I have been trying to run tests and find out actually how Purevideo works.

There doesn't seems to be any straight forward information on how and when the Nvidia cards are utilising PureVideo and GPU hardware acceleration to offload the work from the CPU.

My GPU: Nvidia 6150

If you look at the Nvidia Driver Page:

http://www.nvidia.com/object/winxp_2k_93.71.html

It states it includes "NVIDIA PureVideo™ HD driver" However, when you install the driver, there is no mention of this throughout any of the Nvidia driver menus.

Then there is the PureVideo Decoder:

http://www.nvidia.com/object/dvd_decode ... trial.html

This you have to pay for, but you can get a 30day trial. Which I downloaded and installed.

I ran some tests within MediaPortal. In MediaPortal Setup, DVD--->DVD Codec--->Video Coedc and changing between "MPV Decoder Filter" and "Nvidia Video Decoder".

With the "MPV Decoder Filter" CPU usage was around 10%
With the "Nvidia Video Decoder" CPU usage was around 4%

Also, the Nvidia icon pops up in the taskbar (bottom right) where you can change settings. It only appears when your actually playing the DVD, and disappears when stopped.



I was interested in how well this would work with ffdshow doing some post processing to upscale and sharpen the picture. Therefore, in MediaPortal setup, DVD----DVD Post Processing I added "ffdshow Video Decoder" and in filter propeties changed the resize settings to upscale to 1080p.

Then as in the previous test: In MediaPortal Setup, DVD--->DVD Codec--->Video Coedc and changing between "MPV Decoder Filter" and "Nvidia Video Decoder".

With the "MPV Decoder Filter" CPU usage was around 65%
With the "Nvidia Video Decoder" CPU usage was around 70%

Therefore, CPU usuage was worse when using Nvidia Video Decoder.

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Next test was to see how the mentioned H.264 acceleration would work.

So in MediaPortal Setup, Movies---->Movie Player---->Video Codec I changed this to "Nvidia Video Decoder". Then played an 720p .mkv H.264 video file. There is now no icon in the taskbar to show that Purevideo is working. Also no difference between when "MPV Decoder Filter" is selected, both run around 25% CPU.

I believe this is due to the fact that it doesnt make a difference what you select in Movies---->Movie Player---->Video Codec as its all chosen via DirectShow

To see what filters your file types are using, you need to use Graphedit

I believe the H.264 acceleration would come in if you were to play an actual Blu-ray or HD-DVD disc. Playing one of those disc should then see the Purevideo icon in the taskbar as it does with DVD's. Im only assuming this as I can't test this at the moment.

I'm hoping to do more testing on all this, and will update this post. Also feel free to post up any of your own findings on how Purevideo works.