hash check fails

[Eric Sebalsky]

hi guys!

odd problem here. so far everything has been working well but lately this issue came up:

i make a new DCP and run a hash check with easyDCP player. all fine. i copy the DCP to an external hard drive, run a hash check again and it fails (either at video or audio).
i copy another one and that one tests ok. i go back to the original DCP and now it also fails (but was ok just minutes ago).

i tested all my hard drives and repaired them. i'm using external FW800 interfaces for 3.5" disks and smaller 2.5" USB 2.0 ones.
it happens on all of those drives and to the originals especially when moved another place.

any comment on that? a safe way to avoid it? obviously, some servers won't play a DCP like this!
i had doremis failing at ingesting with the same error.

it happens to NTFS and EXT drives. can one circumvent the hash checks or regenerate the checksums without doing a new DCP?

[Terrence]

have you tried md5sum on the files to see if that changes?

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[Todor]

Hi,
Sounds like you're on OSX - if that is the case how do you mount the NTFS / EXT drives?
I've seen similar behaviour caused by broken Fuse/3G installation.
I guess a safe way to avoid this would be rsync with checksum

[Lars Goldschlager]

Btw if the checksum changes something changed inside the mxf files, I would NOT just regenerate the checksums as they're indicating damage/change in the file contents.

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[Eric Sebalsky]

yes, it's OSX. for NTFS i have the TUXERA driver which is praised by everyone (paragon is more likely to corrupt files) and for EXT i have PARAGON EXTFS (which is better than their NTFS but slow) as well as UBUNTU via parallels. easyDCP player always plays the files without any errors, only a manual hash check fails sometimes.

i also agree that it might be a problem of the source file, that something is wrong in the MXF but that takes way longer to fix of course.
have you had any experience with storing a master on a SSD? is it less likely to corrupt there? what would be the best option to store the master?
i mostly stick to NTFS copies at the moment, as long as there are no hash fails it's been playing great everywhere so far.

so far only some doremis have had problems with hashes, others (also doremis) playback just fine.
thanks for the input. i will certainly try the checksum thing the next time when i create a DCP master.