Outputting DCP at 4096 x 3072

[bengedlow]

I'm a tad confused. (A not unusual circumstance.)

When I'm on the DCP page, I see I have a 'Container' and 'Resolution' choice to make. The original media was a ProRes 4444 XQ master which had a frame size of 4096 x 3072.

So I notice that in DCP tab the 'Container' size, if set at the proper ratio of 4:3, I get a 2880x2160 (not a 4K).

Thus my confusion.

Screen Shot 2017-03-13 at 1.38.27 PM.png

[bengedlow]

I thought it might help to add the first tab of that project.

At the bottom I can see that the image is being 'scaled' down to 2K. Is there a way I can set this to get my full 4096 X 3072 image?:

Screen Shot 2017-03-13 at 4.22.20 PM.png

And this is how I set my audio for a standard 5.1:

Screen Shot 2017-03-13 at 4.27.41 PM.png

[carl]

At the bottom I can see that the image is being 'scaled' down to 2K. Is there a way I can set this to get my full 4096 X 3072 image?

No. DCI 4K is maximum 4096 wide and maximum 2160 high. 4:3 in 4K is 2880x2160.

And this is how I set my audio for a standard 5.1

That doesn't look right. Your screen shot puts channel 1 (probably L) of TROLLEYS-DCP .mov equally on all output channels.

I would guess that you want to map none of the .mov, but map TROLLEYS_51_PM.L.wav to L only, TROLLES_51_PM.R.wav to R only, and so on.

[bengedlow]

Thank you Carl,


So I wonder what IMAX is doing? Are they creating a proprietary DCP of some kind? I know they are releasing some films shot in 4K. But I can't imagine they are being scaled to 2880x2160. The LA post house (that does IMAX) gave us the 4096x3072 as what they are working with as a final output.

Is there no way to create a custom format such as this using DCP-o-matic?

SOUND

"but map TROLLEYS_51_PM.L.wav to L only, TROLLES_51_PM.R.wav to R only, and so on"....

I think I'm getting it, a bit. Forgive my gross ignorance. So does that mean I assign the TROLLEYS_51_PM.C.wav to BOTH the left and right? But then I'm at a loss for where to assign the LFE, Rs and the Ls?

I'm new to the world of DCP; in the past I've always handed off the films just before this process. But I'd love to learn..

Ben

[Ikram]

Hi Ben!
You have to map Sound like this screenshot:

Sound Mapping.png

[carl]

So I wonder what IMAX is doing? Are they creating a proprietary DCP of some kind? I know they are releasing some films shot in 4K. But I can't imagine they are being scaled to 2880x2160. The LA post house (that does IMAX) gave us the 4096x3072 as what they are working with as a final output.

I don't know. I'd guess they have their own proprietary DCP resolutions, as you suggest. Perhaps they are using 2 4K projectors one beneath the other, or something.

Is there no way to create a custom format such as this using DCP-o-matic?

At the moment, no. We could extend it to allow making DCPs at this resolution, but I've no idea if it would work. Do you have any of these 4096x3072 IMAX DCPs to hand?

I think I'm getting it, a bit. Forgive my gross ignorance. So does that mean I assign the TROLLEYS_51_PM.C.wav to BOTH the left and right? But then I'm at a loss for where to assign the LFE, Rs and the Ls?

It might help to read this part of the manual. If TROLLEYS_51_PM.C.wav is a sound file containing what should come out of the centre speaker you need to map it to C. If you click TROLLEYS_51_PM.C.wav in the content list and look at the audio tab you will see one row (which is the single channel from your WAV) and lots of places in the DCP which you could map it to. You probably want to map it only to C.

[Carsten]

The reason IMAX is doing this is probably caused by their special need to create anamorphic DCPs. Their new laser installations use native 1.89:1 4k DLPs like other 4k installations. However, the traditional IMAX screen aspect ratio has been 1.43:1. When they create full screen DCPs, they use an anamorphic lens to expand the image vertically. That means, the image going through that process has to be squeezed vertically to maintain proper aspect ratio on screen.

I haven't broken down these numbers to actually figure out what they are doing. As I said in another thread, IMAX is pretty much obsure about what they are doing techwise, and none of their projectionists have ever been seen in the wild or alive.

The only thing that is known is that IMAX systems are able to play standard flat and scope content in 2k and 4k as long as it is 2D.

The footage you are using is probably proprietary, so you won't be able to supply a screenshot or something? Is it full screen 4096*3072, or are there black bars anywhere? From the title I can only assume it's a short comic like clip. What is the reason this post house gave you this footage (instead of making the DCP on their own)?

If that Quicktime movie is full screen square pixel 4096*3072, I would follow what DCP-o-matic suggests and create a 2880*2160 4k DCP, until they get back to you and tell you it's wrong.

- Carsten

[bengedlow]

Amazing replies gentlemen. Thank you, thank you.

I just need to drive to the office and carefully peruse them and respond.

Carsten I can send you a single frame. This is OUR film.

The reason the LA studio isn't doing it, yet, is that we are trying to see if it's something that can be done in-house here in Montreal. If we can't, then a set of TIFF's or DPX's will be shipped off to LA. For the laser that may be the only choice.

But wouldn't it be wonderful if we could actually do it here, in-house? Even if only for the regular theatres, of which there are still many.

Will respond shortly, will send snaps.


Ben

[Carsten]

I would say, for standard features not going through IMAX mastering, they only use one projector, and without the anamorphic lens. So I think the DCP would be 4096*1716 for scope AR, and 3996*2160 for flat AR.

So, if you can create your footage to fit these dimensions, by cropping/letterboxing/pillarboxing and/or scaling, you should be fine. They need to be able to play this format because they need to be able to play standard DCI footage like trailers that did not undergo IMAX mastering.

The only thing you will probably never be able to do is to fill the full 'classic' IMAX screen aspect ratio of 1.43:1. Not before IMAX opens their specs.

- Carsten

[Carsten]

That doesn't look right. Your screen shot puts channel 1 (probably L) of TROLLEYS-DCP .mov equally on all output channels.

I would guess that you want to map none of the .mov, but map TROLLEYS_51_PM.L.wav to L only, TROLLES_51_PM.R.wav to R only, and so on.

He has 6 audio channels in the project, but his matrix only displays 2 source channels. I can only guess that some of his audio files are now positioned in a sequence, instead of in parallel. Also, with individual audio files, the matrix doesn't offer him the nice view of a full 6ch assignment. Also it appears as if the video/MOV file he uses has it's own stereo/downmix track. Now, for a 5.1 DCP, this stereo track of the MOV file has to be disabled/unchecked completely and only the individual channel files should be assigned.

After unchecking the audio that comes with the MOV, go through the individual track files, make sure they are all at Position 0h0min0s0f under 'Timing', and assign them each individually in the matrix - L.wav to L, R.wav to R, etc.
With separate audiofiles, there is no combined audio matrix display. This is confusing at first. I usually recommend to use multitrack audio files. The resulting DCP will be the same, but it's the better view. It will also allow a simpler overall volume adjustment if necessary, but still allow individual channel based adjustments.

Ben - choose timeline view to check this, and arrange all your audio channels vertically. You should see the audio matrix showing one input track per file vs. the 6 DCP channels. Usually DOMs tries to do this right when importing the footage, but depending on settings and file import order, it may initially come out wrong.

- Carsten