There's basically no way to make this work because, as has been mentioned, in compressed formats there's every chance that title sequences will occur at differe

There's basically no way to make this work because, as has been mentioned, in compressed formats there's every chance that title sequences will occur at different times in the show, so will occur at different points in the group-of-pictures sequences in compressed media. And especially for rips from an already-compressed signal source (like TV), the odds are well against a sequence, although identical visually, encoding into exactly the same sequence of bits digitally, as there are so many factors that can vary the datastream you receive, even before it's ripped and re-encoded. To stand any chance of this working, you'd really need to be storing and comparing uncompressed frames direct from the master, before ANY kind of variable encoding or compression. But if you have enough storage to be working with files on that scale, deduplication is probably not your biggest concern. :)