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a785ff4ca2
We can quite easily generalize the existing AVX512 pushfb implementation to
support vpermb when the shuffle mask is cross-lane.
rgb24 1920x1080 -> rgba 1920x1080, speedup=1.372x faster
This does require some finesse w.r.t. the MOVSIZE macro, to avoid reading or
writing too many bits. In particular, for gray->rgba64le, the pattern even
devolves into 8/64 which would trigger an illegal operand error when combining
movq with zmm registers.
Other than that, we can use {k1}{z} zero masking to cleanly recreate the
semantics of pushfb's implicit zero masking, except for non-zero clear
values where we continue doing what we already do.
Lastly, while EVEX-encoded vpermb can take the source operand directly, this
somewhat defeats the purpose of the READ size optimization; in practice it
was better to keep the read and vpermb separate.
Signed-off-by: Niklas Haas <git@haasn.dev>
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.