e4ac156b7c
The AArch64 assembly accesses those symbols directly, without indirection via e.g. the GOT on ELF. In order for this not to require text relocations, those symbols need to be resolved fully at link time, i.e. those symbols can't be interposable. Normally, so far, this is achieved when linking shared libraries in two ways; we have a version script (libavcodec/libavcodec.v) which marks all symbols that don't start with av* as local. Additionally, we try to add -Wl,-Bsymbolic to the linker options if supported, making sure that such symbol references are resolved fully at link time, instead of making them interposable. When the libavcodec static library is linked into another shared library, there's no guarantee that it uses similar options (even though that would be favourable), which would end up requiring text relocations in the AArch64 assembly. Explicitly mark the symbols that are accessed from AArch64 assembly as hidden, so that they are resolved fully at link time even without the version script and -Wl,-Bsymbolic. Signed-off-by: Martin Storsjö <martin@martin.st>
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.