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Thanks for your long reply. Well the DVD in question was rec
Sorry ...

Thanks for your long reply. Well the DVD in question was recorded in NTSC. However I found that by changing the t.v. system on my Panasonic DVD player from PAL to NTSC the DVD would play OK. But it would NOT play at all on a PC nor allow the files to be ripped to a hard-drive. So with the Panny I was able to copy the files to its hard-drive. Then I used it to burnt a new DVD. And this new DVD plays OK in a computer.

Now I have to use s/w apps to try and estimate the integrity of the recordings on the computer.

Maybe - just maybe - I've found a way of reading faulty optical disks. Use a dedicated Panasonic DVD / CD player rather than the optical drive attached to a computer. Worked for me anyway.

And the DVD(s) and unique recordings are now rescued - this time round.

Chris B.


________________________________
From: Carl Pultz <[log in to unmask]>
To: 'Chris J Brady' <[log in to unmask]> 
Sent: Saturday, 31 August 2013, 16:32
Subject: RE: [ARSCLIST] Reading Bit-rotted DVD


Chris, I've been slow to follow up on the earlier discussion - too many distractions. The idea, as I understand it, is to extract the raw data from a carrier, errors and all, and then put a data recovery utility to work on the resulting file (usually in the form of an ISO image file). In the case of an optical disc, this allows the utility to work independently of the vagaries of optical scanning as it rereads the data in attempts to reassemble the missing chunks. That is, however, dependent on the error correction technique built into the file system of the medium. Compared to most file systems, the audio CD has poor capability (a CDR that can hold only 700 MB of file data will hold 800 MB of music data, iirc, the difference in error correction overhead). DVDs are supposed to have much better error recovery than audio CDs, so a recovery utility should have more to work with. Whether that difference relates to both video DVD and data DVD, I dunno; the
two look more alike than in the case of CD. There are utilities that claim to work on these media. One that we talked about, a linux utility, seems to not work on audio CD data.

Now, if anybody who knows what they're talking about regarding this wants to pick up the thread, please do! Have specialists in the archival world done work on this, or is it still not much explored in regard to audio/video media?

-----Original Message-----
From: Association for Recorded Sound Discussion List [mailto:[log in to unmask]] On Behalf Of Chris J Brady
Sent: Friday, August 30, 2013 5:17 AM
To: [log in to unmask]
Subject: [ARSCLIST] Reading Bit-rotted DVD

A while ago there was a thread on reading / ripping optical disks that had suffered from bit-rot. I have been sent 8 home-burnt DVDs - they are the only known copies of private performances of a band originally recorded onto VHS NTSC tapes (now long gone). The DVD recordings are bad - error prone - but readable with error correcting algorithms. I have copied 7 to a hard-drive and they play well - once the time codes had all been corrected. But the 8'th gives up 10 minutes into the recording. It should be 90 minutes long. I've tried with different DVD players - with no luck. Is there a way of reading a disk slowly and making a bit-by-bit rip to a hard-drive? This is a large rescue project!! Many thanks - Chris B.