A cost effective way to get your colours picture perfect
What is the Murideo Prisma?The Murideo Prisma is a video processor that is designed to offer a lower cost solution to colour calibration. It's a single-input single-output device that includes 17x17x17 3D Cube Look-up Tables (LUT) and the PrismaVue algorithm for picture enhancement. It supports a video bandwidth of 10.2 Gbps, along with interlaced and progressive video formats up to 1080p60 4:4:4 12-bit but doesn't support 4K Ultra HD. The Prisma is ISF certified and comes with pre-programmed LUTs, along with the ability to create your own LUTs using CalMAN calibration software and a built-in window pattern generator. The Prisma comes with a remote control but also includes WebOS, so it can be controlled from any device with a browser. The cost is around £900 based upon current exchange rates (December 2015) and with VAT/import duties added, so does the Prisma do enough to distinguish itself in a niche market.
Design, Connections and ControlThe Prisma is the epitome of minimalist design and is, quite literally, a black box. Of course the Prisma is designed to be unobtrusive and the idea is that it sits in amongst your other equipment, quietly doing its job without drawing attention to itself. There's nothing on the front, aside from the logo, and all the connections are at the rear. The Prisma measures 135x30x105mm (WxHxD) and weighs in at 385g.
The Prisma keeps it simple with a small black box that can be unobtrusive in your equipment rack.
The connections consist of an HDMI input and an HDMI output, along with an Ethernet port, a connection for the IR receiver and a socket for the provided power adapter. There are little lights that indicate when a display and a source are connected, along with another light to indicate that there is power present. And that's it, so clearly the Prisma is intended to sit between a source and a display or, more likely, between an AV receiver and a display.
There is a small remote control included, although to use this you'll need to attach the provided IR receiver. Once you have done this you can immediately control the Prisma remotely and the IR receiver means that you position the unit itself out of sight and still be able to control it. However the processor also includes WebOS, so as long as it is connected to your home network, it can be controlled by any device with a web browser.
FeaturesThe Prisma has been designed to fulfil a specific role whilst also keeping the costs down, so although it isn't feature packed it does include everything you need to configure and control it whilst also being able to place it out of the way amongst your other equipment. In terms of accessories the Prisma comes with the already mentioned IR remote control and IR receiver, as well a 46cm high speed HDMI cable and a 2m Ethernet cable. There's also a 12V DC/AC power supply that works with 110-240 VAC but uses a US-style plug, so you'll need to buy an adapter. The Prisma only draws 3W of power, so you can happily leave it powered up without worrying about destroying the planet.
In terms features the Prisma comes pre-programmed with 6 LUTs, so you can use it right out-of-the-box without the need for any advanced calibration. It allows for colour calibration using a 17x17x17 3D Cube LUT and is compatible with CalMAN, Light Illusion - LightSpace and Argyll, allowing you to choose your own LUT builder engine and colour meter. The Prisma has built-in window patterns so there's no need for an external pattern generator when running calibration software. There is 1Mb of local memory for storing up to 50 LUTs, which means you can create multiple looks and modes, and the Prisma uses standard .3dl files for easy conversion to different formats.
The Prisma is aimed at both the professional and the enthusiast, so it can be used for video production, allowing you to load common 3D LUTs for reproducing specific looks and adjusting raw footage colours. It can also be used for digital signage, allowing you to match colours between panels or for accurate display and colour matching. For the enthusiast you can calibrate the colours on your display using 17x17x17 3D LUTs and there's also the PrismaVue function (5x5 Unsharp Mask in RGB space) which can be used to enhance picture details and reduce compression artefacts. The Prisma supports video bandwidths up to 10.2 Gbps, along with all interlaced and progressive video formats up to 1080p60 4:4:4 12-bit.
