Hello there! So I'm having an issue that I hope someone can help give me some sort of solution.
I got a GoPro not too long ago and have been messing around with some footage shot on a road trip. Today I tried to export some of the footage and noticed that during some parts of the quicktime video some sort of diagonal lines appeared during different parts of the video. I realized they appeared anytime I had a transition or if I had increased the clip speed. This happened while exporting both a quicktime and quicktime conversion.
Later on I found out it would have been best to convert the footage from mpeg4 to something less foreign to final cut, but I've already put in many hours of editing into this project and hope there's some sort of solution to salvage it.
You must transcode to another video codec such as ProRes 422, and you will most likely have to eyeball match to your existing cut, though you could try relinking the new files in place of the old ones.