What is OpenCV
The Open Source Computer Vision Library (OpenCV) is an open-source library that contains several hundred computer vision algorithms. The package includes an OpenCV 2.x API, which is a C++ API. The library is cross-platform and licensed under the Apache 2 open-source license.
Due to its modular structure, OpenCV includes several shared or static libraries. Image Processing (imgproc) is one of the modules. It contains linear and non-linear image filtering and geometrical transformations (resize, affine and perspective warping, generic remappings based on tables), color space conversions, histograms, etc.
AVIF support
OpenCV already supports encoding videos in AV1 with the ffmpeg encoding API for writing videos. As of this writing, a Github issue exists which asks for AVIF support. In January 2021, it was created, but so far has not received much attention. It is uncertain whether OpenCV will add support for AVIF soon.