Stop using alternative colon and alternative slash on video filenames

Those are not well known which could be a problem on parsing, and @joaoantoniocardoso suggested that on compressing/decompressing those files will have those characters changed as they are Unicode.

No file or test is named in the issue. Trace where video filenames are generated, parsed, and handled during compression or decompression; done means the alternative colon and slash characters are no longer used and the relevant filename behavior is covered by tests.

Written by the indexing model from the issue text.