Never checked for DVDs but I'm assuming it'd be similar to CDs because of the technology. The manufacturer you read off the disc is just whoever made the stamping disc used in manufacture. It doesn't identify the actual disc manufacturer itself.

You need several parts to make blank media. The stamping disc to get the groove that the burner follows in the bottom substrate, a dye layer, a metal layer and a protective top layer. Each one of those can have costs cut and be marginal