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Author Topic: DCP pixel dimensions for aspect ratios narrower than 1.85 Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 09-23-2011 12:29 PM                        Doing math gives the following: 1260x1080 - 1.17:1 (Movietone) 1440x1080 - 1.33:1 (silent) 1480x1080 - 1.37:1 (Academy) 1793x1080 - 1.66:1 (European widescreen) 1920x1080 - 1.78:1 (HDTV) Are these values correct? Are they standardized anywhere? Mention of the narrower aspect ratios is curiously absent in the DCI spec. Actually, the spec is looking more and more half-baked every day. This is all rather important to anyone who is attempting to set masking stops.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 09-23-2011 12:41 PM                     That's what is nice with DCI projectors is the zoom option does when going from flat to scope. The lens just zoom the image in to fit the masking tabs since the image on the chip is smaller.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 09-23-2011 12:44 PM                        Right, but you would still need to set masking stops for each of the formats listed above, and there is a reasonable chance that they would not be the same as the masking stops for 35mm. Is there a DCP version of RP40 (err...35PA) that could be used for this purpose? Edit: this is sort of what I had in mind: The smallest white rectangle represents Movietone, the next larger rectangle (black) represents 1.33, then 1.37, etc. Is there a place to get an official version of something like this? Or at least specifications to make it?  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 09-23-2011 01:58 PM                     In some DCI projectors, there are actual screen test programs within the unit that one can run via the menu and one program is like the 35PA, but not the same that the end user can run to set and test masking tabs with. Sometimes I run these programs to check the alignments, along with focus, white light test, et.al.  |  IP: Logged Brian Guckian Jedi Master Film Handler Posts: 594 From: Dublin, Ireland Registered: Apr 2003 posted 09-23-2011 02:37 PM                     Very good points Scott, and I know that that from day one (on the European side at least) there were attempts to have these ratios incorporated into the DCI Specification. It may be that since DCI seemed to be framed with the purely commercial theatres in mind, it was felt that just defining 1.85 and 'Scope would suffice. I believe that there have been moves within the Archival community to have DCI extended to incorporate the other ratios. Also, it's be interesting to know what work has been done lately within SMPTE for example, in terms of defining new Standards in this area. If anyone could give a general overview on that, it would be very helpful.  |  IP: Logged Mark Hajducki Jedi Master Film Handler Posts: 500 From: Edinburgh, UK Registered: May 2003 posted 09-23-2011 03:33 PM                     Arts Alliance Media made a test card frame for systems they installed. It had the boundaries of the various aspect ratios shown. It didn't include movietone, and it only had one out of of 1.33 and 1.37. quote: Edit: this is sort of what I had in mind: You would also want to include the boundaries of 2.39 in the frame as well. quote: Monte L Fullmer going from flat to scope With film I always took flat to refer to the non-anamorphic formats, so all (DCI spec) digital ratios are flat.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 09-23-2011 05:47 PM                        quote: Mark Hajducki Arts Alliance Media made a test card frame for systems they installed. Any idea what pixel dimensions they used? quote: Mark Hajducki You would also want to include the boundaries of 2.39 in the frame as well. That would be interesting, but not useful, as the DCI specification for "scope" only provides for a letterboxed image within (well, not quite) the 1.85 image area. In most cases a lens shift or zoom (or combination of the two) would be necessary to change formats, anyway. I have no idea why they did this, but I suspect that it will prove to be a mistake.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 09-23-2011 05:57 PM                     deleted...  |  IP: Logged Mark Hajducki Jedi Master Film Handler Posts: 500 From: Edinburgh, UK Registered: May 2003 posted 09-23-2011 06:00 PM                     It has been a while since I saw the test card, but I think it was the full 2048:1080 frame, with 1.85 being one of the ratios. 2.39 was just added as horizontal lines. I have shown 1.66 and 1.37 films digitally in past employment with preset format commands for the common ratios. I suspect they went for the multiple aspect ratios as they were supplying the UK Film Council network, which mainly covered art cinemas.  |  IP: Logged Ron Funderburg Jedi Master Film Handler Posts: 814 From: Chickasha, Oklahoma, USA Registered: Nov 2007 posted 09-23-2011 06:12 PM                        quote: Scott Norwood That would be interesting, but not useful, as the DCI specification for "scope" only provides for a letterboxed image within (well, not quite) the 1.85 image area. It was done to have a single lens solution to reduce that particular cost!  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 09-23-2011 07:54 PM                        The scope image could still be full height/width anamorphic. A single-lens theatre could then scale it down to the current dimensions. Theatres with anamorphic lenses could show it properly. And, at some point in the future, wider chips could be developed to allow scope DCPs to be shown without scaling or anamorphics. Since a scope image is typically projected larger than a 1.85 image, it needs to have more resolution, not less.  |  IP: Logged Ron Funderburg Jedi Master Film Handler Posts: 814 From: Chickasha, Oklahoma, USA Registered: Nov 2007 posted 09-23-2011 08:23 PM                        Yup it does that was why it was a poor choice of a place to save cost on a lens or processor chip. then again we aren't the high paid nerds that developed this stuff so who knows!  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 09-23-2011 09:01 PM                     and since these units might be replaced with a period of time due to manufacturer cycles and upgrades, why make the effort? quote: Scott Norwood it needs to have more resolution, not less. This is where SONY wins with their 4K LCoS Chipset - with a HD 1713x4096 resolution in scope-being above the 1080P requirements. And Ti will be the same for their DLP 4K chipsets also. Now, we just need more content in 4K than all of this 2K stuff that doesn't use all of the imagery of the DMD chip.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 09-23-2011 09:41 PM                     Except those fools that leave their 3D lenses in the Sony and only get 2048x858... Scott, in the Series 1 machines with the .TGA test patterns, there was one called "Framing2.TGA" that had many of the dimensions in it...I don't know if anyone has ported it over to .PNG format...which is the format series 2 machines run with (at least in the DLP world). However, anyone with a graphics program that can save in .PNG can make their own test chart now. -Steve  |  IP: Logged Ron Funderburg Jedi Master Film Handler Posts: 814 From: Chickasha, Oklahoma, USA Registered: Nov 2007 posted 09-23-2011 09:46 PM                        So there is separate lens for the 3d format what about scope and flat on those is it a single lens solution on them?  |  IP: Logged

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