@c man begin EXAMPLES
@section Video and Audio grabbing
-FFmpeg can use a video4linux compatible video source and any Open Sound
-System audio source:
+FFmpeg can grab video and audio from devices given that you specify the input
+format and device.
@example
-ffmpeg /tmp/out.mpg
+ffmpeg -f audio_device -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg
@end example
Note that you must activate the right video source and channel before
have to set the audio recording levels correctly with a
standard mixer.
+@section X11 grabbing
+
+FFmpeg can grab the X11 display.
+
+@example
+ffmpeg -f x11grab -i :0.0 /tmp/out.mpg
+@end example
+
+0.0 is display.screen number of your X11 server, same as
+the DISPLAY environment variable.
+
+@example
+ffmpeg -f x11grab -i :0.0+10,20 /tmp/out.mpg
+@end example
+
+0.0 is display.screen number of your X11 server, same as the DISPLAY environment
+variable. 10 is the x-offset and 20 the y-offset for the grabbing.
+
@section Video and Audio file format conversion
* FFmpeg can use any supported file format and protocol as input:
mapping from input stream to output streams:
@example
-ffmpeg -i /tmp/a.wav -ab 64 /tmp/a.mp2 -ab 128 /tmp/b.mp2 -map 0:0 -map 0:0
+ffmpeg -i /tmp/a.wav -ab 64k /tmp/a.mp2 -ab 128k /tmp/b.mp2 -map 0:0 -map 0:0
@end example
Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map
* You can transcode decrypted VOBs
@example
-ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800 -g 300 -bf 2 -acodec mp3 -ab 128 snatch.avi
+ffmpeg -i snatch_1.vob -f avi -vcodec mpeg4 -b 800k -g 300 -bf 2 -acodec mp3 -ab 128k snatch.avi
@end example
This is a typical DVD ripping example; the input is a VOB file, the
@c man end
@end example
@c man begin DESCRIPTION
-If no input file is given, audio/video grabbing is done.
-
As a general rule, options are applied to the next specified
-file. For example, if you give the @option{-b 64} option, it sets the video
-bitrate of the next file. The format option may be needed for raw input
-files.
+file. Therefore, order is important, and you can have the same
+option on the command line multiple times. Each occurrence is
+then applied to the next input or output file.
+
+* To set the video bitrate of the output file to 64kbit/s:
+@example
+ffmpeg -i input.avi -b 64k output.avi
+@end example
+
+* To force the frame rate of the input and output file to 24 fps:
+@example
+ffmpeg -r 24 -i input.avi output.avi
+@end example
+
+* To force the frame rate of the output file to 24 fps:
+@example
+ffmpeg -i input.avi -r 24 output.avi
+@end example
+
+* To force the frame rate of input file to 1 fps and the output file to 24 fps:
+@example
+ffmpeg -r 1 -i input.avi -r 24 output.avi
+@end example
+
+The format option may be needed for raw input files.
By default, FFmpeg tries to convert as losslessly as possible: It
uses the same audio and video parameters for the outputs as the one
@item -h
Show help.
+@item -version
+Show version.
+
@item -formats
Show available formats, codecs, protocols, ...
Set the recording time in seconds.
@code{hh:mm:ss[.xxx]} syntax is also supported.
+@item -fs limit_size
+Set the file size limit.
+
@item -ss position
Seek to given time position in seconds.
@code{hh:mm:ss[.xxx]} syntax is also supported.
+@item -itsoffset offset
+Set the input time offset in seconds.
+@code{[-]hh:mm:ss[.xxx]} syntax is also supported.
+This option affects all the input files that follow it.
+The offset is added to the timestamps of the input files.
+Specifying a positive offset means that the corresponding
+streams are delayed by 'offset' seconds.
+
@item -title string
Set the title.
+@item -timestamp time
+Set the timestamp.
+
@item -author string
Set the author.
@item -comment string
Set the comment.
+@item -album string
+Set the album.
+
+@item -track number
+Set the track.
+
+@item -year number
+Set the year.
+
+@item -v verbose
+Control amount of logging.
+
@item -target type
-Specify target file type ("vcd", "svcd", "dvd", "dv", "pal-vcd",
+Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50", "pal-vcd",
"ntsc-svcd", ... ). All the format options (bitrate, codecs,
buffer sizes) are then set automatically. You can just type:
ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg
@end example
-@item -hq
-Activate high quality settings.
