\input texinfo @c -*- texinfo -*-
-@settitle FFmpeg FAQ
+@settitle Libav FAQ
@titlepage
-@sp 7
-@center @titlefont{FFmpeg FAQ}
-@sp 3
+@center @titlefont{Libav FAQ}
@end titlepage
+@top
-@chapter General Problems
+@contents
+
+@chapter General Questions
+
+@section When will the next Libav version be released? / Why are Libav releases so few and far between?
+
+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 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 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 Libav support feature [xyz]?
+
+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 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 Libav strives to support all codecs natively.
+A DLL loader is not conducive to that goal.
+
+@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 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
+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 Libav.
+@end itemize
+
+@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},
+but, if you post, please remember that our mailing list rules still apply there.
@section I cannot read this file although this format seems to be supported by ffmpeg.
-Even if ffmpeg can read the file format, it may not support all its
+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 How do I encode single pictures to movies?
+@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 like ffdshow or Xvid installed.
+@item mpeg1video
+.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_s16le
+always
+@item libmp3lame
+If some MP3 codec like LAME is installed.
+@end table
+
+
+@chapter Compilation
+
+@section @code{error: can't find a register in class 'GENERAL_REGS' while reloading 'asm'}
+
+This is a bug in gcc. Do not report it to us. Instead, please report it to
+the gcc developers. Note that we will not add workarounds for gcc bugs.
+
+Also note that (some of) the gcc developers believe this is not a bug or
+not a bug they should fix:
+@url{http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11203}.
+Then again, some of them do not know the difference between an undecidable
+problem and an NP-hard problem...
+
+@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 our
+@uref{http://libav.org/bugreports.html, bug reporting guidelines}.
+
+@section How do I encode single pictures into movies?
First, rename your pictures to follow a numerical sequence.
For example, img1.jpg, img2.jpg, img3.jpg,...
@file{img%03d.jpg} means the sequence @file{img001.jpg}, @file{img002.jpg}, etc...
+If you have large number of pictures to rename, you can use the
+following command to ease the burden. The command, using the bourne
+shell syntax, symbolically links all files in the current directory
+that match @code{*jpg} to the @file{/tmp} directory in the sequence of
+@file{img001.jpg}, @file{img002.jpg} and so on.
+
+@example
+ x=1; for i in *jpg; do counter=$(printf %03d $x); ln -s "$i" /tmp/img"$counter".jpg; x=$(($x+1)); done
+@end example
+
+If you want to sequence them by oldest modified first, substitute
+@code{$(ls -r -t *jpg)} in place of @code{*jpg}.
+
+Then run:
+
+@example
+ ffmpeg -f image2 -i /tmp/img%03d.jpg /tmp/a.mpg
+@end example
+
The same logic is used for any image format that ffmpeg reads.
@section How do I encode movie to single pictures?
Beware that there is no "jpeg" codec. Use "mjpeg" instead.
-@section FFmpeg does not support codec XXX. Can you include a Windows DLL loader to support it?
-
-No. FFmpeg only supports open source codecs. Windows DLLs are not
-portable, bloated and often slow.
-
-@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,
@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 AC3 (a.k.a. A/52). AC3 decoding is an optional component in ffmpeg
-as the component that handles AC3 decoding (liba52) is currently released under
-the GPL. If you have liba52 installed on your system, enable AC3 decoding
-with @code{./configure --enable-liba52 --enable-gpl}. Take care: by
-enabling AC3, you automatically change the license of libavcodec from
-LGPL to GPL.
-
-@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
-
-@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 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".
+Use @file{-} as file name.
@section -f jpeg doesn't work.
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 ffmpeg does not work; What is wrong?
+@section How do I encode Xvid or DivX video with ffmpeg?
-Try a 'make distclean' in the ffmpeg source directory before the build. If this does not help see
-(@url{http://ffmpeg.org/bugreports.php}).
-
-@section How do I encode XviD or DivX video with ffmpeg?
-
-Both XviD and DivX (version 4+) are implementations of the ISO MPEG-4
+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
+same standard). Thus, use '-vcodec mpeg4' to encode in 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
@item needed stuff
-acodec libfaac -vcodec mpeg4 width<=320 height<=240
@item working stuff
-4mv, title
+mv4, 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
+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 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
+mv4, 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
+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 h264 width*height<=76800 width%16=0? height%16=0? -ar 48000 -coder 1 -r 30000/1001 or 15000/1001 -f psp
+-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
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
+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 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?
