When testing video resolution with https://webrtchacks.github.io/WebRTC-Camera-Resolution/ for the built-in FaceTime Camera that is built-in to Mac Air (mid-2011), the getUserMedia with exact constraints failed with OverconstrainedError for all video resolutions when performing the Quick or Full Scan. However, when testing with Chrome 76 the getUserMedia is successful for 640x480 and lower resolutions.
<rdar://problem/54615792>
Created attachment 377054 [details] Chrome 76 - QuickScan
Created attachment 377055 [details] Safari 13 Beta - QuickScan