注意這些話

"It is positioned to replace Google's VP9 and to compete with the standards-based High Efficiency Video Codec (HEVC)"
AV1 是用來取代 VP9 去和 HEVC競爭

Once available, YouTube expects to transition to AV1 as quickly as possible, particularly for video configurations such as UHD, HDR, and high frame rate videos where the codec is expected to deliver significant bandwidth savings over VP9.
一旦可以用了,YouTube希望能儘快的轉到AV1