Deteriorating disc

[Clarity3]

I made a backup of an original film in November 2007 and have played this disc a few times, the last time probably twleve months ago.

I decided to watch this film again and on this occassion the film froze and despite trying scene selection I could not get it to run beyond this point.

I scanned the disc which reported crc failures. This I followed with a more in depth scan using Nero CD Speed. Attached is the graphical image showing a significant 'jitter' area on and after the layer break.

I have always used Verbatim +R DL for films greater than 4.7Gb, writing at half speed, using AnyDVD/CloneDVD. (I only use Taiyo Yuden and Verbatim +R SL).

Has anyone else seen this degradation on their backup's or has an explanation?

 

[Frank]

It's a matter of physics

This problem is something you won't get around without periodically making another copy from the original. Some major CD/DVD archives around the world are noticing this also. The culprit is a nasty characteristic of metal to tend to return to its original state after a time, to mean the "pits" burned into the inner layer of the disc will revert back to the way they were before burning. This physical property is known as "metal memory".

You can minimize this effect by keeping some things in mind.

1. consumer-level burners don't usually burn as deeply as production burners

2. Blank quality/reflective factor can play a role

3. Writing speed can play a significant role.

Best is to write/burn at 4x on non-riteaid blanks. Otherwise, invest in a mother-of-all hard drives and always archive the VIDEO_TS folders from the prepared copy as you authored it.

 

[Clarity3]

Frank, thank you for your reply.

I have been looking at some of the disc manufactures information regards longevity of burned data. Interestingly, they suggest 20-30 years life and while the independent investigations are more conservative and bracketed with types of dye and metal the expectation is more than 10 years using standard consumer equipment.

Having a reasonably large library of backup's which are in periodic use, to examine every one will take about twelve months which, implies a 'Forth Bridge painting exercise'. I guess it's a case of, when discovering a 'fatigued' disc, make a new backup.

You suggested a production burner would make a more permanent job but do you have any examples of burners for typical consumer use ie fits in a PC slot and does not need the house re-mortgaged to pay for it?

I may have given the impression I am not writing at the optimum speed. I do set the burn speed at 4x, this being half the suggested speed of the disc (Verbatim 8x). If this is still not the optimum please can you let me know.

 

[quartex]

did you use a wallet or slimcases for your media?

 

[Clarity3]

I use slim cases for my backups with printed labels on the disc.

 

[fast eddie]

This is what I do to keep the disks to the longest life possible. I have some disks that are 9 years old and still working without any video problems.

Also, verify with a different hardware player that the problem is NOT with the hardware player that has worn out. I have had some problems with a worn out hardware player and not the back-up disk problems.

98% of all my disks have stick on labels or blank white disk with printing.

1. Store disks in room temperature or lower.
2. Store vertical in standard size CD case on bookshelves.
3. I have an unknown amount of different brand blank disks
4. Use Imburn burning software with max burn rate with burnproof enabled
5. If you use stick on labels VERIFY you have centered the lables properly or vibration will occur with the spinning disk. Use blank white blank disks as first choice instead of stick on labels.
:agree:

Plan of attack if you see the video is going downhill or audio problems. Usually 65% of the time hardware player worn out and 35% of the time back-up disk is worn out.
1. Check disk with another hardware player
2. Grab the VIDEO TS FOLDER or the BDMV folder and certificate folder and build a NEW copy ASAP.

 

[Clarity3]

Thanks for the reply 'fast eddie'.

I too have the same view and practice for my backup storage but there are a couple of areas where we differ.Taking your points in turn;

Your point 2. I am not sure there would be a difference between slim cases and standard cases. The bonus for slim cases is the space saving. If stored vertically there is little to no pressure on the case surfaces.

Your point 3. There has been much debate about blank disc provenance and I always use what is considered the better manufacturers.

Your point 4. I invariably use CloneDVD to burn and only use ImgBurn for DL where I want to select the layer break position (both use the same software burn commands). With forum advice, I burn DL at 4x (using Verbatim 8x discs).

I am unable to comment on the disc versus player failure rate as I have not had an issue with my players (PC and domestic) and have always confirmed any doubt by scanning the disc with Nero (Quality for jitter).

I have been checking my library by scanning the discs with Nero and interestingly have found two SL discs (circa 2007) where they 'spike' between 50-60%. When played they 'freeze' at that point but can be forced over. My impression is, this is the original layer break position but the issue is clouded as the blanks are from a non-preferred manufacturer.