When Encode experiences an output failure, it should let you return to your settings

[ferdnyc]

Describe the new feature:
I was testing an export just now using hardware encoding, and I tried to encode using VA-API to my Nvidia card. It failed due to an error opening the device, which is fine, the failure was graceful and a dialog box came up to let me know about the issue.

However, after I closed that dialog, the Export window still proceeded to its "post-export" state where only the Done button is enabled, meaning my only option is to close the window.

Describe the solution you'd like:
Ideally, I'd like Export to re-enable the interface, and allow me to attempt the Export again after I change the Target setting to a different codec. (Hardware-accelerated NVENC, in my case, which is how I successfully exported the video after starting the process over from the beginning.)

The worst part is, it doesn't change the interface until after the error popup is closed. So even after the failure, even while that error message is showing, the Export dialog still shows the "Cancel" and "Export" buttons (disabled, like the rest of the interface). Then, when you close the error dialog, instead of reenabling those buttons, they suddenly disappear and the "Done" button takes their place.

Describe any alternatives you've considered:
Well, hell, if we're not going to let the user fix their export settings, we should just auto-close the window when the error popup is acknowledged. Leaving it there, inaccessible, and forcing them to click "Done" (when it's the only active control in the window)... that's just being mean.

Screenshots: (Optional)
Export, after closing the "Export Error" dialog.

[stale]

Thank you so much for submitting an issue to help improve OpenShot Video Editor. We are sorry about this, but this particular issue has gone unnoticed for quite some time. To help keep the OpenShot GitHub Issue Tracker organized and focused, we must ensure that every issue is correctly labelled and triaged, to get the proper attention.
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