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DCP looks a bit muddy in some areas - Bluray does not - what's wrong?

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  • DCP looks a bit muddy in some areas - Bluray does not - what's wrong?

    Hi,

    I did a DCP with openDCP for a festival, but when playing on my computer it sometimes looks a bit muddy - the bluray of the same film looks cleaner. Is this because I'm playing that DCP on my computer in the wrong colour space? I even converted the TIFFs into JPG2000 with the highest rate - or is there anything gone wrong?

    Suppose the festival won't have the time to pick out the better looking copy (bluray vs DCP) and I don't have access to a cinema to check the DCP under real-world-conditions.

    Any advice (except of submitting just the bluray)?

    Thank you!!

    cheers,
    Thomas
    ___________________________
    www.gernemehrfilm.de
    www.berlin3k5.de/

    Will trade my as-new BMPCC 4K v.1.0 for two new BMPCC 4K V.2.0

  • #2
    gmfb, my understanding is that your DCP is XYZ-colorspace. Your computer being RGB requires a player that will playback with an XYZ-colorspace to RGB-colourspace transform. I have not researched this for a while. Pending someone providing you with the appropriate advice, see if you can find a free player that will convert XYZ to RGB colorspace, so that it looks closer to normal than viewing XYZ-colorspace material in RGB environment.

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    • #3
      Thanks WhiteRabbit,

      I'm using the demo of Neo DCP-player, the colours look actually alright - so maybe the colourspace-transformation does cause taht muddiness...
      ___________________________
      www.gernemehrfilm.de
      www.berlin3k5.de/

      Will trade my as-new BMPCC 4K v.1.0 for two new BMPCC 4K V.2.0

      Comment


      • #4
        gmfb, yes, I am sure there will be differences between the encoding software apps and the various players for playback. You may need to test it at a certified post house or try and find a smaller independent cinema with digital projection system and work out a deal to have a test screening? Otherwise, perhaps try and test the DCP at the festival prior to opening, if that is possible, and have your blu-ray ready in the other hand.

        As for the whole colour consistency issue, I tried to use a Premiere plugin that renders direct to JPG2000 in XYZ colourspace. I found that their colour was not consistent with those generate from the TIF image sequence processed by open-DCP into the JPG2000 sequence output in XYZ in preparation of the MXF processing stage. Not sure which was correct, if any at all, hehe. Hopefully someone experienced with this process and with open-DCP can solve your question.

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        • #5
          Thanks WhiteRabbit,

          oh well, will try and see if I can test it somewhere!
          ___________________________
          www.gernemehrfilm.de
          www.berlin3k5.de/

          Will trade my as-new BMPCC 4K v.1.0 for two new BMPCC 4K V.2.0

          Comment


          • #6
            If you try to view an XYZ image directly on your computer, it will look desaturated, greenish and lack detail. It is not a 1:1 conversion between XYZ and RGB, but rather X, Y, and Z are varying combination of the RGB values. In addition, the conversion when done with OpenDCP accounts for destination being a digital cinema projector. Some of the DCP players do a decent job converting back in to RGB, but you may see slight variations in color if you use a image comparison tool. You also need to account for what your source is - sRGB or REC709 or you will also get different results.

            You should not use the full bandwidth value of 250mb/s for 2K@24fps as it will just result in unnecessarily large images. You can easily use 125mb/s and I typically use 75mb/s and sometimes even 50mb/s with no visually noticeable issues. As you increase framerate, 3D, or jump to 4K, then you need to start increase the bandwidth value.

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            • #7
              Thanks tmeiczin,

              I did a test run with the demo of NeoDCP Player, which seems to convert the colour space when playing. The thing I noticed looking worse than in the original prores-files or the bluray-disc is e.g. some leaves in the wind, they really look like badly compressed h264, otherwise the quality was about equal.
              As I have to deliver today, I'll tell the cinema to use the bluray if they can't test the DCP beforehand.
              ___________________________
              www.gernemehrfilm.de
              www.berlin3k5.de/

              Will trade my as-new BMPCC 4K v.1.0 for two new BMPCC 4K V.2.0

              Comment


              • #8
                Was the original source 16-bit and if so, did you export the as 16-bit? Did you scale the images at all?

                Comment


                • #9
                  Thanks tmeiczin,

                  the original material was 10bit Prores, I had the project set to 1920x1080 for the TIFF-export, so the 2k-DCP should just have added some pixel w/o upscaling.
                  Meanwhile I had to submit the DCP and the cinema reported back it played well on their system, which doesn't mean it looks great, but I've given up here, I'll just wait and see then. Maybe I was a bit too picxky about it and all will be fine.
                  ___________________________
                  www.gernemehrfilm.de
                  www.berlin3k5.de/

                  Will trade my as-new BMPCC 4K v.1.0 for two new BMPCC 4K V.2.0

                  Comment


                  • #10
                    gmfb, please let us know how it looked projected, if you make it to the screening. Thanks.

                    Comment


                    • #11
                      You guys may want to check out DCP-o-Matic.

                      It's freeware, works pretty good for me, and accepts a ton of formats, not only tiff sequences.
                      You can also specify if your source footy is sRGB, 709 or something else - and it will take care of that during the conversion to the XYZ space.

                      Works on Win/Mac/Linux


                      http://dcpomatic.com/
                      Blog: http://frankglencairn.wordpress.com/

                      Comment


                      • #12
                        I completely agree with Frank here.

                        I DCP-o-Matic is used here on a weekly basis for the pre-show content in our local cinema.
                        And I also do DCP screenings of my films for my clients in that cinema.

                        DCP-o-Matic, although a little slow, works like a charm.

                        I usually export DNxHD 444 Quicktime Clips from my AVID Timeline, simply put them in DCP-o-Matic and hit render, that's all.
                        The results look great on the big screen.

                        Peter

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                        • #13
                          Thanks a lot, Frank and Peter,

                          sounds awesome!!
                          ___________________________
                          www.gernemehrfilm.de
                          www.berlin3k5.de/

                          Will trade my as-new BMPCC 4K v.1.0 for two new BMPCC 4K V.2.0

                          Comment


                          • #14
                            Originally posted by WhiteRabbit View Post
                            gmfb, please let us know how it looked projected, if you make it to the screening. Thanks.
                            Ta, will do so. It's just around the corner!
                            ___________________________
                            www.gernemehrfilm.de
                            www.berlin3k5.de/

                            Will trade my as-new BMPCC 4K v.1.0 for two new BMPCC 4K V.2.0

                            Comment


                            • #15
                              Thanks, Frank for the o-Matic info.

                              Peter, I had discounted this app from initial skim reading of the specs, thinking it may only load in 8-bit MP4 like footage. Learning you are feeding DNxHD 444 is great. Looking to add CineForm soon, master some to 2K 444 and make a DCP master would be great, together with the usual 1080p 10 and 8 bit versions. I must try this one soon, thanks.

                              gmfb, great to hear you will sit in the cinema and see your skill and art on a big screen. I hope the colour is pleasing to you, based on a calibrated projection for your own future reference and notes to self what you may change for next time. I marvel at the developers of film and colour timing prints for look and how they coloured a few decades ago, while we can click a few buttons and have instant feedback on screen. Amazing.

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