Whites clipping at level 248

[Sean McKinnon]

So... when you "shoot colors" the projector uses that information (that you enter based on uncorrected color readings reflected from the screen) to create a file of "measured color" values. Each format (or macro, or channel, or whatever you want to call it) should have a target color file attached that tells the projector what the measured colors "should" be for that format. Using math the projector makes corrections based on the measured color data you entered to match the target color file. I have run into some technicians that think you need to shoot colors for every format and this is uncorrect. Since the measured colors are uncorrected the same measured colors file is used for all formats. Verification can be done for individual formats.

You mentioned that you are using the HDMI inputs on the Doremi IMB. In this case you should have the channel in the projector set for DCI_XYZ_314_351 instead of rec. 709 as the IMB converts the HDMI input to DCI colorspace. In device controller on the server you can select one of many source colorspace's usually this is left in "Auto" but I have seen that cause an issue before. Unless you have a reason to I would consider getting a DVI adapter and using the DVI inputs on the PIB in which case the projector would use a channel set up for that input with a target color file for rec. 709 and let the projector do all of the color correction.

[Guy Burns]

Update: I was able to correct the missing whites by adjusting the Contrast setting on the Oppo.

When I simulated the missing Christie CP2220 whites on my W7000 at home (by purposely de-calibrating it), I was able to correct by adjusting Contrast down by only 1 notch (of the sixteen available). But when I corrected at the cinema, I had to drop Contrast by 13 notches. Big difference there. But the missing whites (248-255) did become visible.

Thanks for all the feedback and suggestions.

[Mike Babb]

Lots of variables but here are a few points from film festival experience:
Using the projector DVI is usually more reliable than passing through the IMS/IMB in my opinion. If you have the channel setting correct, you should get what you want. But then Bluray settings also matter a lot.

I believe it matters whether you use HDMI 1 or HDMI 2 out on an OPPO and HDMI1 is more reliable. Disconnecting the HDMI cable from the projector and replugging can make a difference, and if you are using a monitor on the other output it can impact the image.

This setting seems to be critical to getting proper levels
RGB PC Level – The HDMI output uses RGB color space and expands the signal range. The expanded signal range is suitable for personal computer (PC) displays. Some TVs are designed to be used as a PC monitor, and expect signal in expanded RGB range when the DVI input is selected. For these displays if the video signal uses the normal RGB range, the black-white contrast will be reduced. You can set the player to use the RGB PC Level output and restore proper contrast.
Otherwise the blacks can be grey.

If you run it through the IMS/IMB, be careful what you change in there, there are some settings for color space conversion which may or may not get you what you want depending on the projector settings, AND I found they can impact the DCI colors if you change and save them. This goes back many years and has perhaps been improved with software revs.

[Leo Enticknap]

HDMI into modern IMS type media blocks is a lot more reliable now than it was even a couple of years ago; progressive firmware improvements have delivered big benefits. In particular, the IMS3000 and SR-1000 will automatically detect the input color space, convert it to DCI XYZ, and send it on its way to the ICP, with 99.9% accuracy, in my experience. The Alchemy and ICP-D are pretty good, too, and all will pass LPCM audio embedded within the HDMI stream through to the AES outputs.

The reason many commercial theaters prefer using the DVI inputs on the CCBs of Series 2 projectors is that the automation is a lot easier doing it that way, than telling an IMS to switch to HDMI mode. With Dolby and Barco in particular, the API commands needed to do this mean getting involved with hex codes, checksums, and that sort of stuff.

[Steve Guttag]

There are gotchas on the audio via HDMI...if you are a 7.1 theatre, back surrounds will come out of channels 7 and 8 so, unless you do custom audio routing, your ADA system will be getting the back surrounds (and vice-versa).

I have found the Barco EDID seems to confuse many A/V vendors and have had problems getting things like HDBaseT to play nice with it. Extron seems to do okay. Atlona, not so much. I've seen a recent IMS3000 not realize the right color space so they can still be fooled. I've seen the HDCP blinking so bad it looks like a turn-signal going off. Hearing that a screen blanked out and came back (with or without sound is not as uncommon as I would like. Again, I generally don't have problem with Extron gear getting the EDID and HDCP part right and their matrix switchers are both sink and source...which helps a lot on HDCP. Most projectors do okay (and IMB/IMS) with DIRECT connection and that is what they are tested with. Older DCIO-H from QSYS can also cause HDCP conflicts (any unit sold before the fall of 2020. Again, if you are plugging in directly and are using HDMI 2.0...it can do okay. Sometimes, things need rebooting. QSC seems to have addressed the problem on the last revision but it is a hardware/firmware change...not something that is updated via a normal QSYS update.

