Hi,
I had this problem too and I want to give my two cent solution into this pot here.
At first: I have an older NCH-Videopad from 2019 and I never had problems with glitching preview shows until some days ago. It started, when I tried to upload a short on YouTube and therefore I had to change the frame for the video from horizontally to vertically longer. That worked with some help of YT-NCH-tutorials, but after the upload I got those glitch problems with my horizontally longer videos - which is the standard format. I saw in the "Options" that beyond the standard default setting of 1920 x 1080 Pixels, I had a picture frequency of 30 000 frames per second, what was not the standard, so I changed that down to 14 000. I then changed the width to 1280 and the height to 720 pixels (preview only) - and then it got better, but not always.
Then I found out that in one of the videos, which were limping in the preview like this, there were micro-sequences, which happen to be created when you cut the video to erase some parts - and then you cut something else in the vicinity, because you want to erase something from the separated sound track below the video track. If you don't have the maximum size of the tracks on the Plus scale on the right side, you won't hit the same division cut again as before, though you think you have cut the video at the same point, and that's where you are creating such video shards of parts of seconds only. They are overlapping with the main video when you unite separate videoparts by swiping them together - as usual after cutting out parts of the video. You don't see these tiny shards in a low solution of the tracks, but they can hamper the flow of the video on some places, the picture there is stuttering and you don't know why.
After finding that out, I maximized the tracks and erased that micro-seconds off the video, and I was careful to put the parts of the video together again afterwards.
Now it works as it should and I'm very happy with Videopad again. I never thought such relatively easy-to-use software for computer dummies like me would be possible. Thank you, NCH! 🙂
