From 734eee1af2c21976e8f57c4ca498593a305fb22e Mon Sep 17 00:00:00 2001 From: Xavier Del Campo Romero Date: Sun, 3 Jan 2021 02:06:58 +0100 Subject: Remove ffmpeg binary from project --- Music/ffmpeg/doc/developer.html | 865 ---------------------------------------- 1 file changed, 865 deletions(-) delete mode 100644 Music/ffmpeg/doc/developer.html (limited to 'Music/ffmpeg/doc/developer.html') diff --git a/Music/ffmpeg/doc/developer.html b/Music/ffmpeg/doc/developer.html deleted file mode 100644 index e613358..0000000 --- a/Music/ffmpeg/doc/developer.html +++ /dev/null @@ -1,865 +0,0 @@ - - - - - - - Developer Documentation - - - - - - -
-

- Developer Documentation -

-
-
- - - - - -

Table of Contents

- -
- - -
- - - -

1 Developers Guide

- - -

1.1 Notes for external developers

- -

This document is mostly useful for internal FFmpeg developers. -External developers who need to use the API in their application should -refer to the API doxygen documentation in the public headers, and -check the examples in doc/examples and in the source code to -see how the public API is employed. -

-

You can use the FFmpeg libraries in your commercial program, but you -are encouraged to publish any patch you make. In this case the -best way to proceed is to send your patches to the ffmpeg-devel -mailing list following the guidelines illustrated in the remainder of -this document. -

-

For more detailed legal information about the use of FFmpeg in -external programs read the LICENSE file in the source tree and -consult https://ffmpeg.org/legal.html. -

- -

1.2 Contributing

- -

There are 3 ways by which code gets into FFmpeg. -

- -

Whichever way, changes should be reviewed by the maintainer of the code -before they are committed. And they should follow the Coding Rules. -The developer making the commit and the author are responsible for their changes -and should try to fix issues their commit causes. -

- -

1.3 Coding Rules

- - -

1.3.1 Code formatting conventions

- -

There are the following guidelines regarding the indentation in files: -

- -

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. -

- -

1.3.2 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 ! in it, i.e. replace -//! with /// and similar. Also @ syntax should be employed -for markup commands, i.e. use @param and not \param. -

-
-
/**
- * @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)
-...
-
- - -

1.3.3 C language features

- -

FFmpeg is programmed in the ISO C90 language with a few additional -features from ISO C99, namely: -

- - -

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: -

- - - -

1.3.4 Naming conventions

-

All names should be composed with underscores (_), not CamelCase. For example, -‘avfilter_get_video_buffer’ is an acceptable function name and -‘AVFilterGetVideo’ is not. The exception from this are type names, like -for example structs and enums; they should always be in CamelCase. -

-

There are the following conventions for naming variables and functions: -

- - -

Furthermore, name space reserved for the system should not be invaded. -Identifiers ending in _t are reserved by -POSIX. -Also avoid names starting with __ or _ followed by an uppercase -letter as they are reserved by the C standard. Names starting with _ -are reserved at the file level and may not be used for externally visible -symbols. If in doubt, just avoid names starting with _ altogether. -

- -

1.3.5 Miscellaneous conventions

- - - - -

1.3.6 Editor configuration

-

In order to configure Vim to follow FFmpeg formatting conventions, paste -the following snippet into your .vimrc: -

-
" 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\+$\|\t/
-" Do not highlight spaces at the end of line while typing on that line.
-autocmd InsertEnter * match ForbiddenWhitespace /\t\|\s\+\%#\@<!$/
-
- -

For Emacs, add these roughly equivalent lines to your .emacs.d/init.el: -

-
(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")
-
- - -

1.4 Development Policy

- - -

1.4.1 Patches/Committing

- -

Licenses for patches must be compatible with FFmpeg.

