Film-Tech Forum ARCHIVE: CPL signature check failed

This is topic CPL signature check failed in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Amanda Mundin (Member # 3386) on 11-06-2012, 02:56 PM:

We have been running a Doremi DCP2000 for about 6 years now and never seen this message before - CPL signature check failed. It brings up a screen that says press Abort to cancel the show otherwise it will automatically start in 5 seconds.
The film is 'The Snows of Kilimanjaro' and is not encrypted.
The film seems to run, it is running now, what does this mean and is it likely to stop half way through?

Posted by Frank Cox (Member # 6258) on 11-06-2012, 04:31 PM:

A CPL is the "Composition Play List", which is defined as follows:

quote:
A text file that contains all of the information on how the files for a specific Composition should be played back, including how the audio and subtitles are synchronized with the picture. The CPL could contain one reel or many reels, and there are different CPLs for each soundtrack or version that
would play back. The CPL is created by the Digital Cinema Packaging Facility

From here

It appears that your DCP (the file on the hard drive that you got from the distributor) is corrupted.

Posted by Amanda Mundin (Member # 3386) on 11-06-2012, 04:45 PM:

The film seemed to run fine, picture, sound, subtitles etc. so whatever the error may be with the file, it must be a minor one

Posted by Dave Macaulay (Member # 813) on 11-06-2012, 05:49 PM:

I've seen this after upgrading the server software, what I was told by Doremi was that the KDM had errors that would be missed on previous versions, but the new version has more stringent security checks. That time the show refused to run, I had to revert to a previous version. You can run the show at least!
What software, firmware, and SM versions are you using?

Posted by Ken Lackner (Member # 1002) on 11-06-2012, 06:57 PM:

I know this isn't much help as to what this message means or what causes it, but I can tell you that I've seen this message before and it has not affected playback. I'm curious to its meaning, too.

quote: Frank Cox
It appears that your DCP (the file on the hard drive that you got from the distributor) is corrupted.

Well, to be accurate, a DCP is actually a collection of files. A CPL is a single file contained inside the DCP. (On certain rare occasions, a DCP may actually contain multiple CPLs, although this is not very common.)

Posted by Marco Giustini (Member # 4544) on 11-07-2012, 03:31 PM:

I can't remember exactly now, but it has something to do with how the CPL is made, it's not actually corrupted. It says the same with some old Dolby test charts. The doremi just says that it does not follow some DCI requirements, but it's happy anyway! [Smile]

Posted by Aleksandar Obradovic (Member # 7266) on 11-11-2012, 08:45 AM:

Like Marco said it is a problem with wrapper or DCP creation software not your Doremi. i've seen this message and similar ones and always wrapper was a reason. i can tell that you are lucky because you had issue with cpl that can work. i had same problem with kdm's and lost few great shows because of distributors mistakes.
note that my servers running latest SW/FW/SM versions

Posted by Wolfgang Woehl (Member # 6901) on 11-11-2012, 10:59 AM:

Amanda, would be great if you could post the CPL in question (Content Manager > Actions > Export CPL). The answer to your question might be quite different from what has been suggested so far.

Anyway, the fact that the machine offers "Ignore" and that playback is fine and complete tells you something about a signature's value in Interop context: It's approaching zip. Interop systems have no way of enforcing a composition's (CPL's) signature in the first place. The implications should be obvious, see Our Interop DCPs are working just fine. Why should we switch to SMPTE DCP again?

Posted by Joel O'Brien (Member # 6986) on 11-11-2012, 10:53 PM:

Hey there guys,

May I suggest that you require Level 2 Modified Transitional 1 KDM's. The new projector handshake along with various recent firmware updates has made this all very painful but by the sounds of it you need a KDM with no ContentAuthenticator and has the assumed trust thumbprint in it.

Hope that helps... [Smile]

Posted by Darryl Spicer (Member # 711) on 11-12-2012, 10:38 AM:

quote: Amanda Mundin
The film is 'The Snows of Kilimanjaro' and is not encrypted.

Since the content she is playing is not encrypted, a KDM is not required.

Posted by Joel O'Brien (Member # 6986) on 11-12-2012, 05:15 PM:

Ahhh my mistake. Well I'd have to agree with the above then... or it could be an older SMPTE phase it was made against during the DCP's ...

Posted by Dave Macaulay (Member # 813) on 11-12-2012, 07:40 PM:

Sorry I was confused about KDM and CPL. The problem I had with "signature checks failed" may have refused to play because it was encrypted. Possibly a non-encrypted CPL would play with the error.
Anyway, I think the CPL is incorrectly produced. This doesn't cause a problem with rather outdated server software/firmware but recent - and particularly DCI compliant versions - are much more stringent checking every detail of the CPL.