HEIF is a container with support for different codecs. HEIC is what it's called when it contains HEVC media. AVIF is in fact a HEIF containing AV1. It all boil

HEIF is a container with support for different codecs. HEIC is what it's called when it contains HEVC media. AVIF is in fact a HEIF containing AV1. It all boils down to codec support. Past year Apple finally started supporting Google codecs, so Safari gained VP9 and WebP.