mirror of
https://github.com/FFmpeg/FFmpeg.git
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Split developer documentation off from general documentation.
Originally committed as revision 19269 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Diego Biurrun
parent
d171a651db
commit
a752069dba
2
Makefile
2
Makefile
@ -76,7 +76,7 @@ cmdutils.o cmdutils.d: version.h
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alltools: $(addsuffix $(EXESUF),$(addprefix tools/, cws2fws pktdumper qt-faststart trasher))
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alltools: $(addsuffix $(EXESUF),$(addprefix tools/, cws2fws pktdumper qt-faststart trasher))
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documentation: $(addprefix doc/, ffmpeg-doc.html faq.html ffserver-doc.html \
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documentation: $(addprefix doc/, developer.html faq.html ffmpeg-doc.html ffserver-doc.html \
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ffplay-doc.html general.html $(ALLMANPAGES))
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ffplay-doc.html general.html $(ALLMANPAGES))
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doc/%.html: doc/%.texi
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doc/%.html: doc/%.texi
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418
doc/developer.texi
Normal file
418
doc/developer.texi
Normal file
@ -0,0 +1,418 @@
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\input texinfo @c -*- texinfo -*-
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@settitle Developer Documentation
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@titlepage
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@sp 7
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@center @titlefont{Developer Documentation}
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@sp 3
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@end titlepage
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@chapter Developers Guide
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@section API
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@itemize @bullet
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@item libavcodec is the library containing the codecs (both encoding and
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decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
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@item libavformat is the library containing the file format handling (mux and
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demux code for several formats). Look at @file{ffplay.c} to use it in a
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player. See @file{libavformat/output-example.c} to use it to generate
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audio or video streams.
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@end itemize
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@section Integrating libavcodec or libavformat in your program
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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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You can use libavcodec or libavformat in your commercial program, but
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@emph{any patch you make must be published}. The best way to proceed is
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to send your patches to the FFmpeg mailing list.
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@node Coding Rules
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@section Coding Rules
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FFmpeg is programmed in the ISO C90 language with a few additional
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features from ISO C99, namely:
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@itemize @bullet
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@item
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the @samp{inline} keyword;
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@item
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@samp{//} comments;
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@item
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designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
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@item
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compound literals (@samp{x = (struct s) @{ 17, 23 @};})
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@end itemize
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These features are supported by all compilers we care about, so we will not
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accept patches to remove their use unless they absolutely do not impair
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clarity and performance.
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All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
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compiles with several other compilers, such as the Compaq ccc compiler
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or Sun Studio 9, and we would like to keep it that way unless it would
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be exceedingly involved. To ensure compatibility, please do not use any
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additional C99 features or GCC extensions. Especially watch out for:
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@itemize @bullet
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@item
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mixing statements and declarations;
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@item
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@samp{long long} (use @samp{int64_t} instead);
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@item
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@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
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@item
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GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
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@end itemize
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Indent size is 4.
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The presentation is the one specified by 'indent -i4 -kr -nut'.
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The TAB character is forbidden outside of Makefiles as is any
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form of trailing whitespace. Commits containing either will be
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rejected by the Subversion repository.
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The main priority in FFmpeg is simplicity and small code size in order to
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minimize the bug count.
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Comments: Use the JavaDoc/Doxygen
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format (see examples below) so that code documentation
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can be generated automatically. All nontrivial functions should have a comment
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above them explaining what the function does, even if it is just one sentence.
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All structures and their member variables should be documented, too.
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@example
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/**
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* @@file mpeg.c
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* MPEG codec.
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* @@author ...
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*/
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/**
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* Summary sentence.
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* more text ...
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* ...
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*/
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typedef struct Foobar@{
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int var1; /**< var1 description */
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int var2; ///< var2 description
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/** var3 description */
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int var3;
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@} Foobar;
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/**
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* Summary sentence.
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* more text ...
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* ...
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* @@param my_parameter description of my_parameter
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* @@return return value description
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*/
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int myfunc(int my_parameter)
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...
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@end example
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fprintf and printf are forbidden in libavformat and libavcodec,
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please use av_log() instead.
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Casts should be used only when necessary. Unneeded parentheses
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should also be avoided if they don't make the code easier to understand.
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@section Development Policy
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@enumerate
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@item
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Contributions should be licensed under the LGPL 2.1, including an
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"or any later version" clause, or the MIT license. GPL 2 including
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an "or any later version" clause is also acceptable, but LGPL is
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preferred.
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@item
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You must not commit code which breaks FFmpeg! (Meaning unfinished but
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enabled code which breaks compilation or compiles but does not work or
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breaks the regression tests)
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You can commit unfinished stuff (for testing etc), but it must be disabled
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(#ifdef etc) by default so it does not interfere with other developers'
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work.
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@item
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You do not have to over-test things. If it works for you, and you think it
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should work for others, then commit. If your code has problems
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(portability, triggers compiler bugs, unusual environment etc) they will be
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reported and eventually fixed.
