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» Film-Tech Forum   » Operations   » Digital Cinema Forum   » Interesting DCP loading instructions.

   
Author Topic: Interesting DCP loading instructions.
Lars Goldschlager
Film Handler

Posts: 12
From: Caracas, Distrito Capital, Venezuela
Registered: Jan 2015


 - posted 09-22-2017 02:33 PM      Profile for Lars Goldschlager   Email Lars Goldschlager   Send New Private Message       Edit/Delete Post 
Good day gentle people.

As a lab we're doing a job producing KDMs locally for an Exhibitor for shows, and the email with the DKDM from the Distributor to the Exhibitor includes an instruction I've never encountered before.

The email emphatically mentions that ALL titles on the disk should be loaded to the Media Server and not just the few titles that will be run (in this case, 3 out of 7) because otherwise it'd "corrupt the contents", and I wonder where this is coming from.

I'm yet to receive a physical copy of the disk for obtaining the CPLs so I do not know if it's arranged in directories with an ASSETMAP per (as far as the standards go there should be only one ASSETMAP per disk but I've seen this practice before), or if there's several CPLs in a single directory with either one or more PKLs.

My suspicion is there might be several CPLs in a single directory, I've read somewhere whether it's right or not, that Dolby MSes index/load DCPs based on the ASSETMAP only and not CPL or PKL, so in this case it might be a case of having to load everything so that no asset files are missing for a chosen CPL, though I doubt this is the case as there's 1TB of data in the hdd which makes me believe the versions are separated by directory with repeated assets.

Has anybody encountered this warning and knows the reasoning behind it?

Also as a plus/bonus, do all different servers load materials based off the ASSETMAP or do others base off PKL or CPL? Does this mean for multiple CPL directories/disks, that all asset files will be loaded on the server regardless of whether the loaded/chosen CPL/s reference them?

Thank you kindly for your feedback.

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Leo Enticknap
Film God

Posts: 6960
From: Loma Linda, CA
Registered: Jul 2000


 - posted 09-22-2017 04:19 PM      Profile for Leo Enticknap   Author's Homepage   Email Leo Enticknap   Send New Private Message       Edit/Delete Post 
I'm wondering if there is a more simple explanation, which is that with some servers, if you ingest a VF, it won't automatically ingest the OV that the VF depends on as well: you have to tell it explicitly to ingest both. I have a dim recollection that the Doremi was like that many software versions ago, but that this was fixed about two years ago.

So if you instruct the projectionist to ingest the entire contents of the drive, regardless of which version they actually want to play, you insure against being bitten by that.

I can, however, think of two other gotchas. The first is the one you point out, namely that it doesn't take too many 1TB drives to fill up a typical server RAID. The second is that if the multiple CPLs are all unencrypted (or even if they are encrypted, and the theater has been issued with KDMs for all the CPLs on the drive), you risk an inexperienced projectionist accidentally playing the wrong one, especially if they don't know how to read ISDCF subtitle codes.

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Monte L Fullmer
Film God

Posts: 8301
From: Nampa, Idaho, USA
Registered: Nov 2004


 - posted 09-22-2017 04:47 PM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
Without the asset map in DCP Content directory, the content is useless.

Almost looks like that the content was broken up into multiple assets and must be assembled in the server to be able to function correctly, each with its own asset map to make the assembled content work.

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Lars Goldschlager
Film Handler

Posts: 12
From: Caracas, Distrito Capital, Venezuela
Registered: Jan 2015


 - posted 09-22-2017 05:27 PM      Profile for Lars Goldschlager   Email Lars Goldschlager   Send New Private Message       Edit/Delete Post 
I should have the disk in my hands in a little while and I'll be able to analyze the structure inside, yet one thing I can tell so far is that all the titles indicate they're OV, no VF among them, so the situation seems a little odd. It could have to do with a distributor that has had to deal with projectionists that have loaded the wrong film+kdm for the exhibition, or from missing assets in one cpl or another.

The warning seems odd to me nonetheless and made me wonder. Specially the dire warnings about causing data corruption, though having worked help desk for an ISP before I know that could easily be a scare tactic to avoid troubles from people ignoring instructions.

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Carsten Kurz
Film God

Posts: 3713
From: Cologne, NRW, Germany
Registered: Aug 2009


 - posted 09-22-2017 07:28 PM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
We see things like that quite often in daily cinema operations. There are different ways to package DCPs, and some appear quite intuitive in the various ingest managers, while others can only be dealt with using trial and error.

E.g. we regularly come accross packages where every CPL has been assigned OV, when in fact some of them are VFs. From a technological point of view, there is no difference between an OV or a VF, and the CPL name is not a valid indicator.

I have never heard of a clear explanation of the various servers ingest mechanisms, though some can be derived from the way their ingest managers present ingest media and perform ingests.

One issue when dealing with this is that there is not even a clear terminology of all aspects involved.

That said - other than some wasted space on our servers, we never had serious issues with the packaging. Sometimes we find that an OV that we thought should go with a specific VF doesn't go with it, so we wasted some time ingesting the wrong OV. Other servers solve that puzzle for us by looking into the actual CPL-Asset references.

Most distributors do know less than we do about these things, so the advice 'just ingest everything' is quite common.

The thing that bothers me most is not the issues themselves, but when I am asked by our staff how ingesting works, and I have to tell them that it needs some intuition to solve it.

- Carsten

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Lars Goldschlager
Film Handler

Posts: 12
From: Caracas, Distrito Capital, Venezuela
Registered: Jan 2015


 - posted 09-22-2017 07:48 PM      Profile for Lars Goldschlager   Email Lars Goldschlager   Send New Private Message       Edit/Delete Post 
Thank you very much for all your responses, and specially yours Mr. Kurz

Now please correct me on a possible misinterpretation, on my part, but it's my understanding functionally a VF CPL is one where not all the referenced assets are included with the CPL or in some cases the PKL or ASSETMAP where this CPL resides, so the OV which includes those assets (be them in the CPL, PKL or assetmap) must be ingested to make sure the assets are present in the MS, am I correct?

I've already received the disk and verified. I have a total of 6 CPLs in 3 first level directories, with one PKL and one assetmap per directory. Of the 3 versions I'm doing KDMs for, the 2 2D versions are 2 of 3 CPLs in a single directory, the 3D version is 1 of 2 CPLs, so I wonder if I should tell the rooms all to load all versions actually to be safe, which space wise will not be easy for them

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Carsten Kurz
Film God

Posts: 3713
From: Cologne, NRW, Germany
Registered: Aug 2009


 - posted 09-22-2017 07:57 PM      Profile for Carsten Kurz   Email Carsten Kurz   Send New Private Message       Edit/Delete Post 
There is no formal indicator in a DCP for OV or VF. The only way to tell wether a VF appears to be a VF is when not all assets it's CPL uses are included in the package, but for this to find out, the whole package has to be analyzed. I think a VF does not even have to include a CPL, it may also just be a supplemental package carrying only media assets.

The trouble is that a simple how-to will not be adequate for the users of the various servers, ay they deal with these things in different ways. On some servers, you only need to select the specific CPL you want to play, and the ingest manager get's everything together by looking into the metadata.

http://isdcf.com/papers/ISDCF-Doc12-Recommended-Practice-for-Ingest-Behavior-DRAFT-20170322.pdf

http://isdcf.com/papers/ISDCF-Doc3-Delivery-Recs.pdf

There's quite some free software around nowadays dealing with DCP creation, playing, subtitles, etc, but I haven't seen anything that displays all CPL-Essence, Assetmap and PKL references in a tree.

- Carsten

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