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This adds a variant of the postfilter for use with 512-bit vectors. Half a vector is enough to perform the scalar product. Normally a whole vector would be used anyhow. Indeed fractional multiplers are no faster than the unit multipler. But in this particular function, a full vector makes up 16 samples, which would be loaded at each iteration of the outer loop. The minimum guaranteed CELT postfilter period is only 15. Accounting for the edges, we can only safely preload up to 13 samples. The fractional multipler is thus used to cap the selected vector length to a safe value of 8 elements or 256 bits. Likewise, we have the 1024-bit variant with the quarter multipler. In theory, a 2048-bit one would be possible with the eigth multipler, but that length is not even defined in the specifications as of yet, nor is it supported by any emulator - forget actual hardware.
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.