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diff --git a/contrib/ffmpeg/doc/faq.texi b/contrib/ffmpeg/doc/faq.texi deleted file mode 100644 index 85a0915b9..000000000 --- a/contrib/ffmpeg/doc/faq.texi +++ /dev/null @@ -1,472 +0,0 @@ -\input texinfo @c -*- texinfo -*- - -@settitle FFmpeg FAQ -@titlepage -@sp 7 -@center @titlefont{FFmpeg FAQ} -@sp 3 -@end titlepage - - -@chapter General Questions - -@section When will the next FFmpeg version be released? / Why are FFmpeg releases so few and far between? - -Like most open source projects FFmpeg suffers from a certain lack of -manpower. For this reason the developers have to prioritize the work -they do and putting out releases is not at the top of the list, fixing -bugs and reviewing patches takes precedence. Please don't complain or -request more timely and/or frequent releases unless you are willing to -help out creating them. - -@section I have a problem with an old version of FFmpeg; where should I report it? -Nowhere. Upgrade to the latest release or if there is no recent release upgrade -to Subversion HEAD. You could also try to report it. Maybe you will get lucky and -become the first person in history to get an answer different from "upgrade -to Subversion HEAD". - -@section Why doesn't FFmpeg support feature [xyz]? - -Because no one has taken on that task yet. FFmpeg development is -driven by the tasks that are important to the individual developers. -If there is a feature that is important to you, the best way to get -it implemented is to undertake the task yourself or sponsor a developer. - -@section FFmpeg does not support codec XXX. Can you include a Windows DLL loader to support it? - -No. Windows DLLs are not portable, bloated and often slow. -Moreover FFmpeg strives to support all codecs natively. -A DLL loader is not conducive to that goal. - -@section My bugreport/mail to ffmpeg-devel/user has not received any replies. - -Likely reasons -@itemize -@item We are busy and haven't had time yet to read your report or -investigate the issue. -@item You didn't follow bugreports.html. -@item You didn't use Subversion HEAD. -@item You reported a segmentation fault without gdb output. -@item You describe a problem but not how to reproduce it. -@item It's unclear if you use ffmpeg as command line tool or use -libav* from another application. -@item You speak about a video having problems on playback but -not what you use to play it. -@item We have no faint clue what you are talking about besides -that it is related to FFmpeg. -@end itemize - -@section Is there a forum for FFmpeg? I do not like mailing lists. - -Yes, (@url{http://dir.gmane.org/gmane.comp.video.ffmpeg.user}). - -@section I cannot read this file although this format seems to be supported by ffmpeg. - -Even if ffmpeg can read the container format, it may not support all its -codecs. Please consult the supported codec list in the ffmpeg -documentation. - -@section Which codecs are supported by Windows? - -Windows does not support standard formats like MPEG very well, unless you -install some additional codecs - -The following list of video codecs should work on most Windows systems: -@table @option -@item msmpeg4v2 -.avi/.asf -@item msmpeg4 -.asf only -@item wmv1 -.asf only -@item wmv2 -.asf only -@item mpeg4 -only if you have some MPEG-4 codec installed like ffdshow or XviD -@item mpeg1 -.mpg only -@end table -Note, ASF files often have .wmv or .wma extensions in Windows. It should also -be mentioned that Microsoft claims a patent on the ASF format, and may sue -or threaten users who create ASF files with non-Microsoft software. It is -strongly advised to avoid ASF where possible. - -The following list of audio codecs should work on most Windows systems: -@table @option -@item adpcm_ima_wav -@item adpcm_ms -@item pcm -@item mp3 -if some MP3 codec like LAME is installed -@end table - - -@chapter Usage - -@section ffmpeg does not work; What is wrong? - -Try a @code{make distclean} in the ffmpeg source directory before the build. If this does not help see -(@url{http://ffmpeg.org/bugreports.html}). - -@section How do I encode single pictures to movies? - -First, rename your pictures to follow a numerical sequence. -For example, img1.jpg, img2.jpg, img3.jpg,... -Then you may run: - -@example - ffmpeg -f image2 -i img%d.jpg /tmp/a.mpg -@end example - -Notice that @samp{%d} is replaced by the image number. - -@file{img%03d.jpg} means the sequence @file{img001.jpg}, @file{img002.jpg}, etc... - -The same logic is used for any image format that ffmpeg reads. - -@section How do I encode movie to single pictures? - -Use: - -@example - ffmpeg -i movie.mpg movie%d.jpg -@end example - -The @file{movie.mpg} used