But the drive will still have to slow down to less than 4X to read a bad disc. This will cause problem when you burn on the fly. Let's say you want to burn on the fly at 4X. The total THEORETICAL best processing time will be 15 min for a full DVD-5. Again, we are NOT compressing the video. Most movies don't fit in one DVD-5.
If you copy to the drive, then burn at 12X, then the processing time will be 18 min (11 min to rip, 7 min to burn).