DVD Size

[Phil A. Lefebvre]

On 12/25/02 at 6:42 PM -0800, Macintosh Digital Video List wrote:
>Larry Richelli wrote:
>>
>>  Hi
>>  I just use the get info on my SpiderMan DVD and it said that it was over 7
>>  gigs. How do they get that much data on a dvd when we can only get 4 gigs or
>  > so on one?
>
>Date: Wed, 25 Dec 2002 11:34:32 -0800
>From: Shirley Kehr <ShirleyKat at worldnet.att.net>
>
>iDVD compresses it.

Well, all MPEG-2 (DVD video) is compressed. In fact, iDVD compresses 
it less than commercial DVDs. iDVD uses constant bit rate encoding at 
a very high bit rate, which is why it can only get 60-90 minutes on 
one 4.4 GB DVD-R. Commercial DVDs use very sophisticated variable bit 
rate encoders to squeeze the maximum quality out of the least amount 
of bits; usually 2-2.5 hrs/per DVD layer. DVD Studio Pro will allow 
you to make those DVDs.

I say layer, because commercial DVDs go one step further and often 
use dual-layer 8.8 GB DVDs, to squeeze 2 DVDs worth of info on one 
disc. There are no "home" DVD-R burners that can burn to dual layer 
DVD blanks (yet). I'm not even sure DVDSP can set up dual layer DVDs.
-- 
__________________________
Phil Lefebvre
Chicago, IL