as input will be converted to -@file{movie1.jpg}, @file{movie2.jpg}, etc... - -Instead of relying on file format self-recognition, you may also use -@table @option -@item -vcodec ppm -@item -vcodec png -@item -vcodec mjpeg -@end table -to force the encoding. - -Applying that to the previous example: -@example - ffmpeg -i movie.mpg -f image2 -vcodec mjpeg menu%d.jpg -@end example - -Beware that there is no "jpeg" codec. Use "mjpeg" instead. - -@section I get "Unsupported codec (id=86043) for input stream #0.1". What is the problem? - -This is the Qcelp codec, FFmpeg has no support for that codec currently. Try mencoder/mplayer it might work. - -@section Why do I see a slight quality degradation with multithreaded MPEG* encoding? - -For multithreaded MPEG* encoding, the encoded slices must be independent, -otherwise thread n would practically have to wait for n-1 to finish, so it's -quite logical that there is a small reduction of quality. This is not a bug. - -@section How can I read from the standard input or write to the standard output? - -Use @file{-} as filename. - -@section Why does FFmpeg not decode audio in VOB files? - -The audio is AC-3 (a.k.a. A/52). AC-3 decoding is an optional component in FFmpeg -as the component that handles AC-3 decoding is currently released under the GPL. -Enable AC-3 decoding with @code{./configure --enable-gpl}. Take care: By -enabling AC-3, you automatically change the license of libavcodec from -LGPL to GPL. - -@section Why does the chrominance data seem to be sampled at a different time from the luminance data on bt8x8 captures on Linux? - -This is a well-known bug in the bt8x8 driver. For 2.4.26 there is a patch at -(@url{http://svn.mplayerhq.hu/michael/trunk/patches/bttv-420-2.4.26.patch?view=co}). This may also -apply cleanly to other 2.4-series kernels. - -@section How do I avoid the ugly aliasing artifacts in bt8x8 captures on Linux? - -Pass 'combfilter=1 lumafilter=1' to the bttv driver. Note though that 'combfilter=1' -will cause somewhat too strong filtering. A fix is to apply (@url{http://svn.mplayerhq.hu/michael/trunk/patches/bttv-comb-2.4.26.patch?view=co}) -or (@url{http://svn.mplayerhq.hu/michael/trunk/patches/bttv-comb-2.6.6.patch?view=co}) -and pass 'combfilter=2'. - -@section -f jpeg doesn't work. - -Try '-f image2 test%d.jpg'. - -@section Why can I not change the framerate? - -Some codecs, like MPEG-1/2, only allow a small number of fixed framerates. -Choose a different codec with the -vcodec command line option. - -@section How do I encode XviD or DivX video with ffmpeg? - -Both XviD and DivX (version 4+) are implementations of the ISO MPEG-4 -standard (note that there are many other coding formats that use this -same standard). Thus, use '-vcodec mpeg4' to encode these formats. The -default fourcc stored in an MPEG-4-coded file will be 'FMP4'. If you want -a different fourcc, use the '-vtag' option. E.g., '-vtag xvid' will -force the fourcc 'xvid' to be stored as the video fourcc rather than the -default. - -@section How do I encode videos which play on the iPod? - -@table @option -@item needed stuff --acodec libfaac -vcodec mpeg4 width<=320 height<=240 -@item working stuff -4mv, title -@item non-working stuff -B-frames -@item example command line -ffmpeg -i input -acodec libfaac -ab 128kb -vcodec mpeg4 -b 1200kb -mbd 2 -flags +4mv+trell -aic 2 -cmp 2 -subcmp 2 -s 320x180 -title X output.mp4 -@end table - -@section How do I encode videos which play on the PSP? - -@table @option -@item needed stuff --acodec libfaac -vcodec mpeg4 width*height<=76800 width%16=0 height%16=0 -ar 24000 -r 30000/1001 or 15000/1001 -f psp -@item working stuff -4mv, title -@item non-working stuff -B-frames -@item example command line -ffmpeg -i input -acodec libfaac -ab 128kb -vcodec mpeg4 -b 1200kb -ar 24000 -mbd 2 -flags +4mv+trell -aic 2 -cmp 2 -subcmp 2 -s 368x192 -r 30000/1001 -title X -f psp output.mp4 -@item needed stuff for H.264 --acodec libfaac -vcodec h264 width*height<=76800 width%16=0? height%16=0? -ar 48000 -coder 1 -r 30000/1001 or 15000/1001 -f psp -@item working stuff for H.264 -title, loop filter -@item non-working stuff for H.264 -CAVLC -@item example command line -ffmpeg -i input -acodec libfaac -ab 128kb -vcodec h264 -b 1200kb -ar 48000 -mbd 2 -coder 1 -cmp 2 -subcmp 2 -s 368x192 -r 30000/1001 -title X -f psp -flags loop -trellis 2 -partitions parti4x4+parti8x8+partp4x4+partp8x8+partb8x8 output.mp4 -@end table - -@section Which are good parameters for encoding high quality MPEG-4? - -'-mbd rd -flags +4mv+trell+aic -cmp 2 -subcmp 2 -g 300 -pass 1/2', -things to try: '-bf 2', '-flags qprd', '-flags mv0', '-flags skiprd'. - -@section Which are good parameters for encoding high