1 Topic by Keoconsult

(1 replies, posted in Support)

Many thanks for your answers to my previous two posts.  I successfully created a 6-minute 4K DCP and projected it in my local theater.  No problems, looked great.

Could you answer another question - I now want to make a longer DCP with more of my data files, but I have a number of different aspect ratios.  Can I mix aspect ratios in the Input Directory?  The DCP I made had tiff files with 3:2 aspect ratio, and OpenDCP filled the screen vertically and filled in the Left and Right edges with black.  If I now mix in files with 4:3 and 16:9 aspect ratios, will OpenDCP automatically letterbox the 4:3 with (wider) black edges, and fill the whole screen with the 16:9 files?

(I found for example with Quicktime, it seems to set the aspect ratio from the first files, and then distorts the following files that have different aspect ratios.)

I could try this by trial and error, but I do not want to wear out my welcome at my local theater!  So your advice will be greatly appreciated.

Robert

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2 Topic by Keoconsult

(1 replies, posted in Support)

Thanks for the reply to my post yesterday re. using a silent track.  I have had no trouble implementing that.

Could I ask you another question about the input tiff files, 16-bit versus 8-bit. All of my original files have been calculated from ImageJ, and are 8-bit/channel RBG files.

I have read about this in relation to OpenDCP, and watched a number of the online help videos.  Most presenters say that it is very important that the tiffs are 16-bit/channel, though some say OpenDCP will accept 8-bit/channel, but the quality will not be as good.  Then in these demos they change their 8-bit files to 16-bit and suggest the problem is solved.

My understanding when you simply go from 8-bit to 16-bit is that all pixel values are multiplied by 256; so for example, if 8-bit pixel counts are 20 and 21 they will become 5120 and 5376, and there will be NO pixels with values between 5120 and 5376. Consequently I do not see how the next conversion to JPEG2000 (XYZ) can be any better than if the conversion was done from the original 8-bit files.

Could you enlighten me if I am wrong, and clarify whether OpenDCP will accept 8-bit/channel with no quality loss compared to 16-bit files derived from 8-bit files.

Many thanks

Robert

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3 Topic by Keoconsult

(2 replies, posted in Support)

Hello everyone: 

I just registered yesterday, and am new to DCPs.  I have been creating large format sequences from NASA data of the sun and northern lights (4K-8K sequential tiff files), with the ultimate goal of Imax theaters.  I want to test project some of this work, so tried to make a DCP using OpenDCP.  All seems to go well up to the required audio files.  I have no audio, and am wondering if it is possible to make a DCP with no sound track - or can I put in some sort of dummy sound track?

I will appreciate any advice.

Robert

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