPEG  @tab     @tab  X
505@item ADPCM IMA WAV          @tab  X  @tab  X
506@item ADPCM IMA Westwood     @tab     @tab  X
507@item ADPCM ISS IMA          @tab     @tab  X
508    @tab Used in FunCom games.
509@item ADPCM IMA Duck DK3     @tab     @tab  X
510    @tab Used in some Sega Saturn console games.
511@item ADPCM IMA Duck DK4     @tab     @tab  X
512    @tab Used in some Sega Saturn console games.
513@item ADPCM Microsoft        @tab  X  @tab  X
514@item ADPCM MS IMA           @tab  X  @tab  X
515@item ADPCM Nintendo Gamecube THP  @tab     @tab  X
516@item ADPCM QT IMA           @tab  X  @tab  X
517@item ADPCM SEGA CRI ADX     @tab  X  @tab  X
518    @tab Used in Sega Dreamcast games.
519@item ADPCM Shockwave Flash  @tab  X  @tab  X
520@item ADPCM SMJPEG IMA       @tab     @tab  X
521    @tab Used in certain Loki game ports.
522@item ADPCM Sound Blaster Pro 2-bit  @tab     @tab  X
523@item ADPCM Sound Blaster Pro 2.6-bit  @tab     @tab  X
524@item ADPCM Sound Blaster Pro 4-bit  @tab     @tab  X
525@item ADPCM Westwood Studios IMA @tab     @tab  X
526    @tab Used in Westwood Studios games like Command and Conquer.
527@item ADPCM Yamaha           @tab  X  @tab  X
528@item AMR-NB                 @tab  E  @tab  E
529    @tab supported through external libraries libamrnb and libopencore-amrnb
530@item AMR-WB                 @tab  E  @tab  E
531    @tab decoding supported through external libraries libamrwb and libopencore-amrwb,
532         encoding supported through external library libamrwb
533@item Apple lossless audio   @tab  X  @tab  X
534    @tab QuickTime fourcc 'alac'
535@item Atrac 3                @tab     @tab  X
536@item Delphine Software International CIN audio  @tab     @tab  X
537    @tab Codec used in Delphine Software International games.
538@item COOK                   @tab     @tab  X
539    @tab All versions except 5.1 are supported.
540@item DCA (DTS Coherent Acoustics)  @tab     @tab  X
541@item DPCM id RoQ            @tab  X  @tab  X
542    @tab Used in Quake III, Jedi Knight 2, other computer games.
543@item DPCM Interplay         @tab     @tab  X
544    @tab Used in various Interplay computer games.
545@item DPCM Sierra Online     @tab     @tab  X
546    @tab Used in Sierra Online game audio files.
547@item DPCM Sol               @tab     @tab  X
548@item DPCM Xan               @tab     @tab  X
549@item DSP Group TrueSpeech   @tab     @tab  X
550@item DV audio               @tab     @tab  X
551@item Enhanced AC-3          @tab     @tab  X
552@item FLAC (Free Lossless Audio Codec)  @tab  X  @tab  IX
553@item G.729                  @tab     @tab  X
554@item GSM                    @tab  E  @tab  E
555    @tab supported through external library libgsm
556@item GSM Microsoft variant  @tab  E  @tab  E
557    @tab supported through external library libgsm
558@item IMC (Intel Music Coder)  @tab     @tab  X
559@item MACE (Macintosh Audio Compression/Expansion) 3:1  @tab     @tab  X
560@item MACE (Macintosh Audio Compression/Expansion) 6:1  @tab     @tab  X
561@item MLP(Meridian Lossless Packing)/TrueHD  @tab     @tab  X
562    @tab Used in DVD-Audio and Blu-Ray discs.
563@item Monkey's Audio         @tab     @tab  X
564    @tab Only versions 3.97-3.99 are supported.
