@contents
-@chapter Notes for external developers
+@chapter Introduction
-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 @file{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 @emph{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.
+This text is concerned with the development @emph{of} FFmpeg itself. Information
+on using the FFmpeg libraries in other programs can be found elsewhere, e.g. in:
+@itemize @bullet
+@item
+the installed header files
+@item
+@url{http://ffmpeg.org/doxygen/trunk/index.html, the Doxygen documentation}
+generated from the headers
+@item
+the examples under @file{doc/examples}
+@end itemize
For more detailed legal information about the use of FFmpeg in
external programs read the @file{LICENSE} file in the source tree and
consult @url{https://ffmpeg.org/legal.html}.
-@chapter Contributing
-
-There are 2 ways by which code gets into FFmpeg:
+If you modify FFmpeg code for your own use case, you are highly encouraged to
+@emph{submit your changes back to us}, using this document as a guide. There are
+both pragmatic and ideological reasons to do so:
@itemize @bullet
-@item Submitting patches to the ffmpeg-devel mailing list.
- See @ref{Submitting patches} for details.
-@item Directly committing changes to the main tree.
+@item
+Maintaining external changes to keep up with upstream development is
+time-consuming and error-prone. With your code in the main tree, it will be
+maintained by FFmpeg developers.
+@item
+FFmpeg developers include leading experts in the field who can find bugs or
+design flaws in your code.
+@item
+By supporting the project you find useful you ensure it continues to be
+maintained and developed.
@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}.
+All proposed code changes should be submitted for review to
+@url{mailto:ffmpeg-devel@@ffmpeg.org, the development mailing list}, as
+described in more detail in the @ref{Submitting patches} chapter. The code
+should comply with the @ref{Development Policy} and 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}
@chapter Coding Rules
+@section Language
+
+FFmpeg is mainly programmed in the ISO C99 language, extended with:
+@itemize @bullet
+@item
+Atomic operations from C11 @file{stdatomic.h}. They are emulated on
+architectures/compilers that do not support them, so all FFmpeg-internal code
+may use atomics without any extra checks. However, @file{stdatomic.h} must not
+be included in public headers, so they stay C99-compatible.
+@end itemize
+
+Compiler-specific extensions may be used with good reason, but must not be
+depended on, i.e. the code must still compile and work with compilers lacking
+the extension.
+
+The following C99 features must not be used anywhere in the codebase:
+@itemize @bullet
+@item
+variable-length arrays;
+
+@item
+complex numbers;
+
+@item
+mixed statements and declarations.
+@end itemize
+
+@subsection SIMD/DSP
+@anchor{SIMD/DSP}
+
+As modern compilers are unable to generate efficient SIMD or other
+performance-critical DSP code from plain C, handwritten assembly is used.
+Usually such code is isolated in a separate function. Then the standard approach
+is writing multiple versions of this function – a plain C one that works
+everywhere and may also be useful for debugging, and potentially multiple
+architecture-specific optimized implementations. Initialization code then
+chooses the best available version at runtime and loads it into a function
+pointer; the function in question is then always called through this pointer.
+
+The specific syntax used for writing assembly is:
+@itemize @bullet
+@item
+NASM on x86;
+
+@item
+GAS on ARM.
+@end itemize
+
+A unit testing framework for assembly called @code{checkasm} lives under
+@file{tests/checkasm}. All new assembly should come with @code{checkasm} tests;
+adding tests for existing assembly that lacks them is also strongly encouraged.
+
+@subsection Other languages
+
+Other languages than C may be used in special cases:
+@itemize @bullet
+@item
+Compiler intrinsics or inline assembly when the code in question cannot be
+written in the standard way described in the @ref{SIMD/DSP} section. This
+typically applies to code that needs to be inlined.
+
+@item
+Objective-C where required for interacting with macOS-specific interfaces.
+@end itemize
+
@section Code formatting conventions
There are the following guidelines regarding the indentation in files:
@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 Vim 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
+
+@subsection Emacs configuration
+For Emacs, add these roughly equivalent lines to your @file{.emacs.d/init.el}:
+@lisp
+(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 lisp
@section Comments
Use the JavaDoc/Doxygen format (see examples below) so that code documentation
...
@end example
-@section 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 @};}).
-
-@item
-for loops with variable definition (@samp{for (int i = 0; i < 8; i++)});
-
-@item
-Variadic macros (@samp{#define ARRAY(nb, ...) (int[nb + 1])@{ nb, __VA_ARGS__ @}});
-
-@item
-Implementation defined behavior for signed integers is assumed to match the
-expected behavior for two's complement. Non representable values in integer
-casts are binary truncated. Shift right of signed values uses sign extension.
