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@ -16,7 +16,7 @@ Even if ffmpeg can read the file format, it may not support all its |
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codecs. Please consult the supported codec list in the ffmpeg |
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documentation. |
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@section How do I encode single pictures to movies ? |
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@section How do I encode single pictures to movies? |
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First, rename your pictures to follow a numerical sequence. |
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For example, img1.jpg, img2.jpg, img3.jpg,... |
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@ -32,7 +32,7 @@ Notice that @samp{%d} is replaced by the image number. |
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The same logic is used for any image format that ffmpeg reads. |
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@section How do I encode movie to single pictures ? |
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@section How do I encode movie to single pictures? |
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Use: |
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@ -58,26 +58,26 @@ Applying that to the previous example: |
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Beware that there is no "jpeg" codec. Use "mjpeg" instead. |
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@section FFmpeg does not support codec XXX. Can you include a Windows DLL loader to support it ? |
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@section FFmpeg does not support codec XXX. Can you include a Windows DLL loader to support it? |
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No. FFmpeg only supports open source codecs. Windows DLLs are not |
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portable, bloated and often slow. |
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@section I get "Unsupported codec (id=86043) for input stream #0.1". What is the problem ? |
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@section I get "Unsupported codec (id=86043) for input stream #0.1". What is the problem? |
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This is the Qcelp codec, FFmpeg has no support for that codec currently. Try mencoder/mplayer it might work. |
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@section Why do I see a slight quality degradation with multithreaded MPEG* encoding ? |
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@section Why do I see a slight quality degradation with multithreaded MPEG* encoding? |
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For multithreaded MPEG* encoding, the encoded slices must be independent, |
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otherwise thread n would practically have to wait for n-1 to finish, so it's |
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quite logical that there is a small reduction of quality. This is not a bug. |
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@section How can I read from the standard input or write to the standard output ? |
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@section How can I read from the standard input or write to the standard output? |
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Use @file{-} as filename. |
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@section Why does ffmpeg not decode audio in VOB files ? |
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@section Why does ffmpeg not decode audio in VOB files? |
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The audio is AC3 (a.k.a. A/52). AC3 decoding is an optional component in ffmpeg |
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as the component that handles AC3 decoding (liba52) is currently released under |
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@ -86,7 +86,7 @@ with @code{./configure --enable-liba52 --enable-gpl}. Take care: by |
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enabling AC3, you automatically change the license of libavcodec from |
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LGPL to GPL. |
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@section Which codecs are supported by Windows ? |
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@section Which codecs are supported by Windows? |
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Windows does not support standard formats like MPEG very well, unless you |
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install some additional codecs |
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@ -326,13 +326,13 @@ If there is a feature that is important to you, the best way to get |
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it implemented is to undertake the task yourself. |
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@section Are there examples illustrating how to use the FFmpeg libraries, particularly libavcodec and libavformat ? |
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@section Are there examples illustrating how to use the FFmpeg libraries, particularly libavcodec and libavformat? |
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Yes. Read the Developers Guide of the FFmpeg documentation. Alternatively, |
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examine the source code for one of the many open source projects that |
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already incorporate ffmpeg at (@url{projects.php}). |
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@section Can you support my C compiler XXX ? |
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@section Can you support my C compiler XXX? |
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It depends. If your compiler is C99-compliant, then patches to support |
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it are likely to be welcome if they do not pollute the source code |
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@ -353,7 +353,7 @@ since MinGW does the job perfectly adequately. None of the core developers |
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work with Visual C++ and thus this item is low priority. Should you find |
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the silver bullet that solves this problem, feel free to shoot it at us. |
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@section Can I use FFmpeg or libavcodec under Windows ? |
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@section Can I use FFmpeg or libavcodec under Windows? |
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Yes, but the MinGW tools @emph{must} be used to compile FFmpeg. You |
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can link the resulting DLLs with any other Windows program. Read the |
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@ -364,24 +364,24 @@ To get help and instructions for using FFmpeg under Windows, check out |
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the FFmpeg Windows Help Forum at |
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@url{http://arrozcru.no-ip.org/ffmpeg/}. |
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@section Can you add automake, libtool or autoconf support ? |
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@section Can you add automake, libtool or autoconf support? |
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No. These tools are too bloated and they complicate the build. |
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@section Why not rewrite ffmpeg in object-oriented C++ ? |
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@section Why not rewrite ffmpeg in object-oriented C++? |
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ffmpeg is already organized in a highly modular manner and does not need to |
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be rewritten in a formal object language. Further, many of the developers |
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favor straight C; it works for them. For more arguments on this matter, |
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read "Programming Religion" at (@url{http://www.tux.org/lkml/#s15}). |
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@section Why are the ffmpeg programs devoid of debugging symbols ? |
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@section Why are the ffmpeg programs devoid of debugging symbols? |
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The build process creates ffmpeg_g, ffplay_g, etc. which contain full debug |
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information. Those binaries are strip'd to create ffmpeg, ffplay, etc. If |
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you need the debug information, used the *_g versions. |
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@section I do not like the LGPL, can I contribute code under the GPL instead ? |
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@section I do not like the LGPL, can I contribute code under the GPL instead? |
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Yes, as long as the code is optional and can easily and cleanly be placed |
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under #ifdef CONFIG_GPL without breaking anything. So for example a new codec |
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@ -395,7 +395,7 @@ the whole libav*. If you wish, disable some parts with configure switches. |
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You can also try to hack it and remove more, but if you had problems fixing |
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the compilation failure then you are probably not qualified for this. |
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@section I have a file in memory / a API different from *open/*read/ libc how do i use it with libavformat ? |
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@section I have a file in memory / a API different from *open/*read/ libc how do i use it with libavformat? |
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You have to implement a URLProtocol, see libavformat/file.c in FFmpeg |
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and libmpdemux/demux_lavf.c in MPlayer sources. |
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