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1) API
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------
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* libavcodec is the library containing the codecs (both encoding and
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decoding). See libavcodec/apiexample.c to see how to use it.
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* libav is the library containing the file formats handling (mux and
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demux code for several formats). (no example yet, the API is likely
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to evolve).
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2) Integrating libavcodec or libav in your GPL'ed program
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---------------------------------------------------------
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You can integrate all the source code of the libraries to link them
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statically to avoid any version problem. All you need is to provide a
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'config.mak' and a 'config.h' in the parent directory. See the defines
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generated by ./configure to understand what is needed.
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3) Coding Rules
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---------------
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ffmpeg is programmed in ANSI C language. GCC extensions are
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tolerated. Indent size is 4. The TAB character should not be used.
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The presentation is the one specified by 'indent -i4 -kr'.
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Main priority in ffmpeg is simplicity and small code size (=less
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bugs).
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Comments: for functions visible from other modules, use the JavaDoc
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format (see examples in libav/utils.c) so that a documentation can be
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generated automatically.
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4) Submitting patches
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---------------------
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When you submit your patch, try to send a unified diff (diff '-u'
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option). I cannot read other diffs :-)
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Run the regression tests before submitting a patch so that you can
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verify that there is no big problems.
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Except if your patch is really big and adds an important feature, by
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submitting it to me, you accept implicitely to put it under my
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copyright. I prefer to do this to avoid potential problems if
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licensing of ffmpeg changes.
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5) Regression tests
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-------------------
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Before submitting a patch (or commiting with CVS), you should at least
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test that you did not break anything.
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The regression test build a synthetic video stream and a synthetic
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audio stream. Then there are encoded then decoded with all codecs or
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formats. The CRC (or MD5) of each generated file is recorded in a
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result file. Then a 'diff' is launched with the reference results and
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the result file.
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Run 'make test' to test all the codecs.
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Run 'make libavtest' to test all the codecs.
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[Of course, some patches may change the regression tests results. In
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this case, the regression tests reference results shall be modified
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accordingly].
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