Problem time-stepping some videos

[emilk]

Problem video: https://github.com/user-attachments/files/17713986/1517176996106838023-vUiO9nkD-I5wwMDD.mp4.zip

on both web and native, the video player will go into an infinite spinner loop if you step backwards, but only for every second step (see attached video)

24-11-12_10_32_11.patched.mp4

[emilk]

Build a tool to help understand this:

• Show all samples/frames in a video in a nice table #8102