September 13, 2012 by EH Staff
By Orrin Charm
When an entertainment system is comprised of multiple video components, such as set-top boxes, Blu-ray players and media servers, it makes sense to share all that content with every TV in your house.The common way to do this is through a device called a matrix switcher. Matrix switchers range from two inputs and two outputs (2x2) for around $200, all the way up to 32 inputs and 32 outputs (32x32) or more for around $16,000.They are intended to be installed and programmed by a custom electronics (CE) professional.
We will focus on Gefen’s ToolBox 4x4 Matrix for HDMI to explain the particulars of matrix switching. Deceptively simple on the outside, this 4x4 Matrix for HDMI is actually a very complex device, containing four 1:4 HDMI splitters, a cross-point matrix, and four 4x1 HDMI switchers, all controlled by a microprocessor. Preserving and respecting HDCP data (see sidebar) while avoiding authentication delays requires a lot of processing power. While the integrated circuit chips do the heavy lifting, custom programming, exhaustive testing and quality of customer support are what differentiate the players in this competitive market.
1. HDMI INPUT (1 OF 4). Video sources are connected to each of these jacks.
2. HDMI OUTPUT (1 OF 4). Video displays are connected to each of these jacks.
3. 4X1 HDMI SWITCH IC. This chip selects the source for each HDMI output and equalizes the HDMI signal.
4. IR RECEIVER. The IR receiver allows the matrix to be controlled by a handheld IR remote.
5. EXTERNAL CONTROL PC BOARD. This board holds the RS-232, external IR control and mini-USB (service) ports.
6. STATUS LEDS (16). These LEDs indicate the current switching status of the matrix.
7. SWITCHING PUSH-BUTTONS. Pressing each of these buttons sequentially changes the source for each display.
8. AUDIO SWITCH. This switch determines if each source sends two-channel or multichannel audio.
Orrin Charm is an expert on systems integration, user interfaces, wiring and installation practices. As the Automation Project Manager at Gefen, he oversees all aspects of Gefen’s new automation and control line of solutions.
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Important Terms Defined
FST (Fast Switching Technology): HDMI requires an HDCP (High-Bandwidth Digital Content Protection) authentication process every time a video source is connected or switched. FST speeds this process and prevents an interruption of video when another display or source is switched.
HDCP (High-Bandwidth Digital Content Protection): HDCP is a form of digital copy protection that prevents the unauthorized copying of digital audio and video content as it travels across connections, from a source to a display.
EDID (Extended Display Identification Data): EDID is a data stream sent from a display to the source to describe its capabilities, so the source will send the proper signal format and resolution. In a system with multiple displays connected to the same source, EDID management is critical, or displays will not show the proper signal quality.
Resolution: A matrix switcher should maintain the integrity of video resolution and quality throughout the switching process. For example, support for 1080p Full HD with Deep Color will ensure that it can handle any video resolution transparently.
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