I tried using a 30-second video clip that was previously uploaded and has previously reliably worked as well. The behavior I observed was that the spinner (shown while the video is pre-processed into the typically 1 fps image sequence) didn’t stop spinning after a full minute, and the ‘Run’ button did not become enabled:
Hope that helps the team with trouble shooting. I am speculating that the video issue might be related to the issue reported here: Urgent: Significant Regression in File Status Transition to ACTIVE