Make it easier to avoid non-IDR warning

[mrj]

When I'm editing out ads, I often get the message

This video uses non-IDR recovery points instead of IDR as keyframes. Picture reordering information in the video stream is not reset at non-IDR frames. The chosen start and end points of the deletion may result in playback interruption due to reversed display order of frames if saved in copy mode. Proceed anyway?

To fix this I have to keep adjusting the start and end, a keyframe at a time, until the message disappears. This can take minutes.

Optimal would be a button to automatically narrow an edit to fix such a problem. Otherwise, being told in the warning whether the problem is at the start and/or the end.

Other than that, it's getting really nice, no longer crashing regularly, and with the force aspect ratio option so I no longer need to run a "fixaspect" script.

One little niggle is that the "Edit->Reset Edit" menu item would be better named "Edit->Reset Edits" or "Edit->Reset All Edits" or "Edit->Undo All Edits".

[eumagga0x2a]

Optimal would be a button to automatically narrow an edit to fix such a problem. Otherwise, being told in the warning whether the problem is at the start and/or the end.

If retrograde POC is detected for a cut point, it always depends on both markers. For this reason the benefit of an automated solution would be near zero.

If flexibility in cut placement and lack of damaged frames is important, re-encoding is the only clean option. IDR-less open GOP streams, used in digital TV broadcasts, cannot be cut anywhere in the middle or merged and remain valid. It just happens to be that many video players can handle such streams pretty well. FFmpeg is worse at it than most others. If you don't need to target FFmpeg-based video players like VLC or mpv, you may (almost) safely ignore the warning.