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@item
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Do not commit unrelated changes together, split them into self-contained
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pieces. Also do not forget that if part B depends on part A, but A does not
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depend on B, then A can and should be committed first and separate from B.
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Keeping changes well split into self-contained parts makes reviewing and
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understanding them on the commit log mailing list easier. This also helps
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in case of debugging later on.
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Also if you have doubts about splitting or not splitting, do not hesitate to
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ask/discuss it on the developer mailing list.
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@item
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Do not change behavior of the program (renaming options etc) without
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first discussing it on the ffmpeg-devel mailing list. Do not remove
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functionality from the code. Just improve!
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Note: Redundant code can be removed.
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@item
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Do not commit changes to the build system (Makefiles, configure script)
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which change behavior, defaults etc, without asking first. The same
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applies to compiler warning fixes, trivial looking fixes and to code
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maintained by other developers. We usually have a reason for doing things
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the way we do. Send your changes as patches to the ffmpeg-devel mailing
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list, and if the code maintainers say OK, you may commit. This does not
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apply to files you wrote and/or maintain.
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@item
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We refuse source indentation and other cosmetic changes if they are mixed
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with functional changes, such commits will be rejected and removed. Every
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developer has his own indentation style, you should not change it. Of course
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if you (re)write something, you can use your own style, even though we would
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prefer if the indentation throughout FFmpeg was consistent (Many projects
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force a given indentation style - we do not.). If you really need to make
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indentation changes (try to avoid this), separate them strictly from real
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changes.
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NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
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then either do NOT change the indentation of the inner part within (do not
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move it to the right)! or do so in a separate commit
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@item
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Always fill out the commit log message. Describe in a few lines what you
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changed and why. You can refer to mailing list postings if you fix a
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particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
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@item
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If you apply a patch by someone else, include the name and email address in
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the log message. Since the ffmpeg-cvslog mailing list is publicly
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archived you should add some SPAM protection to the email address. Send an
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answer to ffmpeg-devel (or wherever you got the patch from) saying that
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you applied the patch.
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@item
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When applying patches that have been discussed (at length) on the mailing
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list, reference the thread in the log message.
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@item
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Do NOT commit to code actively maintained by others without permission.
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Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
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timeframe (12h for build failures and security fixes, 3 days small changes,
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1 week for big patches) then commit your patch if you think it is OK.
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Also note, the maintainer can simply ask for more time to review!
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@item
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Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
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are sent there and reviewed by all the other developers. Bugs and possible
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improvements or general questions regarding commits are discussed there. We
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expect you to react if problems with your code are uncovered.
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@item
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Update the documentation if you change behavior or add features. If you are
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unsure how best to do this, send a patch to ffmpeg-devel, the documentation
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maintainer(s) will review and commit your stuff.
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@item
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Try to keep important discussions and requests (also) on the public
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developer mailing list, so that all developers can benefit from them.
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@item
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Never write to unallocated memory, never write over the end of arrays,
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always check values read from some untrusted source before using them
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as array index or other risky things.
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@item
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Remember to check if you need to bump versions for the specific libav
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parts (libavutil, libavcodec, libavformat) you are changing. You need
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to change the version integer.
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Incrementing the first component means no backward compatibility to
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previous versions (e.g. removal of a function from the public API).
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Incrementing the second component means backward compatible change
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(e.g. addition of a function to the public API or extension of an
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existing data structure).
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Incrementing the third component means a noteworthy binary compatible
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change (e.g. encoder bug fix that matters for the decoder).
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@item
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Compiler warnings indicate potential bugs or code with bad style. If a type of
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warning always points to correct and clean code, that warning should
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be disabled, not the code changed.
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Thus the remaining warnings can either be bugs or correct code.
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If it is a bug, the bug has to be fixed. If it is not, the code should
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be changed to not generate a warning unless that causes a slowdown
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or obfuscates the code.
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@item
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If you add a new file, give it a proper license header. Do not copy and
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paste it from a random place, use an existing file as template.
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@end enumerate
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We think our rules are not too hard. If you have comments, contact us.
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Note, these rules are mostly borrowed from the MPlayer project.
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@section Submitting patches
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First, (@pxref{Coding Rules}) above if you did not yet.
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When you submit your patch, try to send a unified diff (diff '-up'
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|
option). We cannot read other diffs :-)
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Also please do not submit a patch which contains several unrelated changes.
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Split it into separate, self-contained pieces. This does not mean splitting
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|
file by file. Instead, make the patch as small as possible while still
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keeping it as a logical unit that contains an individual change, even
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if it spans multiple files. This makes reviewing your patches much easier
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for us and greatly increases your chances of getting your patch applied.
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Run the regression tests before submitting a patch so that you can
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verify that there are no big problems.
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Patches should be posted as base64 encoded attachments (or any other
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|
encoding which ensures that the patch will not be trashed during
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transmission) to the ffmpeg-devel mailing list, see
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@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
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It also helps quite a bit if you tell us what the patch does (for example
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|
'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
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and has no lrint()')
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|
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Also please if you send several patches, send each patch as a separate mail,
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do not attach several unrelated patches to the same mail.
