Compare an affected video using Firefox's native controls without the SEAS desktop or player code.
Files stay local; this page does not upload or save them.
Pause playback in SEAS, then choose the same file here. Play for at least 30 seconds.
Switch to Read entire file first and repeat from the beginning.
This copies the file's bytes into a new Blob before opening it and uses extra memory.
The browser still controls decoding and buffering.
Compare both results with opening the original file directly in Firefox.
Use Show report after a freeze to inspect buffering and dropped-frame counters.
Choose a video.
These comparisons help narrow down the cause; a smooth result here does not establish which SEAS component is responsible.
No automatic seeks, retries or periodic UI updates run on this page.