[mythtv-users] Working with DVD ISO images
beww at beww.org
Wed Dec 17 00:57:14 UTC 2008
On Tuesday 16 December 2008 17:30:23 Alex Butcher wrote:
> On Tue, 16 Dec 2008, kenneth at berrypatch.net wrote:
> > I have somewhat better understanding now, thank you. Todate all I have
> > ever used is mytharchive. I just checked my mythweb and don't find
> > anything like mythburn. Tonight I will do some more research on
> > installing and use of mythburn.
> Mythburn is an obsolete pre-cursor to Mytharchive, and as such, it doesn't
> do what you want.
> You can either use command-line tools like dd and growisofs to rip and burn
> a DVD (respectively), or, more likely, use something like k3b, which has
> 'Copy DVD' and 'Burn DVD ISO image' options. As you've reported that you've
> used k3b to burn the ISO already, either the ISO is damaged in some way
> (e.g. due to copy protection, or damage to the original disc) or writing
> the data too quickly to the media you're using has resulted in a bad burn.
> If the problem you're running into is copy protection, then this is not the
> place to ask for further information.
> If the problem you're encountering is a damaged disc, try ripping more
> slowly (if you're using k3b, you'll probably need to add a 'speed=1' or
> whatever parameter to 'readcd' in Settings->Configure K3b->Programs->User
> Paramters), using a different drive, increasing the number of read-retries
> during the ripping phase, using some version of ddrescue to rip, or
> professionally cleaning/polishing the disc.
> If the problem is a bad burn, try better media (look to see if your
> writer's manufacturer provides a media compatibility list), look for
> updated writer firmware, or burn more slowly.
It's my understanding (please correct me if I'm wrong) that optical disks
ALWAYS have errors, and even more errors are generated when the disk is read.
CD and DVD drives have error correction of some kind, and as might be expected
the quality of that correction varies from drive to drive.
So - just because a disk or an image seems to work OK in one drive, does not
necessarily mean that the disk is "OK", it simply means that the errors on
the disk can be coped with by the system (drive, software etc.) being used to
play it. Change any of these parameters and it might not work.
Different viewers have differing tolerances for problems. I have seen what
looks to me to be horrendous crap on a DVD playback, while the person sitting
next to me, looking at the very same screen, claims to see nothing wrong.
So DVDs are not a boolean thing, good or bad, rather they run the range from
totally unusable under any circumstances to working well on just about any
setup, and they can be anywhere in between.
So be careful using "it works in my other machine" logic when troubleshooting
Higher speeds, on either read or write, can't help but increase errors, I
If anyone knows more about this I'd be happy to see this confirmed, or
Alex is correct in referring to copy protection as "damage". Such a system
intentionally degrades things in some way (remember the laser holes in
beww at beww.org
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