An SDI (Serial Digital Interface) output connection is usually only found on the highest quality professional equipment. SDI is the standard connection that television studios and other broadcasters use (detailed in SMPTE 259M and SMPTE 292M).
What is it? SDI is a high capacity interface used as a way of exporting uncompressed digital video in real time. That makes SDI – and any camcorder that features it – ideal for live feed productions (such as a live TV show), as well as for editing and monitoring video at the highest possible quality. Since SDI is designed primarily for professional use, it is also compatible with a variety of video devices found in broadcast studios, including monitors, tape decks and switchers. (A switcher is a device that acts as a central control point, from where a number of cameras can be remotely operated in a multi-camera shoot).
SDI exports uncompressed SD and HD video over a single cable. While the data rate of HDV1080i footage recorded to tape, after undergoing compression, is 25mbps, the data rate for direct SD-SDI video output reaches 270Mbps. The standard data rate for HD-SDI is an astonishing 1.485Gbps.
Canon camcorders featuring SDI output provide a pure, broadcast-standard video image.
The Canon XH G1 features an SDI output connection that supports Time Code and audio, sent as an embedded signal within the video signal.