[BUG] Scrubbing in a MOV file or playing the timeline freezes main thread and continues jumping around for 30+ seconds

Platform

MacOS

Browser

Chrome latest

Current Behavior

When dropping a MOV file and scrubbing in it, performance is really bad and the video keeps wildly jumping around for half a minute or so. Can be reproduced with MOV files recorded with Apple's built-in screen recording (a common usecase for a quick video editor – record video and drop it in).

Expected Behavior

Smooth playback would be great
Not continuing to seek after the user has let go would be important
Not freezing the main thread entirely would also be good

Recurrence Probability

Always

Steps To Reproduce

1. Go to https://opencut.app/
2. On Mac, record a screencap with the built-in screen recorder
3. Drop that recording in opencut
4. Scrub the timeline for 2s seconds or so (just move back and forth)
5. Note that for the next 30+ seconds, the video keeps seeking randomly, and CPU freezes a lot while doing so

Anything else?

Here's a video of the issue:

https://github.com/user-attachments/assets/b9cca4a1-e72c-4b6a-be5c-a82db15d109d

Reproduce the issue at https://opencut.app/ using a MOV recording made with macOS's built-in screen recorder, then profile timeline scrubbing while watching seeking and main-thread activity. Done means playback remains responsive, seeking stops when scrubbing ends, and the video no longer continues jumping for 30+ seconds.