Read errors by CloneBD

Discussion in 'CloneBD' started by coopervid, Feb 20, 2019.

  1. coopervid

    coopervid Well-Known Member

    This topic is quite subjective - I know very well and please don't make accusations or call me biased.

    Today I tried to rip the UHD The Predator. CloneBD had a read error right at the beginning and suggested to clean the disc. There were fingerprints on it and I did so. Again read error right at the beginning.
    Then I copied the disc with MakeMKV and no read errors. I took these files as a base to run it through CloneBD for making a 50Gb UHD disc and a 25 Gb BluRay movie only. Was perfect.

    I had similar issues before and didn't have MakeMKV installed. I used then AnyDVD to rip discs with read errors. The downside is that AnyDVD just continues at a certain point and doesn't care about read errors. So you can copy the disc with errors but if you want to process the result with CloneBD the program will fail with the files AnyDVD created with read errors.
    As a note: These errors were most likely more severe than that the one I saw today. So the truth is most likely somewhere in between.

    Bottom line: I think CloneBD should get an option to keep trying to re-read smudged discs as an option in the general settings section and / or use error correction - if not used already.

    No big deal since I found workarounds but that should maybe put on the "CloneBD list of things to do".
     
    Last edited: Feb 20, 2019
  2. James

    James Redfox Development Team Staff Member

    No, it does not. AnyDVD 8.3.4.0 certainly won't.
     
  3. Pete

    Pete Forum Admin Staff Member

    There is a persistent misconception regarding error correction. I should make this a sticky, because it comes up every now and then...

    It's not something our (or any) software can do, error correction happens on the drive - all the time.
    Data is stored on discs with a certain amount of redundancy (Picket codes) and, by that, made robust, so a certain percentage of misread bits can be reconstructed.

    There are two kinds of read errors - recoverable ones and unrecoverable ones. The only ones you ever get to see are the unrecoverable ones.

    Note, that without this error correction active not a single disc, no matter how perfect in condition, will be read without fatal read errors.
    In other words: those read errors happen all the time, constantly and likewise bits are being routinely reconstructed by your drive all the time.
    These recoverable read errors and the correction thereof are part of the design (same with DVB, btw.) - recoverable read errors are expected.

    Those read errors will not ever surface, you won't notice them and from your perspective the data is in perfect condition.
    That's the error correction.

    When you do actually see read errors, the damage was so bad, that a reconstruction was impossible. At least a block of data (64kB) is screwed up (that's the error correction unit on Blu-ray Discs).
    There is no way on earth you can reconstruct that or apply some other "magic error correction" - no additional redundancy is available and since these read errors occur block-wise, at least a sequence of 32 sectors is broken at once.
    That would be a lot of data to guess.

    So at least one frame of video is going to be completely broken. Due to the way AVC and HEVC references frames, this will tear down on average a half second of video (the typical scenario, though, is a group of read errors, multiple blocks).

    The only "error correction" means available to CloneBD, is to warn the user about trouble and try to skip the bad area - the video will more or less noticeably skip pictures.
    CloneBD already does that - it tries to get past the bad stuff. But only up to a point. Sometimes it's not possible to resynchronize.

    Oh... right - re-reading: CloneBD also does that, I think up to 3 times per read error.
     
    whatever_gong82 and testiles like this.
  4. Ch3vr0n

    Ch3vr0n Translator NL & Mod

    @Pete there's already the sticky and it has a reference to read errors. I'll copy your post into it, so it's explained in more detail and there's no need for a new sticky.

    Verstuurd vanaf mijn Nexus 6P met Tapatalk

    * edit * info added to "Read this before you post" sticky.
     
    Last edited: Feb 21, 2019
  5. blank

    blank Well-Known Member

    I don't understand this also.

    I was able to rip my blurays with anydvd - giving no errors.
    Trying to read them with CloneBD gives a warning about read errors.

    What does that mean?

    I suspect a bad drive.
     
  6. SamuriHL

    SamuriHL Retired Moderator

    You should post the CloneBD log so they can take a look at it.
     
  7. James

    James Redfox Development Team Staff Member

    Which AnyDVD version did you use?
     
  8. blank

    blank Well-Known Member

    8.3.4.0 last time - but this isn't new.
     
  9. James

    James Redfox Development Team Staff Member

    What's new is, that 8.3.4.0 fixes the "unreported error" problem.
     
  10. blank

    blank Well-Known Member


    Sorry I don't understand.

    AnyDVD 8.3.4 reports no errors / CloneBD does ... I can make logfiles if needed.

    Please let me know.
     
  11. Pete

    Pete Forum Admin Staff Member

    Yes, of course, please do post log files.

    Previous versions of AnyDVD sometimes would not trigger read errors but instead, under certain circumstances, deliver empty sectors, so the rip could appear to be ok, but wasn't.
     
    blank likes this.
  12. blank

    blank Well-Known Member

    OK so I rip one disc with Anydvd (no errors) - can I save a logfile after ripping?

    Then I try to rip with CloneBD (I will get read errors) - I can save the log.

    Will take some time (usb 2.0)

    Any other steps?
     
  13. blank

    blank Well-Known Member

    Log:
     

    Attached Files:

  14. Pete

    Pete Forum Admin Staff Member

    The log file will not include any errors detected during the rip.
    AnyDVD log files only scan the disc an show what occurred during that scan - which obviously doesn't go over the complete data.

    Anyway, even so, both AnyDVD and CloneBD log files show severe, uncorrectable read errors:

    CloneBD
    Code:
    00:29:24.898 | [00:50:51.625] - [ERROR  ] [0x0000000338c6ff40] Read error at 6763327
    00:30:49.133 | [00:52:02.368] - [ERROR  ] [0x00000003481ffe00] Read error at 6889055
    00:31:07.660 | [00:52:02.745] - [ERROR  ] [0x0000000348310000] Read error at 6889600
    00:31:14.426 | [00:08:09.211] - [ERROR  ] [0x0000000348360000] Read error at 6889760
    
    AnyDVD
    Code:
     19.64s: read sectors failed, sense 3:11:5      // **** L-EC UNCORRECTABLE ERROR
     28.61s: read sectors failed, sense 3:11:5      // **** L-EC UNCORRECTABLE ERROR
     51.42s: read sectors failed, sense 3:11:5      // **** L-EC UNCORRECTABLE ERROR
     58.00s: read sectors failed, sense 3:11:5      // **** L-EC UNCORRECTABLE ERROR
     64.73s: read sectors failed, sense 3:11:5      // **** L-EC UNCORRECTABLE ERROR
     73.30s: read sectors failed, sense 3:11:5      // **** L-EC UNCORRECTABLE ERROR
     80.00s: read sectors failed, sense 3:11:5      // **** L-EC UNCORRECTABLE ERROR
    
     
  15. blank

    blank Well-Known Member

  16. James

    James Redfox Development Team Staff Member

    AnyDVD rips this disc to .iso without showing any errors???? :eek:
     
  17. Ch3vr0n

    Ch3vr0n Translator NL & Mod

    Any slim drive is bad compared to a standard desktop drive. Might not be cheap, but a better option would be a full size desktop drive in a 5.25" bay enclosure.
     
  18. blank

    blank Well-Known Member

    Yes I'm pretty sure.
     
  19. James

    James Redfox Development Team Staff Member

    This would be very bad, if true.
     
  20. blank

    blank Well-Known Member

    I have the same problem with all bluray(s) so I think this drive is s.... Reads CDs & DVDs perfect.