565@item MP1 (MPEG audio layer 1)  @tab     @tab IX
566@item MP2 (MPEG audio layer 2)  @tab IX  @tab IX
567@item MP3 (MPEG audio layer 3)  @tab  E  @tab IX
568    @tab encoding supported through external library LAME, ADU MP3 and MP3onMP4 also supported
569@item Musepack SV7           @tab     @tab  X
570@item Musepack SV8           @tab     @tab  X
571@item Nellymoser Asao        @tab  X  @tab  X
572@item PCM A-law              @tab  X  @tab  X
573@item PCM mu-law             @tab  X  @tab  X
574@item PCM 16-bit little-endian planar  @tab     @tab  X
575@item PCM 32-bit floating point big-endian  @tab  X  @tab  X
576@item PCM 32-bit floating point little-endian  @tab  X  @tab  X
577@item PCM 64-bit floating point big-endian  @tab  X  @tab  X
578@item PCM 64-bit floating point little-endian  @tab  X  @tab  X
579@item PCM D-Cinema audio signed 24-bit   @tab  X  @tab  X
580@item PCM signed 8-bit       @tab  X  @tab  X
581@item PCM signed 16-bit big-endian  @tab  X  @tab  X
582@item PCM signed 16-bit little-endian  @tab  X  @tab  X
583@item PCM signed 24-bit big-endian  @tab  X  @tab  X
584@item PCM signed 24-bit little-endian  @tab  X  @tab  X
585@item PCM signed 32-bit big-endian  @tab  X  @tab  X
586@item PCM signed 32-bit little-endian  @tab  X  @tab  X
587@item PCM unsigned 8-bit     @tab  X  @tab  X
588@item PCM unsigned 16-bit big-endian  @tab  X  @tab  X
589@item PCM unsigned 16-bit little-endian  @tab  X  @tab  X
590@item PCM unsigned 24-bit big-endian  @tab  X  @tab  X
591@item PCM unsigned 24-bit little-endian  @tab  X  @tab  X
592@item PCM unsigned 32-bit big-endian  @tab  X  @tab  X
593@item PCM unsigned 32-bit little-endian  @tab  X  @tab  X
594@item PCM Zork               @tab  X  @tab  X
595@item QCELP / PureVoice      @tab     @tab  X
596@item QDesign Music Codec 2  @tab     @tab  X
597    @tab There are still some distortions.
598@item RealAudio 1.0 (14.4K)  @tab     @tab  X
599    @tab Real 14400 bit/s codec
600@item RealAudio 2.0 (28.8K)  @tab     @tab  X
601    @tab Real 28800 bit/s codec
602@item RealAudio 3.0 (dnet)   @tab IX  @tab  X
603    @tab Real low bitrate AC-3 codec
604@item Shorten                @tab     @tab  X
605@item Sierra VMD audio       @tab     @tab  X
606    @tab Used in Sierra VMD files.
607@item Smacker audio          @tab     @tab  X
608@item Sonic                  @tab  X  @tab  X
609    @tab experimental codec
610@item Sonic lossless         @tab  X  @tab  X
611    @tab experimental codec
612@item Speex                  @tab     @tab  E
613    @tab supported through external library libspeex
614@item True Audio (TTA)       @tab     @tab  X
615@item Vorbis                 @tab  E  @tab  X
616    @ A native but very primitive encoder exists.
617@item WavPack                @tab     @tab  X
618@item Westwood Audio (SND1)  @tab     @tab  X
619@item Windows Media Audio 1  @tab  X  @tab  X
620@item Windows Media Audio 2  @tab  X  @tab  X
621    @tab Used in Origin's Wing Commander IV AVI files.
622@end multitable
623
624@code{X} means that encoding (resp. decoding) is supported.
625
626@code{E} means that support is provided through an external library.
627
628@code{I} means that an integer-only version is available, too (ensures high
629performance on systems without hardware floating point support).
630
631@section Subtitle Formats
632
633@multitable @columnfractions .4 .1 .1 .1 .1 .1
634@item Name @tab Muxing @tab Demuxing @tab Encoding @tab Decoding
635@item SSA/ASS      @tab X @tab X
636@item DVB          @tab X @tab X @tab X @tab X
637@item DVD          @tab X @tab X @tab X @tab X
638@item XSUB         @tab   @tab   @tab   @tab X
639@end multitable
640
641@code{X} means that the feature is supported.
642
643@section Network Protocols
644
645@multitable @columnfractions .4 .1 .1 .1 .1 .1
646@item Name         @tab Support
647@item file         @tab X
648@item Gopher       @tab X
649@item HTTP         @tab X
650@item pipe         @tab X
651@item RTP          @tab X
652@item TCP          @tab X
653@item UDP          @tab X
654@end multitable
655
656@code{X} means that the protocol is supported.
657
658
659@chapter Platform Specific information
660
661@section BSD
662
663BSD make will not build FFmpeg, you need to install and use GNU Make
664(@file{gmake}).
