IOCTL_CAMERA_DEVICE_QUERYVIDEOFORMATS always reports an error -3 to me. IOCTL_CAMERA_DEVICE_QUERYSTILLFORMATS works fine. Even CamTest2 Reference application uses hard coded values instead of querying them. Makes a strange feeling as if this functions has never been used anywhere.
Using Windows CE6 on ARM architecture.
I Tried with different Cameras which all responded the same way.


JHamblen wrote Apr 5, 2010 at 3:44 PM

I just got 10 new Logitech webcams (the Quickcam 9000 model). The new ones do not work with the driver and generate this IOCTL video format error whenever camtest2 starts, but the older ones I have with the same model numbers work just fine. Might be the same for all brand new Logitech cameras? (don't know) – they must have a new version of the internal firmware installed in them that the driver does not like (even though the model numbers are the same as the old ones that work).

JHamblen wrote Apr 27, 2010 at 3:53 PM

Here is some more info back from Logitech QuickCam Forums (see below). It appears that some new supported resolutions might be changing the format response from the camera back to the driver - Wonder if it might work if someone changed the driver/app code to ignore it and continue? The new cameras with issues are called "webcam pro 9000s" and the older ones that work are "quickcam pro 9000s". They look the same once you open the box.

From Logitech QuickCam Forum
RE: QuickCam PRO 9000 on Windows CE 6.0

We don't generally test our cameras on Windows CE, so unfortunately I can't give you much help there. I assume by "new 9000s" you mean the Logitech Webcam Pro 9000 as opposed to the older QuickCam Pro 9000?

The only major difference I can think of is the support of a bunch of new resolutions. Some of those are widescreen. I'm not sure if that is something that the Windows CE UVC driver might be choking on? We haven't seen any similar problems with other generic UVC drivers (Windows, Linux, Mac OS). It would also be important to know whether it's the driver or the app that's reporting these errors.

So, I'm afraid I can't guess where the error comes from. Maybe the original cewebcam/camtest developers might be able to help out.


embedpro wrote May 16, 2010 at 1:29 AM

The error comes from the camtest app. It has "hardcoded" values that work with the older Quickcam and not some of the new hardware. Logitech moved things around and confused the app.

wrote Feb 14, 2013 at 7:19 PM