The copy is exactly the same.
I've been copying my VHS tapes to DVD-R discs on a TV connected DVD recorder. One of the discs that I was recording at the rate of 6 hrs fitting on 1 DVD, got messed up. Therefore, I was not able to copy both parts of the show to 1 disk, as I planned. Now my original VCR tape is not working properly to re-record it. I was wondering if I am to copy the recording from the already recorded (6hr pace) DVD to another DVD will there be a quality reduction, as would have been on a VCR?