+@item -dframes number
+Set the number of data frames to record.
-@item -itsoffset offset
-Set the input time offset in seconds.
-@code{[-]hh:mm:ss[.xxx]} syntax is also supported.
-This option affects all the input files that follow it.
-The offset is added to the timestamps of the input files.
-Specifying a positive offset means that the corresponding
-streams are delayed by 'offset' seconds.
+@item -scodec codec
+Force subtitle codec ('copy' to copy stream).
+
+@item -newsubtitle
+Add a new subtitle stream to the current output stream.
+
+@item -slang code
+Set the ISO 639 language code (3 letters) of the current subtitle stream.
@end table
@table @option
@item -b bitrate
-Set the video bitrate in kbit/s (default = 200 kb/s).
+Set the video bitrate in bit/s (default = 200 kb/s).
+@item -vframes number
+Set the number of video frames to record.
@item -r fps
-Set frame rate (default = 25).
+Set frame rate (Hz value, fraction or abbreviation), (default = 25).
@item -s size
-Set frame size. The format is @samp{wxh} (default = 160x128).
+Set frame size. The format is @samp{wxh} (ffserver default = 160x128, ffmpeg default = same as source).
The following abbreviations are recognized:
@table @samp
@item sqcif
@item -vn
Disable video recording.
@item -bt tolerance
-Set video bitrate tolerance (in kbit/s).
+Set video bitrate tolerance (in bit/s).
@item -maxrate bitrate
-Set max video bitrate tolerance (in kbit/s).
+Set max video bitrate tolerance (in bit/s).
@item -minrate bitrate
-Set min video bitrate tolerance (in kbit/s).
+Set min video bitrate tolerance (in bit/s).
@item -bufsize size
-Set rate control buffer size (in kbit).
+Set rate control buffer size (in bits).
@item -vcodec codec
Force video codec to @var{codec}. Use the @code{copy} special value to
tell that the raw codec data must be copied as is.
@item -passlogfile file
Set two pass logfile name to @var{file}.
+@item -newvideo
+Add a new video stream to the current output stream.
+
@end table
@section Advanced Video Options
@table @option
+@item -pix_fmt format
+Set pixel format.
@item -g gop_size
Set the group of pictures size.
@item -intra
Use only intra frames.
+@item -vdt n
+Discard threshold.
@item -qscale q
-Use fixed video quantiser scale (VBR).
+Use fixed video quantizer scale (VBR).
@item -qmin q
-minimum video quantiser scale (VBR)
+minimum video quantizer scale (VBR)
@item -qmax q
-maximum video quantiser scale (VBR)
+maximum video quantizer scale (VBR)
@item -qdiff q
-maximum difference between the quantiser scales (VBR)
+maximum difference between the quantizer scales (VBR)
@item -qblur blur
-video quantiser scale blur (VBR)
+video quantizer scale blur (VBR)
@item -qcomp compression
-video quantiser scale compression (VBR)
+video quantizer scale compression (VBR)
+
+@item -lmin lambda
+minimum video lagrange factor (VBR)
+@item -lmax lambda
+max video lagrange factor (VBR)
+@item -mblmin lambda
+minimum macroblock quantizer scale (VBR)
+@item -mblmax lambda
+maximum macroblock quantizer scale (VBR)
+
+These four options (lmin, lmax, mblmin, mblmax) use 'lambda' units,
+but you may use the QP2LAMBDA constant to easily convert from 'q' units:
+@example
+ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext
+@end example
@item -rc_init_cplx complexity
initial complexity for single pass encoding
@item -deinterlace
Deinterlace pictures.
-@item -interlace
+@item -ilme
Force interlacing support in encoder (MPEG-2 and MPEG-4 only).
Use this option if your input file is interlaced and you want
to keep the interlaced format for minimum losses.
@item -vhook module
Insert video processing @var{module}. @var{module} contains the module
name and its parameters separated by spaces.
+@item -top n
+top=1/bottom=0/auto=-1 field first
+@item -dc precision
+Intra_dc_precision.
+@item -vtag fourcc/tag
+Force video tag/fourcc.
+@item -qphist
+Show QP histogram.
+@item -vbsf bitstream filter
+Bitstream filters available are "dump_extra", "remove_extra", "noise".
@end table
@section Audio Options
@table @option
+@item -aframes number
+Set the number of audio frames to record.
