mirror of
https://git.ffmpeg.org/ffmpeg.git
synced 2026-06-16 04:32:47 +02:00
Swinney, Jonathan
0ea61725b1
This patch adds code to support specializations of the hscale function and adds a specialization for filterSize == 4. ff_hscale8to15_4_neon is a complete rewrite. Since the main bottleneck here is loading the data from src, this data is loaded a whole block ahead and stored back to the stack to be loaded again with ld4. This arranges the data for most efficient use of the vector instructions and removes the need for completion adds at the end. The number of iterations of the C per iteration of the assembly is increased from 4 to 8, but because of the prefetching, there must be a special section without prefetching when dstW < 16. This improves speed on Graviton 2 (Neoverse N1) dramatically in the case where previously fs=8 would have been required. before: hscale_8_to_15__fs_8_dstW_512_neon: 1962.8 after : hscale_8_to_15__fs_4_dstW_512_neon: 1220.9 Signed-off-by: Jonathan Swinney <jswinney@amazon.com> 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.