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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  • Joe H - Wednesday, June 20, 2012 - link

    This is the type of review that other hardware sites can't even imagine, let alone write. Thanks for putting this and the other HTPC articles together. It's great to see a hardware review site taking HTPC enthusiasts and their needs seriously. Excellent review. Reply
  • n0b0dykn0ws - Wednesday, June 20, 2012 - link

    Is there a chance of a follow up once a few driver updates have been released?

    I would love to see if the card gets even better after a few releases.

    I have a Radeon 6570 right now, and I've found it to be palatable for HTPC purposes.

    n0b0dykn0ws
    Reply
  • Taft12 - Wednesday, June 20, 2012 - link

    They haven't done it before, I don't know why they'd start now. Reply
  • Ryan Smith - Thursday, June 21, 2012 - link

    What specifically are you looking for? Gaming performance or HTPC functionality? Gaming performance isn't likely to improve; even with the newer architecture it's not Kepler that's the limiting factor. HTPC functionality on the other hand can easily be improved with drivers. Reply
  • n0b0dykn0ws - Thursday, June 21, 2012 - link

    HTPC only. For gaming I would get a 670.

    Sometimes drivers break HTPC performance/quality though. At least in the AMD world.

    n0b0dykn0ws
    Reply
  • Kevin G - Wednesday, June 20, 2012 - link

    If they're going to release a DDR3 version, why not just offer a version with no onboard memory and two DIMM slots so that users can add there own? You can get a DDR3-2133 kit which would boost bandwidth limited scenarios by roughly 15%. While I don't see the need, such a card could be upgraded all the way to 16 GB of memory. Reply
  • MrSpadge - Thursday, June 21, 2012 - link

    Sockets
    - are unconventional (I don't think nVidia likes this word)
    - introduce a little cost (GPU manufacturer doesn't like it)
    - make the board larger (GPU manufacturer doesn't like it)
    - make the bus timing worse, so it's harder to clock them as high as directly soldered chips (wouldn't matter with DDR3, though)
    - introduce another point of failure (GPU manufacturer doesn't like higher RAM rates)
    - add cost to the overall product, as the end user wouldn't get as sweet a deal on RAM as the GPU manufacturer (this would eat into the GPU manufacturers profit margin)
    Reply
  • Stuka87 - Wednesday, June 20, 2012 - link

    Sounds like unless temps are really important to you, the 7750-800 is by far the better choice. It outperforms the GT640 (And by a wide margin in some cases) in what looks like, every single test.

    And they are priced the same, which makes the GT640 kind of worthless for its intended price point.
    Reply
  • cjs150 - Wednesday, June 20, 2012 - link

    Great review.

    It is too noisy, and the HDMI socket is an epic design fail. As a card for an HTPC what were Zotac thinking of? This is so badly wrong.

    Now onto frame rates. Nvidia, AMD and Intel really are total and utter idiots or they have decided that we the customers are total and utter idiots. There is simply no excuse for all IGPs and video cards not to be able to lock on to the correct frame rate with absolute precision. It is not as though the frame rate specs for film have changed recently. I cannot decide whether it is sloppiness, arrogance or they simply do not give a rats a##e for the customer experience.
    Reply
  • Stuka87 - Wednesday, June 20, 2012 - link

    God forbid there be a technical reason for it.... Reply

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