There are other similar threads about this but I'm starting a new one because this issue is still not fixed and it should be becasue users rely on Dropbox to serve their most precious information - family photos and video 🙂
When backing up the iOS photo library to Camera Uploads any video shot using the High Efficiency (HEIC) format in iOS cannot be played on the web or any HTML5 player. There is sound but no video.
If I was to copy the same video from my iPhone directly to my computer the video is able to be played so the issue is during the Camera Uploads process.
I have built desktop applications that allow users to browse their entire Dropbox directory, play and share videos and now their libraries (including mine) are full of blank videos.
Please resolve this issue.