665
666@section Windows
667
668To get help and instructions for building FFmpeg under Windows, check out
669the FFmpeg Windows Help Forum at
670@url{http://ffmpeg.arrozcru.org/}.
671
672@subsection Native Windows compilation
673
674FFmpeg can be built to run natively on Windows using the MinGW tools. Install
675the latest versions of MSYS and MinGW from @url{http://www.mingw.org/}.
676You can find detailed installation
677instructions in the download section and the FAQ.
678
679FFmpeg does not build out-of-the-box with the packages the automated MinGW
680installer provides. It also requires coreutils to be installed and many other
681packages updated to the latest version. The minimum version for some packages
682are listed below:
683
684@itemize
685@item bash 3.1
686@item msys-make 3.81-2 (note: not mingw32-make)
687@item w32api 3.13
688@item mingw-runtime 3.15
689@end itemize
690
691You will also need to pass @code{-fno-common} to the compiler to work around
692a GCC bug (see @url{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37216}).
693
694Within the MSYS shell, configure and make with:
695
696@example
697./configure --enable-memalign-hack --extra-cflags=-fno-common
698make
699make install
700@end example
701
702This will install @file{ffmpeg.exe} along with many other development files
703to @file{/usr/local}. You may specify another install path using the
704@code{--prefix} option in @file{configure}.
705
706Notes:
707
708@itemize
709
710@item In order to compile vhooks, you must have a POSIX-compliant libdl in
711your MinGW system. Get dlfcn-win32 from
712@url{http://code.google.com/p/dlfcn-win32}.
713
714@item In order to compile FFplay, you must have the MinGW development library
715of SDL. Get it from @url{http://www.libsdl.org}.
716Edit the @file{bin/sdl-config} script so that it points to the correct prefix
717where SDL was installed. Verify that @file{sdl-config} can be launched from
718the MSYS command line.
719
720@item By using @code{./configure --enable-shared} when configuring FFmpeg,
721you can build libavutil, libavcodec and libavformat as DLLs.
722
723@end itemize
724
725@subsection Microsoft Visual C++ compatibility
726
727As stated in the FAQ, FFmpeg will not compile under MSVC++. However, if you
728want to use the libav* libraries in your own applications, you can still
729compile those applications using MSVC++. But the libav* libraries you link
730to @emph{must} be built with MinGW. However, you will not be able to debug
731inside the libav* libraries, since MSVC++ does not recognize the debug
732symbols generated by GCC.
733We strongly recommend you to move over from MSVC++ to MinGW tools.
734
735This description of how to use the FFmpeg libraries with MSVC++ is based on
736Microsoft Visual C++ 2005 Express Edition. If you have a different version,
737you might have to modify the procedures slightly.
738
739@subsubsection Using static libraries
740
741Assuming you have just built and installed FFmpeg in @file{/usr/local}.
742
743@enumerate
744
745@item Create a new console application ("File / New / Project") and then
746select "Win32 Console Application". On the appropriate page of the
747Application Wizard, uncheck the "Precompiled headers" option.
748
749@item Write the source code for your application, or, for testing, just
750copy the code from an existing sample application into the source file
751that MSVC++ has already created for you. For example, you can copy
752@file{output_example.c} from the FFmpeg distribution.
753
754@item Open the "Project / Properties" dialog box. In the "Configuration"
755combo box, select "All Configurations" so that the changes you make will
756affect both debug and release builds. In the tree view on the left hand
757side, select "C/C++ / General", then edit the "Additional Include
758Directories" setting to contain the path where the FFmpeg includes were
759installed (i.e. @file{c:\msys\1.0\local\include}).
760Do not add MinGW's include directory here, or the include files will
761conflict with MSVC's.
762
763@item Still in the "Project / Properties" dialog box, select
764"Linker / General" from the tree view and edit the
765"Additional Library Directories" setting to contain the @file{lib}
766directory where FFmpeg was installed (i.e. @file{c:\msys\1.0\local\lib}),
767the directory where MinGW libs are installed (i.e. @file{c:\mingw\lib}),
768and the directory where MinGW's GCC libs are installed
769(i.e. @file{C:\mingw\lib\gcc\mingw32\4.2.1-sjlj}). Then select
770"Linker / Input" from the tree view, and add the files @file{libavformat.a},
771@file{libavcodec.a}, @file{libavutil.a}, @file{libmingwex.a},
772@file{libgcc.a}, and any other libraries you used (i.e. @file{libz.a})
773to the end of "Additional Dependencies".
