Playback of some of imported .mp4 files isn't smooth - both in preview and render

[50482864account]

Hello everyone,

I do have a problem, to which I cannot comprehend an undestanding. Maybe you could help, maybe someone have had similar problem.

I do have an issue with playback of SOME of video files imported - they are not smooth. Both in the render and preview.

I do not have any idea, what can cause the problem, it seems random but, it must be some reason behind it.

This is not connected to an image resolution, or to PC hardware(rtx2070s, intel i9, 32gb). I have one folder with files, with whom, the problem occurs. The format of these files is already H.264 .mp4, these are not iPhone files. Some of them plays fine, some doesn't.

I tried to copy files to other locations, but it doesn't seems to do anyting.

DaVinci Resolve, opens it without issues. When rendering and previewing, playback is smooth.