Uniquely identify a DVD

I was wondering if there exists a way to uniquely identify one DVD from another if they are the same movie. For instance, how can I tell the difference between my copy of “How Stella Got Her Groove Back” and my friends copy?

I was reading up on the Burst Cutting Area that was used for DivX back in the day, and it seems like a possible solution. Is this area even used by DVD production facilities these days? If so, would two of the same movie have a different serial number encoded in the BCA?

Does HD-DVD or Blu-ray have something similar to BCA?

Hi kungfumidget and welcome to the forum.

DVD has the option of BCA but I’ve seen none that use it other than like what you mentioned.

The BCA can be put on the disc in more than one way. It can be mastered on (during glass mastering) or it can be burned to each individual replica by a special laser system (which is slower and raises costs). If mastered on, then all replicas from that glass would have the same number. If burned on each replica, then yes, each disc would be unique.

Both Blu-ray and HD DVD use the BCA. I’m not sure if it is mandatory but if the disc is a movie that has AACS, it will have the BCA. This BCA is mastered on so many discs will have the same number.

I can think of no way to determine your copy of a movie from your friend’s copy.

RM

That sucks. Can anyone give me the name of a place that actually manufactures Hollywood DVDs? I want to call them up and see if they can think of anything. I tried looking for one myself, but my google-fu isn’t working.

I imagine that if one were to make a RAW image file including the sub-channel data, and then generate a md5 hash value from it, then one could use the hash value to compare discs. Even if the sectors had identical content, I imagine that there would still be minute differences in the sub-channels that would be unique to the respective glass master.

DVD does not have subchannels like a CD has. Replicated discs are made from a metal stamper that is embossed with the data. Each disc will be identical.

Sorry. I must have been very tired. RichMan, you are correct. They do not.

Each disc would be identical if the stamper(s) were made from only one glass master. Hypothetically, if there were 2 factories spitting out an order for one dvd, each factory might make its own master, from which it makes the stamper. Glass being what it is, can have many microscopic defects. So too can the photoresist.

Maybe a better way to compare the 2 DVDs would be to compare PIO errors.