@item -ar freq
Set the audio sampling frequency (default = 44100 Hz).
@item -ab bitrate
-Set the audio bitrate in kbit/s (default = 64).
+Set the audio bitrate in bit/s (default = 64k).
@item -ac channels
Set the number of audio channels (default = 1).
@item -an
@item -acodec codec
Force audio codec to @var{codec}. Use the @code{copy} special value to
specify that the raw codec data must be copied as is.
+@item -newaudio
+Add a new audio track to the output file. If you want to specify parameters,
+do so before @code{-newaudio} (@code{-acodec}, @code{-ab}, etc..).
+
+Mapping will be done automatically, if the number of output streams is equal to
+the number of input streams, else it will pick the first one that matches. You
+can override the mapping using @code{-map} as usual.
+
+Example:
+@example
+ffmpeg -i file.mpg -vcodec copy -acodec ac3 -ab 384k test.mpg -acodec mp2 -ab 192k -newaudio
+@end example
+@item -alang code
+Set the ISO 639 language code (3 letters) of the current audio stream.
+@end table
+
+@section Advanced Audio options:
+
+@table @option
+@item -atag fourcc/tag
+Force audio tag/fourcc.
+@item -absf bitstream filter
+Bitstream filters available are "dump_extra", "remove_extra", "noise", "mp3comp", "mp3decomp".
+@end table
+
+@section Subtitle options:
+
+@table @option
+@item -scodec codec
+Force subtitle codec ('copy' to copy stream).
+@item -newsubtitle
+Add a new subtitle stream to the current output stream.
+@item -slang code
+Set the ISO 639 language code (3 letters) of the current subtitle stream.
@end table
@section Audio/Video grab options
@table @option
-@item -vd device
-sEt video grab device (e.g. @file{/dev/video0}).
@item -vc channel
Set video grab channel (DV1394 only).
@item -tvstd standard
Set television standard (NTSC, PAL (SECAM)).
-@item -dv1394
-Set DV1394 grab.
-@item -ad device
-Set audio device (e.g. @file{/dev/dsp}).
+@item -isync
+Synchronize read on input.
@end table
@section Advanced options
@table @option
-@item -map file:stream
-Set input stream mapping.
+@item -map input stream id[:input stream id]
+Set stream mapping from input streams to output streams.
+Just enumerate the input streams in the order you want them in the output.
+[input stream id] sets the (input) stream to sync against.
+@item -map_meta_data outfile:infile
+Set meta data information of outfile from infile.
@item -debug
Print specific debug info.
@item -benchmark
Add timings for benchmarking.
-@item -hex
+@item -dump
Dump each input packet.
+@item -hex
+When dumping packets, also dump the payload.
@item -bitexact
Only use bit exact algorithms (for codec testing).
@item -ps size
Set packet size in bits.
@item -re
Read input at native frame rate. Mainly used to simulate a grab device.
-@item -loop
+@item -loop_input
Loop over the input stream. Currently it works only for image
streams. This option is used for automatic FFserver testing.
@item -loop_output number_of_times
Repeatedly loop output for formats that support looping such as animated GIF
(0 will loop the output infinitely).
+@item -threads count
+Thread count.
+@item -vsync parameter
+Video sync method. Video will be stretched/squeezed to match the timestamps,
+it is done by duplicating and dropping frames. With -map you can select from
+which stream the timestamps should be taken. You can leave either video or
+audio unchanged and sync the remaining stream(s) to the unchanged one.
+@item -async samples_per_second
+Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps,
+the parameter is the maximum samples per second by which the audio is changed.
+-async 1 is a special case where only the start of the audio stream is corrected
+without any later correction.
@end table
@node FFmpeg formula evaluator
frames. An example is:
@example
-ffmpeg -g 3 -r 3 -t 10 -b 50 -s qcif -f rv10 /tmp/b.rm
+ffmpeg -g 3 -r 3 -t 10 -b 50k -s qcif -f rv10 /tmp/b.rm
@end example
@item The parameter 'q' which is displayed while encoding is the current
@end itemize
+
+@chapter external libraries
+
+FFmpeg can be hooked up with a number of external libraries to add support
+for more formats. None of them are used by default, their use has to be
+explicitly requested by passing the appropriate flags to @file{./configure}.