774
775@item Now, select "C/C++ / Code Generation" from the tree view. Select
776"Debug" in the "Configuration" combo box. Make sure that "Runtime
777Library" is set to "Multi-threaded Debug DLL". Then, select "Release" in
778the "Configuration" combo box and make sure that "Runtime Library" is
779set to "Multi-threaded DLL".
780
781@item Click "OK" to close the "Project / Properties" dialog box.
782
783@item MSVC++ lacks some C99 header files that are fundamental for FFmpeg.
784Get msinttypes from @url{http://code.google.com/p/msinttypes/downloads/list}
785and install it in MSVC++'s include directory
786(i.e. @file{C:\Program Files\Microsoft Visual Studio 8\VC\include}).
787
788@item MSVC++ also does not understand the @code{inline} keyword used by
789FFmpeg, so you must add this line before @code{#include}ing libav*:
790@example
791#define inline _inline
792@end example
793
794@item Build your application, everything should work.
795
796@end enumerate
797
798@subsubsection Using shared libraries
799
800This is how to create DLL and LIB files that are compatible with MSVC++:
801
802@enumerate
803
804@item Add a call to @file{vcvars32.bat} (which sets up the environment
805variables for the Visual C++ tools) as the first line of @file{msys.bat}.
806The standard location for @file{vcvars32.bat} is
807@file{C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat},
808and the standard location for @file{msys.bat} is @file{C:\msys\1.0\msys.bat}.
809If this corresponds to your setup, add the following line as the first line
810of @file{msys.bat}:
811
812@example
813call "C:\Program Files\Microsoft Visual Studio 8\VC\bin\vcvars32.bat"
814@end example
815
816Alternatively, you may start the @file{Visual Studio 2005 Command Prompt},
817and run @file{c:\msys\1.0\msys.bat} from there.
818
819@item Within the MSYS shell, run @code{lib.exe}. If you get a help message
820from @file{Microsoft (R) Library Manager}, this means your environment
821variables are set up correctly, the @file{Microsoft (R) Library Manager}
822is on the path and will be used by FFmpeg to create
823MSVC++-compatible import libraries.
824
825@item Build FFmpeg with
826
827@example
828./configure --enable-shared --enable-memalign-hack
829make
830make install
831@end example
832
833Your install path (@file{/usr/local/} by default) should now have the
834necessary DLL and LIB files under the @file{bin} directory.
835
836@end enumerate
837
838To use those files with MSVC++, do the same as you would do with
839the static libraries, as described above. But in Step 4,
840you should only need to add the directory where the LIB files are installed
841(i.e. @file{c:\msys\usr\local\bin}). This is not a typo, the LIB files are
842installed in the @file{bin} directory. And instead of adding @file{libxx.a}
843files, you should add @file{avcodec.lib}, @file{avformat.lib}, and
844@file{avutil.lib}. There should be no need for @file{libmingwex.a},
845@file{libgcc.a}, and @file{wsock32.lib}, nor any other external library
846statically linked into the DLLs. The @file{bin} directory contains a bunch
847of DLL files, but the ones that are actually used to run your application
848are the ones with a major version number in their filenames
849(i.e. @file{avcodec-51.dll}).
850
851@subsection Cross compilation for Windows with Linux
852
853You must use the MinGW cross compilation tools available at
854@url{http://www.mingw.org/}.
855
856Then configure FFmpeg with the following options:
857@example
858./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
859@end example
860(you can change the cross-prefix according to the prefix chosen for the
861MinGW tools).
862
863Then you can easily test FFmpeg with Wine
864(@url{http://www.winehq.com/}).
865
866@subsection Compilation under Cygwin
867
868The main issue with the 1.5.x Cygwin versions is that newlib, its C library,
869does not contain llrint().  You need to upgrade to the unstable 1.7.x versions,
870or leverage the implementation in MinGW (as explained below).
871
872Just install your Cygwin with all the "Base" packages, plus the
873following "Devel" ones:
874@example
875binutils, gcc-core, make, subversion, mingw-runtime, diffutils
876@end example
877
878The experimental gcc4 package is still buggy, hence please
879use the official gcc 3.4.4 or a 4.2.x compiled from source by yourself.
880
881Install the current binutils-20080624-2 as they work fine (the old
882binutils-20060709-1 proved buggy on shared builds).
