Undamaged DVD (dual layer) unreadable at outer edge beyond 4× speed

I have a dual layer DVD (factory-pressed) that is completely physically undamaged.

But when error-scanning the disc, something happens towards the outer edge:

  • 2×CLV: Nearly undamaged. Nowhere more than 2 PIF.
  • 4×CAV: Around 3 PIF for the first 3000 MB, then increasing to around 20 PIF towards layer break (last 300 MB) and then 50 PIF after layer break, then descending back to normal.
  • 6×CAV: Around 4 PIF for the first 3000 MV, then icreasing to around 60 PIF in the last ~300 MB towards layer break, then 110 PIF imminently after, then descending.
  • 8×CAV: R.I.P. (150 PIF, 180 PIF)

Tested with multiple optical drives; similar results.

Has anyone else noticed this phenomenon? And what does possibly cause it?

I have encountered similar behavior on tv/movie dvd discs which were poorly manufactured.

The most egregious cases of this were double-sided flipper discs of tv shows from the mid-late 2000s decade. Titles like the original Dallas (almost all 14 seasons), Knight Rider, The A-Team (season 2-4), the original Magnum PI (seasons 1-4), etc …

Some less popular movie companies which manufactured their dvd discs at questionable manufacturing plants, also had this problem.

In general, there is nothing one can do about this other than finding re-released versions which were manufactured at more reputable dvd disc manufacturing plants and/or were redone as single-sided discs.

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Thanks for response.

The discs I used are single-sided.

I have a suspicion that is some kind of copy protection. But I could find no details online.

The disc physically looks fully undamaged. I will share screenshots of the scans soon.
At lower speeds, the error rate is very low, as supposed to. But when increasing the speeds, the error rates towards the outer edges increase exponentially. This should not be the case with factory-pressed discs. A mysterious phenomenon.

It is not a mysterious phenomenon. The disc can by physically in great shape, totally undamaged (like new) and still be unreadable.

In your case it might be a problem with too much platter flex or some vibrations caused by the disc been slightly of center, that can cause tracking and jitter issues. Those problems only get worse at higher angular speeds. All of that is related to cheap manufacturing process.

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Sounds plausible.

I guess they did it deliberately to discourage copying.

Probably not intentionally.

More likely to do with laziness and/or reducing costs by cutting corners and lousy quality control.

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There are some movie companies which used extra drm, which employed deliberate bad sectors that are unreadable by the computer’s dvd drive. It turns out these batches of “deliberate bad sectors” were placed sequentially immediately before and after the actual movie content on the disc.

On a general standalone dvd player, these batches of “deliberate bad sectors” are never actually read at all. If you know how to read the *.ifo files on dvd discs, you will see that this style of extra drm will have commands that jump over the batches of “deliberate bad sectors”.

The only movie company which still uses this style of “deliberate bad sectors” drm, is the american Lionsgate. (Primarily their A-list titles).

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But these are logical errors, and the error rate should be consistent at any speed.

But in my case, the errors are very low at low speeds, while exponentially increasing at higher drive speeds.

This is not the case with most factury-pressed discs, but it happened with one factory-pressed DVD and one factory-pressed audio CD, which had less than 50 C1 errors and 0 C2 errors until around 40 minutes, after which the error rate quickly shot over 1000 C2 errors when read at a high CAV, while staying near-zero at a low CAV.