The Secrets Blu-ray Player HDMI Benchmark - Part 2


Test 1 Summary and Results

Using the Auto-Calibration feature of ChromaPure and the Lumagen Radiance, you can see that the display now has fairly good grayscale tracking, near perfect gamma, and very accurate color decoding. Other than an issue with Blue, all errors are below what should be easily visible. When we run the calibration report using Player A, we can see that the measurements are very close to those of the Lumagen Radiance. The difference in them is small enough to easily be meter error, and had I used a setting of 10 instead of 3 in measurement smoothing they might have been even closer, but it would have been a much longer testing period.

When we look at Player B, we can see three main issues: The Gamma is now much higher than it should be, the peak light output (Y for 100% white) is much lower, and the dE of the grayscale is higher. The most noticeable change is the Gamma value, which is almost off the chart. What is happening is that Player B is incorrectly adjusting the Luminance value of the data, and pushing what should be an accurate Gamma up to a much higher value, which will result in a much darker, flatter image overall. The other issue is that the peak white value has been reduced, so that the brightest whites won't be as bright as they should be.

This incorrect Luminance also shows up in the color decoding, as Luminance (Y in YCbCr) is incorporated into all the colors when it is decoded into RGB. If the Luminance is off, the value of the RGB values is going to be incorrect, and we can see that in these charts. Player A and the Lumagen are nearly identical as colors go, but Player B shows some significant differences in color luminance, particularly green and magenta. While not as bad as the gamma, it certainly is not correct and something that you could possibly notice on a correctly calibrated display.

In the end, Test 1 shows that if you use a Blu-ray player with incorrect colorspace conversion on a correctly calibrated display, you can have some serious image issues that will crop up and be visible.