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@section New codecs or formats checklist
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@enumerate
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@item
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Did you use av_cold for codec initialization and close functions?
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|
@item
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||||||
|
Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
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|
AVInputFormat/AVOutputFormat struct?
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|
@item
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||||||
|
Did you bump the minor version number in @file{avcodec.h} or
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||||||
|
@file{avformat.h}?
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|
@item
|
||||||
|
Did you register it in @file{allcodecs.c} or @file{allformats.c}?
|
||||||
|
@item
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||||||
|
Did you add the CodecID to @file{avcodec.h}?
|
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|
@item
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||||||
|
If it has a fourcc, did you add it to @file{libavformat/riff.c},
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|
even if it is only a decoder?
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||||||
|
@item
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||||||
|
Did you add a rule to compile the appropriate files in the Makefile?
|
||||||
|
Remember to do this even if you're just adding a format to a file that is
|
||||||
|
already being compiled by some other rule, like a raw demuxer.
|
||||||
|
@item
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||||||
|
Did you add an entry to the table of supported formats or codecs in the
|
||||||
|
documentation?
|
||||||
|
@item
|
||||||
|
Did you add an entry in the Changelog?
|
||||||
|
@item
|
||||||
|
If it depends on a parser or a library, did you add that dependency in
|
||||||
|
configure?
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||||||
|
@item
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||||||
|
Did you "svn add" the appropriate files before commiting?
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||||||
|
@end enumerate
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||||||
|
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||||||
|
@section patch submission checklist
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||||||
|
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||||||
|
@enumerate
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||||||
|
@item
|
||||||
|
Do the regression tests pass with the patch applied?
|
||||||
|
@item
|
||||||
|
Does @code{make checkheaders} pass with the patch applied?
|
||||||
|
@item
|
||||||
|
Is the patch a unified diff?
|
||||||
|
@item
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||||||
|
Is the patch against latest FFmpeg SVN?
|
||||||
|
@item
|
||||||
|
Are you subscribed to ffmpeg-dev?
|
||||||
|
(the list is subscribers only due to spam)
|
||||||
|
@item
|
||||||
|
Have you checked that the changes are minimal, so that the same cannot be
|
||||||
|
achieved with a smaller patch and/or simpler final code?
|
||||||
|
@item
|
||||||
|
If the change is to speed critical code, did you benchmark it?
|
||||||
|
@item
|
||||||
|
If you did any benchmarks, did you provide them in the mail?
|
||||||
|
@item
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||||||
|
Have you checked that the patch does not introduce buffer overflows or
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||||||
|
other security issues?
|
||||||
|
@item
|
||||||
|
Did you test your decoder or demuxer against damaged data? If no, see
|
||||||
|
tools/trasher and the noise bitstream filter. Your decoder or demuxer
|
||||||
|
should not crash or end in a (near) infinite loop when fed damaged data.
|
||||||
|
@item
|
||||||
|
Is the patch created from the root of the source tree, so it can be
|
||||||
|
applied with @code{patch -p0}?
|
||||||
|
@item
|
||||||
|
Does the patch not mix functional and cosmetic changes?
|
||||||
|
@item
|
||||||
|
Did you add tabs or trailing whitespace to the code? Both are forbidden.
|
||||||
|
@item
|
||||||
|
Is the patch attached to the email you send?
|
||||||
|
@item
|
||||||
|
Is the mime type of the patch correct? It should be text/x-diff or
|
||||||
|
text/x-patch or at least text/plain and not application/octet-stream.
|
||||||
|
@item
|
||||||
|
If the patch fixes a bug, did you provide a verbose analysis of the bug?
|
||||||
|
@item
|
||||||
|
If the patch fixes a bug, did you provide enough information, including
|
||||||
|
a sample, so the bug can be reproduced and the fix can be verified?
|
||||||
|
Note please do not attach samples >100k to mails but rather provide a
|
||||||
|
URL, you can upload to ftp://upload.ffmpeg.org
|
||||||
|
@item
|
||||||
|
Did you provide a verbose summary about what the patch does change?
|
||||||
|
@item
|
||||||
|
Did you provide a verbose explanation why it changes things like it does?
|
||||||
|
@item
|
||||||
|
Did you provide a verbose summary of the user visible advantages and
|
||||||
|
disadvantages if the patch is applied?
|
||||||
|
@item
|
||||||
|
Did you provide an example so we can verify the new feature added by the
|
||||||
|
patch easily?
|
||||||
|
@item
|
||||||
|
If you added a new file, did you insert a license header? It should be
|
||||||
|
taken from FFmpeg, not randomly copied and pasted from somewhere else.
|
||||||
|
@item
|
||||||
|
You should maintain alphabetical order in alphabetically ordered lists as
|
||||||
|
long as doing so does not break API/ABI compatibility.
