Binary comparison of .m2ts files - strange issues.

Discussion in 'AnyDVD HD (Blu-ray issues)' started by SuperGoof, Apr 1, 2007.

  1. SuperGoof

    SuperGoof Well-Known Member

    Hi,

    Today I had some spare time and did some experiments with AnyDVD HD.

    I was doing binary comparison of .m2ts files on Blu-ray disc (Fantastic 4) with AnyDVD enabled with those backed up to a hard drive some time ago using BackupBluRay tool. Here are my findings, some are very strange and weird, which I don't know how to explain.

    I used "Beyond Compare" (with Hex Viewer plugin) and also "010 Editor" to do file comparison.

    First, I found that all .m2ts files (except one) created by BackupBluRay have several kilobytes of extra data at the end. This I guess is OK. Probably it is because BackupBluRay appends all buffer data to the file on the last iteration while it should cut off some.

    Second (and here strange things begin): For all small .m2ts files there were additional differences INSIDE the files. One block of differences (and it was common to all small files) started at position 00020000 and was exactly 1KB in size.

    Big 17GB .m2ts file (I was only able to compare it using 010 Editor) did not have any differences inside.

    Third: After the comparison of the big file finished, I checked those small files again. To my amazement, now differences DISAPPEARED! Both 010 Editor and Beyond Compare were now reporting that there were only differences at the end (those extra bytes).

    Fourth: I ran the comparison of big .m2ts file in 010 Editor again, and at the same time ran the comparison of one of the small .m2ts files in Beyond Compare. Now I heard that the laser head was rapidly moving from one position to another, and this slowed down everything. So I pressed 'Cancel' in both programs. But for the data they processed that far, they showed A LOT of sections with differences. This clearly indicates about some kind of IO or synchronization problems...

    Some pictures and AnyDVD info attached.

    When doing this comparison, I was running Windows XP. I also have Roxio burning software (EMC 9) installed. Virtual CloneDrive and CloneDVD2 are installed as well. BTW: on the web site you say: "AnyDVD comes with a UDF 2.5 file ripper, no need to install 3rd party UDF 2.5 filesystem under Windows XP". But I still could not see Blu-ray disc files in Windows Explorer until I installed Roxio. (I was just reinstalling the whole system a week ago).

    I hope that you clarify the issues I found.

    P.S.: I recently bought the whole bunch of your programs using 'cricket' discount!
     

    Attached Files:

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    Last edited: Apr 1, 2007
  2. Peer

    Peer Redfox Development Team Staff Member

    You should first rip the files to HDD using the AnyDVD HD ripper, before you do a file compare. Don't do it on the inserted disc. If your filecompare tools do funny stuff like jumping forward and backward (which they will typically do), you will not get a clean decryption.

    Well you will probably have noticed, that AnyDVD HD does its job just fine, even if you don't install the UDF 2.5 FS driver, right? And you can rip files to HDD just as well. That's what the above statement is trying to tell you, not that the files on the disc will appear in Windows Explorer just by installing AnyDVD (that is not its job nor is it required for any of its tasks).
     
  3. SuperGoof

    SuperGoof Well-Known Member

    Will copying them using Windows Explorer do? This is what I usually do even with normal DVDs.

    Actually I did this with one of those small .m2ts files, and then did a comparison with a file created by BackupBluRay. The differences inside the file were still present.

    Probably differences appear at the time AnyDVD processes Blu-ray disc, so they will still present in a file copied to HDD if at that time AnyDVD decides to process the disc in a particular way.

    I still think these issues require some further investigation.

    Right. I noticed that PowerDVD still plays discs. Though the only way to copy them to the hard drive is to use AnyDVD HD ripper.
     
  4. SuperGoof

    SuperGoof Well-Known Member

    Also, this kind of dininishes the whole purpose of AnyDVD. The coolness of AnyDVD is that it works in the background and does everything 'on the fly'. This is what distinguishes it from dozens of other tools, where you have to copy your disc to the hard drive before you can do anything with it.

    So to my understanding, if several programs try to access the disc at the same time, AnyDVD should handle this situation. It can work slower, but it still must give correct data to each program accessing the disc. And if this is not the case, it should be considered as a bug.

    AnyDVD (http://www.slysoft.com/en/anydvd.html):

    AnyDVD HD (http://www.slysoft.com/en/anydvdhd.html):