Test files for still AVIF decoding. Source.
Test file with cropping. The image has an encoded size of 320x280. If the Clean Aperture box is honored, the size of the displayed image will be 180x100. Source.
Test files for animated AVIF decoding. Source.
alpha_video.avif is patched at 0-indexed byte #259 replaced with 0x04 instead of 0x00 as 0x00 is an invalid item_id for the iref box.