|
||||||
|
@item
|
||||||
|
Lines with similar content should be aligned vertically when doing so
|
||||||
|
improves readability.
|
||||||
|
@item
|
||||||
|
Did you provide a suggestion for a clear commit log message?
|
||||||
|
@end enumerate
|
||||||
|
|
||||||
|
@section Patch review process
|
||||||
|
|
||||||
|
All patches posted to ffmpeg-devel will be reviewed, unless they contain a
|
||||||
|
clear note that the patch is not for SVN.
|
||||||
|
Reviews and comments will be posted as replies to the patch on the
|
||||||
|
mailing list. The patch submitter then has to take care of every comment,
|
||||||
|
that can be by resubmitting a changed patch or by discussion. Resubmitted
|
||||||
|
patches will themselves be reviewed like any other patch. If at some point
|
||||||
|
a patch passes review with no comments then it is approved, that can for
|
||||||
|
simple and small patches happen immediately while large patches will generally
|
||||||
|
have to be changed and reviewed many times before they are approved.
|
||||||
|
After a patch is approved it will be committed to the repository.
|
||||||
|
|
||||||
|
We will review all submitted patches, but sometimes we are quite busy so
|
||||||
|
especially for large patches this can take several weeks.
|
||||||
|
|
||||||
|
When resubmitting patches, please do not make any significant changes
|
||||||
|
not related to the comments received during review. Such patches will
|
||||||
|
be rejected. Instead, submit significant changes or new features as
|
||||||
|
separate patches.
|
||||||
|
|
||||||
|
@section Regression tests
|
||||||
|
|
||||||
|
Before submitting a patch (or committing to the repository), you should at least
|
||||||
|
test that you did not break anything.
|
||||||
|
|
||||||
|
The regression tests build a synthetic video stream and a synthetic
|
||||||
|
audio stream. These are then encoded and decoded with all codecs or
|
||||||
|
formats. The CRC (or MD5) of each generated file is recorded in a
|
||||||
|
result file. A 'diff' is launched to compare the reference results and
|
||||||
|
the result file.
|
||||||
|
|
||||||
|
The regression tests then go on to test the FFserver code with a
|
||||||
|
limited set of streams. It is important that this step runs correctly
|
||||||
|
as well.
|
||||||
|
|
||||||
|
Run 'make test' to test all the codecs and formats.
|
||||||
|
|
||||||
|
Run 'make fulltest' to test all the codecs, formats and FFserver.
|
||||||
|
|
||||||
|
[Of course, some patches may change the results of the regression tests. In
|
||||||
|
this case, the reference results of the regression tests shall be modified
|
||||||
|
accordingly].
|
||||||
|
|
||||||
|
@bye
|
||||||
407
doc/general.texi
407
doc/general.texi
@ -983,411 +983,4 @@ BeOS support is broken in mysterious ways.
|
|||||||
For information about compiling FFmpeg on OS/2 see
|
For information about compiling FFmpeg on OS/2 see
|
||||||
@url{http://www.edm2.com/index.php/FFmpeg}.
|
@url{http://www.edm2.com/index.php/FFmpeg}.
|
||||||
|
|
||||||
@chapter Developers Guide
|
|
||||||
|
|
||||||
@section API
|
|
||||||
@itemize @bullet
|
|
||||||
@item libavcodec is the library containing the codecs (both encoding and
|
|
||||||
decoding). Look at @file{libavcodec/apiexample.c} to see how to use it.
|
|
||||||
|
|
||||||
@item libavformat is the library containing the file format handling (mux and
|
|
||||||
demux code for several formats). Look at @file{ffplay.c} to use it in a
|
|
||||||
player. See @file{libavformat/output-example.c} to use it to generate
|
|
||||||
audio or video streams.
|
|
||||||
|
|
||||||
@end itemize
|
|
||||||
|
|
||||||
@section Integrating libavcodec or libavformat in your program
|
|
||||||
|
|
||||||
You can integrate all the source code of the libraries to link them
|
|
||||||
statically to avoid any version problem. All you need is to provide a
|
|
||||||
'config.mak' and a 'config.h' in the parent directory. See the defines
|
|
||||||
generated by ./configure to understand what is needed.
|
|
||||||
|
|
||||||
You can use libavcodec or libavformat in your commercial program, but
|
|
||||||
@emph{any patch you make must be published}. The best way to proceed is
|
|
||||||
to send your patches to the FFmpeg mailing list.
|
|
||||||
|
|
||||||
@node Coding Rules
|
|
||||||
@section Coding Rules
|
|
||||||
|
|
||||||
FFmpeg is programmed in the ISO C90 language with a few additional
|
|
||||||
features from ISO C99, namely:
|
|
||||||
@itemize @bullet
|
|
||||||
@item
|
|
||||||
the @samp{inline} keyword;
|
|
||||||
@item
|
|
||||||
@samp{//} comments;
|
|
||||||
@item
|
|
||||||
designated struct initializers (@samp{struct s x = @{ .i = 17 @};})
|
|
||||||
@item
|
|
||||||
compound literals (@samp{x = (struct s) @{ 17, 23 @};})
|
|
||||||
@end itemize
|
|
||||||
|
|
||||||
These features are supported by all compilers we care about, so we will not
|
|
||||||
accept patches to remove their use unless they absolutely do not impair
|
|
||||||
clarity and performance.