-'-mbd rd -flags +4mv+trell+aic -cmp 2 -subcmp 2 -g 300 -pass 1/2',
+'-mbd rd -flags +mv4+aic -trellis 2 -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'
+'-mbd rd -trellis 2 -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?
+@section Interlaced video looks very bad when encoded with ffmpeg, what is 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}
+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.
-(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:
+... 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 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
+For ANY other help on Avisynth, please visit the
+@uref{http://www.avisynth.org/, Avisynth homepage}.
@section How can I join video files?
Similarly, the yuv4mpegpipe format, and the raw video, raw audio codecs also
allow concatenation, and the transcoding step is almost lossless.
+When using multiple yuv4mpegpipe(s), the first line needs to be discarded
+from all but the first stream. This can be accomplished by piping through
+@code{tail} as seen below. Note that when piping through @code{tail} you
+must use command grouping, @code{@{ ;@}}, to background properly.
For example, let's say we want to join two FLV files into an output.flv file:
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 &
+@{ ffmpeg -i input2.flv -an -f yuv4mpegpipe - < /dev/null | tail -n +2 > temp2.v ; @} &
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 \
rm temp[12].[av] all.[av]
@end example
-@section Is there a forum for ffmpeg, i dont like mailinglists?
-
-yes, (@url{http://dir.gmane.org/gmane.comp.video.ffmpeg.user})
-
-@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, read about video buffer verifer.
+Read the MPEG spec about video buffer verifier.
-@section I want CBR but no matter what i do frame sizes differ
+@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 verifer and constant bitrate.
-The 1 sentence summary is that there is a buffer and the input rate is
+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?
+@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
@chapter Development
-@section When will the next FFmpeg version be released? / Why are FFmpeg releases so few and far between?
+@section Are there examples illustrating how to use the Libav libraries, particularly libavcodec and libavformat?
-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 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.
-
-
-@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,
+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.php}).
+already incorporate Libav at (@url{projects.html}).
@section Can you support my C compiler XXX?
it are likely to be welcome if they do not pollute the source code
with @code{#ifdef}s related to the compiler.
-@section Visual C++ produces many errors.
+@section Is Microsoft Visual C++ supported?
-Visual C++ is not compliant to the C standard and does not support
-the inline assembly used in FFmpeg.
-If you wish - for whatever weird reason - to use Visual C++ for your
-project then you can link the Visual C++ code with libav* as long as
+No. Microsoft Visual C++ is not compliant to the C99 standard and does
+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{Visual C++ compatibility} section in the FFmpeg documentation.
+the @emph{Microsoft Visual C++ compatibility} section in the Libav
+documentation.
-There have been efforts to make FFmpeg compatible with Visual C++ 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 perfectly adequately. None of the core developers
-work with Visual C++ and thus this item is low priority. Should you find
+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.
-@section Can I use FFmpeg or libavcodec under Windows?
+We strongly recommend you to move over from MSVC++ to MinGW tools.
-Yes, but the MinGW tools @emph{must} be used to compile FFmpeg. You
-can link the resulting DLLs with any other Windows program. Read the
-@emph{Native Windows Compilation} and @emph{Visual C++ compatibility}
-sections in the FFmpeg documentation to find more information.
+@section Can I use Libav or libavcodec under 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/}.
+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.
@section Can you add automake, libtool or autoconf support?
@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 strip'd 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?
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.
+under #if CONFIG_GPL without breaking anything. So for example a new codec
+or filter would be OK under GPL while a bug fix to LGPL code would not.
@section I want to compile xyz.c alone but my compiler produced many errors.
@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 have a file in memory / a API different from *open/*read/ libc how do i use it with libavformat?
+@section I'm using libavutil from within my C++ application but the compiler complains about 'UINT64_C' was not declared in this scope
-You have to implement a URLProtocol, see libavformat/file.c in FFmpeg
-and libmpdemux/demux_lavf.c in MPlayer sources.
+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
+Libav and @file{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 tried to pass RTP packets into a decoder, but it doesn't work.
+@section I get "./configure: line <xxx>: pr: command not found" in MSys.
-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.
+The standard MSys install doesn't come with pr. You need to get it from the coreutils package.
@section Where can I find libav* headers for Pascal/Delphi?
@section Where is the documentation about ffv1, msmpeg4, asv1, 4xm?
-see @url{http://svn.mplayerhq.hu/michael/trunk/docs/}
+see @url{http://www.ffmpeg.org/~michael/}
-@section how do I feed H.263-RTP (and other codecs in RTP) to libavcodec?
+@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
projects / ffmpeg / blobdiff