This is the gold standard for high-quality video. It compresses data more efficiently than the older H.264, allowing for 4K quality without massive file sizes.
If by "av4" you were referring to the emerging AV4 codec (a hypothetical or future successor to the AV1 codec), this feature would describe a video stream utilizing next-generation compression efficiency—delivering 4K/8K quality at significantly lower file sizes than current H.265/HEVC standards. av4 us video extra quality
It provides native 4K Ultra High Definition (UHD) , which delivers four times the pixel density of standard high-definition video. This is the gold standard for high-quality video