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diff --git a/ffmpeg1/doc/developer.texi b/ffmpeg1/doc/developer.texi deleted file mode 100644 index bd3f7a7..0000000 --- a/ffmpeg1/doc/developer.texi +++ /dev/null @@ -1,668 +0,0 @@ -\input texinfo @c -*- texinfo -*- - -@settitle Developer Documentation -@titlepage -@center @titlefont{Developer Documentation} -@end titlepage - -@top - -@contents - -@chapter Developers Guide - -@section API -@itemize @bullet -@item libavcodec is the library containing the codecs (both encoding and -decoding). Look at @file{doc/examples/decoding_encoding.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{doc/examples/muxing.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. - -@section Contributing - -There are 3 ways by which code gets into ffmpeg. -@itemize @bullet -@item Submitting Patches to the main developer mailing list - see @ref{Submitting patches} for details. -@item Directly committing changes to the main tree. -@item Committing changes to a git clone, for example on github.com or - gitorious.org. And asking us to merge these changes. -@end itemize - -Whichever way, changes should be reviewed by the maintainer of the code -before they are committed. And they should follow the @ref{Coding Rules}. -The developer making the commit and the author are responsible for their changes -and should try to fix issues their commit causes. - -@anchor{Coding Rules} -@section Coding Rules - -@subsection Code formatting conventions - -There are the following guidelines regarding the indentation in files: -@itemize @bullet -@item -Indent size is 4. -@item -The TAB character is forbidden outside of Makefiles as is any -form of trailing whitespace. Commits containing either will be -rejected by the git repository. -@item -You should try to limit your code lines to 80 characters; however, do so if -and only if this improves readability. -@end itemize -The presentation is one inspired by 'indent -i4 -kr -nut'. - -The main priority in FFmpeg is simplicity and small code size in order to -minimize the bug count. - -@subsection 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. - -Avoid Qt-style and similar Doxygen syntax with @code{!} in it, i.e. replace -@code{//!} with @code{///} and similar. Also @@ syntax should be employed -for markup commands, i.e. use @code{@@param} and not @code{\param}. - -@example -/** - * @@file - * 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 - -@subsection C language features - -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 recent versions of GCC and a number of other -currently supported compilers. To ensure compatibility, please do not use -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 - -@subsection Naming conventions -All names should be composed with underscores (_), not CamelCase. For example, -@samp{avfilter_get_video_buffer} is an acceptable function name and -@samp{AVFilterGetVideo} is not. The exception from this are type names, like -for example structs and enums; they should always be in the CamelCase - -There are the following conventions for naming variables and functions: -@itemize @bullet -@item -For local variables no prefix is required. -@item -For variables and functions declared as @code{static} no prefix is required. -@item -For variables and functions used internally by a library an @code{ff_} -prefix should be used, e.g. @samp{ff_w64_demuxer}. -@item -For variables and functions used internally across multiple libraries, use -@code{avpriv_}. For example, @samp{avpriv_aac_parse_header}. -@item -Each library has its own prefix for public symbols, in addition to the -commonly used @code{av_} (@code{avformat_} for libavformat, -@code{avcodec_} for libavcodec, @code{swr_} for libswresample, etc). -Check the existing code and choose names accordingly. -Note that some symbols without these prefixes are also exported for -retro-compatibility reasons. These exceptions are declared in the -@code{lib<name>/lib<name>.v} files. -@end itemize - -Furthermore, name space reserved for the system should not be invaded. -Identifiers ending in @code{_t} are reserved by -@url{http://pubs.opengroup.org/onlinepubs/007904975/functions/xsh_chap02_02.html#tag_02_02_02, POSIX}. -Also avoid names starting with @code{__} or @code{_} followed by an uppercase -letter as they are reserved by the C standard. Names starting with @code{_} -are reserved at the file level and may not be used for externally visible -symbols. If in doubt, just avoid names starting with @code{_} altogether. - -@subsection Miscellaneous conventions -@itemize @bullet -@item -fprintf and printf are forbidden in libavformat and libavcodec, -please use av_log() instead. -@item -Casts should be used only when necessary. Unneeded parentheses -should also be avoided if they don't make the code easier to understand. -@end itemize - -@subsection Editor configuration -In order to configure Vim to follow FFmpeg formatting conventions, paste -the following snippet into your @file{.vimrc}: -@example -" indentation rules for FFmpeg: 4 spaces, no tabs -set expandtab -set shiftwidth=4 -set softtabstop=4 -set cindent -set cinoptions=(0 -" Allow tabs in Makefiles. -autocmd FileType make,automake set noexpandtab shiftwidth=8 softtabstop=8 -" Trailing whitespace and tabs are forbidden, so highlight them. -highlight ForbiddenWhitespace ctermbg=red guibg=red -match ForbiddenWhitespace /\s\+$\|\t/ -" Do not highlight spaces at the end of line while typing on that line. -autocmd InsertEnter * match ForbiddenWhitespace /\t\|\s\+\%#\@@<!