Film-Tech Forum ARCHIVE: KDM Question

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Posted by Danial Simmonds (Member # 4638) on 06-28-2011, 04:51 PM:

Hi Everyone,

Just wondering is there any rules in DCI that requires a KDM to be released by a certain amount of time?

Lets say if the cinemas going to be playing a movie at 12:05 but gets a kdm that activates at 12:01, is it reasonable?

Posted by Jonathan Althaus (Member # 5042) on 06-28-2011, 07:27 PM:

Reasonable has nothing to do with it, its all up to the studios. Paramount seems to be the worst about it. When they rereleased Iron Man I before the 2nd one, if memory serves right, it activated at the exact time of the start of the film (9pm local). Only after enough exhibitors complained would they change it. Transformers 3 activated a mere 13 hours before 9pm preshows.

Disney seems to be the best about it, Pirates 4 and Cars 2 both activated a few days beforehand.

Just my $0.02

Posted by James Westbrook (Member # 3690) on 06-28-2011, 08:48 PM:

One of the KDMs on one of the movies we were running with the Best Fest earlier this year was only valid for a 4 hour window within the time our company scheduled that particular movie to run. I can't recall if it was Black Swan or The King's Speech.

Posted by Mark Hajducki (Member # 1732) on 06-28-2011, 09:09 PM:

There definitely seems to be no logic to the expiry date of KDMs, some last past 2030 (not that any current generation digital kit will be working then) and others only last for a week.

The KDM length is not proportional to the importance of the film.

Posted by Monte L Fullmer (Member # 2797) on 06-29-2011, 02:49 AM:

With you getting your key, and being over there just on the other side of the International Time Line, which makes you almost a good day ahead of California, I wonder if this is the problem that you're facing... is this huge time difference.

Posted by Todd McCracken (Member # 4718) on 06-29-2011, 01:07 PM:

Jonathan is correct, KMD time and date ranges are set by the studio's. Without a studios direct authorization key date and times cannot be changed by the distributing party. As far as special screenings go the times tend to be especially tight, and key opening times for regular releases are more or less set in stone.

Posted by Frank Angel (Member # 248) on 06-30-2011, 03:46 AM:

quote: Danial Simmonds
Lets say if the cinemas going to be playing a movie at 12:05 but gets a kdm that activates at 12:01, is it reasonable?

Personally, I think the whole KDM is unreasonable and quite frankly, a waste of a layer of technology. Maybe it makes a paranoid studio think they can better control the exibitor, but in reality, if there were no KDM and the D-print were set out so it would be run when the exhibitor opened the package JUST LIKE THEY CAN WITH THE FILM PRINT, then what do the studio execs think will happen? They are afraid while in the hands of the exibitor it would be copied? Like it can't be copied any other time once it is activated?

And it only could be camcorded off the screen, just the same way it can be copied off a film screen. It can't be copied any other way because already each D-print has gazillion safety interlocks, the drive is watermarked down to each indivitual copy, yes? The projectors can't be opened without them exploding or something, so what good does a KDM do, other than to aussuage the studios' already out-of-control paranoia about piracy AT THE THEATRE LEVEL (it's exhibition's fault).

What they REALLY need is to have KDMs on the digital intermediates and digital watermarks on the post-production facility's copies where the REALLY damaging, PRISTINE bootleg copies are made which wind up on the internet BEFORE it opens in theatres; and these are the indistinguishable conterfiet commercial DVD quality copies that wind up in hunders of thousands of video and on-line stores in Russia, China and other parts of the world, not the crap camcopies that no one freakin wants!

But I guess if it makes the studio turks feel better that they can force a theatre to run one of their major blockbusters when they dictate and that happens to wind up being without enough lead-time to do a proper quality prescreening -- let them get their jollies thinking they've really got it under control, because pristine copies NEVER wind up on the internet thanks to tight KDMs, do they.

All a few of the big chains needs to say is, if you don't give us ample time to prep a major opening by setting the KDM by at least a 12hr leeway, then we will hold that opening until the NEXT DAY. Let's see if the KDM is THAT important to a studio that it is willing to loose a Friday night of a big opening weekend. Bet that KDM will quickly be extended to plenty of time in advance of opening night.

But of course, exhibitors who HAVE that kind of power are greedy little chickenshits and will never press anything that vigourously.

