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In case of shared builds, some object files containing tables are currently duplicated into other libraries: log2_tab.c, golomb.c, reverse.c. The check for whether this is duplicated is simply whether CONFIG_SHARED is true. Yet this is crude: E.g. libavdevice includes reverse.c for shared builds, but only needs it for the decklink input device, which given that decklink is not enabled by default will be unused in most libavdevice.so. This commit changes this by making it more explicit about what to duplicate from other libraries. To do this, two new Makefile variables were added: SHLIBOBJS and STLIBOBJS. SHLIBOBJS contains the objects that are duplicated from other libraries in case of shared builds; STLIBOBJS contains stuff that a library has to provide for other libraries in case of static builds. These new variables provide a way to enable/disable with a finer granularity than just whether shared builds are enabled or not. E.g. lavd's Makefile now contains: SHLIBOBJS-$(CONFIG_DECKLINK_INDEV) += reverse.o Another example is provided by the golomb tables. These are provided by lavc for static builds, even if one uses a build configuration that makes only lavf use them. Therefore lavc's Makefile contains STLIBOBJS-$(CONFIG_MXF_MUXER) += golomb.o, whereas lavf's Makefile has a corresponding SHLIBOBJS-$(CONFIG_MXF_MUXER) += golomb_tab.o. E.g. in case the MXF muxer is the only component needing these tables only libavformat.so will contain them for shared builds; currently libavcodec.so does so, too. (There is currently a CONFIG_EXTRA group for golomb. But actually one would need two groups (golomb_avcodec and golomb_avformat) in order to know when and where to include these tables. Therefore this commit uses a Makefile-based approach for this and stops using these groups for the users in libavformat.) Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
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 means to alter decoded audio and video through a directed graph of connected 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.