|
|
||||||
|
|
||||||
All code must compile with GCC 2.95 and GCC 3.3. Currently, FFmpeg also
|
|
||||||
compiles with several other compilers, such as the Compaq ccc compiler
|
|
||||||
or Sun Studio 9, and we would like to keep it that way unless it would
|
|
||||||
be exceedingly involved. To ensure compatibility, please do not use any
|
|
||||||
additional C99 features or GCC extensions. Especially watch out for:
|
|
||||||
@itemize @bullet
|
|
||||||
@item
|
|
||||||
mixing statements and declarations;
|
|
||||||
@item
|
|
||||||
@samp{long long} (use @samp{int64_t} instead);
|
|
||||||
@item
|
|
||||||
@samp{__attribute__} not protected by @samp{#ifdef __GNUC__} or similar;
|
|
||||||
@item
|
|
||||||
GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
|
|
||||||
@end itemize
|
|
||||||
|
|
||||||
Indent size is 4.
|
|
||||||
The presentation is the one specified by 'indent -i4 -kr -nut'.
|
|
||||||
The TAB character is forbidden outside of Makefiles as is any
|
|
||||||
form of trailing whitespace. Commits containing either will be
|
|
||||||
rejected by the Subversion repository.
|
|
||||||
|
|
||||||
The main priority in FFmpeg is simplicity and small code size in order to
|
|
||||||
minimize the bug count.
|
|
||||||
|
|
||||||
Comments: Use the JavaDoc/Doxygen
|
|
||||||
format (see examples below) so that code documentation
|
|
||||||
can be generated automatically. All nontrivial functions should have a comment
|
|
||||||
above them explaining what the function does, even if it is just one sentence.
|
|
||||||
All structures and their member variables should be documented, too.
|
|
||||||
@example
|
|
||||||
/**
|
|
||||||
* @@file mpeg.c
|
|
||||||
* MPEG codec.
|
|
||||||
* @@author ...
|
|
||||||
*/
|
|
||||||
|
|
||||||
/**
|
|
||||||
* Summary sentence.
|
|
||||||
* more text ...
|
|
||||||
* ...
|
|
||||||
*/
|
|
||||||
typedef struct Foobar@{
|
|
||||||
int var1; /**< var1 description */
|
|
||||||
int var2; ///< var2 description
|
|
||||||
/** var3 description */
|
|
||||||
int var3;
|
|
||||||
@} Foobar;
|
|
||||||
|
|
||||||
/**
|
|
||||||
* Summary sentence.
|
|
||||||
* more text ...
|
|
||||||
* ...
|
|
||||||
* @@param my_parameter description of my_parameter
|
|
||||||
* @@return return value description
|
|
||||||
*/
|
|
||||||
int myfunc(int my_parameter)
|
|
||||||
...
|
|
||||||
@end example
|
|
||||||
|
|
||||||
fprintf and printf are forbidden in libavformat and libavcodec,
|
|
||||||
please use av_log() instead.
|
|
||||||
|
|
||||||
Casts should be used only when necessary. Unneeded parentheses
|
|
||||||
should also be avoided if they don't make the code easier to understand.
|
|
||||||
|
|
||||||
@section Development Policy
|
|
||||||
|
|
||||||
@enumerate
|
|
||||||
@item
|
|
||||||
Contributions should be licensed under the LGPL 2.1, including an
|
|
||||||
"or any later version" clause, or the MIT license. GPL 2 including
|
|
||||||
an "or any later version" clause is also acceptable, but LGPL is
|
|
||||||
preferred.
|
|
||||||
@item
|
|
||||||
You must not commit code which breaks FFmpeg! (Meaning unfinished but
|
|
||||||
enabled code which breaks compilation or compiles but does not work or
|
|
||||||
breaks the regression tests)
|
|
||||||
You can commit unfinished stuff (for testing etc), but it must be disabled
|
|
||||||
(#ifdef etc) by default so it does not interfere with other developers'
|
|
||||||
work.
|
|
||||||
@item
|
|
||||||
You do not have to over-test things. If it works for you, and you think it
|
|
||||||
should work for others, then commit. If your code has problems
|
|
||||||
(portability, triggers compiler bugs, unusual environment etc) they will be
|
|
||||||
reported and eventually fixed.
|
|
||||||
@item
|
|
||||||
Do not commit unrelated changes together, split them into self-contained
|
|
||||||
pieces. Also do not forget that if part B depends on part A, but A does not
|
|
||||||
depend on B, then A can and should be committed first and separate from B.
|
|
||||||
Keeping changes well split into self-contained parts makes reviewing and
|
|
||||||
understanding them on the commit log mailing list easier. This also helps
|
|
||||||
in case of debugging later on.
