DVD scanning in Nero CD Speed - reads slower?

I have a Memorex 2.4x DVD+RW drive. I often scan my burned DVDs with Nero CD Speed. However, often the speed goes down in the last 500MB of the disc or so. Does that indicate a higher error rate? Is my data corrupt? Thanks

It usually indicates that the drive is having difficulty reading the disc. whether your data is corrupt is anybodies guess. Suggest your try DVDInfoPro for scanning.

I downloaded DVDInfoPro. It shows some errors. Do DVDs have any error correction to correct these, or are these like “unreadable” errors if I was testing a CD in Nero CD Speed?

Read the help file in DVDInfo.
red = unreadable (at the default read speed)
white = corrected error
green = no error