+
+@section AMR
+
+AMR comes in two different flavors, WB and NB. FFmpeg can make use of the
+AMR WB (floating-point mode) and the AMR NB (both floating-point and
+fixed-point mode) reference decoders and encoders.
+
+@itemize
+
+@item For AMR WB floating-point and AMR NB floating point support, go to
+@url{http://www.penguin.cz/~utx/amr} and follow the instructions for building
+the libraries. Pass @code{--enable-amr-nb} and/or @code{--enable-amr-wb} to
+configure to enable the libraries.
+
+@item For AMR NB fixed-point download TS26.073 REL-6 V6.0.0 from
+@url{http://www.3gpp.org/ftp/Specs/archive/26_series/26.073/26073-600.zip}
+and extract the source to the directory @file{libavcodec/amr}.
+You must also add @code{-DMMS_IO} to @code{CFLAGS} in
+@file{libavcodec/amr/makefile}, i.e.
+``@code{CFLAGS = -Wall -pedantic-errors -I. $(CFLAGS_$(MODE)) -D$(VAD) -DMMS_IO}''.
+Pass @code{--enable-amr-nb-fixed} to configure to enable it.
+
+@end itemize
+
+
@chapter Supported File Formats and Codecs
You can use the @code{-formats} option to have an exhaustive list.
@tab Multimedia format used in games like Mad Dog McCree
@item AVS @tab @tab X
@tab Multimedia format used by the Creature Shock game.
+@item Smacker @tab @tab X
+@tab Multimedia format used by many games.
+@item GXF @tab X @tab X
+@tab General eXchange Format SMPTE 360M, used by Thomson Grass Valley playout servers.
+@item CIN @tab @tab X
+@tab Multimedia format used by Delphine Software games.
+@item MXF @tab @tab X
+@tab Material eXchange Format SMPTE 377M, used by D-Cinema, broadcast industry.
+@item SEQ @tab @tab X
+@tab Tiertex .seq files used in the DOS CDROM version of the game Flashback.
+@item DXA @tab @tab X
+@tab This format is used in non-Windows version of Feeble Files game and
+different game cutscenes repacked for use with ScummVM.
+@item THP @tab @tab X
+@tab Used on the Nintendo GameCube.
+@item C93 @tab @tab X
+@tab Used in the game Cyberia from Interplay.
+@item Bethsoft VID @tab @tab X
+@tab Used in some games from Bethesda Softworks.
+@item CRYO APC @tab @tab X
+@tab Audio format used in some games by CRYO Interactive Entertainment.
@end multitable
@code{X} means that encoding (resp. decoding) is supported.
@item .Y.U.V @tab X @tab X @tab one raw file per component
@item animated GIF @tab X @tab X @tab Only uncompressed GIFs are generated.
@item PNG @tab X @tab X @tab 2 bit and 4 bit/pixel not supported yet.
+@item Targa @tab @tab X @tab Targa (.TGA) image format.
+@item TIFF @tab X @tab X @tab YUV, JPEG and some extension is not supported yet.
@item SGI @tab X @tab X @tab SGI RGB image format
@end multitable
@item Supported Codec @tab Encoding @tab Decoding @tab Comments
@item MPEG-1 video @tab X @tab X
@item MPEG-2 video @tab X @tab X
-@item MPEG-4 @tab X @tab X @tab also known as DivX4/5
+@item MPEG-4 @tab X @tab X
@item MSMPEG4 V1 @tab X @tab X
@item MSMPEG4 V2 @tab X @tab X
-@item MSMPEG4 V3 @tab X @tab X @tab also known as DivX3
+@item MSMPEG4 V3 @tab X @tab X
@item WMV7 @tab X @tab X
@item WMV8 @tab X @tab X @tab not completely working
+@item WMV9 @tab @tab X @tab not completely working
+@item VC1 @tab @tab X
@item H.261 @tab X @tab X
@item H.263(+) @tab X @tab X @tab also known as RealVideo 1.0
@item H.264 @tab @tab X
@item RealVideo 2.0 @tab X @tab X
@item MJPEG @tab X @tab X
@item lossless MJPEG @tab X @tab X
+@item JPEG-LS @tab X @tab X @tab fourcc: MJLS, lossless and near-lossless is supported
@item Apple MJPEG-B @tab @tab X