-@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;
+@anchor{Naming conventions}
+@section Naming conventions
-@item
-GCC statement expressions (@samp{(x = (@{ int y = 4; y; @})}).
-@end itemize
+Names of functions, variables, and struct members must be lowercase, using
+underscores (_) to separate words. For example, @samp{avfilter_get_video_buffer}
+is an acceptable function name and @samp{AVFilterGetVideo} is not.
-@section 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 CamelCase.
+Struct, union, enum, and typedeffed type names must use CamelCase. All structs
+and unions should be typedeffed to the same name as the struct/union tag, e.g.
+@code{typedef struct AVFoo @{ ... @} AVFoo;}. Enums are typically not
+typedeffed.
-There are the following conventions for naming variables and functions:
+Enumeration constants and macros must be UPPERCASE, except for macros
+masquerading as functions, which should use the function naming convention.
+All identifiers in the libraries should be namespaced as follows:
@itemize @bullet
@item
-For local variables no prefix is required.
-
-@item
-For file-scope variables and functions declared as @code{static}, no prefix
-is required.
+No namespacing for identifiers with file and lower scope (e.g. local variables,
+static functions), and struct and union members,
@item
-For variables and functions visible outside of file scope, but only used
-internally by a library, an @code{ff_} prefix should be used,
-e.g. @samp{ff_w64_demuxer}.
+The @code{ff_} prefix must be used for variables and functions visible outside
+of file scope, but only used internally within a single library, e.g.
+@samp{ff_w64_demuxer}. This prevents name collisions when FFmpeg is statically
+linked.
@item
For variables and functions visible outside of file scope, used internally
@samp{avpriv_report_missing_feature}.
@item
+All other internal identifiers, like private type or macro names, should be
+namespaced only to avoid possible internal conflicts. E.g. @code{H264_NAL_SPS}
+vs. @code{HEVC_NAL_SPS}.
+
+@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.
+
+@item
+Other public identifiers (struct, union, enum, macro, type names) must use their
+library's public prefix (@code{AV}, @code{Sws}, or @code{Swr}).
@end itemize
Furthermore, name space reserved for the system should not be invaded.
@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
-@section 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}:
-@lisp
-(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 lisp
-
+@anchor{Development Policy}
@chapter Development Policy
+@section Code behaviour
+
+@subheading Correctness
+The code must be valid. It must not crash, abort, access invalid pointers, leak
+memory, cause data races or signed integer overflow, or otherwise cause
+undefined behaviour. Error codes should be checked and, when applicable,
+forwarded to the caller.
+
+@subheading Thread- and library-safety
+Our libraries may be called by multiple independent callers in the same process.
+These calls may happen from any number of threads and the different call sites
+may not be aware of each other - e.g. a user program may be calling our
+libraries directly, and use one or more libraries that also call our libraries.
+The code must behave correctly under such conditions.
+
+@subheading Robustness
+The code must treat as untrusted any bytestream received from a caller or read
+from a file, network, etc. It must not misbehave when arbitrary data is sent to
+it - typically it should print an error message and return
+@code{AVERROR_INVALIDDATA} on encountering invalid input data.
+
+@subheading Memory allocation
+The code must use the @code{av_malloc()} family of functions from
+@file{libavutil/mem.h} to perform all memory allocation, except in special cases
+(e.g. when interacting with an external library that requires a specific
+allocator to be used).
+
+All allocations should be checked and @code{AVERROR(ENOMEM)} returned on
+failure. A common mistake is that error paths leak memory - make sure that does
+not happen.
+
+@subheading stdio
+Our libraries must not access the stdio streams stdin/stdout/stderr directly
+(e.g. via @code{printf()} family of functions), as that is not library-safe. For
+logging, use @code{av_log()}.
+
@section Patches/Committing
@subheading Licenses for patches must be compatible with FFmpeg.
Contributions should be licensed under the
Always check the mailing list for any reviewers with issues and test
FATE before you push.
-@subheading 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 @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.
+@subheading Commit messages
+Commit messages are highly important tools for informing other developers on
+what a given change does and why. Every commit must always have a properly
+filled out commit message with the following format:
+@example
+area changed: short 1 line description
+
+details describing what and why and giving references.
