AV1

AV1, short for AOMedia Video 1, is described by the Alliance for Open Media as an open video codec. Streaming services adopted it because it compresses further than H.264 and VP9 at similar quality, which saves bandwidth at high resolutions. The cost is decoding work: AV1 asks more of a decoder than the older codecs, so whether a device decodes it in hardware decides whether 4K AV1 plays smoothly and how much battery it costs.

A browser asks about AV1 with a codec string naming a profile, a level and a bit depth. The video decode test asks for Main profile, 8-bit, for example av01.0.13M.08 at 4K and 60 fps, once preferring hardware and once preferring software, so the two answers separate a hardware decoder from a software one. It then decodes a 90-frame clip it encodes itself, 3 times, and sets the median frame rate against the video's own. 1.5 times the rate or more is our line for room to spare.

Supported is not the same as hardware. A processor can decode AV1 in software and still fall behind at 4K and 60 fps. If AV1 is software only, check that hardware acceleration is on in the browser and that the graphics driver is current; on Windows, the AV1 Video Extension may also be missing.