-

Contributions should be licensed under the -LGPL 2.1, -including an "or any later version" clause, or, if you prefer -a gift-style license, the -ISC or -MIT license. -GPL 2 including -an "or any later version" clause is also acceptable, but LGPL is -preferred. -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. -

- -

You must not commit code which breaks FFmpeg!

-

This means unfinished code which is enabled and breaks compilation, -or compiles but does not work/breaks the regression tests. Code which -is unfinished but disabled may be permitted under-circumstances, like -missing samples or an implementation with a small subset of features. -Always check the mailing list for any reviewers with issues and test -FATE before you push. -

- -

Keep the main commit message short with an extended description below.

-

The commit message should have a short first line in the form of -a ‘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. -

- -

Testing must be adequate but not excessive.

-

If it works for you, others, and passes FATE then it should be OK to commit -it, provided it fits the other committing criteria. You should not worry about -over-testing things. If your code has problems (portability, triggers -compiler bugs, unusual environment etc) they will be reported and eventually -fixed. -

- -

Do not commit unrelated changes together.

-

They should be 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. -

- -

Ask before you change the build system (configure, etc).

-

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. -

- -

Cosmetic changes should be kept in separate patches.

-

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 -

- -

Commit messages should always be filled out properly.

-

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.
-
- - -

Credit the author of the patch.

-

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. -

- -

Complex patches should refer to discussion surrounding them.

-

When applying patches that have been discussed (at length) on the mailing -list, reference the thread in the log message. -

- -

Always wait long enough before pushing changes

-

Do NOT commit to code actively maintained by others without permission. -Send a patch to ffmpeg-devel. If no one answers within a reasonable -time-frame (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! -

- -

1.4.2 Code

- -

API/ABI changes should be discussed before they are made.

-

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 widely used functionality or features (redundant code can be removed). -

- -

Remember to check if you need to bump versions for libav*.

-

Depending on the change, you may 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. -

- -

Warnings for correct code may be disabled if there is no other option.

-

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. -

- -

Check untrusted input properly.

-

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. -

- -

1.4.3 Documentation/Other

- -

Subscribe to the ffmpeg-cvslog mailing list.

-

It is important to do this as 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. -

- -

Keep the documentation up to date.

-

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. -

- -

Important discussions should be accessible to all.

-

Try to keep important discussions and requests (also) on the public -developer mailing list, so that all developers can benefit from them. -

- -

Check your entries in MAINTAINERS.

-

Make sure that no parts of the codebase that you maintain are missing from the -MAINTAINERS file. If something that you want to maintain is missing add it with -your name after it. -If at some point you no longer want to maintain some code, then please help in -finding a new maintainer and also don’t forget to update the MAINTAINERS file. -

-

We think our rules are not too hard. If you have comments, contact us. -

- -

1.5 Code of conduct

- -

Be friendly and respectful towards others and third parties. -Treat others the way you yourself want to be treated. -

-

Be considerate. Not everyone shares the same viewpoint and priorities as you do. -Different opinions and interpretations help the project. -Looking at issues from a different perspective assists development. -

-

Do not assume malice for things that can be attributed to incompetence. Even if -it is malice, it’s rarely good to start with that as initial assumption. -

-

Stay friendly even if someone acts contrarily. Everyone has a bad day -once in a while. -If you yourself have a bad day or are angry then try to take a break and reply -once you are calm and without anger if you have to. -

-

Try to help other team members and cooperate if you can. -

-

The goal of software development is to create technical excellence, not for any -individual to be better and "win" against the others. Large software projects -are only possible and successful through teamwork. -

-

If someone struggles do not put them down. Give them a helping hand -instead and point them in the right direction. -

-

Finally, keep in mind the immortal words of Bill and Ted, -"Be excellent to each other." -

- -

1.6 Submitting patches

- -

First, read the Coding Rules above if you did not yet, in particular -the rules regarding patch submission. -

