Fuzzy images on pointcloud film

[noobie]

Hello,

I am having issues converting a film to DCP. It's a UHD film from Premiere that I need to convert to DCP. The images are all pointclouds and have a lot of low greys. My ProRes files are all fine (perfect resolution, colour depth etc) but no matter what I do in DCP-o-matic, the mxf files for the project become highly pixellated and smudgey. Here's an example:

Original image:


Version after conversion with DCPomatic:


This happens no matter what I do! I have tried every possible combination, exporting from Adobe Media Encoder in every mxf format possible, and changing all the options so that there is theoretically no additional jpeg2000 conversion. Am I just an edge case? Is there a way to guarantee that I can create a DCP from my film that doesn't fudge up?

[noobie]

(I know that the images above are of slightly different frames! But the pixellation and fuzziness happens with nearly every frame in this film, it's driving me mad!)

[Carsten]

We can't see your images, and once we can, we need to know how you created these stills.


Pointclouds can be very difficult for J2K.

[noobie]

Apologies for the lack of clarity above. This is an update, so that my issue is a bit clearer. Apologies, I have spent a few days trying to get this to work, and am new to making DCPs so have little idea what I am doing. I’ve read everything I can possibly find, but essentially, I cannot find a way to create a DCP of my film without creating fuzzy, unclear images.

I am compiling a DCP for a film that features greyscale pointclouds. The film was compiled in Premiere with thousands of individual JPEGS at high resolution. The quality of low-level grays is the most important thing, it’s very detailed. The ProRes 4444 file plays back beautifully!

But - whenever I convert this to DCP in DCP-o-matic, every frame goes blurry and pixellated. There is something that happens in the JPEG2000 conversion that seriously degrades the image quality, and I cannot find a setting that bypasses this. I have tried all of the image compression settings possible, but DCP-o-matic seems to always re-compress the images in a lossy way, even when I use high bitrates (250mb/s).

Here’s an input image from Premiere, to show the detail in the images:



And here is a still from the outputted mx2 file from DCP-o-matic (screenshot from DCP’s mxf file, taken with VLC) at about the same time:



The same thing happens no matter which settings I choose (all color settings; mpeg/image range within ‘range’ menu; any jpeg2000 bandwidth). The pixellation/false color shows up in DCP-o-matic player, too.

I have tried to re-encode the input file in various ways, including exporting the entire film as .tiff stills, and also as .j2c stills from Media Encoder using the j2k plugin (https://www.fnordware.com/j2k/). But DCP-o-matic seems to *always* recompress my images and fuzz them up. Is there a way to bypass this?

Thank you in advance for your help!

[Carsten]

Tricky, high detail, high contrast, and black and white...


I'll give it a try myself, but, it may be that your only chance is to filter the image, e.g. with gaussian blur at 1-2 pixel prior to export.

[carl]

We should check that it is the J2K encode which messes things up (not some other part of the pipeline). Do you have a TIFF of a single frame that you can share? (by email to carl@dcpomatic.com if that's better).

DCP-o-matic should not reencode J2C input files so long as they are the right size (and some other things I probably forgot). Perhaps you could also share a J2C file you made in Media Encoder so I can check why DoM is deciding to re-encode. I take it the J2Cs from Media Encoder look good?