continuously video presentation while other processes are running

I have a GUI which contains 3 Compnents (Video-Win-Axes, Start-Button and Calc-Button). On the Video-Win-Axes my video Stream will be presented after clicking on Start-Button.

My Problem is that when i click on Calc-Button the Video Presentation on Video-Win-Axes is stoped until the Processes and Functions in Calc-Button are finished.

How could i get the Video Presentation on Video-Win-Axes continuously while the Processes and Functions in Calc-Button are running ? Thanks