@item Sunplus MJPEG @tab @tab X @tab fourcc: SP5X
@item DV @tab X @tab X
@item Sorenson Video 1 @tab X @tab X @tab fourcc: SVQ1
@item Sorenson Video 3 @tab @tab X @tab fourcc: SVQ3
@item On2 VP3 @tab @tab X @tab still experimental
-@item Theora @tab @tab X @tab still experimental
+@item On2 VP5 @tab @tab X @tab fourcc: VP50
+@item On2 VP6 @tab @tab X @tab fourcc: VP60,VP61,VP62
+@item Theora @tab X @tab X @tab still experimental
@item Intel Indeo 3 @tab @tab X
@item FLV @tab X @tab X @tab Sorenson H.263 used in Flash
+@item Flash Screen Video @tab X @tab X @tab fourcc: FSV1
@item ATI VCR1 @tab @tab X @tab fourcc: VCR1
@item ATI VCR2 @tab @tab X @tab fourcc: VCR2
@item Cirrus Logic AccuPak @tab @tab X @tab fourcc: CLJR
@item Fraps FPS1 @tab @tab X @tab
@item CamStudio @tab @tab X @tab fourcc: CSCD
@item American Laser Games Video @tab @tab X @tab Used in games like Mad Dog McCree
-@item ZMBV @tab @tab X @tab
+@item ZMBV @tab X @tab X @tab Encoder works only on PAL8
@item AVS Video @tab @tab X @tab Video encoding used by the Creature Shock game.
+@item Smacker Video @tab @tab X @tab Video encoding used in Smacker.
+@item RTjpeg @tab @tab X @tab Video encoding used in NuppelVideo files.
+@item KMVC @tab @tab X @tab Codec used in Worms games.
+@item VMware Video @tab @tab X @tab Codec used in videos captured by VMware.
+@item Cin Video @tab @tab X @tab Codec used in Delphine Software games.
+@item Tiertex Seq Video @tab @tab X @tab Codec used in DOS CDROM FlashBack game.
+@item DXA Video @tab @tab X @tab Codec originally used in Feeble Files game.
+@item AVID DNxHD @tab @tab X @tab aka SMPTE VC3
+@item C93 Video @tab @tab X @tab Codec used in Cyberia game.
+@item THP @tab @tab X @tab Used on the Nintendo GameCube.
+@item Bethsoft VID @tab @tab X @tab Used in some games from Bethesda Softworks.
@end multitable
@code{X} means that encoding (resp. decoding) is supported.
-See @url{http://mplayerhq.hu/~michael/codec-features.html} to
-get a precise comparison of the FFmpeg MPEG-4 codec compared to
-other implementations.
-
@section Audio Codecs
@multitable @columnfractions .4 .1 .1 .1 .7
@item AC3 @tab IX @tab IX
@tab liba52 is used internally for decoding.
@item Vorbis @tab X @tab X
-@tab Supported through the external library libvorbis.
-@item WMA V1/V2 @tab @tab X
+@item WMA V1/V2 @tab X @tab X
@item AAC @tab X @tab X
@tab Supported through the external library libfaac/libfaad.
@item Microsoft ADPCM @tab X @tab X
@tab Used in various EA titles.
@item Creative ADPCM @tab @tab X
@tab 16 -> 4, 8 -> 4, 8 -> 3, 8 -> 2
+@item THP ADPCM @tab @tab X
+@tab Used on the Nintendo GameCube.
@item RA144 @tab @tab X
@tab Real 14400 bit/s codec
@item RA288 @tab @tab X
@tab Used in Sierra Online game audio files.
@item Apple MACE 3 @tab @tab X
@item Apple MACE 6 @tab @tab X
-@item FLAC lossless audio @tab @tab X
+@item FLAC lossless audio @tab X @tab X
@item Shorten lossless audio @tab @tab X
@item Apple lossless audio @tab @tab X
@tab QuickTime fourcc 'alac'
@tab All versions except 5.1 are supported
@item DSP Group TrueSpeech @tab @tab X
@item True Audio (TTA) @tab @tab X
+@item Smacker Audio @tab @tab X
+@item WavPack Audio @tab @tab X
+@item Cin Audio @tab @tab X
+@tab Codec used in Delphine Software games.
+@item Intel Music Coder @tab @tab X
+@item Musepack @tab @tab X
+@tab Only SV7 is supported
+@item DT$ Coherent Audio @tab @tab X
@end multitable
@code{X} means that encoding (resp. decoding) is supported.
