Murideo Prisma Video Processor Review

But there are always compromises and ultimately, you have to settle for a few flaws to achieve the best possible picture. If you want the ultimate in precision and accuracy, an outboard video processor is the only way to go. The Murideo Prisma Video Processor features 3D Cube look-up tables (LUTs) and advanced image enhancement courtesy of a 5×5 unsharp mask feature.

Today I’m checking out the Murideo Prisma Video Processor. Over the past decade, I’ve calibrated and reviewed hundreds of flat panels and projectors. In most cases, peak performance was dependent on their ability to be calibrated using controls provided by the manufacturers. Rarely does any display come from the factory in optimal form. Some adjustment is needed to maximize color accuracy and image quality. Since the user is at the mercy of what’s provided in the on-screen menu, that adjustment often requires compromise. Color management systems are a particular challenge for calibrators. Many of them don’t work properly or only adjust a few color points, leaving much of the gamut off the mark.

• Darbee
• Lumagen

The only way around this is to use an outboard video processor. Products from companies like DVDO and Lumagen enable far greater control over color, gamma, grayscale, and video processing. In recent years, a new calibration method has come into vogue, that being the 3D color cube. In a nutshell, a 3D cube look-up table adjusts the hue, saturation, and luminance of potentially thousands of color points to achieve accurate results in all content regardless of makeup.

Murideo calls the Prisma a video color enhancer but at its heart, it’s a video processor. Its main appeal is that it supports automatic 3D color cube calibration. That means you can point your meter at the screen, interface the Prisma with an app like CalMAN, press the GO button, and walk away. Once complete, the LUT is stored in the unit and becomes responsible for that display’s image. In the past such products commanded hefty prices but the Prisma sells for only $999, far less than its competitors. Let’s take a look.

Before I get into the Prisma’s many benefits, let me tell you what it won’t do. First, it can’t switch multiple video sources. It’s designed to accommodate a single source component and a single display. Second, it isn’t something you can simply plug in and enjoy. While it is equipped with six presets, you won’t really derive its full benefit unless you create custom LUTs for your particular signal path. Lastly, the basic Prisma doesn’t support Ultra HD. It’s 1080p-only. But wait, it does support HDR. If you’re wondering about HDR10 and Dolby Vision, the Prisma does not pass those formats. It creates its own HDR enhancement from standard DVD and Blu-ray discs. You’ll still need an HDR-capable display to see the result but currently, the Prisma is the best way to up-convert existing SDR content.

From the front, the Prisma has almost no identifying features save a silk-screened logo. There are no lights, buttons, or any attempt at styling whatsoever. To avoid scratching your shelving or whatever you might place the box on, Murideo has included four stick-on rubber feet in the box.

If you’re wondering about control, that is accommodated via infrared through a stick-on receiver. It plugs into the back panel and can be installed on the front of the box or elsewhere within range of the wire. The Prisma ships with a tiny credit-card (actually, it’s much smaller) remote that loads LUTs and controls the amount of PrismaVue enhancement in the image. Not only is it easy to lose track of, it feels cheap with its bubble-type buttons. I realize it won’t see a lot of use but a larger wand with a backlight would be a nice upgrade.

Around back is the all-important jack panel. Starting at the left we have an IR input followed by Ethernet, HDMI Out, HDMI In, and Power. Green status lights indicate power-on, signal in/out status, and network.

The Ethernet port is important because it enables control for both the Prisma’s browser interface and the LUT-creation software. CalMAN versions 5.6 and later can directly address the box to create tables automatically. The Prisma generates its own patterns so all you need to do is set up your meter and set it loose. Alternately, you can use Light Illusion-Light Space or Argyle to do the same thing.

The Prisma has no on-screen menu so any settings changes have to be accomplished via remote or through the unit’s IP interface. On the bottom is a unique ID that you simply type into your browser’s URL window. The processor can be connected to your local network or directly to a computer via an included Ethernet cable. You can change presets (LUTs), adjust the PrismaVue enhancement, check signal status, and display patterns in any size and color. It’s simple but everything you need is there. In most cases, once you have the unit installed and your calibration completed, you’ll never touch it again.

Speaking of PrismaVue, that is the Prisma’s one nod to actual video processing. All its other functions are devoted to color management. PrismaVue is described by Murideo as a 5×5 unsharp mask. Its method and appearance are similar to DarbeeVision’s DVP-5000S which I reviewed about a year ago. You can control the amount of enhancement with the plus and minus buttons on the remote.

Installation is straightforward whether you’re equipped with calibration gear or not. Once you’ve made all the connections, plug in the DC power cord and fire up your laptop. Type the ID into your browser’s URL window to confirm communication with the Prisma. Turn on your selected source component and display to complete the startup process. Make sure to plug in the IR receiver if you plan to use the remote. There are no on-screen indications other than a change in picture when you switch between presets. I realize this is an installer-oriented product but some simple messages would be nice to indicate which mode you’re in and what level of PrismaVue enhancement is currently in use.

Before moving on to the calibration, I need to point something out. While the Prisma is hardware-compatible with any display, there are instances where its color management will fall short of optimal. Every HDTV and projector has a native color gamut. That is the maximum saturation level allowed by the imaging chips, LCD panel, OLED phosphors, or DLP color wheel. It is important that this gamut be at least equal to if not greater in volume than the standard you’re going for.

In the chart above, Rec.709 is indicated by the squares and the display’s actual measurement is shown by the dots. Notice that the dots don’t quite get to the outer perimeter for blue and red. When the Prisma does its thing, it can fix the hue error in red but it can’t add saturation that isn’t there to start with. If a color is over-saturated, it can be reduced to hit the target. So for optimal results, choose a display that has a wider-then-standard gamut.

