Two defects that arrived with the keep-alive track in v1.3.4 are fixed, and the second of them silently cost a viewer their spatial audio.
A second audio AdaptationSet made video.js offer an audio track selector. Both entries render unlabelled, and choosing the wrong one points the video element at the silent keep-alive, which on the native decode path takes the programme away from the feed. The selector is no longer shown: there is exactly one correct track and the feed already selects it, so the control offered nothing but a way to break playback.
Worse, dash.js persists the last selected track to local storage and restores it on every later visit, so a viewer who touched that menu once stayed silent afterwards, across reloads, until they cleared site data. That cache is now disabled, which stops both the write and the restore, so an affected client recovers on its next load.
Picture-in-Picture is now offered. Both engines pause a backgrounded video by policy and both exempt PiP, so it is the sanctioned way to keep listening after leaving the browser, and the control falls back to webkitSetPresentationMode where the standard call is missing. Closing the window pauses playback; returning to the tab does not. Automatic Picture-in-Picture is not available here, since both engines gate it on the video element being the fullscreen presentation and this one is a texture source for the sphere rather than the picture on screen.