\input texinfo @c -*- texinfo -*-
-@settitle FFmpeg FAQ
+@settitle Libav FAQ
@titlepage
-@center @titlefont{FFmpeg FAQ}
+@center @titlefont{Libav FAQ}
@end titlepage
@top
@chapter General Questions
-@section When will the next FFmpeg version be released? / Why are FFmpeg releases so few and far between?
+@section When will the next Libav version be released? / Why are Libav releases so few and far between?
-Like most open source projects FFmpeg suffers from a certain lack of
+Like most open source projects Libav 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. We do not support old FFmpeg versions in any way, we simply lack
+@section I have a problem with an old version of Libav; where should I report it?
+Nowhere. We do not support old Libav versions in any way, we simply lack
the time, motivation and manpower to do so. If you have a problem with an
-old version of FFmpeg, upgrade to the latest Subversion snapshot. If you
-still experience the problem, then you can report it according to the
-guidelines in @url{http://ffmpeg.org/bugreports.html}.
+old version of Libav, upgrade to the latest git snapshot. If you
+still experience the problem, then you can report it according to our
+@uref{http://libav.org/bugreports.html, bug reporting guidelines}.
-@section Why doesn't FFmpeg support feature [xyz]?
+@section Why doesn't Libav support feature [xyz]?
-Because no one has taken on that task yet. FFmpeg development is
+Because no one has taken on that task yet. Libav 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?
+@section Libav 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.
+Moreover Libav strives to support all codecs natively.
A DLL loader is not conducive to that goal.
-@section My bug report/mail to ffmpeg-devel/user has not received any replies.
+@section My bug report/mail to libav-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 @url{http://ffmpeg.org/bugreports.html}.
-@item You didn't use Subversion HEAD.
+@item You did not follow our
+ @uref{http://libav.org/bugreports.html, bug reporting guidelines}.
+@item You didn't use git master.
@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
@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.
+that it is related to Libav.
@end itemize
-@section Is there a forum for FFmpeg? I do not like mailing lists.
+@section Is there a forum for Libav? I do not like mailing lists.
You may view our mailing lists with a more forum-alike look here:
@url{http://dir.gmane.org/gmane.comp.video.ffmpeg.user},
.asf only
@item mpeg4
Only if you have some MPEG-4 codec like ffdshow or Xvid installed.
-@item mpeg1
+@item mpeg1video
.mpg only
@end table
Note, ASF files often have .wmv or .wma extensions in Windows. It should also
@table @option
@item adpcm_ima_wav
@item adpcm_ms
-@item pcm
+@item pcm_s16le
always
-@item mp3
+@item libmp3lame
If some MP3 codec like LAME is installed.
@end table
@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}).
+Try a @code{make distclean} in the ffmpeg source directory before the build.
+If this does not help see our
+@uref{http://libav.org/bugreports.html, bug reporting guidelines}.
@section How do I encode single pictures into movies?
@file{img001.jpg}, @file{img002.jpg} and so on.
@example
- x=1; for i in *jpg; do counter=$(printf %03d $x); ln "$i" /tmp/img"$counter".jpg; x=$(($x+1)); done
+ x=1; for i in *jpg; do counter=$(printf %03d $x); ln -s "$i" /tmp/img"$counter".jpg; x=$(($x+1)); done
@end example
If you want to sequence them by oldest modified first, substitute
@item non-working stuff
B-frames
@item example command line
-ffmpeg -i input -acodec libfaac -ab 128kb -vcodec mpeg4 -b 1200kb -mbd 2 -flags +mv4 -trellis 2 -aic 2 -cmp 2 -subcmp 2 -s 320x180 -metadata title=X output.mp4
+ffmpeg -i input -acodec libfaac -ab 128k -vcodec mpeg4 -b 1200k -mbd 2 -flags +mv4+aic -trellis 2 -cmp 2 -subcmp 2 -s 320x180 -metadata title=X output.mp4
@end table
@section How do I encode videos which play on the PSP?
