I've recently purchased two DVD+-RW drives, the NEC 3540A and the Pioneer 110D. I purchased the two of them to replace my aging DVD-ROM and CD-RW drives simply to ensure that I had two drives capable of double-checking backups made on DVD writable media. I plan to use the NEC 3540A for most of the writing, while using the Pioneer to double-check the media. I will of course use the NEC for disc quality checks, as the default Pioneer firmware (and maybe all others) does not support PI/PIF scanning. Everything appears fine to date and I have experienced no real problems so far.
However, when I write DVD's written on two different media types (+RW Verbatim (MKM something I believe off the top of my head) and -R TDK (RITEKG05)) and scan the discs using Nero CD-DVD, I experience some unexpected results.
In the benchmark image, you will notice that the speed starts to drop off mid-way through the DVD, both the yellow and green lines are affected. The point at which it occurs is variable, but is around that point. This happens on almost every DVD I burn and in both drives, no matter what media it is on. However, I have not notice this problem appear in any other scans posted by people. Is this result relatively normal, or is something amiss here? Only once I have not seen this occur, and the only visible difference between the scanned disc and the others is that the type was detected as CAV. In all remaining cases I have attempted this, the type is detected as P-CAV.
In the disc quality image, you can see a scan of one of my disc burns. Although the results are acceptable by common standards, I'm interested to know why the PI error rate is highest at the start of the disc and lowest at the end. This again is happening on every DVD I burn, so I'm not sure if it is normal or not.
Does anybody have any opinions or ideas on the results? Thanks for your help.