I used an Oppo BDP-93 Blu-ray player along with my trusty reference Anthem LTX-500 projector. It’s a great candidate for a video processor due to its large color gamut. It has far more green than is necessary in Rec.709. It also has gamma issues that are tough to fix with the supplied multi-point editor. You can adjust the individual brightness levels but they interact so badly, it becomes a long and frustrating exercise to achieve BT.1886 or a clean 2.2 power function. I selected an unused picture memory and set it to factory defaults before creating the LUT.

I chose the Spectracal C6 color meter because it doesn’t need a dark measurement every 10 minutes like the i1 Pro. I profiled it to the spectro first to establish a proper color offset, then let the C6 complete the process.

Calibration with the Prisma is automated but some preliminary work is required if you use the CalMAN 3D LUT workflow like I did. Every step is explained in detail so in theory, a non-professional could make it work. But I recommend hiring an experienced installer if you plan to integrate a one of these boxes into your system. It’s not really a consumer-friendly product given its lack of an on-screen menu and rudimentary network interface.

Since my projector has been calibrated many times, I chose an empty memory slot from its picture modes and reset it to factory defaults. That takes the Anthem’s CMS out of the equation as well as its custom gamma editor. I chose a color temp preset close to D65 and gamma A which averages around 2.03.

Here is the pre-calibration chart showing a color-checker along with RGB levels (white balance) and average errors.

The Anthem’s over-saturated primaries are easy to spot, especially at the green end of the gamut. Though only some of the colors are near-target, the average error is 4.4dE. This isn’t too bad but in actual content, greens look very un-natural and reds are far too warm. When I reviewed this projector back in 2009, it required a firmware update so the CMS could tame its huge color gamut.

There are multiple calibration options available in the Prisma. The deciding factor is how long you wish to devote to the process. It can take up to 10,000 measurements which would require 8-10 hours. I performed a 1000-point calibration which took just over an hour. During that time, I took a break. Once started, there is no user-intervention required.

After loading the LUT, here is the final result.

The improvement is obvious and significant. The color-checker is pretty much perfect as is the grayscale tracking. I specified a gamma curve conforming to BT.1886 which is roughly equivalent to 2.4. That would have been nearly impossible to achieve using the Anthem’s built-in editor. And its CMS does a fine job dialing in the 100-percent color saturation points and luminance levels but it can’t adjust any targets beyond those. So how does it look in practice? Read on…

I chose my favorite color-rich films for this review like Seabiscuit, The Incredibles, The Ten Commandments, and for a look at difficult dark material, Prometheus.

First off, the color is exemplary. When the entire gamut is precisely dialed-in, detail levels climb accordingly. Every subtle shade and nuance is clearly visible. Titles with heavy film grain or stylized textures still pop as much as the more digitally-scrubbed movies of today. Of course, if the original material is lacking in focus or vividness, you’ll see that too. If you prefer neutral components as I do, the Prisma is a perfect addition to any video signal chain. There is really no better way to see color that precisely matches what the creators intended.

I often talk about the importance of accurate gamma in my display reviews. Matching luminance curves from content to display is the key to everything, contrast, color saturation, color accuracy, and detail-rendering. My LTX-500 has always run too bright in that metric and as a result, the image can look a little flat. Only its tremendous dynamic range (static contrast is around 15,000:1) saves the picture quality.

Here I thought BT.1886 might have been the wrong choice for my projector. While everything had the expected 3D-like quality, the overall picture was a little dark. That’s purely a function of the Anthem. It just isn’t very bright. Halfway through my evaluation period, I redid the calibration with a traditional 2.2 power gamma curve. That improved the image considerably. Owners may want to experiment with multiple presets. The Prisma has enough memory to store 10 LUTs so you can tailor the unit to best suit the content at hand.

The other feature I enjoyed experimenting with was PrismaVue. Murideo refers to it as a 5×5 unsharp mask. In practice, it works much like the DarbeeVision processors. You can adjust the level of enhancement with either a slider in the network interface or with buttons on the remote. At around 75%, it provided an ideal level of sharpness without ringing or other artifacts. And once you find your sweet spot, there’s no need to tweak further. I didn’t touch it after the initial adjustment. The Prisma is the first product I’ve experienced that offers the same level of improvement in clarity as Darbee.

My final takeaway after a few weeks of use was that the Prisma definitely improved my already-excellent LTX-500. There’s no question that a no-compromise calibration is the best way to maximize performance from any display.

THE MURIDEO PRISMA VIDEO PROCESSOR is one of the least-expensive ways to add perfect color to most video signal chains.

For picky video-philes, there is no better way to pursue color perfection than with a LUT box like the Murideo Prisma Video Processor. Its ability to auto-calibrate thousands of gamut points means that no matter what, your display will reproduce the colors exactly as they exist in the source material. It turns any projector or flat panel, with a sufficiently large color gamut, into a reference-level component.

From a performance standpoint, the Prisma has no flaws. Once properly set up and calibrated, it provides the best possible image accuracy. You’re only limited by the native gamut of your TV or projector and its native contrast. My only complaint is that it lacks the refinement necessary to be a consumer product. At $999, it’s a relative bargain so my recommendation is to take the money you’ve saved over that more-expensive video processor and hire a professional to install it for you. Having the proper tools for a LUT calibration is a must and an experienced technician will have an easier time navigating the interface and optimizing its performance.

If you simply must have the highest level of color accuracy and image quality, the Murideo Prisma is almost a requirement. No display’s built-in tools can match its capabilities. And its price is pretty attractive too. The Prisma Video Processor earns my highest recommendation.