|
|
||||||
Also if you have doubts about splitting or not splitting, do not hesitate to
|
|
||||||
ask/discuss it on the developer mailing list.
|
|
||||||
@item
|
|
||||||
Do not change behavior of the program (renaming options etc) without
|
|
||||||
first discussing it on the ffmpeg-devel mailing list. Do not remove
|
|
||||||
functionality from the code. Just improve!
|
|
||||||
|
|
||||||
Note: Redundant code can be removed.
|
|
||||||
@item
|
|
||||||
Do not commit changes to the build system (Makefiles, configure script)
|
|
||||||
which change behavior, defaults etc, without asking first. The same
|
|
||||||
applies to compiler warning fixes, trivial looking fixes and to code
|
|
||||||
maintained by other developers. We usually have a reason for doing things
|
|
||||||
the way we do. Send your changes as patches to the ffmpeg-devel mailing
|
|
||||||
list, and if the code maintainers say OK, you may commit. This does not
|
|
||||||
apply to files you wrote and/or maintain.
|
|
||||||
@item
|
|
||||||
We refuse source indentation and other cosmetic changes if they are mixed
|
|
||||||
with functional changes, such commits will be rejected and removed. Every
|
|
||||||
developer has his own indentation style, you should not change it. Of course
|
|
||||||
if you (re)write something, you can use your own style, even though we would
|
|
||||||
prefer if the indentation throughout FFmpeg was consistent (Many projects
|
|
||||||
force a given indentation style - we do not.). If you really need to make
|
|
||||||
indentation changes (try to avoid this), separate them strictly from real
|
|
||||||
changes.
|
|
||||||
|
|
||||||
NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
|
|
||||||
then either do NOT change the indentation of the inner part within (do not
|
|
||||||
move it to the right)! or do so in a separate commit
|
|
||||||
@item
|
|
||||||
Always fill out the commit log message. Describe in a few lines what you
|
|
||||||
changed and why. You can refer to mailing list postings if you fix a
|
|
||||||
particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
|
|
||||||
@item
|
|
||||||
If you apply a patch by someone else, include the name and email address in
|
|
||||||
the log message. Since the ffmpeg-cvslog mailing list is publicly
|
|
||||||
archived you should add some SPAM protection to the email address. Send an
|
|
||||||
answer to ffmpeg-devel (or wherever you got the patch from) saying that
|
|
||||||
you applied the patch.
|
|
||||||
@item
|
|
||||||
When applying patches that have been discussed (at length) on the mailing
|
|
||||||
list, reference the thread in the log message.
|
|
||||||
@item
|
|
||||||
Do NOT commit to code actively maintained by others without permission.
|
|
||||||
Send a patch to ffmpeg-devel instead. If no one answers within a reasonable
|
|
||||||
timeframe (12h for build failures and security fixes, 3 days small changes,
|
|
||||||
1 week for big patches) then commit your patch if you think it is OK.
|
|
||||||
Also note, the maintainer can simply ask for more time to review!
|
|
||||||
@item
|
|
||||||
Subscribe to the ffmpeg-cvslog mailing list. The diffs of all commits
|
|
||||||
are sent there and reviewed by all the other developers. Bugs and possible
|
|
||||||
improvements or general questions regarding commits are discussed there. We
|
|
||||||
expect you to react if problems with your code are uncovered.
|
|
||||||
@item
|
|
||||||
Update the documentation if you change behavior or add features. If you are
|
|
||||||
unsure how best to do this, send a patch to ffmpeg-devel, the documentation
|
|
||||||
maintainer(s) will review and commit your stuff.
|
|
||||||
@item
|
|
||||||
Try to keep important discussions and requests (also) on the public
|
|
||||||
developer mailing list, so that all developers can benefit from them.
|
|
||||||
@item
|
|
||||||
Never write to unallocated memory, never write over the end of arrays,
|
|
||||||
always check values read from some untrusted source before using them
|
|
||||||
as array index or other risky things.
|
|
||||||
@item
|
|
||||||
Remember to check if you need to bump versions for the specific libav
|
|
||||||
parts (libavutil, libavcodec, libavformat) you are changing. You need
|
|
||||||
to change the version integer.
|
|
||||||
Incrementing the first component means no backward compatibility to
|
|
||||||
previous versions (e.g. removal of a function from the public API).
|
|
||||||
Incrementing the second component means backward compatible change
|
|
||||||
(e.g. addition of a function to the public API or extension of an
|
|
||||||
existing data structure).
|
|
||||||
Incrementing the third component means a noteworthy binary compatible
|
|
||||||
change (e.g. encoder bug fix that matters for the decoder).
|
|
||||||
@item
|
|
||||||
Compiler warnings indicate potential bugs or code with bad style. If a type of
|
|
||||||
warning always points to correct and clean code, that warning should
|
|
||||||
be disabled, not the code changed.
|
|
||||||
Thus the remaining warnings can either be bugs or correct code.
