Capacity of DVD: same or varies?

[Cadillac84]

Greetings!

I apologize in advance if this has been discussed previously, but I couldn't find it, so I'll ask.

Using WinXP Pro SP-2
CDBurnerXP Pro 3
USB connected DVD burner (LG GSA-5163D)
Current media Philips DVD-R (4.7 GB, 1-16X)

Have used other sftwr and have used other media but always DVD-R.

Question: does the actual space available on DVD vary from brand to brand? disc to disc? burning software? any of the above? none of the above?

It seems to me I am not able to put as much on these DVDs as I remember being able to put on in the past. If I have used Maxell, Imation, Sony and other "name brand" DVD-R blanks in the past, might I be seeing different capacities even though all are nominally 4.7 GB?

Thanks in advance for any input on this topic.

[BIG JOHN]

All writable DVD formats devote the same amount of usable space to data (2,048 bytes per sector). DVD+R, DVD+RW and DVD-RAM specify the number of sectors available for user information (1.46 GB DVD+R/+RW 714,544 sectors, 4.7 GB DVD+R/+RW 2,295,104 sectors, 1.46 GB DVD-RAM 714,480 sectors, 2.6 GB DVD-RAM 1,218,960 sectors, 4.7 GB DVD-RAM 2,295,072 sectors) so disc capacity can be calculated by multiplying the user data area size by the number of disc sectors. For example, a 4.7 GB DVD+R disc: 2,048 bytes/sector x 2,295,104 sectors = 4,700,372,992 bytes. This rounds to roughly 4.7 GB (decimal notation).

DVD-R and DVD-RW, on the other hand, do not stipulate the number of sectors that are dedicated to user information but simply that a minimum capacity must be available on the disc. In the case of DVD-R (version 1.0) this is 3.95 (12 cm) and 1.23 (8 cm) billion bytes and for DVD-R (Authoring), DVD-R (General) and DVD-RW 4.7 (12 cm) and 1.46 (8 cm) billion bytes. Consequently, real world capacity can vary slightly among discs from different media manufacturers although many have informally settled on 2,298,496 sectors (4,707,319,808 bytes) for a DVD-R (General) 4.7 GB disc. BJ

[Cadillac84]

I understand now what I am seeing. These Philips DVD-R blanks don't seem to hold quite as much as the other brands I've used.

My burning software reports 4488.06 MB on the blank that's in there now. I can't find now, but I've other blanks around somewhere in this mess; I'll have to compare them later.

Thanks for your prompt and detailed answer.

Chuck

[BIG JOHN]

You are very welcome, after I posted I thought it might have been to much information. BJ

[liam858]

Yup, it's the old binary vs decimal war, 4.7gb is really 4.38gb.


Liam