This library supports AVIF encoding via libheif. That library has many useful parameters like speed, threads which are not supported by libvips. They should be added since AVIF support is going live in Chrome on 25h August and usage of that is expected to increase: https://github.com/strukturag/libheif/blob/2dff6b4282d5e03feb5bd8dea5b09710e635cf68/libheif/heif_encoder_aom.cc