2048x1152 DCP Problem

[1.66_Forever]

Hi there,

I've used DCP-O-Matic for various short films I've used before and there has been no problems. Recently I've been given two master files for shorts I've cut. The first one is a scope film that was given to me in 2048x1152. I cut the video and audio (5.1) down to the right size on Avid and exported it to
the various .mov (DnxHD185) and WAV's. The video was in 2048x1152.

I brought it into DCP-O-Matic put a crop on the black bars and made the DCP. When i checked it on a Sony 4k projector, the titles and end credits looked jaggedy and at times during the film there seemed to be slight interlacing in the picture.

I've read an interesting article by this chap and he describes quite succinctly the same problem.

http://endcrawl.com/blog/2048x1152-is-a-total-crock/

Any advice would be greatly appreciated.


Jon

p.s. I haven't even mentioned the other short that is 4:3 in a 2048x1152 container!

[marcogiustini]

Hi,

as the article mentions, D-Cinema is 2048x1080 maximum so you'll have to rescale or to crop. Rescaling is never a painless process. I do not know how DCP-o-matic does that but maybe it would be best to rescale during post production and then just do the master with DOM. This way your customer/client can also approve the final result.

[Carsten]

What does 'scope film in 2048x1152' mean? You mention black bars? What is the active pixel area of this clip? Can you post some stills from this file - pre/source and post conversion (post conversion snapshots can be created by opening the J2C MXF in VLC and create a VLC snapshot).

- Carsten

[carl]

DCP-o-matic uses FFmpeg's bicubic scaler. I don't know where it sits in the quality stakes. As Marco says you may be better off scaling it in something posher (if you do need to scale). Or if your source is letterboxed scope inside a 1.78 frame you may be better off using "Flat" as the container in DOM and then having the image both letterboxed and pillarboxed inside a flat frame. It will be a smaller image than scope (if the cinema is using a common-height screen) but at least there will be no scaling artefacts.