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Martin Storsjö
6258e61c4d
Older versions of Clang (Xcode 14, llvm.org Clang 13 and 14) do support and recognize SME, but when enabled through ".arch_extension sme" it fails to transitively enable support for Streaming SVE; this was fixed in [1]. This issue results in those versions currently detecting support for SME, but later failing to build cpu_sme.s with errors like "error: instruction requires: sve or sme" or "error: instruction requires: streaming-sve or sve", on the "cntb x0" instruction. Extend the check for this instruction set extension, to test with two instructions, both specifically a SME instruction (smstart) and an instruction that is available in Streaming SVE mode (cntb). For the configure check, add an extra parameter to check_archext_insn for an optional second instruction to check. It would be tempting to just pass both instructions through the same parameter, as "smstart; cntb x0". However, Darwin targets use a different token (%%) for starting a new instruction on the same line - those targets interpret ";" as the start of a comment. Due to that, such a check would entirely ignore the second instruction on Darwin targets. To avoid dealing with the variability in passing multiple instructions on one line, just pass the optional second instruction on a separate line. [1] https://github.com/llvm/llvm-project/commit/ff3f3a54e2d1b05c36943bf88ae0be7475d622ed
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.