WD Purple™ Storage Calculator App How much storage does your smart security system need? The WD Purple Storage Calculator app takes your input and calculates the ideal capacity for your application. microSD™ cards Some key considerations for microSD cards are video resolution, frame rate, minimum video length to retain, and how much endurance is needed. High-res video and higher frame rate increase your capacity need. If your camera is difficult to reach, greater endurance allows you to replac