quality MPEG-1/MPEG-2? - -'-mbd rd -flags +trell -cmp 2 -subcmp 2 -g 100 -pass 1/2' -but beware the '-g 100' might cause problems with some decoders. -Things to try: '-bf 2', '-flags qprd', '-flags mv0', '-flags skiprd. - -@section Interlaced video looks very bad when encoded with ffmpeg, whats wrong? - -You should use '-flags +ilme+ildct' and maybe '-flags +alt' for interlaced -material, and try '-top 0/1' if the result looks really messed-up. - -@section How can I read DirectShow files? - -If you have built FFmpeg with @code{./configure --enable-avisynth} -(only possible on MinGW/Cygwin platforms), -then you may use any file that DirectShow can read as input. -(Be aware that this feature has been recently added, -so you will need to help yourself in case of problems.) - -Just create an "input.avs" text file with this single line ... -@example - DirectShowSource("C:\path to your file\yourfile.asf") -@end example -... and then feed that text file to FFmpeg: -@example - ffmpeg -i input.avs -@end example - -For ANY other help on Avisynth, please visit @url{http://www.avisynth.org/}. - -@section How can I join video files? - -A few multimedia containers (MPEG-1, MPEG-2 PS, DV) allow to join video files by -merely concatenating them. - -Hence you may concatenate your multimedia files by first transcoding them to -these privileged formats, then using the humble @code{cat} command (or the -equally humble @code{copy} under Windows), and finally transcoding back to your -format of choice. - -@example -ffmpeg -i input1.avi -sameq intermediate1.mpg -ffmpeg -i input2.avi -sameq intermediate2.mpg -cat intermediate1.mpg intermediate2.mpg > intermediate_all.mpg -ffmpeg -i intermediate_all.mpg -sameq output.avi -@end example - -Notice that you should either use @code{-sameq} or set a reasonably high -bitrate for your intermediate and output files, if you want to preserve -video quality. - -Also notice that you may avoid the huge intermediate files by taking advantage -of named pipes, should your platform support it: - -@example -mkfifo intermediate1.mpg -mkfifo intermediate2.mpg -ffmpeg -i input1.avi -sameq -y intermediate1.mpg < /dev/null & -ffmpeg -i input2.avi -sameq -y intermediate2.mpg < /dev/null & -cat intermediate1.mpg intermediate2.mpg |\ -ffmpeg -f mpeg -i - -sameq -vcodec mpeg4 -acodec libmp3lame output.avi -@end example - -Similarly, the yuv4mpegpipe format, and the raw video, raw audio codecs also -allow concatenation, and the transcoding step is almost lossless. - -For example, let's say we want to join two FLV files into an output.flv file: - -@example -mkfifo temp1.a -mkfifo temp1.v -mkfifo temp2.a -mkfifo temp2.v -mkfifo all.a -mkfifo all.v -ffmpeg -i input1.flv -vn -f u16le -acodec pcm_s16le -ac 2 -ar 44100 - > temp1.a < /dev/null & -ffmpeg -i input2.flv -vn -f u16le -acodec pcm_s16le -ac 2 -ar 44100 - > temp2.a < /dev/null & -ffmpeg -i input1.flv -an -f yuv4mpegpipe - > temp1.v < /dev/null & -ffmpeg -i input2.flv -an -f yuv4mpegpipe - > temp2.v < /dev/null & -cat temp1.a temp2.a > all.a & -cat temp1.v temp2.v > all.v & -ffmpeg -f u16le -acodec pcm_s16le -ac 2 -ar 44100 -i all.a \ - -f yuv4mpegpipe -i all.v \ - -sameq -y output.flv -rm temp[12].[av] all.[av] -@end example - -@section FFmpeg does not adhere to the -maxrate setting, some frames are bigger than maxrate/fps. - -Read the MPEG spec about video buffer verifier. - -@section I want CBR, but no matter what I do frame sizes differ. - -You do not understand what CBR is, please read the MPEG spec. -Read about video buffer verifier and constant bitrate. -The one sentence summary is that there is a buffer and the input rate is -constant, the output can vary as needed. - -@section How do I check if a stream is CBR? - -To quote the MPEG-2 spec: -"There is no way to tell that a bitstream is constant bitrate without -examining all of the vbv_delay values and making complicated computations." - - -@chapter Development - -@section Are there examples illustrating how to use the FFmpeg libraries, particularly libavcodec and libavformat? - -Yes. Read the Developers Guide of the FFmpeg documentation. Alternatively, -examine the source code for one of the many open source projects that -already incorporate ffmpeg at (@url{projects.html}). - -@section Can you support my C compiler XXX? - -It depends. If your compiler is C99-compliant, then patches to support -it are likely to be welcome if they do not pollute the source code -with @code{#ifdef}s related to the compiler. - -@section Is Microsoft Visual C++ supported? - -No. Microsoft Visual C++ is not compliant to the C99 standard and does -not - among other things - support the inline assembly used in FFmpeg. -If you wish to use