Now in Version 3, the MD-QUAD is a 4-channel SD/HD/3G-SDI quad-split multiviewer that also works as a multiplexer. Four auto-detecting SDI inputs are each independent and low-latency buffered, letting the unit display all four simultaneously on an optional monitor even when each is a different format or frame rate. It outputs to SDI and HDMI. Version 3 adds a test-pattern generator, an audio-tone generator, audio-channel pass-through, and an on-screen display on the optional connected monitor. Control is via a rotary encoder and push buttons rather than a computer, output format is selectable, variable aspect ratios are supported, and the locking power socket guards against accidental power loss.