New Test Gear and New Measurements Part I
In an ongoing effort to present the most comprehensive and accurate measurements possible, we’re revamping our video measurements and adding new test gear. In this first installment, I’ll look at the new gear. Next month, I’ll dive into a whole new measurement box, with several new measurements.
Sencore VP403C Video Pro Multimedia Video Generator
And after all that buildup, the reality is that the number of new tests the VP403C adds to our regimen is very minimal. It’s more of a facilitator—and a more accurate one at that. We have almost all of the patterns in this device elsewhere, but they’re spread out across several different discs and different formats. Now, instead of tediously navigating several different titles and chapters on Digital Video Essentials and the Silicon Optix Benchmark discs, it’s all in one place. What historically took upwards of 30 minutes can now take less than 10. So, I guess this part isn’t about increasing our accuracy; it’s more about saving me time. I can live with that.
The accuracy part deserves some explanation. During the last measurement revamp in 2004, my thought was to use DVDs for the majority of our testing. I based this on the idea that DVD via a DVD player was more indicative of what you’d see in the real world. You don’t use a test generator to set up your TV; you use DVDs. I still feel this way, but I’ve come to realize that this was hopelessly optimistic. First, I was always on the lookout for a DVD player that would output patterns perfectly (hence, the fact that we’re still using the Onkyo DV-SP800, which comes closest). Also, DVDs are rarely, if ever, authored perfectly. There were too many variables beyond my control. Seeing as I was looking for perfect patterns output perfectly, I was essentially searching for a test-pattern generator in everything but name. Thus, I’ve sacrificed some abstract feeling of realism for more real-world accuracy. So be it. In reality, the difference will be so minimal that any measurement equipment won’t be able to detect it anyway. The VP403C outputs all of its patterns as close to perfectly as I can verify (as you’d hope). The government uses Sencore products (now there’s a glowing endorsement), as do many manufacturers to test their own TVs.
There are more patterns on the VP403C than I have space to talk about, but here are the highlights.
This colorful pattern has two functions. With a blue filter, you use the lower section to set the TV’s color and tint levels. Then, with a red filter and a green filter, you can check the color decoder’s accuracy. It’s essentially an easier-to-use version of the old-fashioned color bars.
This pattern vastly simplifies the process of setting up a digital TV’s contrast and brightness controls. It’s hard to make out with the image printed here, but in the middle of the 100-percent-white bottom portion is a 97.5-percent-white box within a larger 95-percent-white box. The idea is to set the contrast as high as it can go without crushing whites, which would make these boxes disappear. You do the reverse with the top portion of the image to set the brightness control without crushing blacks.
This pattern is even better for getting the brightness controls set perfectly. The inner rectangle flashes between 0 IRE and –4 IRE. The trick is to lower the brightness until you can’t see it flashing anymore.
You can use this pattern for several things, but the most important for us is the one-pixel-on/one-pixel-off pattern on the right side. We’ve been checking if 1080p TVs can do this absolute resolution with both HDMI and component for some time; this just makes it easier.
The top of this pattern is the same as the Multiburst. The bottom, with all its single-pixel black lines, allows you to fine-tune the sharpness control. Set it too low on some TVs, and the image will appear soft. On most displays, the Sharpness control is merely an edge-enhancement control. This allows you to quickly test the amount of edge enhancement and to see what all the “fancy” enhancement circuits on many TVs do.
The VP403C outputs everything from composite all the way up to DVI/HDMI and everything in between. It does 480i all the way up to 1080p/60 and 1080p/24. This makes it faster and easier for us to determine which inputs can accept these formats. In this capacity, and with the myriad of patterns, I used the Sencore to help set up the TVs in our Face Off this month.
This is only part (and it’s the less interesting part, actually) of what the VP403C can do for us. Next month, we’ll see how it interacts with another new addition to our lab to completely change how our measurement box looks.