Looks like something regressed in the initialization of the audio context when using the popup video handler on Safari 13.0 (just released today).
On a page like https://commons.wikimedia.org/wiki/Main_Page scroll down to the media of the day and click the play button -- it will pop up a video player dialog and should start playback, but does not.
Close the video and try again and it will work.
Video players shown directly such as on File: pages or with video.js mode are not affected.
Looks like the audio wasn't getting initialized at the right time (how did it work on iOS? no clue!) unless mwEmbedSupport has already been loaded.
I'll have to the ext.tmh.OgvJsSupport module as a dep on mw.PopUpThumbVideo and call it there, I think.
Change 538110 had a related patch set uploaded (by Brion VIBBER; owner: Brion VIBBER):
[mediawiki/extensions/TimedMediaHandler@master] Fix Safari 13.0 regression in video playback with audio
Change 538110 merged by jenkins-bot:
[mediawiki/extensions/TimedMediaHandler@master] Fix Safari 13.0 regression in video playback with audio
Change 538130 had a related patch set uploaded (by Jforrester; owner: Brion VIBBER):
[mediawiki/extensions/TimedMediaHandler@wmf/1.34.0-wmf.23] Fix Safari 13.0 regression in video playback with audio
Change 538130 merged by jenkins-bot:
[mediawiki/extensions/TimedMediaHandler@wmf/1.34.0-wmf.23] Fix Safari 13.0 regression in video playback with audio
Mentioned in SAL (#wikimedia-operations) [2019-09-20T01:05:08Z] <jforrester@deploy1001> Synchronized php-1.34.0-wmf.23/extensions/TimedMediaHandler/: T233360 Fix Safari 13.0 regression in video playback with audio (duration: 00m 58s)