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
Comments Locked

62 Comments

View All Comments

  • Rand - Monday, December 20, 2004 - link

    Anand- Could you provide the details on what the test platform in use was?
    You mentioned the processor of course, but it would be appreciated if you could disclose the other components in use.

    Thanks.
  • Spike - Monday, December 20, 2004 - link

    But the 6800's come with NVDVD (at least mine did), isn't that basically their decoder? Other users are reporting their new (just recieved today) 6800 GT's coming with the DVD decoder on CD.

    -spike
  • Anand Lal Shimpi - Monday, December 20, 2004 - link

    NVIDIA's DVD decoder has always been $20, unfortunately I don't know of a single manufacturer that gives away their DVD decoders for free.

    The WMV9 acceleration can be had without the DVD decoder, however that you will have to wait on Microsoft for as WMP10 needs to be updated.

    The features right now are mostly for HTPC enthusiasts who want the image quality benefits offered by PureVideo.

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

    I am still confused on the "free" comment. If I have to pay $20 to enable a feature that was supposed to come with my 6800 GT, how is that free?

    Thanks,
    spike
  • Anand Lal Shimpi - Monday, December 20, 2004 - link

    How to enable WMV9 hardware acceleration on ATI cards:

    Note: WMV9 acceleration has been disabled until Microsoft issues a new patch for WMV9. To enable this with other versions of Catalyst (with some rendering errors), RUN regedit -> HKEY_LOCAL_MACHINE -> SYSTEM -> CurrentControlSet -> Control ->Video and find your ATI reg value. The key to update is DXVA_WMV = 1

    Take care,
    Anand
  • gordon151 - Monday, December 20, 2004 - link

    #16, It does. It just doesn't have the full capabilities that it was advertised as having. If you look at the descriptions you'll see only the 6600 AGP/PCI-E and 6800 PCI-E have use of the full capabilities of the encoder.
  • Klaasman - Monday, December 20, 2004 - link

    I don't see on Nvidia's website where the 6800GT does NOT have PureVideo capability. They say all Ge Force 6 series.
  • OriginalReaper - Monday, December 20, 2004 - link

    why couldn't *those* sites shut down next week instead :-\
  • Gatak - Monday, December 20, 2004 - link

    There are some facts missing when it comes to differences between interlaced and progressive video.

    NTSC TV broadcasts are recorded at 60fps, not 30fps. (PAL is 50fps). Each field is recorded after eachother in time. There is a 16.7ms delay between each field.

    If you were to de-interlace two fields into one frame you would loose half of the temporal resolution! This is a big mistake - especially for fast moving things like a football or hockey game.

    A proper de-interlacing method would render each field as a separate frame (like a TV does!), not blend or discard fields.

    24fps content, on the other hand, need to be converted to fit the 60fps NTSC (or 50fps PAL). It is nasty and should be banned. A DVD/MPEG-2 video is perfectly capable of storing 24fps progressive.

    So, what we want is to render 24fps content as 24fps progressive and TV content as 60fps progressive.

    Remember, a TV is already interlaced. There will be no problems with interlaced content because each field is rendered consecutively. It is only on a computer monitor which is progressive where we need to do field deinterlacing.
  • SlinkyDink - Monday, December 20, 2004 - link

    How can we enable hardware acceleration on our ATI cards now? (I believe its a registry edit)

Log in

Don't have an account? Sign up now