The single HDMI input and single HDMI output means that the Prisma is designed to sit between a source and a display but if you're using an AV receiver then clearly more than one source can be connected indirectly. In terms of control there's the provided IR remote but the Prisma can also be connected to your local network with a DNS server via Ethernet. The Prisma includes WebOS which allows you to load LUTs, as well as perform basic and advanced control of the unit from any device with a browser. There are five control screens in total, which we'll go through in more detail in the next section. You can use the USB HID interface for firmware updates and direct API for easy software/automation integration.
Configuring and updating the Prisma is simple and it supports CalMAN to create new 3D LUT files.
Setup & OperationThe Prisma is very easy to set up, all you need to do is connect the source to the HDMI input and connect the display to the HDMI output - the small lights will indicate that the signal is being received and passed on. Then you need to connect the IR receiver so that you can use the remote and obviously plug in the power adapter. If you want to, you can start using the Prisma immediately by selecting one of the pre-loaded LUTs (Movie, Game, Sports, Animation, B&W and Graphics) and experimenting with the PrismaVue image enhancement feature by turning it up and down.
However to get the most out of the Prisma you need to use the full menu system which, thanks to WebOS can be accessed by connecting the unit to your home network using an Ethernet cable. Then you can simply control the Prisma using any device with a browser. If you're using a PC the address to use is http://prisma-xxxx and if you use a Mac it's http://prisma-xxxx.local where xxxx is the serial number of your unit, which you'll find on the bottom. Once you have accessed the various menu screens, you can then control the Prisma in more detail, configure it and even update the firmware.
The first screen shows the preset selected, the Cube LUT selected and the PrismaVue control. On this screen you can select Cube LUTs created using CalMAN and then upload them to the Prisma in order to use the new Cube LUTs. The second screen shows demo modes that reveal the effect that the Cube LUT or PrismaVue is having on the image. The third screen shows details of the input and output signals, whilst the fourth screen allows you to manually select the various window patterns. The final screen shows details about the unit itself and allows you to select and upload files in order to update the firmware.
Murideo Prisma Video Review
PerformanceThe big selling point of the Prisma is that it offers the chance to create 3D Cube LUTs and thus you can accurately calibrate the colours on your display to a degree that was only previously possible with far more expensive processors. Of course the Prisma does have certain limitations when compared to many other video processors but then it is designed to hit a certain price point. First of all there's only one input and one output but if you have an AV receiver and only one display that shouldn't be an issue.
Secondly the Prisma isn't a deinterlacer or scaler, so whatever video resolution the processor receives is the same one that it outputs. Since the majority of our viewing content is high definition these days, the lack of any deinterlacing or scaling also shouldn't be much of an issue and if the source is lower resolution, your display will probably be quite effective at handling the deinterlacing and scaling itself. The maximum resolution supported by the Prisma does reveal another issue, in that it doesn't support either of the 4K resolutions, which obviously limits its future usefulness.
The Prisma is also limited to calibrating colours to the current industry standard of Rec.709 and whilst this covers the vast majority of content, it does limit the processor's future effectiveness because the standards are changing. It seems likely that future Ultra HD content will use the wider DCI colour space, which the Prisma doesn't support. However if you're not planning on upgrading to Ultra HD any time soon, then the lack of 4K and DCI support on the Prisma won't be an issue. Finally there's no support for 3D content but if you have dual outputs on your Blu-ray player or AV receiver that won't be a problem either.
We used the Prisma to calibrate the colours on our Full HD and decidedly 2D Pioneer Kuro and we also used it to calibrate the 2D image on our JVC X3. The latter doesn't have a colour management system and whilst the former does, it is notoriously rubbish, so the Prisma gave us a chance to accurately calibrate the colours on both devices. It's worth remembering that the Prisma is calibrating the native colour space of your display, so if it is restricted when compared to Rec.709 then the processor can't add colours that aren't there but it can certainly work within the colour space available. Most modern displays have colour gamuts that are at least as big as Rec.709, so the Prisma should be able to deliver an excellent result.