+@end example
+
+If the commit addresses a known bug on our bug tracker or other external issue
+(e.g. CVE), the commit message should include the relevant bug ID(s) or other
+external identifiers. Note that this should be done in addition to a proper
+explanation and not instead of it. Comments such as "fixed!" or "Changed it."
+are not acceptable.
+
+When applying patches that have been discussed at length on the mailing list,
+reference the thread in the commit message.
@subheading Testing must be adequate but not excessive.
If it works for you, others, and passes FATE then it should be OK to commit
Also if you have doubts about splitting or not splitting, do not hesitate to
ask/discuss it on the developer mailing list.
-@subheading 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.
-
@subheading 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
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
-@subheading 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:
-
-@example
-area changed: Short 1 line description
-
-details describing what and why and giving references.
-@end example
-
@subheading 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.
-@subheading 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.
-
@subheading 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
Also note, the maintainer can simply ask for more time to review!
@section Code
-@subheading 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).
-
-@subheading 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.
-
@subheading 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 changed to not generate a warning unless that causes a slowdown
or obfuscates the code.
-@subheading 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.
+@section Library public interfaces
+Every library in FFmpeg provides a set of public APIs in its installed headers,
+which are those listed in the variable @code{HEADERS} in that library's
+@file{Makefile}. All identifiers defined in those headers (except for those
+explicitly documented otherwise), and corresponding symbols exported from
+compiled shared or static libraries are considered public interfaces and must
+comply with the API and ABI compatibility rules described in this section.
+
+Public APIs must be backward compatible within a given major version. I.e. any
+valid user code that compiles and works with a given library version must still
+compile and work with any later version, as long as the major version number is
+unchanged. "Valid user code" here means code that is calling our APIs in a
+documented and/or intended manner and is not relying on any undefined behavior.
+Incrementing the major version may break backward compatibility, but only to the
+extent described in @ref{Major version bumps}.
+
+We also guarantee backward ABI compatibility for shared and static libraries.
+I.e. it should be possible to replace a shared or static build of our library
+with a build of any later version (re-linking the user binary in the static
+case) without breaking any valid user binaries, as long as the major version
+number remains unchanged.
+
+@subsection Adding new interfaces
+Any new public identifiers in installed headers are considered new API - this
+includes new functions, structs, macros, enum values, typedefs, new fields in
+existing structs, new installed headers, etc. Consider the following
+guidelines when adding new APIs.
+
+@subsubheading Motivation
+While new APIs can be added relatively easily, changing or removing them is much
+harder due to abovementioned compatibility requirements. You should then
+consider carefully whether the functionality you are adding really needs to be
+exposed to our callers as new public API.
+
+Your new API should have at least one well-established use case outside of the
+library that cannot be easily achieved with existing APIs. Every library in
+FFmpeg also has a defined scope - your new API must fit within it.
+
+@subsubheading Replacing existing APIs
+If your new API is replacing an existing one, it should be strictly superior to
+it, so that the advantages of using the new API outweight the cost to the
+callers of changing their code. After adding the new API you should then
+deprecate the old one and schedule it for removal, as described in
+@ref{Removing interfaces}.
+
+If you deem an existing API deficient and want to fix it, the preferred approach
+in most cases is to add a differently-named replacement and deprecate the
+existing API rather than modify it. It is important to make the changes visible
+to our callers (e.g. through compile- or run-time deprecation warnings) and make
+it clear how to transition to the new API (e.g. in the Doxygen documentation or
+on the wiki).
+
+@subsubheading API design
+The FFmpeg libraries are used by a variety of callers to perform a wide range of
+multimedia-related processing tasks. You should therefore - within reason - try
+to design your new API for the broadest feasible set of use cases and avoid
+unnecessarily limiting it to a specific type of callers (e.g. just media
+playback or just transcoding).
+
+@subsubheading Consistency
+Check whether similar APIs already exist in FFmpeg. If they do, try to model
+your new addition on them to achieve better overall consistency.
+
+The naming of your new identifiers should follow the @ref{Naming conventions}
+and be aligned with other similar APIs, if applicable.
+
+@subsubheading Extensibility
+You should also consider how your API might be extended in the future in a
+backward-compatible way. If you are adding a new struct @code{AVFoo}, the
+standard approach is requiring the caller to always allocate it through a
+constructor function, typically named @code{av_foo_alloc()}. This way new fields
+may be added to the end of the struct without breaking ABI compatibility.
+Typically you will also want a destructor - @code{av_foo_free(AVFoo**)} that
+frees the indirectly supplied object (and its contents, if applicable) and
+writes @code{NULL} to the supplied pointer, thus eliminating the potential
+dangling pointer in the caller's memory.
