Re: [DCP-o-matic] P3 to XYZ conversion matrix (fwd)

---------- Forwarded message ---------- Date: Wed, 15 Oct 2014 14:47:14 +0100 From: A. R. Madabushi <armadabushi(a)gmail.com> To: Carl Hetherington <cth(a)carlh.net> Subject: Re: [DCP-o-matic] P3 to XYZ conversion matrix (fwd) Hi Carl thanks for the info! The film is currently a DPX sequence in Resolve that was rendered in P3 colour space already. My DCP program doesn’t allow me to passthrough the file as is, without performing an XYZ transform…which means I just need to make sure the DCP output looks the same as the DPX sequence. If I export TIFFs from Resolve with an XYZ LUT applied, the DCP program will end up doing it again - so that’s XYZ conversion done TWICE, which I want to avoid. I found this site: http://www.brucelindbloom.com/index.html?Eqn_RGB_XYZ_Matrix.html …and given the info Carsten sent through I could make it…IF I understood how to do this kind of maths! If I can figure out the maths - I could make it work! So CLOSE!!! On 15 Oct 2014, at 14:38, Carl Hetherington <cth(a)carlh.net> wrote: ---------- Forwarded message ---------- Date: Wed, 15 Oct 2014 15:03:08 +0200 From: Carsten Kurz <audiovisual(a)t-online.de> To: DCP-o-matic carlh net <DCPomatic(a)carlh.net> Subject: Re: [DCP-o-matic] P3 to XYZ conversion matrix Maybe this helps in creating a matrix: DCI-P3 Gamma 2.6 White point x 0.314 y 0.351  Red x 0.680 y 0.320 Green x 0.265 y 0.690 Blue x 0.150 y 0.060 From what I understand now, xyz is the storage format within the DCP, while P3 is the color space used by DCI projector itself. When a server plays a DCP, it transmits xyz to the projector. The projector will convert to and show P3. In a grading situation with a projector connected directly to the grading workstation for realtime playout, the xyz conversion is omited and P3 is played directly from the grading workstation into the projector. A DCI projector therefore needs at least two different input profiles - P3 1:1, or xyz->P3. Now if you say you have a file sitting in P3 color space - what does that mean? Is it the color space associated with the editing project, or do you have a file rendered out in P3 - if so, which container/codec? - Carsten _______________________________________________ DCPomatic mailing list DCPomatic(a)carlh.net http://main.carlh.net/cgi-bin/mailman/listinfo/dcpomatic