883
884Then create a small library that just contains llrint():
885
886@example
887ar x /usr/lib/mingw/libmingwex.a llrint.o
888ar cq /usr/local/lib/libllrint.a llrint.o
889@end example
890
891Then run
892
893@example
894./configure --enable-static --disable-shared  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
895@end example
896
897to make a static build or
898
899@example
900./configure --enable-shared --disable-static  --extra-ldflags='-L /usr/local/lib' --extra-libs='-l llrint'
901@end example
902
903to build shared libraries.
904
905If you want to build FFmpeg with additional libraries, download Cygwin
906"Devel" packages for Ogg and Vorbis from any Cygwin packages repository:
907@example
908libogg-devel, libvorbis-devel
909@end example
910
911These library packages are only available from Cygwin Ports
912(@url{http://sourceware.org/cygwinports/}) :
913
914@example
915yasm, libSDL-devel, libdirac-devel, libfaac-devel, libfaad-devel, libgsm-devel,
916libmp3lame-devel, libschroedinger1.0-devel, speex-devel, libtheora-devel,
917libxvidcore-devel
918@end example
919
920The recommendation for libnut and x264 is to build them from source by
921yourself, as they evolve too quickly for Cygwin Ports to be up to date.
922
923Cygwin 1.7.x has IPv6 support. You can add IPv6 to Cygwin 1.5.x by means
924of the @code{libgetaddrinfo-devel} package, available at Cygwin Ports.
925
926@subsection Crosscompilation for Windows under Cygwin
927
928With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
929
930Just install your Cygwin as explained before, plus these additional
931"Devel" packages:
932@example
933gcc-mingw-core, mingw-runtime, mingw-zlib
934@end example
935
936and add some special flags to your configure invocation.
937
938For a static build run
939@example
940./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
941@end example
942
943and for a build with shared libraries
944@example
945./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
946@end example
947
948@section BeOS
949
950BeOS support is broken in mysterious ways.
951
952@section OS/2
953
954For information about compiling FFmpeg on OS/2 see
955@url{http://www.edm2.com/index.php/FFmpeg}.
956
957@chapter Developers Guide
958
959@section API
960@itemize @bullet
961@item libavcodec is the library containing the codecs (both encoding and
962decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
963
964@item libavformat is the library containing the file format handling (mux and
965demux code for several formats). Look at @file{ffplay.c} to use it in a
966player. See @file{output_example.c} to use it to generate audio or video
967streams.
968
969@end itemize
970
971@section Integrating libavcodec or libavformat in your program
972
973You can integrate all the source code of the libraries to link them
974statically to avoid any version problem. All you need is to provide a
975'config.mak' and a 'config.h' in the parent directory. See the defines
976generated by ./configure to understand what is needed.
977
978You can use libavcodec or libavformat in your commercial program, but
979@emph{any patch you make must be published}. The best way to proceed is
980to send your patches to the FFmpeg mailing list.
981
982@node Coding Rules
983@section Coding Rules
984
985FFmpeg is programmed in the ISO C90 language with a few additional
986features from ISO C99, namely:
987@itemize @bullet
988@item
989the @samp{inline} keyword;
990@item
991@samp{//} comments;
992@item
993designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
994@item
995compound literals (@samp{x = (struct s) @{ 17, 23 @};})
996@end itemize
997
998These features are supported by all compilers we care about, so we will not
999accept patches to remove their use unless they absolutely do not impair
1000clarity and performance.
1001
1002All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
1003compiles with several other compilers, such as the Compaq ccc compiler
1004or Sun Studio 9, and we would like to keep it that way unless it would
1005be exceedingly involved. To ensure compatibility, please do not use any
1006additional C99 features or GCC extensions. Especially watch out for:
1007@itemize @bullet
1008@item
1009mixing statements and declarations;
1010@item
1011@samp{long long} (use @samp{int64_t} instead);
1012@item
1013@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
1014@item
1015GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
1016@end itemize
1017
1018Indent size is 4.
1019The presentation is the one specified by 'indent -i4 -kr -nut'.
1020The TAB character is forbidden outside of Makefiles as is any
1021form of trailing whitespace. Commits containing either will be
1022rejected by the Subversion repository.
1023
1024The main priority in FFmpeg is simplicity and small code size in order to
1025minimize the bug count.
1026
1027Comments: Use the JavaDoc/Doxygen
1028format (see examples below) so that code documentation
1029can be generated automatically. All nontrivial functions should have a comment
1030above them explaining what the function does, even if it is just one sentence.