Posted by Ken Lackner (Member # 1002) on 06-30-2011, 07:28 AM:

Content that requires a KDM to play is encrypted. The KDM is coded to the serial number of the media block and the projector head. Without an Ethernet connection between the two, encrypted content cannot be played, even if a valid KDM is present on the server. What does this mean? It means that you can't run the output of the server into some kind of recording deck to record the content. Obviously with film this is not possible, but if digital prints were not encrypted, it would be, and that is at least one of the things the KDM is designed to prevent.

I'm not saying your typical booth staff at most theaters would do this. I'm simply pointing out what the KDM is for, that it's not about the studios controlling when the exhibitors can play the show. At least not from what I can tell.

Posted by Terrence Meiczinger (Member # 5059) on 06-30-2011, 08:24 AM:

Currently, the KDM is only used by the media block to decrypt content. The connection between the media block and projector are secured in a different manner. The time expiration of a KDM is only good if the server honors it. Once it has the key to decrypt the content it could, in theory, use it for as long as it likes.

Posted by Ken Lackner (Member # 1002) on 06-30-2011, 10:05 AM:

Actually, you are right about the serial number. I stand corrected on that. But if the Ethernet connection between the player and projector is broken, then the projector would not be able to play encrypted content, correct?

Posted by Dave Macaulay (Member # 813) on 06-30-2011, 10:35 AM:

What Encryption and the KDMs are is a separate issues from the nutty time limits on the actual KDM. The studios are definitely over the top on security, but I agree that encryption is necessary and that the key must be locked to a server - this avoids some undesirable piracy vectors. But once you contract with a cinema to show your movie, what do you gain from prohibiting them from showing it until two hours before show time? A diligent exhibitor will want to do a test run and it's to the distributor's advantage to have a test run so that problems are dealt with.
The KDM controls watermarking as well. Any camcorded copy is readily traceable to the KDM and thus the server it ran on. Someone pirating that way will be busted pretty quickly, why assume we're all pirates and mess up our lives by setting idiotic KDM time windows? I'd like to run a test show in the morning Thursday so I can get home at a decent time and know Friday's show will be good. The fricking KDM opens at noon on Thursday so I don't have time before the matinees to run a test... so I can stay up all night Thursday or have no time to get a replacement drive if I find a problem Friday morning. Typical.

Posted by Frank Cox (Member # 6258) on 06-30-2011, 01:31 PM:

quote: Dave Macaulay
The KDM controls watermarking as well. Any camcorded copy is readily traceable to the KDM and thus the server it ran on.

What does that actually do? I assume that it puts something on the screen to mark the movie as being played on server X, but I've never yet seen anything on my digital playback that looks like anything other than the actual movie.

I remember occasionally seeing a pattern of dots on a few movies that I played on 35mm some years ago and assumed that was a mark to show what the print number was, though I suppose it could also have been some kind of a defect in the prints.

Maybe I'm just not sufficiently observant to notice the watermarking patterns. What do they look like?

Posted by Carsten Kurz (Member # 5396) on 06-30-2011, 05:29 PM:

Watermarking is visually and audibly undetectable - that's the whole idea about it.

http://en.wikipedia.org/wiki/Digital_watermarking

Watermarking is done on the image and on the audio.

When a rip is handed out to a service lab, they can decode the watermarking and trace it back to the specific cinema, screen and date/time it has been pirated. So the code is per cinema, per screen (media block serial), and timestamped.

The dots you mention are only used on film, it's a Kodak patent and is called CAP Code

http://en.wikipedia.org/wiki/Coded_Anti-Piracy

It was meant to serve like watermarking, at least during the first showings of a movie to trace down theaters where pirating would occur unusuably often.
However, as you say, it usually can be easily detected visually, so if someone would want he could easily remove it before distributing a copy.
That doesn't work with digital watermarking. They say visual and audio watermarking will survive all typical massacres of digital conversions.
Wether that is really true, I could reveal to you - but then I would have to kill you.

- Carsten

Posted by Terrence Meiczinger (Member # 5059) on 07-01-2011, 01:30 AM:

quote: Ken Lackner
Actually, you are right about the serial number. I stand corrected on that. But if the Ethernet connection between the player and projector is broken, then the projector would not be able to play encrypted content, correct?

The encryption is handle by the HD-SDI link between the projector and digital server, much like HDCP. So, pulling the ethernet connection shouldn't affect playback based on encrypted or un-encryped criteria. It may break playback in general, if the server no longer detects the projector for control purposes.

quote: Carsten Kurz
That doesn't work with digital watermarking. They say visual and audio watermarking will survive all typical massacres of digital conversions.
Wether that is really true, I could reveal to you - but then I would have to kill you.

