Image Acquisition

I am working on a project using the Image Acquisition Toolbox.
I am trying to read frames from the input received on the
tuner/capture card. The code that i am using goes likes this:

obj = videoinput('winvideo');
start(obj);
preview(obj);

The trigger type by default is set at 'immediate' and number of
frames to be acquired is 10.

But, the problem is that the preview window shows the status as
"Logging Frame 1",without producing the desired result.
That is,the object is not able to acquire any frames and continues to
be in the logging state.

Please help me in troubleshooting the above problem.Thanks in advance.

I am facing the same problem. I am using mercury TV in card and only gets a
gray window as output.