Video in Photos now 2fps?!

Hi

For about 5 years I have been upload and saving my non-iphone video (ie Canon digicam) footage in Photos. I've never checked it, and now that I have come to edit it, I have found that file size is tiny, the reason being is the resolution has reduced to 160x90, the frame rate is 2fps using codec H264.

That's a lot of family video that is unviewable now, and I'm a bit heartbroken. I found some backups dating back 3 years, but it looks like the "corruption" was before then.

Anyone any idea how this might have happened?

I am assuming that I have lost these for ever now?

Cheers