Anyone who is familiar with the review pages here on AVForums will know how important it is for a display to produce an accurate [tip=GreyScale]greyscale[/tip] and colour [tip=gamut]gamut[/tip]. Sadly, anyone familiar with the review pages here on AVForums will also know how often manufacturers not only fail to provide an accurate image but also fail to provide the necessary controls to allow an accurate image to be calibrated. The VideoEq Pro is AVFoundry's answer to this problem and will allow anyone with the necessary tools an opportunity to accurately calibrate a display's greyscale and colour gamut. The VideoEq Pro provides ten point greyscale control coupled with a full six-axis Colour Management System that controls all three primary and all three secondary colours. Assuming your display has a wide enough colour gamut, after all you can't create what isn't there, then a professional calibrator will be able to create reference quality images using the VideoEq Pro. Using an uncalibrated display let's see just how good the VideoEq Pro is at producing an accurate greyscale and colour gamut.
Styling and Connections
Whatever its abilities as a video colour processor, I doubt the VideoEq Pro will be winning any design awards in the near future. This is clearly a good example of function over form with the performance of the VideoEq taking priority over any design aesthetic. With its brushed aluminium front and back panels, black metal sides and black screws in each corner the VideoEq Pro has a very utilitarian and slightly retro look to it. It is also very small, measuring only 11cm wide by 8.5cm deep by 3cm high. The reason for its diminutive size is presumably to allow users to hide the VideoEq Pro on the back of their display if they wish, thus keeping things tidy. On the front there are two bright LEDs that indicate that there is power, and that the link is OK, but these can be turned off. There are also LED lights to indicate whether you have chosen a Preset or a Custom mode, although it doesn’t tell you which of the preset or custom modes you have actually chosen. There are also two small black buttons for cycling through the four presets and the four custom modes. On the back there is one HDMI input and one HDMI output, along with a USB port and a mini-jack for the power cable. The VideoEQ Pro also comes with a 0.5m HDMI cable, a USB cable, the VideoEq Pro software, a quick start guide and a 5V power supply.
The VideoEq Pro isn’t exactly feature laden but at least what features it has are actually useful. First, and by far the best, is the automated calibration software when used in conjunction with CalMAN V4. This allows CalMAN V4 to take a series of performance measurements, calculate and program the optimal VideoEq Pro calibration adjustments and then re-measures to verify optimum display performance.
There is a 6-Axis Colour Management System that can accurately match a display’s colours to an [tip=IndStand]industry standard[/tip] system such as [tip=Rec709]Rec709[/tip] or Rec601. There is also full 10-bit processing for gamma and [tip=WhireBal]white balance[/tip] calibration.
The VideoEq Pro has a transparent input/output pass-thru of RGB, 4:4:4 and 4:2:2 colour space signals coupled with a HDCP compliant and transparent HDMI repeater design.
The VideoEq Pro also has custom presets that allow calibrated adjustments for up to four different sources and viewing conditions as four gamma curves, three white balance standards and three colour gamut memories.
Finally, as previously mentioned, there is an electrical 1/8” IR jack for optional simple universal remote control or for an automated system integration.
For the purposes of this review, I was using my Pioneer PDP LX5090 coupled with a Sencore MP500 video test generator, the Klein K-10 colorimeter and CalMAN V4. The LX5090 is our reference display here at AVForums and actually has its own calibration controls that are capable of producing a highly accurate greyscale and colour gamut on its own. However, in order to test the full capabilities of the VideoEq Pro, I deliberately chose the display’s Standard setting as opposed to the more accurate Movie setting, which is slightly artificial but would make for a more dramatic comparison. Obviously, under normal circumstances you would chose the most accurate gamma setting and colour temperature, as well as a wide colour gamut prior to using the the VideoEq Pro to calibrate the display’s greyscale and colour accuracy.
As you can see, unlike the Movie setting, the Standard setting has a rather inaccurate greyscale with blue tracking off the scale and red tracking at 10% below the target and green tracking at 15% below the target line. This results in a DeltaE that measures between 5 and 10 across the IRE steps, errors that are quite noticeable to the human eye as colouration in a greyscale test pattern. An accurate greyscale is very important as it forms the backbone of any image, which is why the combinations of red, green and blue at each IRE step need to be accurate to ensure a smooth transition from black to white. The gamma is also inaccurate, measuring above the target of 2.2 from 0 to 40IRE and below the target from 40 to 100IRE. We use 2.2 as a benchmark for gamma when reviewing a display, in a standard domestic setting at night, but you might use a higher (darker) setting such as 2.3 or 2.4 in a completely black viewing room or a lower (lighter) setting like 2.0 for daytime viewing. As measured, the current gamma is too dark below 40IRE and too light above 40IRE.