1031All structures and their member variables should be documented, too.
1032@example
1033/**
1034 * @@file mpeg.c
1035 * MPEG codec.
1036 * @@author ...
1037 */
1038
1039/**
1040 * Summary sentence.
1041 * more text ...
1042 * ...
1043 */
1044typedef struct Foobar@{
1045    int var1; /**< var1 description */
1046    int var2; ///< var2 description
1047    /** var3 description */
1048    int var3;
1049@} Foobar;
1050
1051/**
1052 * Summary sentence.
1053 * more text ...
1054 * ...
1055 * @@param my_parameter description of my_parameter
1056 * @@return return value description
1057 */
1058int myfunc(int my_parameter)
1059...
1060@end example
1061
1062fprintf and printf are forbidden in libavformat and libavcodec,
1063please use av_log() instead.
1064
1065Casts should be used only when necessary. Unneeded parentheses
1066should also be avoided if they don't make the code easier to understand.
1067
1068@section Development Policy
1069
1070@enumerate
1071@item
1072   Contributions should be licensed under the LGPL 2.1, including an
1073   "or any later version" clause, or the MIT license.  GPL 2 including
1074   an "or any later version" clause is also acceptable, but LGPL is
1075   preferred.
1076@item
1077   You must not commit code which breaks FFmpeg! (Meaning unfinished but
1078   enabled code which breaks compilation or compiles but does not work or
1079   breaks the regression tests)
1080   You can commit unfinished stuff (for testing etc), but it must be disabled
1081   (#ifdef etc) by default so it does not interfere with other developers'
1082   work.
1083@item
1084   You do not have to over-test things. If it works for you, and you think it
1085   should work for others, then commit. If your code has problems
1086   (portability, triggers compiler bugs, unusual environment etc) they will be
1087   reported and eventually fixed.
1088@item
1089   Do not commit unrelated changes together, split them into self-contained
1090   pieces. Also do not forget that if part B depends on part A, but A does not
1091   depend on B, then A can and should be committed first and separate from B.
1092   Keeping changes well split into self-contained parts makes reviewing and
1093   understanding them on the commit log mailing list easier. This also helps
1094   in case of debugging later on.
1095   Also if you have doubts about splitting or not splitting, do not hesitate to
1096   ask/discuss it on the developer mailing list.
1097@item
1098   Do not change behavior of the program (renaming options etc) without
1099   first discussing it on the ffmpeg-devel mailing list. Do not remove
1100   functionality from the code. Just improve!
1101
1102   Note: Redundant code can be removed.
1103@item
1104   Do not commit changes to the build system (Makefiles, configure script)
1105   which change behavior, defaults etc, without asking first. The same
1106   applies to compiler warning fixes, trivial looking fixes and to code
1107   maintained by other developers. We usually have a reason for doing things
1108   the way we do. Send your changes as patches to the ffmpeg-devel mailing
1109   list, and if the code maintainers say OK, you may commit. This does not
1110   apply to files you wrote and/or maintain.
1111@item
1112   We refuse source indentation and other cosmetic changes if they are mixed
1113   with functional changes, such commits will be rejected and removed. Every
1114   developer has his own indentation style, you should not change it. Of course
1115   if you (re)write something, you can use your own style, even though we would
1116   prefer if the indentation throughout FFmpeg was consistent (Many projects
1117   force a given indentation style - we do not.). If you really need to make
1118   indentation changes (try to avoid this), separate them strictly from real
1119   changes.
1120
1121   NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
1122   then either do NOT change the indentation of the inner part within (do not
1123   move it to the right)! or do so in a separate commit
1124@item
1125   Always fill out the commit log message. Describe in a few lines what you
1126   changed and why. You can refer to mailing list postings if you fix a
1127   particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
1128@item
1129   If you apply a patch by someone else, include the name and email address in
1130   the log message. Since the ffmpeg-cvslog mailing list is publicly
1131   archived you should add some SPAM protection to the email address. Send an
1132   answer to ffmpeg-devel (or wherever you got the patch from) saying that
1133   you applied the patch.
1134@item
1135   When applying patches that have been discussed (at length) on the mailing
1136   list, reference the thread in the log message.
1137@item
1138    Do NOT commit to code actively maintained by others without permission.
1139    Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
1140    timeframe (12h for build failures and security fixes, 3 days small changes,
1141    1 week for big patches) then commit your patch if you think it is OK.
