Using DirectX / DirectShow, how can I control the capture resolution of a Logitech webcam in source code without showing any dialogue boxes?
I have been researching this on the internet for a while. All I can come up with is that many people ask this question, but there are no answers!
Top points for this one!
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(1) how can I control the capture resolution of a Logitech webcam in source code
Simultaneous Previewing & Video Capture using DirectShow
This article explains a method to perform previewing and grabbing simultaneously from a Webcam using DirectShow. Rather than using the conventional ISampleGrabber interface, this application used Directshow VMR filters & IPin interfaces.
http://www.codeguru.com/cp
(2) without showing any dialogue boxes ?<< dont know
That article looks good - I will go through it carefully, thanks.
Regarding the change of resolution, at the moment I don't really care if dialogue boxes are shown or not. I just need to be able to change the resolution of the camera. I have seen some sample code that shows a windows style property dialogue for the webcam being invoked, but this does not have resolution adjustments on it. Only the Logitech application has this as far as I have seen. There must surely be a way...
Ok great, that example pretty much shows me all I need to know.
Curiously enough, with that code I can iterate though all of the resolution / display modes of the camera, but not up to the maximum supported by the Logitech software. For example, with a QuickCam, you can supposedly go up to 1.3 MegaPixels, but this setting does not appear when iterating over the modes, whereas 640x480 does.
Now, using the Logitech software to take pictures, the 640x480 image is in my opinion a better quality image than the 1.3 MegaPixel one. Conclusion? 1.3 mode MP mode is emulated. Looking also at the Sphere MP camera, this also has top end modes that appear to me similarly emulated. The maximum real physical resolution is that which appears when iterating over the modes in software.
Cheers Merete.
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by: MeretePosted on 2007-07-05 at 17:06:12ID: 19428572
Daeljan you answered it yourelf. Its not possible.