In short HDCP and EDID make consumer to Digital Cinema a nightmare. Anyone that does this much will tell you..."convert to DCP" if you have the time. That ALWAYS works. That said, we continue to put in HDMI systems, in cinemas. Mostly with Extron 4x2 switchers and various forms of audio decoding (DCIO-H, Extron's new SSP 200, IMS/IMB and direct analog audio if the Blu-ray player is capable. We are starting to standardize on Tascam's BD-MP1 and BD-MP4K players (1U tall, direct analog decode up to 7.1 with 2-channel mixdown). We have one site with a customer supplied "goFaco" 4x4 switcher (think Amazon). So far, it seems to be working though the switches take longer than Extron or Crestron "quick switch" type switchers. I did make a QSYS driver for goFanco switcher, if anyone needs it.

The next hot-lick thing happening in HDMI video and switching is AV over IT stuff like Visionary Solutions where one just buys end points and has sufficient IT infrastructure to handle the bandwidth. But, with something like that, you have a big a matrix switcher as you could possibly want (just buy the endpoints you need) and they are reported to not have the EDID and HDCP issues. That is likely the future, if not the present of HDMI control and distribution.

[Leo Enticknap]

We use Visionary Solutions D4100s and E4100s a lot. You need switches that can handle a lot of bandwidth (and PoE), and there is a known issue whereby they can crash if you're feeding Dolby TrueHD audio through them (so set any DVD/BD player to be used with them to output LPCM only). Apart from that, they work great. We generally use Kramer scaler/switchers in our new installs, and have found that they play nicely with Dolby, GDC and Barco media blocks; and that for an existing system that is having problems adding a new HDMI device, an HDFury is our preferred fix. I don't have any experience with Extron stuff.

[Steve Guttag]

I've had mostly good experiences with Kramer stuff. Back in the RS232 days, they have (and still have) the VP-14 that essentially is an RS232 hub (like having a network switch, but for RS232)...it works really well. I'm curious which switchers (or scalers) you use by Kramer. We, generally, want two outputs (program and preview and having 3-4 outputs is a plus since then I can send a dedicated line to an audio decoder...be that the DCIO-H or something like the SSP 200...which we just got our first one in). The fewer things HDMI has to go "through" the better. Repeaters have to send the HDCP keys along and that is a prime place for there to get a momentary blackout on screen when the HDCP check happens.

A Blu-ray player that seems to play real well with others is the Sony UBP-X1100ES. It's rackmount is dumb (sticks out 1/4") and they are stingy with their API...particularly Ethernet but it, so far has done rather well with the various EDIDs I've thrown at it. If could get a reliable feedback from it, I'd do a driver like I did for the Tascam BD-MP4K.

[Marcel Birgelen]

For anything not involving HDCP, like notebooks, we recently switched to using HDMI-to-SDI converters for anything that needs to bridge a certain distance. HDMI to SDI converters are cheap and the setup seems to be highly reliable. Maybe, in the future we see some reliable, low-latency "over-IP" default options on devices, like NDI, until then, we're stuck with transporting HDMI...

We're currently using a BlackmagicDesign Teranext AV box as the swiss-army knife format conversion/scaler/formwat switcher, it fits neatly into your rack as 1U unit. It allows remote-control via Ethernet and it supports both HDMI 2.0a and SDI upto 12G. It also comes with a small built-in monitor screen which is really neat.

For any EDID related issues, we have a bunch of HDFury devices to remedy the issue. We also have a bunch of no-name Chinese HDMI splitters, which are compatible up to HDMI 1.4a, which magically make HDCP go away. When we bought them, we never asked for that feature, we just later found out that that's the way they operate.

[Steve Guttag]

The problem I find with using magic boxes to fix things on a case-by-case basis is that then you need a group of trained people to know which box to use in particular situations. This also means, as staff changes, that the information has to also passed on (and understood). All of this as the landscape of moving the signal itself changes (e.g. HDMI 1.3 moves to HDMI 2.0 with HDCP changes along the way). There are a couple of our sites where they will have such staff. Most fo the time though, it is just the hapless theatre manager that is scheduled that night so whatever gets plugged in just has to work. With the Extron stuff, that seems to be the case. I can set the EDID so the device that walks in see what it is up against and the infrastructure can transport it. I minimize the use of repeaters as much as possible (they are where most EDID and HDCP issue crop up.

Most digital cinema projection equipment really is only designed around plugging the device directly into to projector and possibly dealing with the sound separately (e.g. the DVI port gets you the picture, what you do with the sound is up to you). I've seen MANY people use a Toslink or coax cable to get the sound into a CP750 or even just straight up analog stereo via Non-Sync. Back in the days of Oppo, we'd use the analog outputs into the CP750's analog inputs. The current Tascam players give us that option too though the CP750 is no more. QSYS' DCIO-H is a near-miss because it doesn't support Dolby True-HD and it comes up (it does support Dolby Digital Plus). The Extron SSP 200 supports it all (up to Dolby Atmos and DTS-X) but does exceed the cost of many people's alternative content system so it isn't for every installation.

[Carsten Kurz]

Let me say AP20/AP25. Best decision we ever made, especially with respect to alternative content.