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Yet another frame rate question...
Anonymous
9 years
Hi STeven,

I'm trying to understand the difference in frame rate when I use the same camera on two different machines running Windows XP, the latest version of DirectX, and the latest drivers for the webcam.  The two systems are:

1. HP Pavillion tower with 2.2 GHz AMD and 3 Gb RAM
2. Mini-ITX single board computer (EN12000EG) running at 1.2 GHz with 1 Gb RAM

The camera is a Creative Labs Voice! that I specifically chose because it has one of the widest FOVs among available webcams (about 75 degrees).

Running the same version of RoboRealm (the latest), no modules, preview off, resolution set to 160x120, and the webcam set to the lowest exposure setting (1), I get nearly 30 fps on the HP and only 13 fps on the Mini-ITX.  CPU load on the Mini-ITX is only 50% so it doesn't seem to be a load issue.

I have one clue that might be critical:  using the Creative supplied "Cam Center" software, I can view the video image on either machine outside of RoboRealm.  When I do this, the video is noticeably slower on the Mini-ITX which is consistent with the RoboRealm results.  But even stranger--the Cam Center software has an option to superimpose the frame rate on the image--on the HP this option is functional and displays 27 fps on the image, again consistent with RR.  However, on the Mini-ITX, this option is greyed out!  So it's as if there is some subtle interaction between the Creative webcam driver, DirectX, Windows XP and the Mini-ITX.  I don't expect you to spend any time debugging this since it doesn't seem to be a RoboRealm problem, but if something obvious jumps to mind, I'd love to hear it.

Thanks,
patrick
Anonymous 9 years
Just a quick update to my earlier post.  I've decided to use a Logitech Fusion webcam instead of the Creative Live Voice.  Once I made that substitution, all my problems went away.  I get 27 frames per second in RoboRealm on the Mini-ITX using the Fusion (no modules, no preview) and my robot's head tracking routine runs smoothly using the COG X and Y variables returned from RR.  So all is well.  Guess I can use the Creative webcam for Skype. (-:

--patrick
Anonymous 9 years
Cool! Thanks for the note. Good to hear that your fps is finally within reason:-)

STeven.
Anonymous 9 years
After reading your initial post again ... there might be a hardware limitation that directX is picking up on and thus not allowing the rate to be above 13 fps. Do you know the usb speed (1 or 2) on the ITX? Perhaps the communication bandwidth of the Logitech camera is lower than the Creative? Although this still seems unlikely due to the really small image size that you are using. If you want to find the cause perhaps the next step would be to post exactly your question in the Creative forum and see if anyone else has this issue with the ITX.

STeven.

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