[Bug-ddrescue] Very slow reading DVD

[spoo]

Recently bought a DVD set used. Having extreme difficulty playing one of the 
discs on any player. The disc is not significantly scratched. This is what 
dd_rescue is doing:

ddrescue -n -b2048 /dev/dvd /disk3/b5_2_1 mapfile

GNU ddrescue 1.20
Press Ctrl-C to interrupt
rescued:     1793 MB,   errsize:         0 B,    current rate:       0 B/s
   ipos:     5002 MB,    errors:         0,      average rate:    205 kB/s
   opos:     5002 MB,  run time:  2h 25m 21s,  remaining time:  1d 19h 22m
time since last successful read:         10s

I don't think this is a bug and the DVD drive I'm using works fine with other 
discs. What is going on here? Is it bit rot?