MSVC++ for your -project then you can link the MSVC++ code with libav* as long as -you compile the latter with a working C compiler. For more information, see -the @emph{Microsoft Visual C++ compatibility} section in the FFmpeg -documentation. - -There have been efforts to make FFmpeg compatible with MSVC++ in the -past. However, they have all been rejected as too intrusive, especially -since MinGW does the job adequately. None of the core developers -work with MSVC++ and thus this item is low priority. Should you find -the silver bullet that solves this problem, feel free to shoot it at us. - -We strongly recommend you to move over from MSVC++ to MinGW tools. - -@section Can I use FFmpeg or libavcodec under Windows? - -Yes, but the Cygwin or MinGW tools @emph{must} be used to compile FFmpeg. -Read the @emph{Windows} section in the FFmpeg documentation to find more -information. - -To get help and instructions for building FFmpeg under Windows, check out -the FFmpeg Windows Help Forum at -@url{http://arrozcru.no-ip.org/ffmpeg/}. - -@section Can you add automake, libtool or autoconf support? - -No. These tools are too bloated and they complicate the build. - -@section Why not rewrite ffmpeg in object-oriented C++? - -ffmpeg is already organized in a highly modular manner and does not need to -be rewritten in a formal object language. Further, many of the developers -favor straight C; it works for them. For more arguments on this matter, -read "Programming Religion" at (@url{http://www.tux.org/lkml/#s15}). - -@section Why are the ffmpeg programs devoid of debugging symbols? - -The build process creates ffmpeg_g, ffplay_g, etc. which contain full debug -information. Those binaries are strip'd to create ffmpeg, ffplay, etc. If -you need the debug information, used the *_g versions. - -@section I do not like the LGPL, can I contribute code under the GPL instead? - -Yes, as long as the code is optional and can easily and cleanly be placed -under #ifdef CONFIG_GPL without breaking anything. So for example a new codec -or filter would be OK under GPL while a bugfix to LGPL code would not. - -@section I want to compile xyz.c alone but my compiler produced many errors. - -Common code is in its own files in libav* and is used by the individual -codecs. They will not work without the common parts, you have to compile -the whole libav*. If you wish, disable some parts with configure switches. -You can also try to hack it and remove more, but if you had problems fixing -the compilation failure then you are probably not qualified for this. - -@section I'm using libavcodec from within my C++ application but the linker complains about missing symbols which seem to be available. - -FFmpeg is a pure C project, so to use the libraries within your C++ application -you need to explicitly state that you are using a C library. You can do this by -encompassing your FFmpeg includes using @code{extern "C"}. - -See @url{http://www.parashift.com/c++-faq-lite/mixing-c-and-cpp.html#faq-32.3} - -@section I have a file in memory / a API different from *open/*read/ libc how do i use it with libavformat? - -You have to implement a URLProtocol, see libavformat/file.c in FFmpeg -and libmpdemux/demux_lavf.c in MPlayer sources. - -@section I get "No compatible shell script interpreter found." in MSys. - -The standard MSys bash (2.04) is broken. You need to install 2.05 or later. - -@section I get "./configure: line <xxx>: pr: command not found" in MSys. - -The standard MSys install doesn't come with pr. You need to get it from the coreutils package. - -@section I tried to pass RTP packets into a decoder, but it doesn't work. - -RTP is a container format like any other, you must first depacketize the -codec frames/samples stored in RTP and then feed to the decoder. - -@section Where can I find libav* headers for Pascal/Delphi? - -see @url{http://www.iversenit.dk/dev/ffmpeg-headers/} - -@section Where is the documentation about ffv1, msmpeg4, asv1, 4xm? - -see @url{http://svn.mplayerhq.hu/michael/trunk/docs/} - -@section How do I feed H.263-RTP (and other codecs in RTP) to libavcodec? - -Even if peculiar since it is network oriented, RTP is a container like any -other. You have to @emph{demux} RTP before feeding the payload to libavcodec. -In this specific case please look at RFC 4629 to see how it should be done. - -@section AVStream.r_frame_rate is wrong, it is much larger than the framerate. - -r_frame_rate is NOT the average framerate, it is the smallest framerate -that can accurately represent all timestamps. So no, it is not -wrong if it is larger than the average! -For example, if you have mixed 25 and 30 fps content, then r_frame_rate -will be 150. - -@bye |