Alliance Video Codec, version 1 is a royalty free video compression codec developed by AOM. AV1 is the spiritual successor to the VP line of codecs, particularly VP9. It could be considered roughly equivalent to H.266/Versatile Video Coding. While AV1 is relatively new, most evergreen desktop browsers have added decoding support for the format; support for mobile devices is still spotty, including in leading-edge chipsets as of 2021.
AV1 provides exceptional video quality at very low bitrates, but is extremely computationally expensive to encode. It is therefore not suitable (at least for now) for live video encoding, and only economical in environments where a single video receives a large number of views by offsetting the high encoding cost with bandwidth savings.