@mr-berlin
I see this post is a little old, but I have exactly the same problem. Did you find a solution in the end?
I have read the posts above and will try out the suggestions, but I was hoping that "scaping" would automate the process so that I did not have to manually download or re-code all those videos.
FYI - Raspberry Pi 4B 1GB Retropie 4.7.4 - Scraped with Steven Self’s optional scraper package.