HD Decode Performance

The other aspect of PureVideo that matters is its decode acceleration. DVD decoding isn't really an issue these days, as even the slowest CPUs are powerful enough to handle DVD decoding - the new stress test is decoding of HD content. We used Windows Media Player 10 and the publicly available Terminator 2 trailers in 720p and 1080p formats. However because our test bed was limited to 1600 x 1200, the 1080p test was fairly useless as we were resolution bound on the machine, making the 720p test much more stressful.

We measured average, minimum and maximum CPU utilization over the entire 1:59 trailer. Our test bed was an Intel Pentium 4 570J (3.8GHz), however higher CPU utilizations on this test bed will translate into proportionally higher CPU utilizations on slower CPUs. We tested in both Overlay and VMR9 modes, the latter being directly applicable to Windows XP Media Center Edition as it uses VMR9 exclusively.

In Overlay mode in a window, ATI has significantly lower CPU utilization:

WMV9 CPU Utilization (Lower is Better) - Overlay Window - 720p Terminator Trailer
  Minimum Average Maximum
ATI 9.4 22 35.2
NVIDIA 14.8 28.3 40.6


WMV9 CPU Utilization (Lower is Better) - Overlay Full Screen - 720p Terminator Trailer
  Minimum Average Maximum
ATI 11.7 22.3 33.6
NVIDIA 25 37.7 46.9


ATI sees a very small performance penalty when scaling up to full screen, while NVIDIA faces a huge performance penalty in full screen mode. VMR9 is much more stressful on ATI than it is on NVIDIA, the winner here is NVIDIA.

WMV9 CPU Utilization (Lower is Better) - VMR9 Window - 720p Terminator Trailer
  Minimum Average Maximum
ATI 28.9 41.4 50.8
NVIDIA 15.6 26.6 40.6


WMV9 CPU Utilization (Lower is Better) - VMR9 Full Screen - 720p Terminator Trailer
  Minimum Average Maximum
ATI 31.3 42.2 50
NVIDIA 20.3 38.5 50.8


Even in full screen mode, NVIDIA is able to offer slightly lower CPU utilization than ATI.

DVD Playback Quality (continued 2) A Preview of the Future - Fully Hardware Accelerated HD Decode
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  • Anand Lal Shimpi - Monday, December 20, 2004 - link

    gordon151

    I should have made this more clear, I used the NVIDIA codec for NVIDIA's tests and I used ATI's codec for ATI's tests. I used Zoom Player for both of them.

    ViRGE

    They never briefed me on anything like that but I can always ask :)

    Take care,
    Anand
  • ViRGE - Monday, December 20, 2004 - link

    Thanks Crimson, but I'm talking about the video features, not the elusive cards themselves. ;-)
  • crimson117 - Monday, December 20, 2004 - link

    #29: http://anandtech.com/news/shownews.aspx?i=23531
  • ViRGE - Monday, December 20, 2004 - link

    I know this is an Nvidia article Anand, but could you get on ATI's butt about their lack of features too, and find out what's going on? When the X800 was launched, ATI was talking about decode acceleration for MPEG4 along along with some sort of encode acceleration(i.e. all the features NV promissed but never delivered on). I'm curious to know what happened to that, and if we're going to get something new out of ATI besides WMV acceleration.
  • gordon151 - Monday, December 20, 2004 - link

    I was wondering why AT's results were different than PCPers and just noticed they used MMC & 4.12 while AT used the nVidia codec and player for both cards tests.
  • Anand Lal Shimpi - Monday, December 20, 2004 - link

    Ytterbium

    I've asked numerous times, never gotten a response. I'll try again :)

    For those of you who are wondering, I have asked NVIDIA what their official statement is to early 6800 adopters, but that has also been met with no response.

    Take care,
    Anand
  • Ytterbium - Monday, December 20, 2004 - link

    I'm dissapointed that the encode function never made it, that was a killer feature. Any idea if it will come?
  • Spike - Monday, December 20, 2004 - link

    Thanks for that! I have the BFG 6800 GT and on the BFG cd there is the nvDVD software. It's nice to know I can actually use the VP that I paid for!

    -spike
  • Gatak - Monday, December 20, 2004 - link

    Here are some examples of interlacing artifacts when redering on a progressive screen:

    1) http://moment22.mine.nu/interlace_1.jpg

    Most software DVDs either blend or remove one of the fields by some partial de-interlacing algorithm. nvidia's DVD decoder does it ok. The image is sharp but still leaves only half framerate.

    2) http://moment22.mine.nu/interlace_2.jpg

    But in reality, half temporal resolution is lost. What should have been done is to render each field as a separate frame.

    3) http://moment22.mine.nu/interlace_3.jpg
  • Anand Lal Shimpi - Monday, December 20, 2004 - link

    Spike

    I wasn't aware that the 6800s are coming with NVDVD, in that case you are good to go. Just download the updated version (1.00.67 is the official version) from the website.

    Rand

    The full system was configured as follows:

    Intel Pentium 4 570J
    Intel D915GUX Motherboard
    2 x 512MB DDR2-533 DIMMs
    Intel HD Audio Enabled

    Windows XP SP2 w/ DX9c

    Take care,
    Anand

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