HTPC Aspects : HQV 2.0 Benchmarking and Video Post Processing in Action

HTPC enthusiasts are often concerned about the quality of pictures output by the system.  While this is a very subjective metric, we have decided to take as much of an objective approach as possible. Starting with the Core 100 review in 2010, we have been using the HQV 2.0 benchmark for this purpose.

The HQV 2.0 test suite consists of 39 different streams divided into 4 different classes. The playback device is assigned scores for each, depending on how well it plays the stream.  Each test was repeated multiple times to ensure that the correct score was assigned. The scoring details are available in the testing guide on the HQV website.

In the table below, we indicate the maximum score possible for each test, and how much the Zotac GT 640 was able to get. As mentioned in the previous section, we used NVIDIA Graphics Driver v301.42 for the benchmarking.

 
HQV 2.0 Benchmark - Zotac GT 640
Test Class Chapter Tests Max. Score Zotac GT 640
Video Conversion Video Resolution Dial 5 5
Dial with Static Pattern 5 5
Gray Bars 5 5
Violin 5 5
Film Resolution Stadium 2:2 5 5
Stadium 3:2 5 5
Overlay On Film Horizontal Text Scroll 5 5
Vertical Text Scroll 5 3
Cadence Response Time Transition to 3:2 Lock 5 5
Transition to 2:2 Lock 5 5
Multi-Cadence 2:2:2:4 24 FPS DVCam Video 5 5
2:3:3:2 24 FPS DVCam Video 5 5
3:2:3:2:2 24 FPS Vari-Speed 5 5
5:5 12 FPS Animation 5 5
6:4 12 FPS Animation 5 5
8:7 8 FPS Animation 5 5
Color Upsampling Errors Interlace Chroma Problem (ICP) 5 5
Chroma Upsampling Error (CUE) 5 5
Noise and Artifact Reduction Random Noise SailBoat 5 5
Flower 5 5
Sunrise 5 5
Harbour Night 5 5
Compression Artifacts Scrolling Text 5 5
Roller Coaster 5 5
Ferris Wheel 5 5
Bridge Traffic 5 5
Upscaled Compression Artifacts Text Pattern 5 3
Roller Coaster 5 3
Ferris Wheel 5 3
Bridge Traffic 5 3
Image Scaling and Enhancements Scaling and Filtering Luminance Frequency Bands 5 5
Chrominance Frequency Bands 5 5
Vanishing Text 5 5
Resolution Enhancement Brook, Mountain, Flower, Hair, Wood 15 15
Video Conversion Contrast Enhancement Theme Park 5 2
Driftwood 5 2
Beach at Dusk 5 2
White and Black Cats 5 2
Skin Tone Correction Skin Tones 10 0
         
    Total Score 210 178

We find that score closely tracks what we had for the GT 540M in the ASRock Vision 3D 252B review. In fact, the only difference is the fact that the horizontal scroll response time has been improved a bit, enabling it to score two more points in that test. Given that the GT 540M had no trouble deinterlacing 1080i60 content, it was not a surprise to find that the GT 640 sailed through those tests. In the next section, we will look at some rendering benchmarks to see how deinterlacing operations load up the GPU. Chroma upsampling algorithms are passable, and there is no difference in quality between what was obtained through the 540M and what we got with the GT 640.

In our review of the video post processing features of the GT 540M, we had indicated that the contrast enhancement and skin tone correction features didn't work. We found no change in the v301.42 drivers. However, we did find contrast enhancement working with the black level testing clip in the AVS HD 709 calibration suite. This just proves that the dynamic contrast enhancement feature in the NVIDIA drivers doesn't work as effectively as Intel's or AMD's.

Should the low HQV score or lack of proper dynamic contrast enhancement prevent you from choosing the GT 640 for your HTPC? Definitely not! The nice aspect about NVIDIA GPUs is the fact that there are lots of HTPC software packages available to take advantage of the GPU resources. As long as the hardware deinterlacer works (it does, as the HQV scores for those tests indicate), and there are enough shaders and other computing resources available to let madVR work its magic, the HTPC end-user has no reason to worry. Advanced HTPC users tend to distrust any post processing done by the drivers, and would rather not let the driver mess with the video output by applying its custom post processing algorithms (which tend to break with every new driver release).