Using a single source it is difficult to remove an embedded watermark, unless you have the transfer function, know where the watermark is, or deteriorate the quality such that the multiple markers are destroyed. We are talking hundreds of pixels amongst several million for video, so it is a good chance they will survive in at least one frame. The watermark could even shift on a per frame basis. I think audio watermarking is even harder to detect, let alone to remove.

If you have multiple sources, it is possible to use differential comparison to detect and distort (or maybe remove) the watermark. In a practical sense this would not work because two camcorder recordings from different screens would have so many inherit differences it would make differential analysis useless. But... as we've seen time and time again, where there is a will there may be a way.

That is my non-authorative understanding anyway...

Posted by Steve Guttag (Member # 268) on 07-01-2011, 04:12 AM:

Actually, that Ethernet link is also part of the handshake too...if it is not there, you should get an error from the player saying it can not connect to the projector and refuse to play the content...irrespective if the player is also using the Ethernet connection for some part of automation needs.

This does not contradict that the Link Encryption/Decryption is indeed processed on the HDSDI connection (what the DCI refers to as "uncompressed essence" via an "enigma" module on Series 2 projectors.

However, the Ethernet connection is also part of the security system as well as contains data needed for other parts of the performance.

-Steve

Posted by Terrence Meiczinger (Member # 5059) on 07-01-2011, 08:26 AM:

quote: Steve Guttag
Actually, that Ethernet link is also part of the handshake too...if it is not there, you should get an error from the player saying it can not connect to the projector and refuse to play the content...irrespective if the player is also using the Ethernet connection for some part of automation needs.

Agreed, I didn't mean to imply there was no need for the ethernet link, just that it is not tied to a KDM. I do seem to recall being able to pull the ethernet connection during playback and it continue playing at least for some period of time. This was several years ago, so I may be mistaken or things have changed.

Future implementations of KDMs may include device lists which would extend key validation to the projector or any device which has contact with the media, adding further overkill to the process.

Posted by Danial Simmonds (Member # 4638) on 07-02-2011, 12:59 PM:

Well going back to the KDM timing, what happens to standalone servers that has been running for years and the time has gone behind thanks to no NTP connection?

I know on the Doremi DCI Dolphins were only allowed 1800 seconds what if we need adjust more than that? Even if the region has been set correctly.

Posted by Chris Slycord (Member # 4239) on 07-02-2011, 01:43 PM:

I don't know if the servers allow you to do this but I know the ntp package for linux (which all the servers I've seen are linux-based) allows you to use your own system clock as an ntp server itself as a backup if no external ones are available and then you can have it so that when you reboot, the hardware clock is reset to match that of the system one. So that way, drift would be reduced quite a lot since your system clock drifts a lot less quickly than the hardware clock.

Posted by Carsten Kurz (Member # 5396) on 07-03-2011, 01:55 PM:

There is a procedure to realign the clock on the Doremis, it's mentioned in the FAQs. Simply contact Doremi about it.

- Carsten

Posted by Danial Simmonds (Member # 4638) on 07-04-2011, 07:39 PM:

In the servers with the Dolphin-B we can adjust from the bios by inserting the correct GMT time.

But on the Dolphin DCI only can adjust 1800 seconds

Thats what i got... not sure if we adjust the bios time on the servers with a DCI version Dolphin will work or not.

Posted by Carsten Kurz (Member # 5396) on 07-04-2011, 07:52 PM:

You can adjust system time offset from IMB time to a maximum of 1800s, various methods.

For anything else, you need to contact Doremi.

- Carsten

Posted by William F Green (Member # 3192) on 07-18-2011, 09:26 PM:

I heard this second-hand so can't verify if it's true or not (sounds crazy enough to be true though) but I was told recently that one independent UK distributor was charging a higher minimum guarantee on a digital bookings than they did with 35mm bookings. Apparently citing the cost of third party KDM production as the reason.

Posted by Amanda Mundin (Member # 3386) on 07-21-2011, 11:43 AM:

True, what you have to wonder is whether some distributors actually know they don't have to use KDMs, we have had a few films that haven't been locked, therefore don't need KDMs, not from major distributors though. I can see the point of KDMs for new films that need some level of piracy protection but to issue KDMs for older films that are already available on DVD / Blu-Ray just seems pointless. We also have some KDMs issued that allow us to play the film until the year 2019!