This looks like an Apple .mov file. .mov files submissions to use are rare.
We store it on submission so that it can be downloaded and reviewed, but it is not one of the HTML5 native video formats that we support for playback in the browser.
The best way to deal with a sighting like this is to download and play the video on a computer with iTunes (or /mov support generally) and upload still frames back to the Encounter.
As a follow-on to this, we’ll be sure to list the supported formats in the new documentation and what to do if an unsupported format is uploaded.
Thanks!
Tanya