Some Discs Fail to Rip Half Way Through

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Joined: Sat Nov 09, 2019 2:41 am

Some Discs Fail to Rip Half Way Through

Post by bswann93 » Sat Nov 09, 2019 3:09 am

Ive been ripping my UHD blu ray library for my plex server just fine for the most part but some discs will just go down to kilobytes read speed about half way through and just sit there forever until i abort the rip. no physical damage on discs and makeMKV program doesnt throw any type of error code. my reader just spins like all the way down to almost stopped for seemingly no reason. is there some kind of work around or fix that i can employ to fix this? please forgive me in advance i am kind of a noob with this stuff still.

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Re: Some Discs Fail to Rip Half Way Through

Post by VarHD » Mon Nov 11, 2019 9:09 pm

bswann93 wrote:
Sat Nov 09, 2019 3:09 am
no physical damage on discs
What made you sure about this? Did you use a microscope to check the entire surface of the disc? Especially if those were 3-layered discs, the damage can be really small and it will be enough for the drive to fail to read it.

Based on what you describe it sounds exactly like what happens when a disc is damaged. The drive can't read it at full speed so it slows down to try to re-read it multiple times hoping it'll succeed eventually. I suggest cleaning the disc and I hope that'll do.

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Re: Some Discs Fail to Rip Half Way Through

Post by awdspyder » Sat Dec 07, 2019 8:03 pm

With all due respect, I can say with near certainty that these types of issues do not seem to be due to damage on the disks. I've done well north of 50 rips, and I've seen this behavior over and over again - I don't think they're all damaged. If I had to put my money on something, I'd say it's probably due to cheap hardware and optics in these drives. Let's face it - they're massed-produced Chinese parts that don't exactly exude quality. That said, do I think the discs are super-high quality? Hell no. First, they all need a good wiping with a dry microfiber cloth, and I suspect like anything churned out by the thousands, there's minimal QC, fairly low standards for passing QC, and a fairly wide range of quality overall. Some discs will certainly be better than others.

Some observations I've made to support this notion:
  1. Subsequent rips with the same disc, drive, PC, OS, no additional cleaning in between attempts, etc., results in wildly different rip speeds - damage to a disc would likely be more consistent between rips.
  2. Subsequent rips with the same disc, drive, PC, OS, no cleaning in between attempts, etc., results in slowdowns that occur at different points in the rip. I always take note of exactly where the slowdown occurs, so I can monitor during subsequent rips - damage to a disc should result in slowdowns or errors at consistent points.
  3. High-quality players like the Oppo have no issues reading the discs at these points. No stutter, no blocking, no errors - just pristine playback.
  4. Sometimes, a simple reboot and rip with no other applications running resolves the slowdown issue altogether.
  5. It's nearly always near the middle of the disc. Not the beginning, not the end, but near the middle. Typically, if I can make it through the middle 25% of the rip without issue (whether it's the 1st or 10th try), read speeds will carry pretty well through the remainder of the disk. I'm incredulous that every damaged disc is somehow damaged only in the middle.
  6. Even on a clean rip, speeds typically go like this: Beginning > End > Middle. There's something about the middle of the disc that these drives struggle with.
  7. There are other times I'll open a disc with MakeMKV and I'll be greeted with a wonderful, "ca-chunka, ca-chunka, ca-chunka." I know when this happens, there's no way I'll get a clean rip. A reboot usually is required, and though this is not the same issue as described above, I believe this further points to an overall issue with the hardware - or at the very least an interaction between the hardware and OS. Note I didn't implicate the application here - when this happens, Windows seems to struggle even opening the disc in Explorer, absolving the MakeMKV application layer.

I believe that read-errors, on the other hand, are much more likely due to disc issues, though I've even had some of these clear up as well with some of the above trial-and-error. I will say that when read errors do occur, the results tend to be much more consistent, and usually a disc replacement is the only solution.

I've also considered the possibility of the drives overheating (the discs do come out quite warm), but if that was the case, I would expect immediate attempts to re-rip to fail near the beginning of the disc, which does not happen. We also have to consider the firmware. I've been in IT for over 20 years and old firmware is almost never better than new. In this case, it serves a purpose for us, but newer firmware almost always addresses bugs and stability issues. Regardless of the root cause, however, it would seem that at some points during a rip, the optics have a difficult time tracking the pits, and once they get "out of the groove" so to speak, there's no getting back on track.

Despite all of this, and the frustration that comes along with an 4-6hr rip, I find that even the slowest of slow rips tend play back fine (and are typically the exact same file size, though I will typically re-rip for peace of mind. It seems that perseverance is key in getting these things to rip fast and clean.

Good luck.

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