1142    Also note, the maintainer can simply ask for more time to review!
1143@item
1144    Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
1145    are sent there and reviewed by all the other developers. Bugs and possible
1146    improvements or general questions regarding commits are discussed there. We
1147    expect you to react if problems with your code are uncovered.
1148@item
1149    Update the documentation if you change behavior or add features. If you are
1150    unsure how best to do this, send a patch to ffmpeg-devel, the documentation
1151    maintainer(s) will review and commit your stuff.
1152@item
1153    Try to keep important discussions and requests (also) on the public
1154    developer mailing list, so that all developers can benefit from them.
1155@item
1156    Never write to unallocated memory, never write over the end of arrays,
1157    always check values read from some untrusted source before using them
1158    as array index or other risky things.
1159@item
1160    Remember to check if you need to bump versions for the specific libav
1161    parts (libavutil, libavcodec, libavformat) you are changing. You need
1162    to change the version integer.
1163    Incrementing the first component means no backward compatibility to
1164    previous versions (e.g. removal of a function from the public API).
1165    Incrementing the second component means backward compatible change
1166    (e.g. addition of a function to the public API or extension of an
1167    existing data structure).
1168    Incrementing the third component means a noteworthy binary compatible
1169    change (e.g. encoder bug fix that matters for the decoder).
1170@item
1171    Compiler warnings indicate potential bugs or code with bad style. If a type of
1172    warning always points to correct and clean code, that warning should
1173    be disabled, not the code changed.
1174    Thus the remaining warnings can either be bugs or correct code.
1175    If it is a bug, the bug has to be fixed. If it is not, the code should
1176    be changed to not generate a warning unless that causes a slowdown
1177    or obfuscates the code.
1178@item
1179    If you add a new file, give it a proper license header. Do not copy and
1180    paste it from a random place, use an existing file as template.
1181@end enumerate
1182
1183We think our rules are not too hard. If you have comments, contact us.
1184
1185Note, these rules are mostly borrowed from the MPlayer project.
1186
1187@section Submitting patches
1188
1189First, (@pxref{Coding Rules}) above if you did not yet.
1190
1191When you submit your patch, try to send a unified diff (diff '-up'
1192option). We cannot read other diffs :-)
1193
1194Also please do not submit a patch which contains several unrelated changes.
1195Split it into separate, self-contained pieces. This does not mean splitting
1196file by file. Instead, make the patch as small as possible while still
1197keeping it as a logical unit that contains an individual change, even
1198if it spans multiple files. This makes reviewing your patches much easier
1199for us and greatly increases your chances of getting your patch applied.
1200
1201Run the regression tests before submitting a patch so that you can
1202verify that there are no big problems.
1203
1204Patches should be posted as base64 encoded attachments (or any other
1205encoding which ensures that the patch will not be trashed during
1206transmission) to the ffmpeg-devel mailing list, see
1207@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
1208
1209It also helps quite a bit if you tell us what the patch does (for example
1210'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
1211and has no lrint()')
1212
1213Also please if you send several patches, send each patch as a separate mail,
1214do not attach several unrelated patches to the same mail.
1215
1216@section New codecs or formats checklist
1217
1218@enumerate
1219@item
1220    Did you use av_cold for codec initialization and close functions?
1221@item
1222    Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
1223    AVInputFormat/AVOutputFormat struct?
1224@item
1225    Did you bump the minor version number in @file{avcodec.h} or
1226    @file{avformat.h}?
1227@item
1228    Did you register it in @file{allcodecs.c} or @file{allformats.c}?
1229@item
1230    Did you add the CodecID to @file{avcodec.h}?
1231@item
1232    If it has a fourcc, did you add it to @file{libavformat/riff.c},
1233    even if it is only a decoder?
1234@item
1235    Did you add a rule to compile the appropriate files in the Makefile?
1236    Remember to do this even if you're just adding a format to a file that is
1237    already being compiled by some other rule, like a raw demuxer.
1238@item
1239    Did you add an entry to the table of supported formats or codecs in the
1240    documentation?
1241@item
1242    Did you add an entry in the Changelog?
1243@item
1244    If it depends on a parser or a library, did you add that dependency in
1245    configure?