|
|
||||||
If it is a bug, the bug has to be fixed. If it is not, the code should
|
|
||||||
be changed to not generate a warning unless that causes a slowdown
|
|
||||||
or obfuscates the code.
|
|
||||||
@item
|
|
||||||
If you add a new file, give it a proper license header. Do not copy and
|
|
||||||
paste it from a random place, use an existing file as template.
|
|
||||||
@end enumerate
|
|
||||||
|
|
||||||
We think our rules are not too hard. If you have comments, contact us.
|
|
||||||
|
|
||||||
Note, these rules are mostly borrowed from the MPlayer project.
|
|
||||||
|
|
||||||
@section Submitting patches
|
|
||||||
|
|
||||||
First, (@pxref{Coding Rules}) above if you did not yet.
|
|
||||||
|
|
||||||
When you submit your patch, try to send a unified diff (diff '-up'
|
|
||||||
option). We cannot read other diffs :-)
|
|
||||||
|
|
||||||
Also please do not submit a patch which contains several unrelated changes.
|
|
||||||
Split it into separate, self-contained pieces. This does not mean splitting
|
|
||||||
file by file. Instead, make the patch as small as possible while still
|
|
||||||
keeping it as a logical unit that contains an individual change, even
|
|
||||||
if it spans multiple files. This makes reviewing your patches much easier
|
|
||||||
for us and greatly increases your chances of getting your patch applied.
|
|
||||||
|
|
||||||
Run the regression tests before submitting a patch so that you can
|
|
||||||
verify that there are no big problems.
|
|
||||||
|
|
||||||
Patches should be posted as base64 encoded attachments (or any other
|
|
||||||
encoding which ensures that the patch will not be trashed during
|
|
||||||
transmission) to the ffmpeg-devel mailing list, see
|
|
||||||
@url{http://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel}
|
|
||||||
|
|
||||||
It also helps quite a bit if you tell us what the patch does (for example
|
|
||||||
'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
|
|
||||||
and has no lrint()')
|
|
||||||
|
|
||||||
Also please if you send several patches, send each patch as a separate mail,
|
|
||||||
do not attach several unrelated patches to the same mail.
|
|
||||||
|
|
||||||
@section New codecs or formats checklist
|
|
||||||
|
|
||||||
@enumerate
|
|
||||||
@item
|
|
||||||
Did you use av_cold for codec initialization and close functions?
|
|
||||||
@item
|
|
||||||
Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or
|
|
||||||
AVInputFormat/AVOutputFormat struct?
|
|
||||||
@item
|
|
||||||
Did you bump the minor version number in @file{avcodec.h} or
|
|
||||||
@file{avformat.h}?
|
|
||||||
@item
|
|
||||||
Did you register it in @file{allcodecs.c} or @file{allformats.c}?
|
|
||||||
@item
|
|
||||||
Did you add the CodecID to @file{avcodec.h}?
|
|
||||||
@item
|
|
||||||
If it has a fourcc, did you add it to @file{libavformat/riff.c},
|
|
||||||
even if it is only a decoder?
|
|
||||||
@item
|
|
||||||
Did you add a rule to compile the appropriate files in the Makefile?
|
|
||||||
Remember to do this even if you're just adding a format to a file that is
|
|
||||||
already being compiled by some other rule, like a raw demuxer.
|
|
||||||
@item
|
|
||||||
Did you add an entry to the table of supported formats or codecs in the
|
|
||||||
documentation?
|
|
||||||
@item
|
|
||||||
Did you add an entry in the Changelog?
|
|
||||||
@item
|
|
||||||
If it depends on a parser or a library, did you add that dependency in
|
|
||||||
configure?
|
|
||||||
@item
|
|
||||||
Did you "svn add" the appropriate files before commiting?
|
|
||||||
@end enumerate
|
|
||||||
|
|
||||||
@section patch submission checklist
|
|
||||||
|
|
||||||
@enumerate
|
|
||||||
@item
|
|
||||||
Do the regression tests pass with the patch applied?
|
|
||||||
@item
|
|
||||||
Does @code{make checkheaders} pass with the patch applied?
|
|
||||||
@item
|
|
||||||
Is the patch a unified diff?
|
|
||||||
@item
|
|
||||||
Is the patch against latest FFmpeg SVN?
|
|
||||||
@item
|
|
||||||
Are you subscribed to ffmpeg-dev?
|
|
||||||
(the list is subscribers only due to spam)
|
|
||||||
@item
|
|
||||||
Have you checked that the changes are minimal, so that the same cannot be
|
|
||||||
achieved with a smaller patch and/or simpler final code?
|
|
||||||
@item
|
|
||||||
If the change is to speed critical code, did you benchmark it?
|
|
||||||
@item
|
|
||||||
If you did any benchmarks, did you provide them in the mail?
|
|
||||||
@item
|
|
||||||
Have you checked that the patch does not introduce buffer overflows or
|
|
||||||
other security issues?