In conjunction with CalMAN V4 the VideoEq Pro offers an unprecedented degree of automation that goes way beyond anything I have seen before. As I mentioned previously, the best approach when using the VideoEq Pro is to select a picture mode as close to [tip=D65]D65[/tip] as possible, adjust the black level and white level for the best possible dynamic range and select a native or wide (fully saturated) colour gamut. You may have noticed that we always calibrate the greyscale first in our reviews and there is a valid reason for this; firstly the adjustments in the greyscale tracking are an additive process that will offset the entire colour gamut and secondly the adjustments will linearize the gamma so that when you adjust the CMS the changes will be correct at all luminance levels.
To calibrate the greyscale, using the automatic calibration software, you simply use the Interactive Greyscale function within CalMAN V4 and starting at 100IRE and working left to 0 you drag each white bar (representing total luminance) to the yellow line. CalMAN V4 will then automatically level the relative contributions of red, green and blue as evenly as possible. You can also, if necessary, individually adjust the red, green and blue bars by dragging each one to the yellow line. The DeltaE should ideally show readings below 3 from 30 to 100IRE but it may be difficult to get accurate readings below 30IRE, depending on your colorimeter. After adjusting each individual IRE step you should measure all the points again to see whether the changes have affected neighbouring points and, if necessary, make further adjustments. It really was that simple and the results were incredibly accurate with a DeltaE of less than 2 and in some cases less than 1 for most of the IRE steps.
Whilst I was very impressed with the Interactive greyscale function, and the results were very accurate, I also took a more ‘old school’ approach and calibrated the greyscale manually using the VideoEq Pro menu page. Here I can adjust red, green and blue individually at each IRE step until they are all measuring at the target line of 100. I could also adjust the gamma by changing the red, green and blue settings in equal amounts. In the original measurement I needed to lighten below 40IRE and darken above 40IRE so I add equal amounts of RGB to lighten the image and I subtract equal amounts of RGB to darken the image at different IRE steps. Once you have made changes you use the Save to VideoEq button to save the settings in the VideoEq Pro itself.
There is a function called Gamma in VideoEq Pro which is very useful for changing the overall gamma setting of your display. If, for example, you wanted to change the gamma from 2.2 to 2.3 you simply set the Measured gamma at 2.2 and the Target gamma at 2.3 and hit the Initialize Table button. The VideoEq Pro then does a series of calculations to adjust the luminance levels until they measure at the new target. If you have already calibrated your gamma accurately this is a quick and easy way of changing the gamma to suit different viewing conditions.
As you can see from the graph, the VideoEq Pro is capable of producing a greyscale that is, for want of a better word, perfect. The RGB tracking is measuring at, or very near, the 100 target from 10 to 100IRE and the DeltaE is less than 0.5 in most cases which is exceptional. In addition, the gamma is measuring at our target of 2.2 and the gamma luminance is spot on as well. This is a reference performance and the only other time I have seen greyscale measurements this accurate was using my Radiance XD.
Colour Gamut Performance
As I mentioned previously, it is best to choose a native or wide (oversaturated) colour gamut thus ensuring that the initial colour measurements on the CIE chart are outside the target points, this allows the processor to move the colours in to meet whichever industry standard you are calibrating for. Unfortunately, if the native colour gamut of the display is within the target points, then there is nothing the VideoEq Pro can do because it can’t change the base physical characteristics of the display. In other words, you can’t add what isn’t there. However, since the trend these days is for manufacturers to provide oversaturated colour gamuts, on their displays, it is unlikely that this will be a problem.
As you can see from the CIE chart above the Standard setting on my LX5090 is suitably saturated with the exception of blue which is already very accurate. For the other colours, however, there is a reasonable degree of saturation in both the Colour and Hue, although the Luminance (Brightness) is actually very good. The resulting DetaE for the three colours ranges from 4 to 10 but with calibration we would look to get this down to below 2.
As with the greyscale, there is an Interactive Gamut function which allows you to use the automated calibration software to set the colours. This time you start by dragging each bar of the Gamut Luminance chart to the target line. This may take a bit of time as the VideoEq Pro and CalMAN V4 work together to get a close to the target as possible, using multiple iterations. After that you simply drag and drop each coloured dot to the white square representing its target. Since each colour is truly independent it doesn’t actually matter which order to do this in but it is recommended that you start with the primary colours (R,G,B) and then do the secondary colours (C,M,Y). Once again I was very impressed with the level of accuracy that can be achieved using this software, the results were genuinely excellent.