1246@item
1247    Did you "svn add" the appropriate files before commiting?
1248@end enumerate
1249
1250@section patch submission checklist
1251
1252@enumerate
1253@item
1254    Do the regression tests pass with the patch applied?
1255@item
1256    Does @code{make checkheaders} pass with the patch applied?
1257@item
1258    Is the patch a unified diff?
1259@item
1260    Is the patch against latest FFmpeg SVN?
1261@item
1262    Are you subscribed to ffmpeg-dev?
1263    (the list is subscribers only due to spam)
1264@item
1265    Have you checked that the changes are minimal, so that the same cannot be
1266    achieved with a smaller patch and/or simpler final code?
1267@item
1268    If the change is to speed critical code, did you benchmark it?
1269@item
1270    If you did any benchmarks, did you provide them in the mail?
1271@item
1272    Have you checked that the patch does not introduce buffer overflows or
1273    other security issues?
1274@item
1275    Did you test your decoder or demuxer against damaged data? If no, see
1276    tools/trasher and the noise bitstream filter. Your decoder or demuxer
1277    should not crash or end in a (near) infinite loop when fed damaged data.
1278@item
1279    Is the patch created from the root of the source tree, so it can be
1280    applied with @code{patch -p0}?
1281@item
1282    Does the patch not mix functional and cosmetic changes?
1283@item
1284    Did you add tabs or trailing whitespace to the code? Both are forbidden.
1285@item
1286    Is the patch attached to the email you send?
1287@item
1288    Is the mime type of the patch correct? It should be text/x-diff or
1289    text/x-patch or at least text/plain and not application/octet-stream.
1290@item
1291    If the patch fixes a bug, did you provide a verbose analysis of the bug?
1292@item
1293    If the patch fixes a bug, did you provide enough information, including
1294    a sample, so the bug can be reproduced and the fix can be verified?
1295    Note please do not attach samples >100k to mails but rather provide a
1296    URL, you can upload to ftp://upload.ffmpeg.org
1297@item
1298    Did you provide a verbose summary about what the patch does change?
1299@item
1300    Did you provide a verbose explanation why it changes things like it does?
1301@item
1302    Did you provide a verbose summary of the user visible advantages and
1303    disadvantages if the patch is applied?
1304@item
1305    Did you provide an example so we can verify the new feature added by the
1306    patch easily?
1307@item
1308    If you added a new file, did you insert a license header? It should be
1309    taken from FFmpeg, not randomly copied and pasted from somewhere else.
1310@item
1311    You should maintain alphabetical order in alphabetically ordered lists as
1312    long as doing so does not break API/ABI compatibility.
1313@item
1314    Lines with similar content should be aligned vertically when doing so
1315    improves readability.
1316@item
1317    Did you provide a suggestion for a clear commit log message?
1318@end enumerate
1319
1320@section Patch review process
1321
1322All patches posted to ffmpeg-devel will be reviewed, unless they contain a
1323clear note that the patch is not for SVN.
1324Reviews and comments will be posted as replies to the patch on the
1325mailing list. The patch submitter then has to take care of every comment,
1326that can be by resubmitting a changed patch or by discussion. Resubmitted
1327patches will themselves be reviewed like any other patch. If at some point
1328a patch passes review with no comments then it is approved, that can for
1329simple and small patches happen immediately while large patches will generally
1330have to be changed and reviewed many times before they are approved.
1331After a patch is approved it will be committed to the repository.
1332
1333We will review all submitted patches, but sometimes we are quite busy so
1334especially for large patches this can take several weeks.
1335
1336When resubmitting patches, please do not make any significant changes
1337not related to the comments received during review. Such patches will
1338be rejected. Instead, submit  significant changes or new features as
1339separate patches.
1340
1341@section Regression tests
1342
1343Before submitting a patch (or committing to the repository), you should at least
1344test that you did not break anything.
1345
1346The regression tests build a synthetic video stream and a synthetic
1347audio stream. These are then encoded and decoded with all codecs or
1348formats. The CRC (or MD5) of each generated file is recorded in a
1349result file. A 'diff' is launched to compare the reference results and
1350the result file.
1351
1352The regression tests then go on to test the FFserver code with a
1353limited set of streams. It is important that this step runs correctly
1354as well.
1355
1356Run 'make test' to test all the codecs and formats.
1357
1358Run 'make fulltest' to test all the codecs, formats and FFserver.
1359
1360[Of course, some patches may change the results of the regression tests. In
1361this case, the reference results of the regression tests shall be modified
1362accordingly].
1363
1364@bye
1365