@chapter Platform Specific information
-@section Linux
-
-FFmpeg should be compiled with at least GCC 2.95.3. GCC 3.2 is the
-preferred compiler now for FFmpeg. All future optimizations will depend on
-features only found in GCC 3.2.
-
@section BSD
BSD make will not build FFmpeg, you need to install and use GNU Make
@section Windows
+To get help and instructions for using FFmpeg under Windows, check out
+the FFmpeg Windows Help Forum at
+@url{http://arrozcru.no-ip.org/ffmpeg/}.
+
@subsection Native Windows compilation
@itemize
@url{http://www.mingw.org/}. You can find detailed installation
instructions in the download section and the FAQ.
+NOTE: Use at least bash 3.1. Older versions are known to be failing on the
+configure script.
+
@item If you want to test the FFplay, also download
the MinGW development library of SDL 1.2.x
(@file{SDL-devel-1.2.x-mingw32.tar.gz}) from
@file{sdl-config} can be launched from the MSYS command line.
@item You can install FFmpeg in @file{Program Files/FFmpeg} by typing
-@file{make install}. Don't forget to copy @file{SDL.dll} to the place
+@file{make install}. Do not forget to copy @file{SDL.dll} to the place
you launch @file{ffplay} from.
@end itemize
@enumerate
-@item Install Visual C++ (if you haven't done so already).
+@item Install Visual C++ (if you have not done so already).
@item Install MinGW and MSYS as described above.
@item Type the command
@code{./configure --enable-shared --disable-static --enable-memalign-hack}
-to configure and, if that didn't produce any errors,
+to configure and, if that did not produce any errors,
type @code{make} to build FFmpeg.
@item The subdirectories @file{libavformat}, @file{libavcodec}, and
@item Write the source code for your application, or, for testing, just
copy the code from an existing sample application into the source file
that Visual C++ has already created for you. (Note that your source
-filehas to have a @code{.cpp} extension; otherwise, Visual C++ won't
-compile the FFmpeg headers correctly because in C mode, it doesn't
+filehas to have a @code{.cpp} extension; otherwise, Visual C++ will not
+compile the FFmpeg headers correctly because in C mode, it does not
recognize the @code{inline} keyword.) For example, you can copy
@file{output_example.c} from the FFmpeg distribution (but you will
have to make minor modifications so the code will compile under
the application. Hopefully, it should compile and run cleanly. If you
used @file{output_example.c} as your sample application, you will get a
few compiler errors, but they are easy to fix. The first type of error
-occurs because Visual C++ doesn't allow an @code{int} to be converted to
+occurs because Visual C++ does not allow an @code{int} to be converted to
an @code{enum} without a cast. To solve the problem, insert the required
casts (this error occurs once for a @code{CodecID} and once for a
@code{CodecType}). The second type of error occurs because C++ requires
Then configure FFmpeg with the following options:
@example
-./configure --enable-mingw32 --cross-prefix=i386-mingw32msvc-
+./configure --target-os=mingw32 --cross-prefix=i386-mingw32msvc-
@end example
(you can change the cross-prefix according to the prefix chosen for the
MinGW tools).
Then you can easily test FFmpeg with Wine
(@url{http://www.winehq.com/}).
-@section Mac OS X
+@subsection Compilation under Cygwin
+
+Cygwin works very much like Unix.
+
+Just install your Cygwin with all the "Base" packages, plus the
+following "Devel" ones:
+@example
+binutils, gcc-core, make, subversion
+@end example
+
+Do not install binutils-20060709-1 (they are buggy on shared builds);
+use binutils-20050610-1 instead.
+
+Then run
+
+@example
+./configure --enable-static --disable-shared
+@end example
+
+to make a static build or
+
+@example
+./configure --enable-shared --disable-static
+@end example
+
+to build shared libraries.
+
+If you want to build FFmpeg with additional libraries, download Cygwin
+"Devel" packages for Ogg and Vorbis from any Cygwin packages repository
+and/or SDL, xvid, faac, faad2 packages from Cygwin Ports,
+(@url{http://cygwinports.dotsrc.org/}).
+
+@subsection Crosscompilation for Windows under Cygwin
+
+With Cygwin you can create Windows binaries that do not need the cygwin1.dll.
