mirror of
https://git.ffmpeg.org/ffmpeg.git
synced 2026-10-28 10:04:37 +08:00
Timo Rothenpieler
447b72d90f
Resizing is done on the RGB side: YUV to RGB conversion converts at the visible input size before scaling, RGB to YUV conversion converts after scaling at the output size. Every scaling pass then works on a single packed plane and reuses the generic RGB kernels, and the conversion kernels are reused with a float RGB side. The RGB intermediates hold normalized floats, so filter overshoot and out of gamut colors are not clipped before the scaler rounds and clamps once. As conversion and filtering are linear, the result matches scaling on the YUV side, apart from rounding and the chroma upsampling of the conversion kernels. Resizing during conversion always uses the generic filters with the selected interp_algo, with nearest using point sampling weights. Conversion without resizing keeps using the direct conversion kernels. Assisted-By: Claude Opus 5.5
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.