Safari 16.4 changes
Released March 27, 2023 — Version 16.4 (18615.1.26)
developer.apple.com
Media
New Features
- Added improvements to audio quality for web video conferencing.
- Added support for a subset of the AudioSession Web API.
- Added support for AVCapture virtual cameras.
- Added support for inbound rtp trackIdentifier stat field.
- Added support for the AV1 codec in the MediaCapabilities API.
- Added support for video stats overlay with developer tools enabled.
- Added support for VTT-based extended audio descriptions.
- Added support to allow a site to provide an “alternate” URL to be used during AirPlay.
- Added video-only support for Web Codecs.
- Added WebRTC support for hardware AV1 decoding on supported device configurations.
If you look at Develop menu I see these unchecked
WebCodecs AV1 codec
WebRTC AV1 codec
WebRTC H256 codec
WebRTC VP9 profile 2 codec
Of course so far YouTube doesn't show AV1 running.