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033e58941e
This commit rewrites the PNS implementation and significantly improves sonic quality. The previous implementation marked an incredibly big amount of SFBs to predict when there was no need for this and this resulted in quite a large amount of artifacts. Also the quantization was incorrect (av_clip(4+log2f(...))) which led to 3x the intensity for PNS values leading to even more artifacts. This commit rewrites the PNS search function and introduces a major change: the PNS values are synthesized and are compared to the current coefficients in addition to passing through the revised checks to see whether PNS can be used. This decreases distortions and makes the current PNS implementation mainly focused on replacing any low-power non-zero bands as well as adding any zeroed bands back. The current encoder's performance is enough (especially with IS) so PNS isn't really required except to fill in the occasional few bands as well as extend any zeroed high frequency, so this combination which is already enabled by default works to get as much quality as it can within the bits allowed. Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
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 a mean to alter decoded Audio and Video through chain of 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.
- ffserver is a multimedia streaming server for live broadcasts.
- 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.