+
+Just install your Cygwin as explained before, plus these additional
+"Devel" packages:
+@example
+gcc-mingw-core, mingw-runtime, mingw-zlib
+@end example
+
+and add some special flags to your configure invocation.
+
+For a static build run
+@example
+./configure --target-os=mingw32 --enable-memalign-hack --enable-static --disable-shared --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
+@end example
+
+and for a build with shared libraries
+@example
+./configure --target-os=mingw32 --enable-memalign-hack --enable-shared --disable-static --extra-cflags=-mno-cygwin --extra-libs=-mno-cygwin
+@end example
@section BeOS
François Revol - revol at free dot fr - April 2002
The configure script should guess the configuration itself,
-however I still didn't test building on the net_server version of BeOS.
+however I still did not test building on the net_server version of BeOS.
FFserver is broken (needs poll() implementation).
@chapter Developers Guide
@section API
-@itemize
+@itemize @bullet
@item libavcodec is the library containing the codecs (both encoding and
decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
compound literals (@samp{x = (struct s) @{ 17, 23 @};})
@end itemize
-These features are supported by all compilers we care about, so we won't
-accept patches to remove their use unless they absolutely don't impair
+These features are supported by all compilers we care about, so we will not
+accept patches to remove their use unless they absolutely do not impair
clarity and performance.
All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
compiles with several other compilers, such as the Compaq ccc compiler
or Sun Studio 9, and we would like to keep it that way unless it would
-be exceedingly involved. To ensure compatibility, please don't use any
+be exceedingly involved. To ensure compatibility, please do not use any
additional C99 features or GCC extensions. Especially watch out for:
@itemize @bullet
@item
The presentation is the one specified by 'indent -i4 -kr -nut'.
The TAB character is forbidden outside of Makefiles as is any
form of trailing whitespace. Commits containing either will be
-rejected by the CVS repository.
+rejected by the Subversion repository.
Main priority in FFmpeg is simplicity and small code size (=less
bugs).
Comments: Use the JavaDoc/Doxygen
format (see examples below) so that code documentation
can be generated automatically. All nontrivial functions should have a comment
-above them explaining what the function does, even if it's just one sentence.
+above them explaining what the function does, even if it is just one sentence.
All structures and their member variables should be documented, too.
@example
/**
fprintf and printf are forbidden in libavformat and libavcodec,
please use av_log() instead.
-@node CVS Policy
-@section CVS Policy
+@section Development Policy
@enumerate
@item
(#ifdef etc) by default so it does not interfere with other developers'
work.
@item
- You don't have to over-test things. If it works for you, and you think it
+ You do not have to over-test things. If it works for you, and you think it
should work for others, then commit. If your code has problems
(portability, triggers compiler bugs, unusual environment etc) they will be
reported and eventually fixed.
@item
Do not commit unrelated changes together, split them into self-contained
- pieces.
+ pieces. Also do not forget that if part B depends on part A, but A does not
+ depend on B, then A can and should be committed first and separate from B.
+ Keeping changes well split into self-contained parts makes reviewing and
+ understanding them on the commit log mailing list easier. This also helps
+ in case of debugging later on.
+ Also if you have doubts about splitting or not splitting, do not hesitate to
+ ask/disscuss it on the developer mailing list.
@item
Do not change behavior of the program (renaming options etc) without
first discussing it on the ffmpeg-devel mailing list. Do not remove
developer has his own indentation style, you should not change it. Of course
if you (re)write something, you can use your own style, even though we would
prefer if the indentation throughout FFmpeg was consistent (Many projects
- force a given indentation style - we don't.). If you really need to make
+ force a given indentation style - we do not.). If you really need to make
indentation changes (try to avoid this), separate them strictly from real
changes.
NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
- then either do NOT change the indentation of the inner part within (don't
+ then either do NOT change the indentation of the inner part within (do not
move it to the right)! or do so in a separate commit
@item
Always fill out the commit log message. Describe in a few lines what you
particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
@item
If you apply a patch by someone else, include the name and email address in
- the CVS log message. Since the ffmpeg-cvslog mailing list is publicly
+ the log message. Since the ffmpeg-cvslog mailing list is publicly
archived you should add some SPAM protection to the email address. Send an
answer to ffmpeg-devel (or wherever you got the patch from) saying that
you applied the patch.
@item
- Do NOT commit to code actively maintained by others without permission. Send
- a patch to ffmpeg-devel instead.
