Okay,
but find . -maxdepth 1 -iname "some regex" will only find the names of files matching the regex right? the only files in the folder are the 22 files, with nothing else. I think that I don't need to use the "find" command. An if loop with a condition that the file ending in .avi should suffice.

The hard part is for me how to extract the numbers from the string.