Video is split into quadrants, ie what should be the top right corner of the video is in the bottom left, bottom left corner is in the top right, etc.
Sorry if this issue is already known/resolved, I couldn't find the right search terms to look for this because everything I searched about the video being off center or misaligned led to more typical errors about videos being misaligned from the center of the screen.
For more context: I have two large (4 GB) AVI files, each composed of ~150 frames that are high resolution electron micrographs. These movies were exported as AVIs from the proprietary software used to run the microscope to a server, where I downloaded them onto my Mac (Big Sur 11.6). When I pull either one of them up in VLC, I am confronted with four quadrants—the top right of the video is in the bottom left, the bottom right corner is in the top left, the top left corner is in the bottom right, and the bottom left of the video is in the top right. The video is not flipped vertically or horizontally. It appears non-contiguously, as if you dragged the video off-screen, but the part of the video that went off-screen wrapped around to the other side of the screen instead. This happens with both AVIs (which are two videos taken simultaneously of the same FOV on the same microscope with different detectors).
Even more confusingly, the boundaries of this discontinuity move throughout the playback of the video. At the start of the video, the point at which the four quadrants meet is ~75% of the way to the right of the image and ~60% of the way up from the bottom. It stays there for the first ~10% of the video, then abruptly jumps to near the middle of the image. Three or four more times it jumps, always jumping farther left and farther down, and always after staying still for a number of frames. By the end of the video, the point where the four quadrants meet has found its way to the bottom left corner, and the last few frames of the video play correctly, all the corners in their correct position.
This happens with both videos, and while I have not gone frame by frame to check this with absolute certainty, scrubbing through quickly it looks like the jumps happen at the same time and in the same places for both videos. This makes me suspect that it may be a problem of the original export of the AVIs, but there are vastly fewer users of the proprietary microscope software than there are of VLC so I was hoping I might be able to get some help here with figuring out how to fix the alignment of these frames.