+ When applying patches that have been discussed (at length) on the mailing
+ list, reference the thread in the log message.
+@item
+ Do NOT commit to code actively maintained by others without permission.
+ Send a patch to ffmpeg-devel instead. If noone answers within a reasonable
+ timeframe (12h for build failures and security fixes, 3 days small changes,
+ 1 week for big patches) then commit your patch if you think it is OK.
+ Also note, the maintainer can simply ask for more time to review!
@item
- Subscribe to the ffmpeg-cvslog mailing list. The diffs of all CVS commits
+ Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
are sent there and reviewed by all the other developers. Bugs and possible
improvements or general questions regarding commits are discussed there. We
expect you to react if problems with your code are uncovered.
unsure how best to do this, send a patch to ffmpeg-devel, the documentation
maintainer(s) will review and commit your stuff.
@item
- Revert a commit ONLY in case of a big blunder like committing something not
- intended to be committed or committing a wrong file, the wrong version of a
- patch, CVS policy violation or broken code and you are going to recommit the
- right thing immediately.
-
- Never revert changes made a long time ago or buggy code. Fix it in the
- normal way instead.
+ Try to keep important discussions and requests (also) on the public
+ developer mailing list, so that all developers can benefit from them.
@item
Never write to unallocated memory, never write over the end of arrays,
always check values read from some untrusted source before using them
parts (libavutil, libavcodec, libavformat) you are changing. You need
to change the version integer and the version string.
Incrementing the first component means no backward compatibility to
- previous versions (e.g. removal of a function).
+ previous versions (e.g. removal of a function from the public API).
Incrementing the second component means backward compatible change
- (e.g. addition of a function).
+ (e.g. addition of a function to the public API).
Incrementing the third component means a noteworthy binary compatible
change (e.g. encoder bug fix that matters for the decoder).
@item
component of the @file{libavcodec} version number appropriately. If
it has a fourcc, add it to @file{libavformat/avienc.c}, even if it
is only a decoder.
+@item
+ Do not change code to hide warnings without ensuring that the underlying
+ logic is correct and thus the warning was inappropriate.
@end enumerate
We think our rules are not too hard. If you have comments, contact us.
Note, these rules are mostly borrowed from the MPlayer project.
-@subsection Renaming/moving files or content of files
- You CANNOT do that. Post a request for such a change to the mailing list
- Do NOT remove & readd a file - it will kill the changelog!!!!
-
@section Submitting patches
-First, (@pxref{Coding Rules}) above if you didn't yet.
+First, (@pxref{Coding Rules}) above if you did not yet.
When you submit your patch, try to send a unified diff (diff '-up'
option). I cannot read other diffs :-)
verify that there are no big problems.
Patches should be posted as base64 encoded attachments (or any other
-encoding which ensures that the patch won't be trashed during
+encoding which ensures that the patch will not be trashed during
transmission) to the ffmpeg-devel mailing list, see
-@url{http://www1.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
+@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
It also helps quite a bit if you tell us what the patch does (for example
'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
and has no lrint()')
-We reply to all submitted patches and either apply or reject with some
-explanation why, but sometimes we are quite busy so it can take a week or two.
+Also please if you send several patches, send each patch as seperate mail,
+dont attach several unrelated patches to the same mail.
+
+@section Patch review process
+
+All patches posted to ffmpeg-devel will be reviewed, unless they contain a
+clear note that the patch is not for SVN.
+Reviews and comments will be posted as replies to the patch on the
+mailing list. The patch submitter then has to take care of every comment,
+that can be by resubmitting a changed patch or by disscussion. Resubmitted
+patches will themselves be reviewed like any other patch. If at some point
+a patch passes review with no comments then it is approved, that can for
+simple and small patches happen immediately while large patches will generally
+have to be changed and reviewed many times before they are approved.
+After a patch is approved it will be committed to the repository.
+
+We will review all submitted patches, but sometimes we are quite busy so
+especially for large patches this can take several weeks.
+
+When resubmitting patches, please do not make any significant changes
+not related to the comments received during review. Such patches will
+be rejected. Instead, submit significant changes or new features as
+separate patches.
@section Regression tests
-Before submitting a patch (or committing to CVS), you should at least
+Before submitting a patch (or committing to the repository), you should at least
test that you did not break anything.
The regression tests build a synthetic video stream and a synthetic
projects / ffmpeg / blobdiff