Moreover Libav strives to support all codecs natively.
A DLL loader is not conducive to that goal.
-@section I cannot read this file although this format seems to be supported by ffmpeg.
+@section I cannot read this file although this format seems to be supported by avconv.
-Even if ffmpeg can read the container format, it may not support all its
-codecs. Please consult the supported codec list in the ffmpeg
+Even if avconv can read the container format, it may not support all its
+codecs. Please consult the supported codec list in the avconv
documentation.
@section Which codecs are supported by Windows?
@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.
Then you may run:
@example
- ffmpeg -f image2 -i img%d.jpg /tmp/a.mpg
+ avconv -f image2 -i img%d.jpg /tmp/a.mpg
@end example
Notice that @samp{%d} is replaced by the image number.
Then run:
@example
- ffmpeg -f image2 -i /tmp/img%03d.jpg /tmp/a.mpg
+ avconv -f image2 -i /tmp/img%03d.jpg /tmp/a.mpg
@end example
-The same logic is used for any image format that ffmpeg reads.
+The same logic is used for any image format that avconv reads.
@section How do I encode movie to single pictures?
Use:
@example
- ffmpeg -i movie.mpg movie%d.jpg
+ avconv -i movie.mpg movie%d.jpg
@end example
The @file{movie.mpg} used as input will be converted to
Instead of relying on file format self-recognition, you may also use
@table @option
-@item -vcodec ppm
-@item -vcodec png
-@item -vcodec mjpeg
+@item -c:v ppm
+@item -c:v png
+@item -c:v 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
+ avconv -i movie.mpg -f image2 -c:v mjpeg menu%d.jpg
@end example
Beware that there is no "jpeg" codec. Use "mjpeg" instead.
@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.
+Choose a different codec with the -c:v command line option.
-@section How do I encode Xvid or DivX video with ffmpeg?
+@section How do I encode Xvid or DivX video with avconv?
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 in these formats. The
+same standard). Thus, use '-c:v 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
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, what is wrong?
+@section Interlaced video looks very bad when encoded with avconv, 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.
@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 avconv:
@example
- ffmpeg -i input.avs
+ avconv -i input.avs
@end example
-For ANY other help on Avisynth, please visit the
-@uref{http://www.avisynth.org/, Avisynth homepage}.
+For ANY other help on AviSynth, please visit the
+@uref{http://www.avisynth.org/, AviSynth homepage}.
@section How can I join video files?
format of choice.
@example
-ffmpeg -i input1.avi -sameq intermediate1.mpg
-ffmpeg -i input2.avi -sameq intermediate2.mpg
+avconv -i input1.avi intermediate1.mpg
+avconv -i input2.avi intermediate2.mpg
cat intermediate1.mpg intermediate2.mpg > intermediate_all.mpg
-ffmpeg -i intermediate_all.mpg -sameq output.avi
+avconv -i intermediate_all.mpg 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.
+Notice that you should 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 &
+avconv -i input1.avi -y intermediate1.mpg < /dev/null &
+avconv -i input2.avi -y intermediate2.mpg < /dev/null &
cat intermediate1.mpg intermediate2.mpg |\
-ffmpeg -f mpeg -i - -sameq -vcodec mpeg4 -acodec libmp3lame output.avi
+avconv -f mpeg -i - -c:v mpeg4 -acodec libmp3lame output.avi
@end example
Similarly, the yuv4mpegpipe format, and the raw video, raw audio codecs also
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 - < /dev/null | tail -n +2 > temp2.v ; @} &
+avconv -i input1.flv -vn -f u16le -acodec pcm_s16le -ac 2 -ar 44100 - > temp1.a < /dev/null &
+avconv -i input2.flv -vn -f u16le -acodec pcm_s16le -ac 2 -ar 44100 - > temp2.a < /dev/null &
+avconv -i input1.flv -an -f yuv4mpegpipe - > temp1.v < /dev/null &
+@{ avconv -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 \
+avconv -f u16le -acodec pcm_s16le -ac 2 -ar 44100 -i all.a \
-f yuv4mpegpipe -i all.v \
- -sameq -y output.flv
+ -y output.flv
rm temp[12].[av] all.[av]
@end example
+@section -profile option fails when encoding H.264 video with AAC audio
+
+@command{avconv} prints an error like
+
+@example
+Undefined constant or missing '(' in 'baseline'
+Unable to parse option value "baseline"
+Error setting option profile to value baseline.
+@end example
+
+Short answer: write @option{-profile:v} instead of @option{-profile}.
+
+Long answer: this happens because the @option{-profile} option can apply to both
+video and audio. Specifically the AAC encoder also defines some profiles, none
+of which are named @var{baseline}.
+
+The solution is to apply the @option{-profile} option to the video stream only
+by using @url{http://libav.org/avconv.html#Stream-specifiers-1, Stream specifiers}.
+Appending @code{:v} to it will do exactly that.
+
@chapter Development
@section Are there examples illustrating how to use the Libav libraries, particularly libavcodec and libavformat?
@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 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 Libav
-documentation.
-
-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
-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 Libav or libavcodec under Windows?
-
-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.
+Yes. Please see the @uref{platform.html, Microsoft Visual C++}
+section in the Libav documentation.
@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++?
+@section Why not rewrite Libav in object-oriented C++?
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
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'm using libavcodec from within my C++ application but the linker complains about missing symbols which seem to be available.
+@section I'm using Libav from within my C++ application but the linker complains about missing symbols which seem to be available.
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
@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.
+You have to create a custom AVIOContext using @code{avio_alloc_context},
+see @file{libavformat/aviobuf.c} in Libav and @file{libmpdemux/demux_lavf.c} in MPlayer2 sources.
+
+@section Why is @code{make fate} not running all tests?
+
+Make sure you have the fate-suite samples and the @code{SAMPLES} Make variable
+or @code{FATE_SAMPLES} environment variable or the @code{--samples}
+@command{configure} option is set to the right path.
+
+@section Why is @code{make fate} not finding the samples?
+
+Do you happen to have a @code{~} character in the samples path to indicate a
+home directory? The value is used in ways where the shell cannot expand it,
+causing FATE to not find files. Just replace @code{~} by the full path.
@bye
projects / ffmpeg / blobdiff