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lusoris
2a8c6d30b9
export_film_grain() copied cb_mult, cb_luma_mult and cb_offset (and the Cr equivalents) straight from the bitstream, where they are coded with a bias of 128, 128 and 256. AVFilmGrainAOMParams holds them unbiased: the uv_offset documentation gives a range of [-256, 255], the AFGS1 parser in aom_film_grain.c subtracts the bias, the film grain synthesizer uses the values as signed multipliers and offsets, and libdav1d exports them unbiased. The AR coefficients a few lines above are already unbiased the same way. With -export_side_data film_grain and a hwaccel, the native decoder therefore exported values 128 or 256 higher than libdav1d for the same stream, and any consumer applying the exported grain scaled chroma noise wrong. Signed-off-by: lusoris <lusoris@proton.me>
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 Forgejo or 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.
See https://ffmpeg.org/developer.html for more information.