With AVIF, multiple spatial layers can be encoded in one frame. A spatial layer may increase the quality or resolution of the decoded image based on one or more previous layers. A layer may also provide the decoded image independently. Moreover, not every layer produces images intended for rendering. Sometimes, decoded images are used only as intermediate images.
Does AVIF support layers
Primary sources1. AVIF - The Full Guide and FAQ2. AVIF AOMedia Specification3. AVIF Wikipedia4. Jake Archibald Article5. AVIF Netflix article