So You Think You Want IMag?
IMag is an acronym that describes a functional capability within a live video production system. Image Magnification, to be specific, is the real-time reproduction and display of an enlarged image, as captured by one or more video cameras.
Within the range of the camera’s lenses, and the sufficiency of the lighting system, the enlarged image can include any of the various activities taking place on stage or elsewhere in a facility. In a House of Worship setting, the enlarged image is typically that of a leader or teacher while delivering a message or lesson.
The need for IMag capabilities most often becomes necessary in facilities that are quite large; so large that many of the seats in the room are too distant to allow a reasonably good view of the people and activities taking place on the stage or platform. One or more displays may be used. Both video projection and direct, flat-panel displays can work well in this application.
IMag presents significant technical challenges. When considering an IMag signal path, the video signal latency can easily become a problem if the signal path through-put timing (between the cameras, projectors and displays) is not kept to an absolute minimum. However, achieving this goal comes at a cost, which may become prohibitive for the Owner.
For IMag applications, the currently-accepted “standard” for maximum video latency is 7 video frames, or a total of 116.67ms when using a 60 fps refresh rate. 116.67ms is just a little over 1/10 of one second. Anything greater in length becomes obvious to the average viewer, and a distraction to the desired performance or presentation on stage.
Why the distraction? The presentation of the enlarged image can easily arrive too late, and is therefore not in sync with the live presentation or performance that is taking place right next to the large display(s).In order to perform successfully, IMag systems require a very specific combination of hardware and software, as well as some skilled human interaction. Key elements include, but are not limited to:
Reasonably high-quality hardware, capable of high-speed signal through-put. (Read minimal latency.)
Hardware capable of operating natively within the desired system-wide signal format. HD-SDI is what we recommend and use.
Hardware capable of accepting a master clock or house-sync reference signal.
One or more HD video cameras.
Centralized video switching hardware and software, with full and simultaneous monitoring of all input and output signals.
Integrated or compatible graphics software to provide for still and full-motion background images as well as keyed text and IMag insertion.
One video director or production manager. (Optional for facilities with only one camera)
One video switch operator
One camera operator for each manned-camera position, or one camera operator for controlling multiple robotic cameras.
A two- (or more) channel production intercom system. (Optional for facilities with only one camera)
One or more large format displays.
IMag may sound like a nice idea but it is fraught with technical, operational and financial obstacles. If you are facing the IMag challenge alone, we would like to help. Our best results start with a conversation that outlines the needs, constraints and goals for your new systems.
Copyright - Michael Fay 2011 - All Rights Reserved