Dual Screen DCP playback.. is it possible ?

[Yuri Mamaev]

Have you got this project solved?

I've seen that Chase mode on Doremi servers should be free now, but only 1 CPL could be played in sync (according to documentation, have not tested chase mode as of now). The other way will be single server + 2xSDI splitters, dual projector KDM and SDI inputs + LDs for both the projectors.

Other issues with echo should be dealt on the PA (correct alignment of the line array, and possibly other ways of audio cancellation in the unwanted areas). If you have 2 second delay for the sound travelling, you can still deal with it manipulating DCP playback on one of the synced servers if you use Chase mode, but this I suppose will require some trial. I've also thoughts, that Barco ICMPs could be synced (license needed) and should use the LTC input to sync the playback, so possible manipulations of the sync here.

[Marcel Birgelen]

Having to deal with some of those "post persons", I doubt even they will notice, at least if you don't tell them, because, once you start telling people stuff, they magically start to see and hear stuff... While 12 bit per components is 4 times the resolution per "color" than 10 bit, in my opinion, 10 bit is good enough for DCI-P3. Maybe once we go into the realms of Rec.2020 and beyond, those two extra bits can work their magic.

This is definitely a MAJOR motion picture. Its about as MAJOR as you can get. We shot them a price with the cost of the live PA included in the 4 wall rental. Have yet to hear back if they'll accept it or not. If they do, that's great. If they don't, that's fine too. Sometimes you just want to play movies and go home at a normal time.

So, the wireless headphone idea isn't the solution you're looking for? They're bikers and they want their sound to be heard by everybody? :P

[Steve Guttag]

It will be 10bit color, but absolutely nobody will notice at a drive-in.

Ha! Nobody would notice in an indoor either. You might get a post person to notice...someone that color times things but that is about it.

[Brad Miller]

Barry, the easiest way I can think of is if you can borrow a Dolby DSS200 server, set it to 3D mode and take one HDSDI into HDSDI-A on one screen and take the other HDSDI cable from the server and go into HDSDI-A on the second screen. Then edit the macros on the two projectors to only look at the A input. It will be 10bit color, but absolutely nobody will notice at a drive-in. You are absolutely assured that will play frame-for-frame in sync because both projectors are being fed from the one server.

[Martin McCaffery]

Get your money up front!

[Barry Floyd]

Just curious, is this a MAJOR MOTION PICTURE!!! or just some indie thing?
I've had a few studio rentals over the years, at least one brought in all of their own sound equipment (this was in the days before we had stereo). If they want you to do something that requires renting a bunch of equipment because they want to do something you are unequipped to to in your Drive-In, shouldn't they be footing the bill for the equipment THEY are using? Also, paying for its design and setup.

This is definitely a MAJOR motion picture. Its about as MAJOR as you can get. We shot them a price with the cost of the live PA included in the 4 wall rental. Have yet to hear back if they'll accept it or not. If they do, that's great. If they don't, that's fine too. Sometimes you just want to play movies and go home at a normal time.

[Steve Guttag]

I have two sites where we have provided for using LC/RC for Left/Right on Flat or "narrow" movies. At the Uptown in DC, we used LC/RC for Left/Right on 1.85 movies. The screen was large enough and the curve was deep enough that one would be very aware of Left/Right were nowhere near the edge of the 1.85 image. Plus, we would stop the curtain once it got past the masking for 1.85 so not to have the huge black area on left/right.

Most theatres today, particularly with a constant width, would not benefit from the speaker interchange. It would be easy enough to do on our Dolby Atmos rooms since they have 5-screen channels but again, none of those theatres would really benefit from it.

[Gordon McLeod]

No, they are not used for scope movies. I understand the original intention was to have a full 5-across setup as they often play classic 70mm and other formats. Once they had them, it turned out simple to switch them for flat vs. scope.

I once read about auditoriums that had L and R on motorized movers for the same purpose...

On the CP200 it allowed to switch to reverse the LE L and RE R for flat and scope

[Marcel Birgelen]

Well, EBU recommendation is for television, with a typical viewing distance of a few meters. While the typical minimum viewing distance in a decent sized cinema is more like 5-10m.