However, video post processing algorithms are not the only issue-prone HTPC aspects in the driver. Proper black levels are necessary irrespective of the color space being output. The gallery below shows that the behavior of the driver doesn't correlate in any way to the settings in the control panel. NVIDIA drivers seem to adopt two modes for the limited (16-235) and full (0-255) settings, one for global (desktop, photos etc.) and one for videos. Global mode is chosen to be limited (16-235) for all in-built resolutions and full (0-255) for all custom resolutions when in YCbCr mode with no way to change this (the gallery below shows correct dynamic range being chosen in RGB mode for still photos / desktop). The dynamic range for video and desktops are also different. Toggling the dynamic contrast enhancement box also seems to affect this setting. In addition, there is no way to specifically choose RGB Full or RGB Limited in the current drivers.

This dynamic range issue was apparently present in the Vista days, and fixed earlier. There appears to be a regression in the state of this bug recently, and we have been observing problems since May 2011 at least. A method to fix the issue has been outlined on Microsoft's official Windows community forums. It is disappointing to note that NVIDIA has still not fixed the issue despite the bug being a major annoyance for many HTPC users.

HTPC Aspects : Custom Refresh Rates HTPC Aspects : Decoding and Rendering Benchmarks
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  • MrSpadge - Thursday, June 21, 2012 - link

    And they support newer features and cost significantly less to run. Still, the price is ridiculous, especially for DDR3. Reply
  • Taft12 - Wednesday, June 20, 2012 - link

    "Zotac has worked themselves into an interesting position as the only partner currently offering a single-slot card"

    I think EVGA's launched even before Zotac. No blocked mini-HDMI port either!

    http://www.newegg.ca/Product/Product.aspx?Item=N82...
    Reply
  • nathanddrews - Wednesday, June 20, 2012 - link

    First off, I want to thank you for testing the 4K capabilities of this card. While disappointing that there is no DP output for 4K@60Hz, I suppose it's only a matter of time.

    Second, and more important, I wanted to make you aware of this in case you haven't seen it. Shot in 4K, edited in 4K, mastered in 4K and you can buy it in any format including Blu-ray (1080p), 2560x1440p, and even its raw 140GB 4K Cineform resolution. Seeing as how one of you awesome people now has the Sony 1000ES (jealous!), you definitely shouldn't waste time showing 4K YouTube clips!

    http://timescapes.org/products/default.aspx
    http://www.youtube.com/watch?v=e-GYrbecb88
    Reply
  • Hrel - Wednesday, June 20, 2012 - link

    I saw a GTX560 on newegg for 145bucks after MIR today. Whenever people ask me about gaming cards and say they don't want to spend much more than 100 bucks I say, cut back on coffee for a week or skip that night at the bars and just spend the extra 30 bucks or so. Makes absolutely NO sense to handicap yourself over 30 bucks. GTX560 FTW!!! Reply
  • just4U - Thursday, June 21, 2012 - link

    That's pretty much where the 7750 comes in. Performance overall is fairly similiar. Plus you can do away with the confusion since the 560 comes in 4-5 different flavors, yes? Reply
  • maroon1 - Saturday, June 23, 2012 - link

    What ?! GTX 560 is much faster than even HD7770.

    http://www.anandtech.com/show/5541/amd-radeon-hd-7...
    Reply
  • Lolimaster - Wednesday, June 20, 2012 - link

    So slow that a 6670 feels like high end and 7750 a total monster. $109 for these joke of a gpu (gt640)? You must be trolling. Reply
  • Lolimaster - Wednesday, June 20, 2012 - link

    A8 5800K is a tiny bit slow thatn 6670 so it should be faster (for free with the APU) than a $109 nvidia discrete gpu. Reply
  • bhima - Wednesday, June 20, 2012 - link

    This card is horrible. I was initially unimpressed with AMD's 7750 and 7770 performance, but now those cards just look beastly compared to this. This should be a $50-60 card at max for that kind of performance. Hell I think my 540m performs almost as good as this card. Reply
  • staryoshi - Wednesday, June 20, 2012 - link

    GDDR5 would have really lifted the performance of this card. I'm sure they went with GDDR3 as a cost-saving measure and to not canibalize the sale of other cards.. but at this price point it's not a compelling item at all for most.

    They really need to get the 28nm process under control and wrangle in pricing on this pup.
    Reply

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