-

When you submit your patch, please use git format-patch or -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 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 -ffmpeg-devel -mailing list. Use 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. Also ensure the correct mime type is used -(text/x-diff or text/x-patch or at least text/plain) and that only one -patch is inline or attached per mail. -You can check https://patchwork.ffmpeg.org, if your patch does not show up, its mime type -likely was wrong. -

-

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. -

- - -

1.7 New codecs or formats checklist

- -
    -
  1. Did you use av_cold for codec initialization and close functions? - -
  2. Did you add a long_name under NULL_IF_CONFIG_SMALL to the AVCodec or -AVInputFormat/AVOutputFormat struct? - -
  3. Did you bump the minor version number (and reset the micro version -number) in libavcodec/version.h or libavformat/version.h? - -
  4. Did you register it in allcodecs.c or allformats.c? - -
  5. Did you add the AVCodecID to avcodec.h? -When adding new codec IDs, also add an entry to the codec descriptor -list in libavcodec/codec_desc.c. - -
  6. If it has a FourCC, did you add it to libavformat/riff.c, -even if it is only a decoder? - -
  7. 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. - -
  8. Did you add an entry to the table of supported formats or codecs in -doc/general.texi? - -
  9. Did you add an entry in the Changelog? - -
  10. If it depends on a parser or a library, did you add that dependency in -configure? - -
  11. Did you git add the appropriate files before committing? - -
  12. Did you make sure it compiles standalone, i.e. with -configure --disable-everything --enable-decoder=foo -(or --enable-demuxer or whatever your component is)? -
- - - -

1.8 patch submission checklist

- -
    -
  1. Does make fate pass with the patch applied? - -
  2. Was the patch generated with git format-patch or send-email? - -
  3. Did you sign off your patch? (git commit -s) -See http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob_plain;f=Documentation/SubmittingPatches for the meaning -of sign off. - -
  4. Did you provide a clear git commit log message? - -
  5. Is the patch against latest FFmpeg git master branch? - -
  6. Are you subscribed to ffmpeg-devel? -(the list is subscribers only due to spam) - -
  7. Have you checked that the changes are minimal, so that the same cannot be -achieved with a smaller patch and/or simpler final code? - -
  8. If the change is to speed critical code, did you benchmark it? - -
  9. If you did any benchmarks, did you provide them in the mail? - -
  10. Have you checked that the patch does not introduce buffer overflows or -other security issues? - -
  11. Did you test your decoder or demuxer against damaged data? If no, see -tools/trasher, the noise bitstream filter, and -zzuf. Your decoder or demuxer -should not crash, end in a (near) infinite loop, or allocate ridiculous -amounts of memory when fed damaged data. - -
  12. Did you test your decoder or demuxer against sample files? -Samples may be obtained at https://samples.ffmpeg.org. - -
  13. Does the patch not mix functional and cosmetic changes? - -
  14. Did you add tabs or trailing whitespace to the code? Both are forbidden. - -
  15. Is the patch attached to the email you send? - -
  16. 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. - -
  17. If the patch fixes a bug, did you provide a verbose analysis of the bug? - -
  18. 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. - -
  19. Did you provide a verbose summary about what the patch does change? - -
  20. Did you provide a verbose explanation why it changes things like it does? - -
  21. Did you provide a verbose summary of the user visible advantages and -disadvantages if the patch is applied? - -
  22. Did you provide an example so we can verify the new feature added by the -patch easily? - -
  23. 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. - -
  24. You should maintain alphabetical order in alphabetically ordered lists as -long as doing so does not break API/ABI compatibility. - -
  25. Lines with similar content should be aligned vertically when doing so -improves readability. - -
  26. Consider adding a regression test for your code. - -
  27. If you added YASM code please check that things still work with –disable-yasm. - -
  28. Make sure you check the return values of function and return appropriate -error codes. Especially memory allocation functions like av_malloc() -are notoriously left unchecked, which is a serious problem. - -
  29. Test your code with valgrind and or Address Sanitizer to ensure it’s free -of leaks, out of array accesses, etc. -
- - -

