720p, 1080p & QHD Video Modes Cause Video Glitches & Crashes

Shotcut version 21.12.24
Windows 10

There is a major regression when the video mode is set to 720p, 1080p or QHD. While having one of those video modes on, bring one whole video clip (don’t split it) to the timeline, set the playhead in the middle of a clip and drag the clip in either direction. Drop the clip and drag the clip again in the opposite direction. You will see a very annoying video glitch appear each time in the player. Here is a demo to show what I mean.

Furthermore, it seems that this video glitch can produce a crash. Bring a clip down to the timeline of a new project. Don’t move the playhead. Just take the whole clip and drag it back then release then drag it forward and release. Do that a few times and Shotcut will crash. Demo.

That’s not all. Follow the instructions above where I said to set the playhead in the middle of a whole clip (not split) and drag the clip in either direction at the same time as having the video mode to 720p, 1080p or QHD but this time do it while specifically being on the Color layout and Shotcut will crash every single time.

Shotcut does not crash with the video mode set to 2.7k, UHD 4K, DCI 4K, 5K. If you do this with the DCI 2K video mode, Shotcut does not crash but the video glitch still happens in the player.

This video glitch and crash bug seems to have been introduced sometime between early July and the end of August. It surprises me that I didn’t catch this pretty big regression before. A big reason for this I believe is because if the clip is split then the last clip in the track will be the one to produce the video glitches. The split sections ahead of it will not. I demonstrate that here.

Is Setting > Realtime on or off? Does it make a difference?