this repo offers a simple reproduction case for an issue with blob url compatibility which was introduced with video.js v7.2.1
clone repo, spin up a little webserver (eg python -m SimpleHTTPServer) and check
index-7.2.0.html (works) and index-7.2.1.html (doesn't work).
what happens is that videojs never sets its source cache correctly when a blob url is being passed as src and therefor it thinks that the sources are not ready (or sth like that...)
this was introduced with this PR: videojs/video.js#5371