[mythtv-users] DVD ISO playback problems: Invalid IFO

Seth Daniel mythtv.org at sethdaniel.org
Wed Jan 9 22:49:27 UTC 2008

On Wed, Jan 09, 2008 at 03:34:52PM -0700, kim Gross wrote:
> >> I would be willing to bet you are hitting deliberate bad sectors used to
> >> stop copying of the disc.  Your player will skip over the bad sector
> >> without to much trouble, but if you try to duplicate or rip the disc the
> >> software will hang trying to read the data.  Discs like this can take a
> >> long time to rip because of the time for  retries etc. When I have one I
> >> just setup dvddecrypter to ignore errors and to only retry errors once.
> >> Still takes an hour or two to rip because the drive will retry a few
> >> times before it sends the error to the software.
> >>     
> >
> > This is another place where dd_rescue can help.  You can tell
> > dd_rescue to copy either forwards or in reverse.  If your encountering
> > bad sectors near the beginning of the disc, just copy in reverse.  It
> > won't truncate the data (unless you want it to) and you can still read
> > in the entire ISO.  Granted, reading in reverse is slower than
> > forward, but still much faster than waiting for the disc to error out
> > on each sector.
> >
> > The finished image works just fine for a lot of my DVDs with similar
> > read errors.
> >
> >   
> So do you read from the front to the error and then read from the back 
> to the error and put it together some how?  What if the disc has 
> multiple bad spots on it?  I am thinking that my Pirates III has 4 bad 
> spots rather than just one.

You don't have to 'put it back together'.  You can let dd_rescue read
from the beginning and let it go until the end.  It will do what it can
with bad sectors, but it won't die the way dd or other copying tools do.

seth /\ sethdaniel.org

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