DCP Question

This is probably not the right forum, however a lot of folks here with good across-the-board knowledge. Plus this relates to films being cut with FCPX. The question relates to how best to crop or pad a 16x9 master for 2K DCI Flat (DCP). I've also cross-posted this on Creative COW.

Here's the dilemma. The final master is 1920x1080 16:9. The DCP spec for 2K Flat is 1998x1080 1.85:1. So you can either fit, fill or stretch. If you fill, then it's a slight blow-up and you have common sides, but with a cropped top/bottom. Or you can slide it down to have a common top and have all of the cropping come off of the bottom.

I don't want to stretch the image, so the other viable approach is to use fit, so you have a common top/bottom, but with pillarbox sides (black edges on left and right side of frame). I've poked around in some forums and see no clear consensus about which way is the best solution. I've seen a few forum posts in some projection forums that state that pillarboxing will negatively affect the apparent contrast in the projected image. Does anyone know if this is true?

In see some DCPs done on projects that I've cut or graded, the result in the theater looked to be more cropped than using fill conform would indicate. It looks like some additional masking is occurring in the projection. Yet, from these projection forums that doesn't sound like its an option. Supposedly the projectionist can only choose between scope and flat.

Thoughts on the best way to create a DCP in this situation? Thanks,

- Oliver

The best route is likely pillar box if you really need 16:9. Make sure the pillars are as black as possible, that's what affects apparent contrast. Try and see what a 1.85:1 crop would look like in FCPX, if you think apparent contrast is more important than original intended crop factor.

As regards to additional masking you are seeing in the theatre. That sounds like improper DCP creation or the projectionist didn't setup proper aspect ratio for the film. It depends on the theatre, sometime if the trailers are Scope and the feature afterwords is Flat the projector will not switch out of scope, hence the apparent crop.

Wildgiles wrote: That sounds like improper DCP creation or the projectionist didn't setup proper aspect ratio for the film. It depends on the theatre, sometime if the trailers are Scope and the feature afterwords is Flat the projector will not switch out of scope, hence the apparent crop.

The crop wasn't that extreme. This was a four-walled screening for friends & family, so no trailers. I'm pretty sure there was no operator error, since the producer previewed the presentation the day before. However, it could be that internal projection masking may still account for some slight additional crop. The producer is still trying to determine that by comparing the DCP itself to the master when he gets a chance.

In FCP X if you put a 1920 x 1080 file into a custom 1998 x 1080 project and spatial conform with common sides, that effectively is a 4% blow-up. You crop about 22 pixels top & bottom if left center-cropped. This doesn't seem like much, but that's what we are checking.

- Oliver

Hi Oliver,

Yea it's either scope or flat for DCP. I'd highly recommend pillar-boxing, unless you are prepared to go in and do an attuned pan & scan for a 1.85 sequence. There should only be a negligible amount of softness resultant of the blow up if you go that route. Preferably, you should pillar-box for pixel accuracy. Are you working in DaVinci Resolve, EasyDCP?

If you are already DCI compliant and in P3 color space you should be fine. Set your sequence to 2K DCI Flat and don't worry about blanking or cropping. You shouldn't have to but select Conform Sequence to Fit in your project settings, if it hasn't naturally.

I've personally had a 4K feature (2.39) that, in some instances, needed to play Flat projection, so there was letter-boxing involved for that version. No pollution in the image when sequence settings are correct, for me at least.

While I'm sure it might be irksome, don't worry about pillar box, it's wild how often one will see it in wide releases with unusual aspect ratios - almost no one notices.

Thanks for the feedback. I'm not creating the DCP, only involved in prepping the file. Another vendor is creating the DCP. I've already seen a preliminary DCP from one project. It was "blown up" for Flat and it looked fine, as far as resolution was concerned.

- Oliver

Hi Oliver,

As you realized the difference between 1998 and 1980 isn't that big.
For a 15 meter wide screen it will be about 7 centimeters. I doubt anybody would notice.

Depending on the app you use it will either scale up or create a pillar box - none of them will be vsible in quality.

Andreas