have another question or an idea. some people suggest to format an SD card, then record the video test. assuming the card is 50% full, what the purpose to format the card? the camera doesn't really format it, I think, it performs something like a "quick format", just removing the list of content on the card. if the card is good, not the "full format", or "quick format", or 3 formats on a computer and the camera would solve the problem with the video, right?
but what if the card is full and the camera starts over writing the oldest files, which are not exactly of the same size? a peace of a file doesn't fit into a space of a deleted file, and where the camera writes the rest of it? if the camera would delete 2 older files before writing the first new one, then the file written will be in one peace and in one place, not all over the card. the files on the card would not be fragmented, which would give the CPU enough time to properly write the current file.
it would make sense to format a card, if you change the video resolution or the length of the file.
how the camera writes or over writes the files?