$/ -@end example - -For Emacs, add these roughly equivalent lines to your @file{.emacs.d/init.el}: -@example -(c-add-style "ffmpeg" - '("k&r" - (c-basic-offset . 4) - (indent-tabs-mode . nil) - (show-trailing-whitespace . t) - (c-offsets-alist - (statement-cont . (c-lineup-assignments +))) - ) - ) -(setq c-default-style "ffmpeg") -@end example - -@section Development Policy - -@enumerate -@item - Contributions should be licensed under the - @uref{http://www.gnu.org/licenses/lgpl-2.1.html, LGPL 2.1}, - including an "or any later version" clause, or, if you prefer - a gift-style license, the - @uref{http://www.isc.org/software/license/, ISC} or - @uref{http://mit-license.org/, MIT} license. - @uref{http://www.gnu.org/licenses/gpl-2.0.html, 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 - The commit message should have a short first line in the form of - a @samp{topic: short description} as a header, separated by a newline - from the body consisting of an explanation of why the change is necessary. - If the commit fixes a known bug on the bug tracker, the commit message - should include its bug ID. Referring to the issue on the bug tracker does - not exempt you from writing an excerpt of the bug in the commit message. -@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 programs (renaming options etc) or public - API or ABI 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. - Recommended format: - area changed: Short 1 line description - - details describing what and why and giving references. -@item - Make sure the author of the commit is set correctly. (see git commit --author) - If you apply a patch, 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). The third - component always starts at 100 to distinguish FFmpeg from Libav. -@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. - -@anchor{Submitting patches} -@section Submitting patches - -First, read the @ref{Coding Rules} above if you did not yet, in particular -the rules regarding patch submission. - -When you submit your patch, please use @code{git format-patch} or -@code{git send-email}. 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. - -Use the patcheck tool of FFmpeg to check your patch. -The tool is located in the tools directory. - -Run the @ref{Regression tests} before submitting a patch in order to verify -it does not cause unexpected problems. - -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. - -Patches should be posted to the -@uref{http://lists.ffmpeg.org/mailman/listinfo/ffmpeg-devel, ffmpeg-devel} -mailing list. Use @code{git send-email} when possible since it will properly -send patches without requiring extra care. If you cannot, then send patches -as base64-encoded attachments, so your patch is not trashed during -transmission. - -Your patch will be reviewed on the mailing list. You will likely be asked -to make some changes and are expected to send in an improved version that -incorporates the requests from the review. This process may go through -several iterations. Once your patch is deemed good enough, some developer -will pick it up and commit it to the official FFmpeg tree. - -Give us a few days to react. But if some time passes without reaction, -send a reminder by email. Your patch should eventually be dealt with. - - -@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 (and reset the micro version - number) in @file{libavcodec/version.h} or @file{libavformat/version.h}? -@item - Did you register it in @file{allcodecs.c} or @file{allformats.c}? -@item - Did you add the AVCodecID to @file{avcodec.h}? - When adding new codec IDs, also add an entry to the codec descriptor - list in @file{libavcodec/codec_desc.c}. -@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 - @file{doc/general.texi}? -@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 @code{git add} the appropriate files before committing? -@item - Did you make sure it compiles standalone, i.e. with - @code{configure --disable-everything --enable-decoder=foo} - (or @code{--enable-demuxer} or whatever your component is)? -@end enumerate - - -@section patch submission checklist - -@enumerate -@item - Does @code{make fate} pass with the patch applied? -@item - Was the patch generated with git format-patch or send-email? -@item - Did you sign off your patch? (git commit -s) - See @url{http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob_plain;f=Documentation/SubmittingPatches} for the meaning - of sign off. -@item - Did you provide a clear git commit log message? -@item - Is the patch against latest FFmpeg git master branch? -@item - Are you subscribed to ffmpeg-devel? - (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, the noise bitstream filter, and - @uref{http://caca.zoy.org/wiki/zzuf, zzuf}. Your decoder or demuxer - should not crash, end in a (near) infinite loop, or allocate ridiculous - amounts of memory when fed damaged data. -@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 - Consider to add a regression test for your code. -@item - If you added YASM code please check that things still work with --disable-yasm -@item - Make sure you check the return values of function and return appropriate - error codes. Especially memory allocation functions like @code{av_malloc()} - are notoriously left unchecked, which is a serious problem. -@item - Test your code with valgrind and or Address Sanitizer to ensure it's free - of leaks, out of array accesses, etc. -@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 the git master branch. -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. - -If you feel that the review process is too slow and you are willing to try to -take over maintainership of the area of code you change then just clone -git master and maintain the area of code there. We will merge each area from -where its best maintained. - -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. - -@anchor{Regression tests} -@section Regression tests - -Before submitting a patch (or committing to the repository), you should at least -test that you did not break anything. - -Running 'make fate' accomplishes this, please see @url{fate.html} for details. - -[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]. - -@subsection Adding files to the fate-suite dataset - -When there is no muxer or encoder available to generate test media for a -specific test then the media has to be inlcuded in the fate-suite. -First please make sure that the sample file is as small as possible to test the -respective decoder or demuxer sufficiently. Large files increase network -bandwidth and disk space requirements. -Once you have a working fate test and fate sample, provide in the commit -message or introductionary message for the patch series that you post to -the ffmpeg-devel mailing list, a direct link to download the sample media. - - -@anchor{Release process} -@section Release process - -FFmpeg maintains a set of @strong{release branches}, which are the -recommended deliverable for system integrators and distributors (such as -Linux distributions, etc.). At regular times, a @strong{release -manager} prepares, tests and publishes tarballs on the -@url{http://ffmpeg.org} website. - -There are two kinds of releases: - -@enumerate -@item - @strong{Major releases} always include the latest and greatest - features and functionality. -@item - @strong{Point releases} are cut from @strong{release} branches, - which are named @code{release/X}, with @code{X} being the release - version number. -@end enumerate - -Note that we promise to our users that shared libraries from any FFmpeg -release never break programs that have been @strong{compiled} against -previous versions of @strong{the same release series} in any case! - -However, from time to time, we do make API changes that require adaptations -in applications. Such changes are only allowed in (new) major releases and -require further steps such as bumping library version numbers and/or -adjustments to the symbol versioning file. Please discuss such changes -on the @strong{ffmpeg-devel} mailing list in time to allow forward planning. - -@anchor{Criteria for Point Releases} -@subsection Criteria for Point Releases - -Changes that match the following criteria are valid candidates for -inclusion into a point release: - -@enumerate -@item - Fixes a security issue, preferably identified by a @strong{CVE - number} issued by @url{http://cve.mitre.org/}. -@item - Fixes a documented bug in @url{https://ffmpeg.org/trac/ffmpeg}. -@item - Improves the included documentation. -@item - Retains both source code and binary compatibility with previous - point releases of the same release branch. -@end enumerate - -The order for checking the rules is (1 OR 2 OR 3) AND 4. - - -@subsection Release Checklist - -The release process involves the following steps: - -@enumerate -@item - Ensure that the @file{RELEASE} file contains the version number for - the upcoming release. -@item - Add the release at @url{https://ffmpeg.org/trac/ffmpeg/admin/ticket/versions}. -@item - Announce the intent to do a release to the mailing list. -@item - Make sure all relevant security fixes have been backported. See - @url{https://ffmpeg.org/security.html}. -@item - Ensure that the FATE regression suite still passes in the release - branch on at least @strong{i386} and @strong{amd64} - (cf. @ref{Regression tests}). -@item - Prepare the release tarballs in @code{bz2} and @code{gz} formats, and - supplementing files that contain @code{gpg} signatures -@item - Publish the tarballs at @url{http://ffmpeg.org/releases}. Create and - push an annotated tag in the form @code{nX}, with @code{X} - containing the version number. -@item - Propose and send a patch to the @strong{ffmpeg-devel} mailing list - with a news entry for the website. -@item - Publish the news entry. -@item - Send announcement to the mailing list. -@end enumerate - -@bye |