- Written by Chris Heinonen
- Published on 24 May 2011
- The Secrets Blu-ray Player HDMI Benchmark - Part I
- Page 2: Blu-ray Player HDMI Benchmark - Why This Matters
- Page 3: Blu-ray Player HDMI Benchmark - What We Will Report
- Page 4: Blu-ray Player HDMI Benchmark - Data Examples
- Page 5: Blu-ray Player HDMI Benchmark - Conclusions and Industry Feedback
- All Pages
For our examples here, we went to players we have reviewed here previously: The Sony BDP-S570, and a set of OPPO players (BDP-83SE, BDP-93, and BDP-95). All of these players were very well regarded during our prior looks at them and have garnered year-end awards from us as well.
How would they hold up to more advanced testing that wasn't possible before?
Let's begin with the OPPO players. They support all of the color spaces we want, as well as a Source Direct mode. Additionally, the 93 and 95 have dual HDMI outputs on them, so we need to test both of them to see if one offers better performance than the other for video. Numbers in green mean the player passed the test, and if in red, the player failed the test.
Looking at the Oppo BDP-83SE, the data are spot-on. The dE in the output stays near 0, with an average dE of 0.1 for RGB. 4:2:2 and 4:4:4 come across perfectly when compared to their reference values. The OPPO does have a Source Direct mode, but we did not test that on the players this time. The Oppo behaves perfectly on the tests and would work well as a reference point for your video system, and we could easily use it to calibrate a display.
Moving onto the newer 93 and 95 models from Oppo, these have the same video chipset in them, so we expected the same video performance, and that is what we got. The only errors were over HDMI 2, and only at RGB levels 0 and 255, which were 1 and 254 respectively. All other RGB values between these were perfect, and on HDMI 1 they were all correct. As OPPO recommends using HDMI 2 for audio or a secondary display, we would suggest the same; though the amount of error here was nothing we would ever think twice about.
Similarly, 4:2:2 and 4:4:4 data looked perfect over both HDMI 1 and HDMI 2. The OPPO handled the color space conversions perfectly, and output all data formats correctly, so once again this player could be introduced into any consumer system and work ideally. Other aspects of the OPPO performance have been covered in our reviews of the players, so we will stick to the HDMI data alone, and on that, all of the OPPO players were fantastic.
Next, we looked at the Sony player. It also supports 4:2:2, 4:4:4 and RGB color spaces, but does not have a Source Direct mode that the OPPO has. It also only has a single HDMI output, so there are much less data to look over than with the recent OPPO players. Let's look at the chart of the Sony data below, and then the implications of those results:
Unlike the Oppo players, we have a lot of data here that is different that the reference values. Lets go over some of the issues and why they are problems.
- The Y value for 4:4:4 and 4:2:2 color space is incorrect. In this case, the Luma value, which is the black and white image and responsible for the majority of the detail you perceive, is being radically adjusted by the Sony.
- WTW (Whiter than White) and BTB (Blacker than Black) data, which exist on Blu-ray discs, but you will typically not see much of, will be visible in the image when they should be hidden on a properly calibrated display. The BTB data will be correct here, but values over 235 that are WTW would typically be hidden after a calibration. With this player, the highest Y value output by the Sony is 232. All values above that have been adjusted down below the WTW mark, and a value that would typically be bright white (235) has been adjusted down to 224, or a very light gray instead of white.
- In addition to passing all this WTW data, the dynamic range of the image has been altered. Take the peak white value of 235. A value of 225 should be a full 10 steps below that, but on the Sony, the 235 renders it as 224, and the 225 comes out at 219. A dynamic range of 10 has been shrunk down to 6. The overall dynamic range we would expect from the Sony has gone from 220 values (16-235) down to 209. That's a loss of 5% of your dynamic range.
- Looking at the RGB values, you can see the dE numbers there for the five values for each color, and an average of the 25%, 50%, 75%, and 100% values (0 has been omitted as it's less important and less visible). Red has a dE of 0.9, and Blue has a small dE of 0.1, but Green has a dE of 4.7. Because of the error in green, there is no way to calibrate a display to not have an error in how it displays green that is visible to the end user without introducing other errors.
- Finally, these issues are present in all the color spaces, not just RGB. Because of this, you can't select a different mode to get around this issue.
We were quite surprised by these data, as it seemed that everyone, including ourselves, had loved the Sony player. Comparing the output of the Sony with an OPPO player on a calibrated reference projector, and using the Spears and Munsil HD Benchmark Blu-ray test disc, it was possible to see the problems. Gradients were perfectly smooth on the OPPO but were blocky and showed the effects of the lack of dynamic range on the Sony. With the WTW patterns, it was possible to see all of the white blocks since they were adjusted down below where the contrast was calibrated, but on the OPPO, the WTW blocks correctly blended into the white background.
With these issues, I can no longer recommend the Sony player, because its output is incorrect and will compromise the performance of the rest of your system. The OPPO players might be more expensive than the El-Cheapos at the bargain counter, but they offer every single color space that you might need, Source Direct mode, and have perfect color conversion with a dE of 0, so it won't be holding back your system at all in image quality.
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