So what is a 3D Cube Look-Up Table? Well a 3D LUT places colour and luminance (brightness) in a three-dimensional space (often referred to as a cube) that’s much more representative of how colour works in the real world. From the point of view of colour reproduction, a 3D Cube LUT is much more useful for capturing and relaying the complex colours within a transfer than a one-dimensional LUT. The Prisma uses a 17x17x17 point cube or in other words there are a total of 4,913 points that it can analyse within that cube. This allows for a far greater level of accuracy than is possible on most colour management systems found on modern displays, which tend to use one-dimensional LUTs.
The result is that the Prisma can deliver a remarkable level of colour accuracy, giving the images on your display far greater realism throughout the entire three dimensional colour space. We created custom LUTs for both the Kuro and the X3 using CalMAN and our Klein colour meter and the results were very impressive. After calibrating the greyscale and gamma, CalMAN runs thousands of measurements that can take up to thirty minutes or longer in order to calculate precise adjustments to calibrate the colour performance. To get the best results can be very time consuming, with the option to either choose how many reading to take or how long to take readings for but there's also the 'lightning' option, which can deliver a quick and dirty calibration in about five minutes.
The Prisma also includes the PrismaVue picture enhancement algorithm which is designed to help improve compressed video content. In the manual for the Prisma, Murideo accept that whilst the video purist might not want to use the feature, not all the digital content that we watch these days is of the highest quality and is often heavily compressed. So if you're watching a high quality source like Blu-ray, then we would recommend leaving PrismaVue off but for content that suffers from compression artefacts, then it's certainly worth experimenting with and we found it very effective.
The Prisma can deliver incredible levels of colour accuracy that can take your display to another level.
- Impressive colour accuracy
- Excellent calibration controls
- Easy to setup
- Simple to control
- CalMAN support
- Attractive price
- No deinterlacing or scaling
- Doesn't support 3D, 4K or DCI
Murideo Prisma Video Processor Review
Should I buy one?
The appeal of the Murideo Prisma will very much depend on your needs and your budget. To a certain extent the little black box is aimed at post-production facilities and high-end installers but it's also useful for the enthusiast. So if your main interest is Full HD, rather than Ultra HD, and 3D isn't a big priority, then the Prisma has a lot of potential. Murideo has certainly succeeded in keeping the device simple to set up, inconspicuous to install and easy to control. It also comes with some handy accessories and the price is attractive, especially when compared to much of the competition. The ability to control the Prisma via WebOS is also useful and we controlled the device from an iPad whilst running it with CalMAN on our laptop.
It does have some imitations but it delivers pre-installed 3D Cube LUTs as well as PrismaVue image enhancement for use with compressed video material, so the device is 'plug-and-play'. Of course the main reason for buying the Prisma is to create customised 3D Cube LUTs for your display and here the little device really delivers. You'll need dedicated calibration software to take full advantage of the Prisma but the built-in pattern generator means that the entire calibration process is totally automated and the results are spectacular. You can create and save different LUTs for different displays or certain content, making the Prisma very flexible, and any perceived limitations are easy to circumvent, making it an excellent colour calibration solution.
What are my alternatives?
Years ago we reviewed the VideoEQ by AVFoundry, which was in effect a predecessor to the Prisma and at the time it offered a level of greyscale, gamma and colour calibration control that was unheard of at the price point. Technology has moved on and the Prisma represents the latest in terms of the evolution of colour calibration with 3D LUTs for unprecedented colour accuracy. In terms of current competition, the obvious alternative to the Prisma is the eeColor 3D LUT Box which retails for about £260 once you take into account VAT and import duties. The eeColor offers an almost identical set of features and specifications, with a massive 65-point 3D LUT, although once you go past 17-point 3D LUTs, the law of diminishing returns sets in. The Murideo Prisma remains worthy of a recommendation based upon its features and performance but it is aimed primarily at the professional market. So in terms of pure value it's hard to fault the eeColor 3D LUT Box and, given both are limited to Full HD and Rec.709, it would seem to be an ideal choice for enthusiasts.
Processed Picture Quality8
Value for Money9
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