More NVidia PureVideo Decoder testing: conclusion - NVidia DxHA stinks

[wtg]

I've done bit more testing with GB-PVR and the NVidia Decoder to figure out why playback uses so much CPU and is generally unfavorable. When I opened a MPG file in WMP or GraphEdt (letting it create a default graph) playback was good and had very low CPU usage, and I wanted the same within GB-PVR.

The conclusion? NVidia PureVideo decoders perform terrible with VMR enabled and supposed harware accelleration, worse than the Nero decoders w/o hardware accelleration. The good performance I was seeing in WMP and GraphEdt were due to Overlay mode (which has Pros and Cons) - VMR mode stinks.

Results might be different for you with your hardware.

My System:
AMD 2500
768 Meg RAM
NVidia 6200 w/ 256 Meg
NVidia 93.71 Forceware Drivers
Latest PureVideo Decoders (as of today - 12/15)

Testing: I tested by selecting my video mode and decoder in GB-PVR's config, playing the same segment of a video each time. Within GB-PVR I would play the video briefly, stop it and then open LastGraph.grf in the GB-PVR directory with GraphEdt. This allowed me to see the filters present, check their options and play the file for a couple minutes, watching CPU usage. The Overlay mode graph I couldn't open with GraphEdt (I got an unregistered filter error) so instead I did playback in GB-PVR and graphed it's CPU usage.

In VMR mode I did some tests removing GB-PVR specific filters from the graphs (GB-PVR Flow Status and GB-PVR Parser) to see what impact there was. As sub predicted, there was no impact whatsoever. The GB-PVR filters are not introducing performance penalties.

The only area that I have some uncertainty about is Overlay mode. GB-PVR's use of the NVidia Decoders doesn't perform as well as GraphEdt or WMP in Overlay mode - the difference is significant. I can't tell what's going on because I can't open the Overlay mode graph. I have a little more to investigate that might shed some light on it, but at this point I've proven GB-PVR isn't at fault for the VMR mode problems anyway.

Take a look at the graphs below:

[wtg]

Additionally, here's the GraphEdt decoder properties, the first being the VMR9 graph out of GB-PVR, the second the default overlay mode from graph GraphEdt comes up with. Finally, a graph of CPU usage in Overlay mode with GraphEdt default graph for the same file.

[sub]

I find it really bizarre that you have these regular repeating pattern of peaks, which makes me thing you've got something funny happening on your machine. Below is the CPU usage with a graph with the nvidia decoder with hardware accelleration, graphedit, VMR9.

You strangely seem to have this peaking occurring in all VMR graphs, so makes me think maybe something wrong with your video card drivers, or directshow itself.

[wtg]

Yeah, I don't know what the peaks mean. You can see that they only occur with VMR - overlay mode has no dramatic peaks. There's probably a clue in there somewhere and if you have any suggestions for figuring out what they are related to, I'm all ears.

[wtg]

Sub,

Any ideas about Overlay mode? Presumably I should be able to get the same CPU usage in GB-PVR that I get in WMP or GraphEdt in Overlay mode, but I don't. As you can see, the difference is pretty dramatic.

Thanks again for your time.
Tim

[Koenie]

My former setup was very similar (Athlon XP 2 ghz + Nvidia 6200) and was having the exact same regular wave pattern when using the Nvidia purevideo decoder with VMR9. I since use the Hauppauge supplied decoder (the last version on the Hauppauge.tv site performs really well I think).

[sub]

Any ideas about Overlay mode? Presumably I should be able to get the same CPU usage in GB-PVR that I get in WMP or GraphEdt in Overlay mode, but I don't. As you can see, the difference is pretty dramatic.

Nothing springs to mind, but it might be the additional load add by the Overlay Mixer filter, or possible the extra overheads of directshow applying the slight zoom or aspect ratio control that you might not see when you use all the defaults as generated by GraphEdit.

[acegolfer]

I read that Nvidia 93.71 driver doesn't work best for 6xxx cards with VMR9. Try older version such as 84.21.

I just upgraded to 7900GS and the picture is perfect for 720p and 1080i using VMR9. Better than anything that I saw in the last 3 years of watching HDTV.

[Braklet]

I just upgraded to 7900GS and the picture is perfect for 720p and 1080i using VMR9. Better than anything that I saw in the last 3 years of watching HDTV.

Well, there's hope for me and my last 2% of desired HD performance, then. I'm currently running a 6600 card and most HD looks fine (PureVideo, HW accel, overlay mode).

I haven't pursued a 7xxx upgrade because from what I've seen those GPUs don't support analog VGA output. That's the only way I can input 1080p into my HDTV. I'm limited to 1080i via HDMI or DVI. It is probably not that big a deal and a fine price to pay if I could truly never see a frame drop again.

[pBS]

first off i see you're not using the anamorphic aspect ratios...anything else always messed up my aspect ratios....also, have you fiddled with anything on the color tab? if you do you'll see significant performance issues...!
reset to defaults in color settings tab and try anamorphic aspect and see what it does...

also, i notice you're getting only mode A accelleration..[idct only]
every Radeon ever made does mode C at least[idct and motion estimation and something else]..i thought the 6200 had hardware accell...my fx5200 does same as yours..maybe a driver version issue..i heard things..try older ones..
i have a radeon 7000 that accellerates really nicely...
or try the dscaler codec...it may get accelleration going but not sure how to check...

also, is that a agp or PCIE card? big differences between the 2 for memory transfers...