Forward playback of a screen-recorded H.264 MP4 is acceptable, but scrubbing backward is painfully slow. Is that normal long-GOP behavior or a sign the timestamps are broken?
Long-GOP media is naturally less friendly to random access because a requested frame may depend on earlier reference frames. Backward scrubbing exposes that cost more than normal forward playback.
VFR/irregular timestamps can make seeking worse, so inspect them too. Then compare with a proxy or intraframe copy.
A smaller proxy can feel dramatically faster even when the original is perfectly healthy. File size and editing friendliness are not the same metric.
A proxy makes backward scrubbing nearly instant, so I will keep the original for export and stop treating the slow seek as file corruption.