Perhaps I figured out the issue. The bug is with Crop: Rectangle.
Steps
Video Mode 1080p 60fps
V1: Color (white)
V2: Color (black)
V2: Apply Crop: Rectangle, adjust, and set Padding color : Alpha Channel= 0
Save file
Close Shotcut
Reopen Shotcut
Reopen saved file
Attempt to close Shotcut with open file.
This is when Shotcut crashes every single time with this file or any file I have open with Crop: Rectangle with version 20.04.12.
I have the same problem with Text: Html. on V20-04 (and V20-02)
Applying the filter on a V2 clip
Save project and exit.
Re-open project
Select the clip with filter
File -> Exit
SC asks if I want to save the project (which I have not modified). If I answer “yes” SC quits normally, if I answer “no” SC crashes.
I’m running Shotcut 20.04.12 as AppImage on Ubuntu 16.04.
In my case, Shotcut hangs every time I attempt to close a project, when Video::Crop:Rectangle is enabled. I have created two very simple projects that don’t use external resources. Please find attached their MLT files:
Both projects have the same two video layers; one runs a clock, the other acts as background. The only difference is that the one labelled as “DoesNotHang” has the Crop:Rectangle filter disabled.
I can open and close “DoesNotHang” as many times as I want and even on multiple windows at a time.
Even after a freshly started computer session, attempting to close “Hangs” hangs my Shotcut. No activity seems to happen for, at least, one hour.
These are known problems that are not easily fixed until they are completely rewritten to not use HTML/WebVfx. The easiest workaround to the hang problem is to not have the playhead over a clip that is using it at the time of closing.
This is fixed for the next version 20.09 by rewriting the Crop: Rectangle and Crop: Circle filters to not use WebVfx and HTML. Old projects are seamlessly updated upon open.