Disc Id differences

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Disc Id differences


Introduction:

Over a period, we have had a number of reports from users where their disc id differs to the one on the profile in our service, and we have come to learn that two specific issues is causing problems with disc id reading.

Issue 1:

This issue affects only DVD titles, and only on Windows 10, since the update named "October 2018 Update", released on November 13'th 2018.

This update to Windows 10 changes something in the cdrom.sys driver, causing it to read totally different disc ids. We at this time consider this to be a bug in Windows, but we have been unable to determine if the Windows team is aware, and if this is a problem that we are going to see permanently, or if this is a bug that will be corrected.

Fact is that when reading disc ids on Windows 10 after the October 2018 update, the disc ids will be totally different than what we consider to be the correct ids, and you should therefore not read and contribute disc ids on DVDs to the online service if you are on Windows 10 after this update, unless you have upgraded to 5.25 Pre Release 5 or later of the My Movies software, which works around the issue.

The issue is resolved with the 5.25 Pre Release 5 release of the My Movies software, by not using the Windows calls, but instead calculating the disc id directly from the file system, or from AnyDVD when AnyDVD is running and enabled. The problem with reading disc ids from the file system when decrypters are running, including DVDFab Decrypter, DVD43 and others will return incorrect disc ids - therefore the software will refuse to read a disc id if you have a combination of Windows 10, and any known decrypter software running. Overall, with the exception of AnyDVD, you should never read disc ids when decrypter software is running.

Besides identifying discs though the disc id, My Movies also has a chapter based id which it uses  internally, which means that discs will be able to be identified, also when the disc id is incorrect or not read, but this id may not give the exact same release of a title, in cases where the main movie is identical, but bonus material and other outside material differs.

To protect the service against incorrect disc ids, we will be blocking software versions on Windows prior to 5.25 Pre Release 5 from contributing data with any disc id additions or changes, as we cannot know if the system the disc was read from was an affected Windows 10 system, and we will be blocking data contributions in general from older clients, as they contribute though a part of the API which is unable to determine which specific changes a contribution contains.

Should you find any disc id in the service which does not correspond to your disc id, when having the exact same release by barcode, please report this to us using the report incorrect data function, for us to investigate, before changing the disc id.

Issue 2:

This issue affects only Blu-ray titles, and only when AnyDVD is running.

The disc id My Movies uses for Blu-ray is gathered though a SHA-1 hash of one of the AACS files on the disc, specifically the Unit_Key_RO.inf file. We have though communication with the team behind AnyDVD learned that AnyDVD in some situations needs to use the sector space for other file information, which ultimately alters the Unit_Key_RO.inf file, giving the disc a different disc id.

With version 8.3.8.2 and above of AnyDVD (this release is not yet a final release at the time this is written), AnyDVD is now writing the unaltered SHA-1 hash of this file into a file on the disc, which My Movies as of version My Movies 5.25 Pre Release 5 can read.

It is therefore important that you disable AnyDVD while reading Blu-ray disc ids, until you are certain to have the combination of the two versions of AnyDVD (8.3.8.2 or later) and My Movies (5.25 Pre Release 5 or later) mentioned above.

Due to the fact that we are also internally reading a different disc id for Blu-ray discs, we typically have the option of automatically adding alternative ids to the profiles internally, which we have done in batches daily since September 9'th based on queries to our database.

However, since we are yet to determine if the above explained situation is the cause of all of the differences to disc ids we see is not yet known, we would love to receive as many reports as possible though the "Report Incorrect Data" function, when your disc id read without AnyDVD running differs from the profile. We would like that you are updated to My Movies 5.25 Pre Release 5 or later when reading and reporting the difference. If you find that you can read a different disc id with AnyDVD enabled and disabled, we also would like to hear from you in this situation.

Most importantly, there can be situations where the disc id stored on a profile may be the wrong id, and therefore we would like for you to report any situation you have where your disc id, read without AnyDVD running differs from the one on the profile.

General:

- Both of the mentioned issues does not affect Mac OS X.
- The information on this page will be updated as we gather more information on the topic.


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Last Modified:11-09-2019 14:32:32

Last Modified By: Administrator

Type: INFO

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