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FFmpeg git repo
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According to C99, there has to be at least one argument for every ... in a variadic function-like macro. In practice most (all?) compilers also allow to leave it completely out, but it is nevertheless required: In a variadic macro "there shall be more arguments in the invocation than there are parameters in the macro definition (excluding the ...)." (C99, 6.10.3.4). CBS (not the framework itself, but the macros used in the cbs_*_syntax_template.c files) relies on the compiler allowing to leave a variadic macro argument out. This leads to warnings when compiling in -pedantic mode, e.g. "warning: must specify at least one argument for '...' parameter of variadic macro [-Wgnu-zero-variadic-macro-arguments]" from Clang. Most of these warnings can be easily avoided: The syntax_templates mostly contain helper macros that expand to more complex variadic macros and these helper macros often omit an argument for the .... Modifying them to always expand to complex macros with an empty argument for the ... at the end fixes most of these warnings: The number of warnings went down from 400 to 0 for cbs_av1, from 1114 to 32 for cbs_h2645, from 38 to 0 for cbs_jpeg, from 166 to 0 for cbs_mpeg2 and from 110 to 8 for cbs_vp9. These eight remaining warnings for cbs_vp9 have been fixed by switching to another macro in cbs_vp9_syntax_template: The fixed values for the sync bytes as well as the trailing bits for byte-alignment are now read via the fixed() macro (this also adds a check to ensure that trailing bits are indeed zero as they have to be). Reviewed-by: Mark Thompson <sw@jkqxz.net> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> |
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| compat | ||
| doc | ||
| ffbuild | ||
| fftools | ||
| libavcodec | ||
| libavdevice | ||
| libavfilter | ||
| libavformat | ||
| libavresample | ||
| libavutil | ||
| libpostproc | ||
| libswresample | ||
| libswscale | ||
| presets | ||
| tests | ||
| tools | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .travis.yml | ||
| Changelog | ||
| configure | ||
| CONTRIBUTING.md | ||
| COPYING.GPLv2 | ||
| COPYING.GPLv3 | ||
| COPYING.LGPLv2.1 | ||
| COPYING.LGPLv3 | ||
| CREDITS | ||
| INSTALL.md | ||
| LICENSE.md | ||
| MAINTAINERS | ||
| Makefile | ||
| README.md | ||
| RELEASE | ||
FFmpeg README
FFmpeg is a collection of libraries and tools to process multimedia content such as audio, video, subtitles and related metadata.
Libraries
libavcodecprovides implementation of a wider range of codecs.libavformatimplements streaming protocols, container formats and basic I/O access.libavutilincludes hashers, decompressors and miscellaneous utility functions.libavfilterprovides a mean to alter decoded Audio and Video through chain of filters.libavdeviceprovides an abstraction to access capture and playback devices.libswresampleimplements audio mixing and resampling routines.libswscaleimplements color conversion and scaling routines.
Tools
- ffmpeg is a command line toolbox to manipulate, convert and stream multimedia content.
- ffplay is a minimalistic multimedia player.
- ffprobe is a simple analysis tool to inspect multimedia content.
- Additional small tools such as
aviocat,ismindexandqt-faststart.
Documentation
The offline documentation is available in the doc/ directory.
The online documentation is available in the main website and in the wiki.
Examples
Coding examples are available in the doc/examples directory.
License
FFmpeg codebase is mainly LGPL-licensed with optional components licensed under GPL. Please refer to the LICENSE file for detailed information.
Contributing
Patches should be submitted to the ffmpeg-devel mailing list using
git format-patch or git send-email. Github pull requests should be
avoided because they are not part of our review process and will be ignored.