Colour problems

Anything and everything to do with DCP-o-matic.
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Shannon
Posts: 5
Joined: Fri Aug 04, 2017 10:42 pm

Colour problems

Post by Shannon »

Hi, people. I converted a video for a cinema and in one of the rooms (3d) it worked well, but in the other (2d), even saved right the colour went "green" . Please, help me.

Settings used:

Interop (SMTPE didn´t work there)
2D
Rec. 709
2 channels audio
Carsten
Posts: 2648
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: Colour problems

Post by Carsten »

frame rate?

- Carsten
Shannon
Posts: 5
Joined: Fri Aug 04, 2017 10:42 pm

Re: Colour problems

Post by Shannon »

Frame rate is 60.
Shannon
Posts: 5
Joined: Fri Aug 04, 2017 10:42 pm

Frame rate x colour

Post by Shannon »

Frame rate: 60. But is there any relationship between frame rate and colour?
Carsten
Posts: 2648
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: Colour problems

Post by Carsten »

Yes, depending on the system you play this on. The only real 'safe' frame rate for DCP is 24fps. Some systems (probably the one you quote as '3D') is using an IMB and that is 60fps (HFR) capable. If you try to play 60 fps on a older system, like one with HD-SDI connection, the server may try to play it in 3D mode, which changes the color (again on HD-SDI systems). I have seen this happening before.

Try to create the DCP again, this time choosing a frame rate of 30fps under the DCP tab, (and don't ignore the warning under 'hints'). This will throw away any other frame, but chances are higher that a 30fps DCP will play on more systems.

60fps is a bad frame rate to start with for a real compatible DCP. If it only needs to play on select systems, you may get away with it if you are able to test it on any system, or are able to do some pre-qalification.

- Carsten
Shannon
Posts: 5
Joined: Fri Aug 04, 2017 10:42 pm

Re: Colour problems

Post by Shannon »

Carsten,

Thanks for the help, I´ll try it and reply the result.
Stephen Furley
Posts: 10
Joined: Sat Aug 20, 2016 5:53 pm

Re: Colour problems

Post by Stephen Furley »

I have just had a similar problem with today"s show. We are screening "reach for the Sky' in a joint presentation with a group involved in a local Second World War airfield where part of the film was shot. Before the feature there will be a PowerPoint presentation, and a short consisting of footage shot from a drone flying over the former airfield.

We were provided with a link to a website from which to download the short. There were several different versions, including three different 1080p ones of different sizes; I picked the largest, and it played fine in QuickTime 7 Pro on my laptop.

Made the DCP a few weeks ago, and it was nearly all green, with patches of magenta. Come to think of it, this did look rather like a 3-D DCP did when I tried playing one once just to see what would happen, but I hadn't thought of that before.

This is with a series 1 projector, NEC NC-800C, and Doremi server. Our equipment was supplied as part of the Digital Screen Network scheme, and is now ten years old. The projector has four different formats for 1.78 aspect ratio, one for normal DCI, one for HD, one for alternative content from the Christie Cine-IPM 2k and one named HD 1.78 DS. I once selected this one in error when showing a normal DCP, and the colours were all wrong. However, the DCP of this short played fine in this format. I didn't understand why, but had noticed that the original video was at a highb frame rate, 50 fps. Could the DS be double speed?

I don't know exactly what the difference is between this format and the normal one, I haven't seen it documented anywhere, and our service engineer didn't know when I asked him last year. I also don't know is this special format is standard on this projector, or on other series 1 projectors, or if it is something defined by AAM, but it does seem to solve this problem. See if you have a format on your projector with DS in the name.
Carsten
Posts: 2648
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: Colour problems

Post by Carsten »

The connection will revert to component for 3D, as opposed to P3-RGB for 'standard' DCPs. 50fps is close enough to 48fps and will work in component signaling. But this is only a solution if there is no way or time left to fix the DCP, as results are erratic.

DCP-o-matic issues clear warnings for higher frame rates, and it is wise to not neglect them.

- Carsten
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