Random scrambled pictures

Hi, I notice a lot of scrambled pictures during editing of iPhone footage. It looks like a shot used before is in between. Not only on my MacBook Catalina and 10,4.7. Also friends of mine encounter this problem on iMacs and Mojave. The scrambled pictures also appear in the export. It has occasionaly happened with footage of a high end cam. Any ideas?

I use iPhone Xs, also older iPhone 7s daily, not seen any issues, Mojave and Cataline, iMac Pro, iMac, rMBP. I shoot 4K 30p on iPhone, edit in 1080 59.94. But if multiple folks are seeing this issue, I'm curious as to what is causing it.

See screenshot

excuses moi, no screen shot. Will figure out later

I think it might be HEVC related combined with unstable frame rate.

Hi, Thanks. This could be the problem. First scan all affected shots are HEVC. Although filmed 30fps edited 30fps

The problem is in the crappy camera. If you look at the files in the QT player you'll often see frame rates like 30.01 and 29.99 and other odd numbers, which basically indicates the frame rates are not stable. Usually dedicated shooting apps like Filmic Pro and Mavis produce better results.

I'll look in to that. I normally use filmic. The footage we have problems with is shot by others on their phones. I just heard that optimizing helps to solve the problem.

F ionic has been having this problem as well. 30.01. 30.02.