Issue:
- I do call CancelGrabber() before de-register any image buffers. But s/w crashes when de-registering.
- Why not the driver de-register all image buffers internally when user application calls CancelGrabber()?
- It's difficult for application to keep track of how many image buffers are registered in streamGrab when using external trigger. 


Solution:
- add in below line after cancelGrab() and before de-register image buffer, this will solve the problem.


for (GrabResult r; m_streamGrabber.RetrieveResult(r);); // Get all buffers back.