[Bug-ddrescue] Best options for rescuing a DVD?

[Ian Oliver]

Hello,

I was given three DVDs containing video taken from some old Super 8 
cine. Of course, the original media no longer exists and these are the 
only copies of the DVDs...

Two read fairly quickly, with just a few bad sectors each. A bit of 
splitting and a few retries later, I had the lot.

The third is different. I'm now in day 3 and have rescued 2471MB. I 
don't know how much data is on the disk: ddrescue went for all 4GB+ but 
I suspect that some sectors are missing at the start such that the size 
is unknown. Which driver/layer/device is responsible for determining 
size of tha DVD?

As it slowed to a stop after about 2500MB, I'm now using this command 
line.

ddrescue -r 100 -b 2048 -c 1 -s 2500MB -d /dev/sr0 mem1.iso mem1.log

Is this the best I can do? Any other ideas? (I added the -c 1 and -d 
after the first "fast" pass.)

I'm currently seeing -

Initial status (read from logfile)
rescued:     2461 MB,  errsize:  38072 kB,  errors:    4725
Current status
rescued:     2471 MB,  errsize:  28211 kB,  current rate:        0 B/s
   ipos:     2224 MB,   errors:    4273,    average rate:      216 B/s
   opos:     2224 MB,     time from last successful read:      42 s
Retrying bad sectors... Retry 1

The last run has been going for 12 hours and has got another 10MB to 
scrape off. Look at that average rate - even assuming it doesn't slow 
down, it'll be another two days to get all 2500MB, and I'll then have 
to move on to the rest of the disk.

Thanks

Ian