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Windows 7 camera problem with vfw

2011-10-31
2013-02-02
  • When I run zbarcam on Windows 7, after a reboot with the camera plugged in, I get the following erronous behaviour:

    1. A dialog "Choose source" appears (it should appear at all).
    2. After selecting the camera and pressing OK, zbarcam reports failure.

    I workaround this by unplugging the camera and plugging it again. Provided Windows load the correct driver, I can use zbarcam normally later on.

    Maybe there is a better solution, like closing or disabling some other application that probably blocked the camera. Appearing of the "Choose source" dialog on XP means that another app took the camera.

     
  • klaus triendl
    klaus triendl
    2012-02-03

    I think that the problem isn't related to zbar. I suspect that newer cameras don't have a proper WDM driver for VFW.
    On an older Dell vostro laptop, zbar is working perfectly, on my new Dell latitude it works sometimes. On a new hp tablet it doesn't work at all… Operating system is always Windows 7.

    I investigated further and wrote a very simple VFW test program, which shows the same behavior as zbar. Directshow doesn't have those problems at all…