Film-Tech Forum ARCHIVE: Question About KDM's Expiration

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Posted by Bradley J Sime (Member # 9423) on 03-07-2018, 08:09 PM:

We have a film beginning at 9:30 tonight with keys set to expire at 11:59. If the keys expire while the film is playing, what happens? Does it cut out right away, or does the film finish?

Posted by Carsten Kurz (Member # 5396) on 03-07-2018, 08:13 PM:

There is a maximum time window of 6 hours beyond the KDM expiration during which a show will not stop IF started before expiration.

So, if your keys expire at 00:00 midnight, and you started the show (playlist) at 23:59, you will be able to play the show to end up until 06:00.

I tested this on two different servers, starting a show just before the KDMs expired, and leaving it in play/pause mode. If you STOP, then try to restart, you are burnt.

Not all servers may follow the 'pause' mode extends expiration scheme. But, in your case, you should be safe. Extra check your KDM on the server in order to be sure that the correct timezone is applied.

- Carsten

Posted by Bradley J Sime (Member # 9423) on 03-07-2018, 08:14 PM:

Thanks, man!

Posted by Max Hayman (Member # 8726) on 03-12-2018, 10:38 AM:

You can, although i don't recommend it shift the time on the server a bit. Our server shifted a few hours before we hooked it up to a NTP server.

Posted by Carsten Kurz (Member # 5396) on 03-12-2018, 10:52 AM:

DCI compliant systems only allow to adjust the secure clock within +/-6min per year through the operator. Larger adjustments are possible, if authorized by the server manufacturer on a case-by-case basis. You need to call your manufacturer support to receive a code, DLM, etc. to allow this.

The secure clock is the one actually being used for the KDM validity window.

Your server/show manager may use a time that is not synced with the secure clock. While you may schedule a show based on the show manager clock, the feature will not play if the secure clock doesn't match the KDM validity window.

Even if you configure an NTP server on your system, the secure clock will not follow the NTP further than the allowed +/- 6min per year. Larger deviations will be ignored.
Your show manager clock, though, is allowed to follow larger NTP offsets.

Secure clock and KDMs are all referenced to UTC. Your server will typically adjust time display to your local timezone configured on the server. As such, adjusting the time zone will not allow you to play a feature earlier or later.

- Carsten

Posted by Kirk Futrell (Member # 5006) on 09-13-2018, 03:56 PM:

quote: Carsten Kurz
So, if your keys expire at 00:00 midnight, and you started the show (playlist) at 23:59, you will be able to play the show to end up until 06:00

What happens at 06:00 in this case? Does the movie stop? What would happen if you filled a play list with say 7 hours of movies before the one with an expired KDM is supposed to play. Will it always finish a playlist or will the movie stop mid play once 6 hours is up?

Posted by Monte L Fullmer (Member # 2797) on 09-13-2018, 04:02 PM:

I would build the SPL with the feature that has a key that will expire the soonest to be the first on the screen.

That way, that feature is done and the other will play normally.

Posted by Marcel Birgelen (Member # 6801) on 09-13-2018, 04:02 PM:

It will not play. What Carsten is referring to is the CPL the KDM applies to will play until the end if it was started before the expiration date.

If you make a playlist yourself and put 7 hours of content in front of the expiring content, then when you hit the content after it has expired, you're simply out of luck.

I would always try to avoid those situations if possible. If you're required to restart the show beyond the KDM validity window for whatever reason, you're equally screwed.

Posted by Carsten Kurz (Member # 5396) on 09-13-2018, 05:16 PM:

Kirk - if you want to try what your specific equipment is doing, you can try to create suitable KDMs yourself with e.g. DCP-o-matic. I don't know what happens when you start an SPL if the SMS can already calculate that, based on the SPL runtime, the expiration will come into effect. As you may be able to pause and skip or fast forward legitimately within an SPL, the SMS may allow you to start that SPL, but whenever the expiration/tolerance window is hit, it will simply stop. Aside from this being a hypothetical consideration, I actually rarely used this option for my own personal needs, e.g. when I wanted to watch an expiring DCP after the last show myself and was kept busy with cleaning, restocking and such. So I started the feature and hit pause in time, to be safe that I would be able to continue watching it beyond the expiration time.
As for single screenings, we often get KDMs that expire on the day of the official screening at midnight. We were never in the situation that we needed to stretch it for public screenings, though. Also, our secure clock is always on time, just a few seconds of drift.

- Carsten