1.9 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. -

-

Everyone is welcome to review patches. Also if you are waiting for your patch -to be reviewed, please consider helping to review other patches, that is a great -way to get everyone’s patches reviewed sooner. -

- -

1.10 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 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]. -

- -

1.10.1 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 included 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 introductory message for the patch series that you post to -the ffmpeg-devel mailing list, a direct link to download the sample media. -

- -

1.10.2 Visualizing Test Coverage

- -

The FFmpeg build system allows visualizing the test coverage in an easy -manner with the coverage tools gcov/lcov. This involves -the following steps: -

-
    -
  1. Configure to compile with instrumentation enabled: - configure --toolchain=gcov. - -
  2. Run your test case, either manually or via FATE. This can be either - the full FATE regression suite, or any arbitrary invocation of any - front-end tool provided by FFmpeg, in any combination. - -
  3. Run make lcov to generate coverage data in HTML format. - -
  4. View lcov/index.html in your preferred HTML viewer. -
- -

You can use the command make lcov-reset to reset the coverage -measurements. You will need to rerun make lcov after running a -new test. -

- -

1.10.3 Using Valgrind

- -

The configure script provides a shortcut for using valgrind to spot bugs -related to memory handling. Just add the option ---toolchain=valgrind-memcheck or --toolchain=valgrind-massif -to your configure line, and reasonable defaults will be set for running -FATE under the supervision of either the memcheck or the -massif tool of the valgrind suite. -

-

In case you need finer control over how valgrind is invoked, use the ---target-exec='valgrind <your_custom_valgrind_options> option in -your configure line instead. -

- -

1.11 Release process

- -

FFmpeg maintains a set of release branches, which are the -recommended deliverable for system integrators and distributors (such as -Linux distributions, etc.). At regular times, a release -manager prepares, tests and publishes tarballs on the -https://ffmpeg.org website. -

-

There are two kinds of releases: -

-
    -
  1. Major releases always include the latest and greatest -features and functionality. - -
  2. Point releases are cut from release branches, -which are named release/X, with X being the release -version number. -
- -

Note that we promise to our users that shared libraries from any FFmpeg -release never break programs that have been compiled against -previous versions of 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 ffmpeg-devel mailing list in time to allow forward planning. -

- -

1.11.1 Criteria for Point Releases

- -

Changes that match the following criteria are valid candidates for -inclusion into a point release: -

-
    -
  1. Fixes a security issue, preferably identified by a CVE -number issued by http://cve.mitre.org/. - -
  2. Fixes a documented bug in https://trac.ffmpeg.org. - -
  3. Improves the included documentation. - -
  4. Retains both source code and binary compatibility with previous -point releases of the same release branch. -
- -

The order for checking the rules is (1 OR 2 OR 3) AND 4. -

- - -

1.11.2 Release Checklist

- -

The release process involves the following steps: -

-
    -
  1. Ensure that the RELEASE file contains the version number for -the upcoming release. - -
  2. Add the release at https://trac.ffmpeg.org/admin/ticket/versions. - -
  3. Announce the intent to do a release to the mailing list. - -
  4. Make sure all relevant security fixes have been backported. See -https://ffmpeg.org/security.html. - -
  5. Ensure that the FATE regression suite still passes in the release -branch on at least i386 and amd64 -(cf. Regression tests). - -
  6. Prepare the release tarballs in bz2 and gz formats, and -supplementing files that contain gpg signatures - -
  7. Publish the tarballs at https://ffmpeg.org/releases. Create and -push an annotated tag in the form nX, with X -containing the version number. - -
  8. Propose and send a patch to the ffmpeg-devel mailing list -with a news entry for the website. - -
  9. Publish the news entry. - -
  10. Send an announcement to the mailing list. -
- - -

- This document was generated using makeinfo. -

-
- - -- cgit v1.2.3