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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
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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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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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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||||
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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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||||
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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
|
||||
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
|
||||
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
|
||||
|
||||
Indent size is 4.
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||||
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
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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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|
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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.
|
||||
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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/**
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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
|
||||
/** var3 description */
|
||||
int var3;
|
||||
@} Foobar;
|
||||
|
||||
/**
|
||||
* Summary sentence.
|
||||
* more text ...
|
||||
* ...
|
||||
* @@param my_parameter description of my_parameter
|
||||
* @@return return value description
|
||||
*/
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||||
int myfunc(int my_parameter)
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||||
...
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||||
@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
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||||
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
|
||||
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
|
||||
@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
|
||||
|
||||
Reference in New Issue
Block a user