+
+If you are adding new functions, consider whether it might be desirable to tweak
+their behavior in the future - you may want to add a flags argument, even though
+it would be unused initially.
+
+@subsubheading Documentation
+All new APIs must be documented as Doxygen-formatted comments above the
+identifiers you add to the public headers. You should also briefly mention the
+change in @file{doc/APIchanges}.
+
+@subsubheading Bump the version
+Backward-incompatible API or ABI changes require incrementing (bumping) the
+major version number, as described in @ref{Major version bumps}. Major
+bumps are significant events that happen on a schedule - so if your change
+strictly requires one you should add it under @code{#if} preprocesor guards that
+disable it until the next major bump happens.
+
+New APIs that can be added without breaking API or ABI compatibility require
+bumping the minor version number.
+
+Incrementing the third (micro) version 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.
+
+@anchor{Removing interfaces}
+@subsection Removing interfaces
+Due to abovementioned compatibility guarantees, removing APIs is an involved
+process that should only be undertaken with good reason. Typically a deficient,
+restrictive, or otherwise inadequate API is replaced by a superior one, though
+it does at times happen that we remove an API without any replacement (e.g. when
+the feature it provides is deemed not worth the maintenance effort, out of scope
+of the project, fundamentally flawed, etc.).
+
+The removal has two steps - first the API is deprecated and scheduled for
+removal, but remains present and functional. The second step is actually
+removing the API - this is described in @ref{Major version bumps}.
+
+To deprecate an API you should signal to our users that they should stop using
+it. E.g. if you intend to remove struct members or functions, you should mark
+them with @code{attribute_deprecated}. When this cannot be done, it may be
+possible to detect the use of the deprecated API at runtime and print a warning
+(though take care not to print it too often). You should also document the
+deprecation (and the replacement, if applicable) in the relevant Doxygen
+documentation block.
+
+Finally, you should define a deprecation guard along the lines of
+@code{#define FF_API_<FOO> (LIBAVBAR_VERSION_MAJOR < XX)} (where XX is the major
+version in which the API will be removed) in @file{libavbar/version_major.h}
+(@file{version.h} in case of @code{libavutil}). Then wrap all uses of the
+deprecated API in @code{#if FF_API_<FOO> .... #endif}, so that the code will
+automatically get disabled once the major version reaches XX. You can also use
+@code{FF_DISABLE_DEPRECATION_WARNINGS} and @code{FF_ENABLE_DEPRECATION_WARNINGS}
+to suppress compiler deprecation warnings inside these guards. You should test
+that the code compiles and works with the guard macro evaluating to both true
+and false.
+
+@anchor{Major version bumps}
+@subsection Major version bumps
+A major version bump signifies an API and/or ABI compatibility break. To reduce
+the negative effects on our callers, who are required to adapt their code,
+backward-incompatible changes during a major bump should be limited to:
+@itemize @bullet
+@item
+Removing previously deprecated APIs.
+
+@item
+Performing ABI- but not API-breaking changes, like reordering struct contents.
+@end itemize
@section Documentation/Other
@subheading Subscribe to the ffmpeg-devel mailing list.
We think our rules are not too hard. If you have comments, contact us.
-@chapter 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."
-
@anchor{Submitting patches}
@chapter Submitting patches
You can check @url{https://patchwork.ffmpeg.org}, if your patch does not show up, its mime type
likely was wrong.
+@subheading Sending patches from email clients
+Using @code{git send-email} might not be desirable for everyone. The
+following trick allows to send patches via email clients in a safe
+way. It has been tested with Outlook and Thunderbird (with X-Unsent
+extension) and might work with other applications.
+
+Create your patch like this:
+
+@verbatim
+git format-patch -s -o "outputfolder" --add-header "X-Unsent: 1" --suffix .eml --to ffmpeg-devel@ffmpeg.org -1 1a2b3c4d
+@end verbatim
+
+Now you'll just need to open the eml file with the email application
+and execute 'Send'.
+
+@subheading Reviews
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
improves readability.
@item
-Consider adding a regression test for your code.
+Consider adding a regression test for your code. All new modules
+should be covered by tests. That includes demuxers, muxers, decoders, encoders
+filters, bitstream filters, parsers. If its not possible to do that, add
+an explanation why to your patchset, its ok to not test if theres a reason.
@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 Adding files to the fate-suite dataset
+If you need a sample uploaded send a mail to samples-request.
+
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
projects / platform / upstream / ffmpeg.git / blobdiff