@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 +mv4 -trellis 2 -aic 2 -cmp 2 -subcmp 2 -s 368x192 -r 30000/1001 -metadata title=X -f psp output.mp4
+ffmpeg -i input -acodec libfaac -ab 128k -vcodec mpeg4 -b 1200k -ar 24000 -mbd 2 -flags +mv4+aic -trellis 2 -cmp 2 -subcmp 2 -s 368x192 -r 30000/1001 -metadata title=X -f psp output.mp4
@item needed stuff for H.264
-acodec libfaac -vcodec libx264 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
@item non-working stuff for H.264
CAVLC
@item example command line
-ffmpeg -i input -acodec libfaac -ab 128kb -vcodec libx264 -b 1200kb -ar 48000 -mbd 2 -coder 1 -cmp 2 -subcmp 2 -s 368x192 -r 30000/1001 -metadata title=X -f psp -flags loop -trellis 2 -partitions parti4x4+parti8x8+partp4x4+partp8x8+partb8x8 output.mp4
+ffmpeg -i input -acodec libfaac -ab 128k -vcodec libx264 -b 1200k -ar 48000 -mbd 2 -coder 1 -cmp 2 -subcmp 2 -s 368x192 -r 30000/1001 -metadata title=X -f psp -flags loop -trellis 2 -partitions parti4x4+parti8x8+partp4x4+partp8x8+partb8x8 output.mp4
@item higher resolution for newer PSP firmwares, width<=480, height<=272
-vcodec libx264 -level 21 -coder 1 -f psp
@item example command line
-ffmpeg -i input -acodec libfaac -ab 128kb -ac 2 -ar 48000 -vcodec libx264 -level 21 -b 640kb -coder 1 -f psp -flags +loop -trellis 2 -partitions +parti4x4+parti8x8+partp4x4+partp8x8+partb8x8 -g 250 -s 480x272 output.mp4
+ffmpeg -i input -acodec libfaac -ab 128k -ac 2 -ar 48000 -vcodec libx264 -level 21 -b 640k -coder 1 -f psp -flags +loop -trellis 2 -partitions +parti4x4+parti8x8+partp4x4+partp8x8+partb8x8 -g 250 -s 480x272 output.mp4
@end table
@section Which are good parameters for encoding high quality MPEG-4?
@section How can I read DirectShow files?
-If you have built FFmpeg with @code{./configure --enable-avisynth}
+If you have built Libav with @code{./configure --enable-avisynth}
(only possible on MinGW/Cygwin platforms),
then you may use any file that DirectShow can read as input.
@example
DirectShowSource("C:\path to your file\yourfile.asf")
@end example
-... and then feed that text file to FFmpeg:
+... 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/}.
+For ANY other help on Avisynth, please visit the
+@uref{http://www.avisynth.org/, Avisynth homepage}.
@section How can I join video files?
rm temp[12].[av] all.[av]
@end example
-@section FFmpeg does not adhere to the -maxrate setting, some frames are bigger than maxrate/fps.
+@section The ffmpeg program does not respect the -maxrate setting, some frames are bigger than maxrate/fps.
Read the MPEG spec about video buffer verifier.
@chapter Development
-@section Are there examples illustrating how to use the FFmpeg libraries, particularly libavcodec and libavformat?
+@section Are there examples illustrating how to use the Libav libraries, particularly libavcodec and libavformat?
-Yes. Read the Developers Guide of the FFmpeg documentation. Alternatively,
+Yes. Read the Developers Guide of the Libav documentation. Alternatively,
examine the source code for one of the many open source projects that
-already incorporate FFmpeg at (@url{projects.html}).
+already incorporate Libav at (@url{projects.html}).
@section Can you support my C compiler XXX?
@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.
+not - among other things - support the inline assembly used in Libav.
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
+the @emph{Microsoft Visual C++ compatibility} section in the Libav
documentation.
-There have been efforts to make FFmpeg compatible with MSVC++ in the
+There have been efforts to make Libav 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
We strongly recommend you to move over from MSVC++ to MinGW tools.
-@section Can I use FFmpeg or libavcodec under Windows?
+@section Can I use Libav 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
+Yes, but the Cygwin or MinGW tools @emph{must} be used to compile Libav.
+Read the @emph{Windows} section in the Libav 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://ffmpeg.arrozcru.org/}.
-
@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
+Libav 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 stripped to create ffmpeg, ffplay, etc. If
-you need the debug information, used the *_g versions.
+read @uref{http://www.tux.org/lkml/#s15, "Programming Religion"}.
@section I do not like the LGPL, can I contribute code under the GPL instead?
@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
+Libav 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"}.
+encompassing your Libav includes using @code{extern "C"}.
See @url{http://www.parashift.com/c++-faq-lite/mixing-c-and-cpp.html#faq-32.3}
+@section I'm using libavutil from within my C++ application but the compiler complains about 'UINT64_C' was not declared in this scope
+
+Libav is a pure C project using C99 math features, in order to enable C++
+to use them you have to append -D__STDC_CONSTANT_MACROS to your CXXFLAGS
+
@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 @file{libavformat/file.c} in
-FFmpeg and @file{libmpdemux/demux_lavf.c} in MPlayer sources.
+Libav and @file{libmpdemux/demux_lavf.c} in MPlayer sources.
@section I get "No compatible shell script interpreter found." in MSys.
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