catch Posted May 14, 2011 Posted May 14, 2011 Hello, this is my first topic. Sorry for my english. Today i've burnt my first DL disc with imgburn. Everything is OK, but there's one thing I don't understand about pad sectors. I know the LBA of the cell where the layer break occurs must be multiple of 16, but look at this picture: http://imageshack.us/photo/my-images/688/dibujokco.jpg/ If I choose the cell with the blue star: with 1 pad sector, the LBA of the cell would become multiple of 16, why imgburn is adding 401233 pad sectors then? I'm using version 2.5.1.0 Thank you.
mmalves Posted May 14, 2011 Posted May 14, 2011 To even the number of sectors on each layer (look at the % column) as DVD players seem to like better discs with a 50/50 ratio.
catch Posted May 14, 2011 Author Posted May 14, 2011 To even the number of sectors on each layer (look at the % column) as DVD players seem to like better discs with a 50/50 ratio. Thank you mmalves, you gave me the clue: if I'm not wrong the dvd specification says layer 1 must be equal or smaller than layer 0. The total numbers of sectors I was burning are 3 450 856 that divided by 2 = 1 725 428. The LBA of the cell I choose for the layer break is 1 524 959. Adding just one pad sector makes the LBA multiple of 16 but the layer 1 would be bigger than layer 0... The dvd I was burning is an exact copy of a pressed dvd of my own, the layer break is the original layer break of the pressed dvd, then, do the pressed DVDs have null sectors at the beginning of the disc or this disc doesn't meet the specification? I know that in the authoring process they use dumb video to make layer 0 bigger than layer 1 but this is no the case. Thank you
mmalves Posted May 14, 2011 Posted May 14, 2011 Pressed DVDs are PTP (Parallel Track Path), which means both layers are read from the center of the disc towards the edge, and PTP discs can have L1 bigger than L0. Writeable media is OTP (Opposite Track Path), where L0 is read from the center of the disc towards the edge and L1 is read from the edge towards the center of the disc, and this is why L1 can't be bigger than L0 (they wouldn't be aligned).
Recommended Posts