So I tried a version with no video but at the original 48khz sampling and got the static back So I added the video back but sampled at 44.1 khz and the audio cleaned up again.
And there is another factor. I changed the volume from 0.26 to 0.25. That seems to also help
So the two factors that seem to affect the noise are the sampling rate and the volume. Setting the volume to 0.25 and the sampling rate to 44.1 khz in the audio file gives me much cleaner audio. Having the video frames along for the ride doesn’t seem to be a factor.
It isn’t perfect, but it is clearly better than the original. I still get a very occasional pops when moving the view. And I also get a very muted and subtle motor boat sound when I rotate the view quickly. It is much easier to notice when the box is behind the camera view. My bet is that the pops are Playcanvas/browser/player artifacts while the “motor boat” is actually system electrical noise induced into my very cheap sound card from the GPU or something similar.
Anyway, much cleaner at 44.1 khz and 0.25 volume.
Note: I re-encoded using Adobe Media encoder. Message me your email if you don’t have an easy way to re-encode and I can send you the re-encoded files.