|
|
||||||
@item
|
|
||||||
Did you test your decoder or demuxer against damaged data? If no, see
|
|
||||||
tools/trasher and the noise bitstream filter. Your decoder or demuxer
|
|
||||||
should not crash or end in a (near) infinite loop when fed damaged data.
|
|
||||||
@item
|
|
||||||
Is the patch created from the root of the source tree, so it can be
|
|
||||||
applied with @code{patch -p0}?
|
|
||||||
@item
|
|
||||||
Does the patch not mix functional and cosmetic changes?
|
|
||||||
@item
|
|
||||||
Did you add tabs or trailing whitespace to the code? Both are forbidden.
|
|
||||||
@item
|
|
||||||
Is the patch attached to the email you send?
|
|
||||||
@item
|
|
||||||
Is the mime type of the patch correct? It should be text/x-diff or
|
|
||||||
text/x-patch or at least text/plain and not application/octet-stream.
|
|
||||||
@item
|
|
||||||
If the patch fixes a bug, did you provide a verbose analysis of the bug?
|
|
||||||
@item
|
|
||||||
If the patch fixes a bug, did you provide enough information, including
|
|
||||||
a sample, so the bug can be reproduced and the fix can be verified?
|
|
||||||
Note please do not attach samples >100k to mails but rather provide a
|
|
||||||
URL, you can upload to ftp://upload.ffmpeg.org
|
|
||||||
@item
|
|
||||||
Did you provide a verbose summary about what the patch does change?
|
|
||||||
@item
|
|
||||||
Did you provide a verbose explanation why it changes things like it does?
|
|
||||||
@item
|
|
||||||
Did you provide a verbose summary of the user visible advantages and
|
|
||||||
disadvantages if the patch is applied?
|
|
||||||
@item
|
|
||||||
Did you provide an example so we can verify the new feature added by the
|
|
||||||
patch easily?
|
|
||||||
@item
|
|
||||||
If you added a new file, did you insert a license header? It should be
|
|
||||||
taken from FFmpeg, not randomly copied and pasted from somewhere else.
|
|
||||||
@item
|
|
||||||
You should maintain alphabetical order in alphabetically ordered lists as
|
|
||||||
long as doing so does not break API/ABI compatibility.
|
|
||||||
@item
|
|
||||||
Lines with similar content should be aligned vertically when doing so
|
|
||||||
improves readability.
|
|
||||||
@item
|
|
||||||
Did you provide a suggestion for a clear commit log message?
|
|
||||||
@end enumerate
|
|
||||||
|
|
||||||
@section Patch review process
|
|
||||||
|
|
||||||
All patches posted to ffmpeg-devel will be reviewed, unless they contain a
|
|
||||||
clear note that the patch is not for SVN.
|
|
||||||
Reviews and comments will be posted as replies to the patch on the
|
|
||||||
mailing list. The patch submitter then has to take care of every comment,
|
|
||||||
that can be by resubmitting a changed patch or by discussion. Resubmitted
|
|
||||||
patches will themselves be reviewed like any other patch. If at some point
|
|
||||||
a patch passes review with no comments then it is approved, that can for
|
|
||||||
simple and small patches happen immediately while large patches will generally
|
|
||||||
have to be changed and reviewed many times before they are approved.
|
|
||||||
After a patch is approved it will be committed to the repository.
|
|
||||||
|
|
||||||
We will review all submitted patches, but sometimes we are quite busy so
|
|
||||||
especially for large patches this can take several weeks.
|
|
||||||
|
|
||||||
When resubmitting patches, please do not make any significant changes
|
|
||||||
not related to the comments received during review. Such patches will
|
|
||||||
be rejected. Instead, submit significant changes or new features as
|
|
||||||
separate patches.
|
|
||||||
|
|
||||||
@section Regression tests
|
|
||||||
|
|
||||||
Before submitting a patch (or committing to the repository), you should at least
|
|
||||||
test that you did not break anything.
|
|
||||||
|
|
||||||
The regression tests build a synthetic video stream and a synthetic
|
|
||||||
audio stream. These are then encoded and decoded with all codecs or
|
|
||||||
formats. The CRC (or MD5) of each generated file is recorded in a
|
|
||||||
result file. A 'diff' is launched to compare the reference results and
|
|
||||||
the result file.
|
|
||||||
|
|
||||||
The regression tests then go on to test the FFserver code with a
|
|
||||||
limited set of streams. It is important that this step runs correctly
|
|
||||||
as well.
|
|
||||||
|
|
||||||
Run 'make test' to test all the codecs and formats.
|
|
||||||
|
|
||||||
Run 'make fulltest' to test all the codecs, formats and FFserver.
|
|
||||||
|
|
||||||
[Of course, some patches may change the results of the regression tests. In
|
|
||||||
this case, the reference results of the regression tests shall be modified
|
|
||||||
accordingly].
|
|
||||||
|
|
||||||
@bye
|
@bye
|
||||||
|
|||||||
Loading…
Reference in New Issue
Block a user