This official AVIF encode/decode library continues being rounded out with more features and improvements. In libavif 1.4 there is now support for converting JPEG files with Apple-style gain maps, supporting some Sample Transform schemes defined by the AVIF v1.2 specification, support for dealing with PNG cICP chunks, support reading Sample-Transform-based 16-bit AVIF files, and various other improvements.
The AVIF encoder "avifenc" is also now able to read PNG and JPEG files from the standard input plus there are a few other options added.
Downloads and more details on the updated libavif 1.4 release via GitHub .