IMS3000 HDMI color profile MacOS

[Abraham Robinson]

I'm unsure which is the correct color profile to choose when outputting hdmi from a macbookpro into the IMS3000 and an NEC3240S-A. Colors on the projector are calibrated regularly by a cinema tech with a proper color meter. I understand this is more of a mac / color correction suite setup question than a dci question, but I hoped some people here might be more familiar with the proper signal flow when it comes to digital cinema hardware, where most of the info I can find online is for reference monitors.

I'm not having any major color space issues, for example where everything looks all green/purple, etc, I'm already in the right range. I'm just trying to understand which color profile on the MacOS display output will get me the closest match to DCP playback. I assume the mac's "SMPTE RP 431-2-2007 DCI (P3)" preset would be the correct choice, but there are many options with subtle differences in black levels / gamma / contrast.

Or am I actually on the wrong path, and should be setting the color profile depending on the file type? With all of this, assume grading was done in a professional environment on a calibrated monitor, etc and I am showing something like a 4K ProRes export that will eventually be converted to DCP for distribution.


thanks from a confused projectionist,

[Steve Guttag]

Most of the time, computers present themselves looking for a REC709 (HD) color space. Computers normally do not present themselves as P3. I suspect that newer ones will go for REC2020 if that is an option for them. In general though, for typical power-point and like interactions...I try to get computers to play with 1080p/60 and nothing too fancy. When possible, I also try to have laptops go through an Extron scaler that takes care of whatever strange Apple resolution they've dreamed up and put the output to 1080p/60 and well behaved. However, that, typically adds a lot to a system's hardware costs. But that's me.

Normally, when I'm commissioning a system or testing the HDMI spigot, I just plug my laptop in with a straight up HDMI cable. In the case of the IMS3000, it takes care of converting the HDMI input into an XYZ color space for the projector. So, you can use you normal FLAT preset with the HDMI input, unless you want to create another screen file. Historically, I've tried to avoid cropping off corners since Start Menus menu as well as the normal menus live in the corners.

Looking at an IMS3000, here are some configuration parameters (though most leave it in Auto:

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Here are the list of supported formats:

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[Abraham Robinson]

Thanks Steve! appreciate the response, have learned a lot from your posts over the years.

At my venue we have a Crestron DM system and I typically run all non-dcp content / powerpoints through that, since we may need to route to additional downstage monitors, overflow rooms etc. If I go that route all content passes through a crestron scaler before coming in the DVI input on the NEC. I keep everything 1080p and it has been a very reliable system. Sometimes I get comments 'it looks a little different than on my screen at home', but no major complaints and I assume that their setup at home is likely not calibrated or correctly accounting for ambient light etc etc.

In this case I was trying to use the IMS3000 HDMI input direct from a laptop, so that I could get 4k ProRes content with as few conversions as possible direct into the projector, as an attempt to mimic a calibrated color correction suite as closely as possible. I'll check the settings on the IMS, if it is set to rec709 and I set the laptop to output P3, that's probably not going to get me the results I'm looking for...

[Marcel Birgelen]

For HDMI, keep it to Rec709. Trying to get BT.2020 / HDR to output correct colors on MacOS X via HDMI is an absolute headache, especially if Apple hasn't made a decent color profile for it and it hasn't for the IMS3000 and certainly not for the specific projector you're using it with. If you want to mimic P3, you'd need BT.2020, because Rec709 simply doesn't cover DCI P3. Still, this route is an absolute headache.

Also, the Mac might recognize the IMS as a video sink device, in that case, it will switch over to 4:2:2 YCbCr. It's a pain to correct this with the builtin tools. Therefore, I'd advise you to consider BetterDisplay, a small utility allowing you to hard-switch the HDMI output to 4:4:4 RGB in 8 or 10 bit color depth in more recent versions. It allows also for some quick and easy global color corrections.

Unless you calibrated the entire chain from HDMI playback device up until the projector, don't expect the colors via HDMI to be perfectly color calibrated.

[Abraham Robinson]

Thank you Marcel!

for general use, I will continue to run everything 1080p/rec709 through the crestron DM chain into the projector DVI input, that has been good for 99% of my needs.

I was hoping that by removing that additional crestron components and going direct from laptop into the IMS I could control the variables enough to get properly color calibrated HDMI (or at least very close) for the rare times it is requested and converting to dcp in advance is not possible.

It looks like BetterDisplay might be an essential tool for that particular situation.

I am still admittedly a bit confused by BT.2020 vs SMPTE DCI P3 but really do appreciate the comments so far - thanks!

[Ryan Gallagher]

From the two tables Steve shared, it would seem the alt input on the ims3000 doesn’t even try to support P3 directly, so rec709 is the best you can get with an alt source unless you want to experiment with rec2020.

if color reproduction is that critical, I’d suggest converting the ProRes P3 to a DCP in DCP-o-matic as a method to get full P3 coverage. That may not work for you but seems like the only “real” path.

post screening rooms probably have a solution that does not involve hdmi or the IMS for direct playback with correct colors.

[Fraser Falconer]

Hello Abraham,
If you wish to use the DVI port on the SIB signal input board, and have login credentials to DCC in the Title setup for the DVI channel you can change the PCF file from DVI to HDTV colour space, or vise versa and that will solve your issue. You'll just need to swap it back after your event.

Cheers Fraser

[Ryan Gallagher]

Hello Abraham,
If you wish to use the DVI port on the SIB signal input board, and have login credentials to DCC in the Title setup for the DVI channel you can change the PCF file from DVI to HDTV colour space, or vise versa and that will solve your issue. You'll just need to swap it back after your event.

Cheers Fraser

HDTV color space is just REC.709 is it not? I would think that method would require being about to set it to BT.2020 to cover the DCI.P3 space. But DVI connection has a bandwidth limit that prevents 10bit color depth, which is needed for DCI.P3. (Which sounds like Abraham's target).

[Ioannis Syrogiannis]

I was hoping that by removing that additional crestron components and going direct from laptop into the IMS I could control the variables enough to get properly color calibrated HDMI (or at least very close) for the rare times it is requested and converting to dcp in advance is not possible.

It looks like BetterDisplay might be an essential tool for that particular situation.

Connecting directly to the IMS3000 from the booth may be a solution for carrying the sound through the IMS to the audio processor as well. Even though, DTS, for instance, is out of the question. That decoding would have to be done on the computer or media player connected*.

The catch, here, is the aspect ratio. You can't use the projector for an aspect ratio other than 16:9 (for HD), unless it's the 4096x2160p. Therefore, you would either need to use that and mask/crop accordingly, or make new screen files and presets for HDMI / Alternative content.
The latter way being more reasonable, since, if you lack the time to make a DCP, you won't have the time to crop the black bands that letterbox a Flat or Scope movie into the BluRay or DVD (?) container.

Subtitles, is another matter, I suppose you don't care about them, I won't get into it.

Edit:
*Unless you have a Datasat AP20 audio processor, for instance. Yet, the HDMI of that is 1.3, if you need to pass the video through the audio processor. I am assuming you are using the IMS for processing, so I am just writing this to be here.