PCem hardlocks on resolution change while dumping video

[fsvgm777]

Anytime PCem changes resolution whilst dumping video, the emulator hardlocks completely, making it a severe hassle to properly dump PCem movies on 1.4.7. It will only produce the segment from before the hardlock occurs.

This is a regression from 1.4.6, as that version does properly split video on resolution change without issue. It has not been fixed as of the latest commit as of this writing (e997120)

Here's the output from terminal (cleaned up a bit):

[nut @ 0x63760aa77a00] No main startcode found. [in#0 @ 0x63760aa77900] Error opening input: Invalid data found when processing input Error opening input file -. Error opening input files: Invalid data found when processing input