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Lynne
a387d21c32
A range coded slice is encoded by a workgroup of 32 invocations, but only the first one ran the range coder, on a coder state and context states kept in shared memory, with two barriers per sample. The slice is now encoded by a single subgroup. Each invocation holds one of the 32 states of the current context, and the range coder runs on uniform values, in a new encoder section of rangecoder_subgroup.glsl. A decision reads its state from the invocation that holds it and updates it there, so no barriers are needed. The coder keeps the top of its interval instead of the bottom, which coding a one leaves unchanged. The line cache of the range coded encoder is kept per invocation, as in the decoder, and subgroups of 32 invocations are required. The output is unchanged. Encoding a 6464x4852 16-bit RGB frame with 1024 slices on an RX 6900 XT, with the frame in VRAM, goes from 202.5/178.5 ms to 179.0/154.9 ms with context model 1/0.
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.