Ramakant Yadav the Internet edition

Random Ramblings Of Ramakant Yadav

22 Jul 2011

WIAis really dead. I had worked on a WIA based image acquisition tool a long time ago. Recently, I had some time on my hands and decided to see if I could do the same with my windows XP virtual machine and integrated laptop camera.

My first attempt to access images using WIA did not really work out because the USB ports of the virtual machine only supported USB 1.0, so I kept getting "out of bandwidth" error messages. Since I use Virtual box for my testing, I simply downloaded the extension pack from the virtualbox.org site.

The idea was that the images would be taken in a quick succession. That way, one can use it as a motion detector or whatever else that comes to mind. However, after taking three images, the camera would just stop working. The USB access symbol would switch on, the camera's "in use" light would come on too, but no picture.

After a lot of fiddling around with the code[which worked flawlessly(if I remember right) on my older hardware(desktop with USB camera) many years ago], I was still at the same place.

For some reason, the third image would be last image in the sequence, after that the camera would just hang up. After a few hours of searching on the internet, I came up with nothing. By this time, it was late in the evening and I did not fancy working on this for the entire night.

The next morning, it struck me: the problem was not with my code, the problem was with the camera's WIA implementation. To test out my hypothesis, I tried taking a few pictures using the My Computer->WIA interface. Sure enough, after a few pictures, it just seemed to hang up. Windows would stop responding and things would come to a stop. So, it was a problem with badly implemented WIA after all.

Either way, it would seem that support for WIA was patchy at best. So, if you are looking to implement image capture on current hardware: avoid WIA.

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