As good as the automated calibration was, I felt that I could improve on it using a manual adjustments, just as I had for the greyscale. The CMS in the VideoEq Pro allows you to control the Luminance, Colour and Hue of all three primary colours and all three secondary colours independently of each other. This level of control should allow a professional calibrator to achieve near perfect colour accuracy. In terms of the CIE chart, the Colour control moves the coloured dot towards or away from the centre and the Hue moves the dot from side to side. The Luminance control affects the brightness of the colour but this isn’t represented the CIE chart because it’s only in two dimensions. Again, once you have made changes, you use the Save to VideoEq button to save the settings in the VideoEq Pro itself.
As the CIE chart shows, the colour accuracy is now reference quality with the errors in Luminance, Colour and Hue all being negligible with the exception of a minor blip in the Colour measurement of blue. In terms of overall performance, the DetlaE for each colour is now below 2 and in most cases below 1. As with the greyscale, the VideoEq Pro is capable of producing a colour gamut that is nearly perfect and, once again, the only other time I have seen a performance like this was using my Radiance XD.
With actual viewing material, the resulting image produced by the VideoEq Pro was excellent with the accurate greyscale, gamma and colour gamut really paying dividends. When watching material that I was familiar with I could see that the colours looked natural and realistic, not just with flesh tones but across the entire spectrum. I often find that people who are used to oversaturated images will complain that the colours look muted when watching a properly calibrated display. However, over time, they realise that the colours they are looking at accurately reflect what the director wanted you to see and if a specific colour should stand out it is because that was the intended effect.
The accurate greyscale was also evident with the image showing smooth transitions from dark to light and excellent shadow detail. The accurate gamma also allowed me to take full advantage of the LX5090’s already superb blacks as well as its impressive dynamic range. Overall, this was a very pleasing image and quite simply one of the most accurate that I have ever seen in terms of both colour and greyscale.
The custom settings were very useful here because they allowed me to switch between the calibrated and uncalibrated image which brought the differences into sharp relief. The different custom settings are also useful if you wanted to have different gamma settings for different viewing conditions or perhaps different calibrations for different displays.
- Reference 10-point Gamma and Greyscale control
- Reference independent 6-axis colour control
- Automated Calibration software in conjunction with CalMan V4
- Simple menu based control software
- Four custom presets
- Pure signal pass-through
- Direct IR control
- Boring and utilitarian design
- No scaling or deinterlacing capabilities
- Only one HDMI input so no HDMI switching capability
- Relatively expensive considering the above
AVFoundry VideoEQ Pro Review
The VideoEq Pro is an exceptional product that provides a staggering level of control over a display’s greyscale, gamma and colour gamut. In conjunction with CalMAN V4 it also offers a degree of automation that is as impressive as it is effective.
I can’t help but feel that the automated software now available through products like CalMAN V4 and the VideoEq Pro will soon allow anyone with suitable equipment to calibrate a display to a high degree of accuracy. Having said that, it is unlikely that a non-professional would have expensive equipment like the K-10, the MP500 or CalMAN V4 so, at this moment, it remains a moot point. Besides, no matter how good the automated software, it will never be as accurate as a manual calibration performed by a trained professional.
I do feel that at £1000 the aesthetic design of the VideoEq Pro could be better, it is rather unimpressive considering the cost but I also appreciate that AV Foundry is a small company operating in a niche market. However despite its price tag I think where the VideoEq Pro can add real value for money is in conjunction with a projector that doesn't have a proper colour management system. If for example you own a JVC HD550 the addition of a VideoEq Pro will result in performance that is comparable to the far more expensive HD950 or HD990. In this sort of example the Video Eq Pro offers a very cost effective method of upgrading the performance of your projector.
I should stress that anyone thinking of buying the VideoEq Pro needs to know that it is neither a scaler nor a deinterlacer so if necessary these functions will need to be done elsewhere, either in the display, the player, a receiver or perhaps another outboard processor. It also only has one HDMI input so you will also need to do all your HDMI switching elsewhere before connecting the VideoEq Pro. However as I mentioned earlier the VideoEq Pro is really designed to fit between the receiver and the display device so these additional costly features are unnecessary.
Ultimately these are minor points because ,at the end of the day, the VideoEq Pro is designed to calibrate the greyscale, gamma and colour gamut of a display to a reference level of accuracy and in this regard it does exactly what it promises.
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