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b6c207f535
The problem is that with particularly complex images and especially at high bit depths and 5-level transforms the coefficients would overflow, causing huge artifacts to appear. This was discovered thanks to the fate tests, which will have to be redone as this fixes a multitude of problems and increases PSNR. There is a slight performance drop associated with this change, making the encoder slower by 1.15 times, however this is necessary in order to avoid undefined behavior and overflows. It would be worth to template the transforms to keep the performance for 8 bit images as 32 bit coefficients are unnecessary for that case, but the primary use of the encoder is to encode video at 10 bits. Reviewed-by: Christophe Gisquet <christophe.gisquet@gmail.com> Reviewed-by: Michael Niedermayer <michael@niedermayer.cc> 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.
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. Few developers
follow pull requests so they will likely be ignored.