Also, you have to factor in that they always need to spec tolerances, and the max tolerance should still work for both the closest and the back seats.

The time the sound needs to travel between the TV and the viewer, since it's for TV applications, is seen as negligible. The specs account for the lipsync issues that can occur in the entire processing and broadcasting chain, where video may have a lot more processing and buffering than audio. The end results are the same though and the viewing distance here isn't really the issue, light is fast enough not to be a problem factor we need to account for.

What is an issue though, is the fact that images are usually much larger than for typical TV applications, but I don't find any conclusive studies that compare lipsync detectability with "perceived image size", so maybe for the sake of simplicity we should omit this factor. There definitely is some factor in it: I watched a lot of dubbed movies on German TV when I was still a kid, this never really bothered me. But seeing dubbed content in a cinema almost freaks me out. (Maybe I'm exaggerating a bit to make a point.)

But what's clear that the SMTPE requirements of +/-22ms won't work for any large setup, with the average speed of sound in air, those +/- 22ms give you a total "wiggle room" of just 15,0 meters or 50 ft, when you consider the center as your zero-point. While that may be good enough for most common rooms, it won't work for any open-air application.

If you take the more lenient -40ms/+80ms, this gives you 41,1m or about 135 ft to work with, where the zero point is at 1/3rds from the front. That's almost the length of an Olympic swimming pool and much more realistic for out-door applications.

[Carsten Kurz]

Well, EBU recommendation is for television, with a typical viewing distance of a few meters. While the typical minimum viewing distance in a decent sized cinema is more like 5-10m.

Also, you have to factor in that they always need to spec tolerances, and the max tolerance should still work for both the closest and the back seats.

[Martin McCaffery]

Those people who come up with the ideas usually have no idea whatsoever. But major studios can fly in a crew of experienced people who know exactly what they are doing and how to do it. Small independents or individual filmmakers are generally just a pain in the ass because there film is the most important film ever made and "everybody" is dying to see it.

[Marcel Birgelen]

Just curious, is this a MAJOR MOTION PICTURE!!! or just some indie thing?
I've had a few studio rentals over the years, at least one brought in all of their own sound equipment (this was in the days before we had stereo). If they want you to do something that requires renting a bunch of equipment because they want to do something you are unequipped to to in your Drive-In, shouldn't they be footing the bill for the equipment THEY are using? Also, paying for its design and setup.

I guess it depends a bit on what position you're putting yourself in. Events don't organize themselves and I've seen more than once that those people who come up with those ideas aren't the best at managing them. But if you're good at it, why not try to earn a few extra bucks helping to get the event off the ground.

Thanks Marcel for the comment on tolerable sound before image. I had not considered that.

No problem, an interesting source is EBU recomendation R037, which reccomends anything between 40ms before picture and 60ms after picture. There is an ITU recomendation which keeps it between 45ms before picture and 125ms after picture. So, my guideline has always been between 40ms before picture and 80ms after picture if the SMTPE reference of +/- 22ms can't be achieved

[Martin McCaffery]

Just curious, is this a MAJOR MOTION PICTURE!!! or just some indie thing?
I've had a few studio rentals over the years, at least one brought in all of their own sound equipment (this was in the days before we had stereo). If they want you to do something that requires renting a bunch of equipment because they want to do something you are unequipped to to in your Drive-In, shouldn't they be footing the bill for the equipment THEY are using? Also, paying for its design and setup.

[Mike Blakesley]

How about creating a "wall" between screen 1 and 2 by getting a bunch of truck drivers to pull semi-trailers in there and line them up end to end between the two fields? That way you would have "some" bleed through but not too much and synchronization wouldn't be as much of an issue.

I figure since we're all spitballing ideas here, anything is possible.

[Carsten Kurz]

No, they are not used for scope movies. I understand the original intention was to have a full 5-across setup as they often play classic 70mm and other formats. Once they had them, it turned out simple to switch them for flat vs. scope.

I once read about auditoriums that had L and R on motorized movers for the same purpose...