Roland Professional A/V VR-4HD HD AV MixerVR 4HD from Roland, an all in one AV mixer, integrates a digital audio mixer, video switcher, multi viewer with touch screen and USB video audio output streaming all into a stand alone device. It's a complete portable HD studio in a single unit, allowing single person production of sound and video using tactile faders, buttons, and touch screen. The VR 4HD features professional quality Broadcast controls and switches ensuring more accurate, faster