High Definition Multimedia Interface cables carry enormous amounts of high-definition video and uncompressed audio. Numerous internal conductors carry control, audiovisual, copy protection and communication data all along one cable. You can connect two devices with HDMI cables if they both contain an HDMI port. These devices can include computers, televisions, projectors, video game systems, and Blu-ray players, among others.
HDMI cables allow top performance from a single cable. Connecting your Blu-ray, satellite decoder and video game system to a home theater receiver involves only three total HDMI cables. A fourth HDMI cable leads from the receiver to your television or projector. HDMI also allows passage of Internet data from source to source, using Ethernet over HDMI. This is useful for Web-based apps on modern displays, as well as facilitating advanced gaming and special feature content on Blu-ray players.
There are many HDMI cables on the market, spanning large ranges in price. HDMI operates using a digital signal. Since the data is digital, only major defects or breaks in the cable result in diminished quality. On occasion, an extremely long HDMI cable running in excess of 50 feet may result in intermittent performance, but these are largely solved using repeaters. These devices regenerate the HDMI signal to prevent losses over longer runs. Repeaters often allow the maximum range to double or triple, depending on the repeating device. The highest priority for HDMI selection is selecting an adequate gauge for the distance the cable must traverse. Beyond this simple electrical requirement, HDMI cable cost is influenced by appearance, silver content in the internal wiring, brand and sundry marketing costs passed to the consumer.
HDCP and Analog Cables
High Definition Copy Protection, or HDCP, requires a digital identifying "handshake" from source devices to the television or projector in an HDMI-connected system. This security verification informs these devices that they operate within the HDCP structure. Due to HDCP, hardware manufacturers often limit resolution to standard definition when using analog connectors, regardless of the cable's capabilities. Component video and VGA cables are capable of high-end video performance with resolution comparable to HDMI but do not incorporate HDCP or audio. Component video and VGA jacks are rarely present on modern devices to reduce manufacturing costs with the prevalence of HDMI on receivers and televisions. Basic analog composite and S-video cabling cannot handle the bandwidth needed for high-definition video, and no analog cables simultaneously carry audio. DVI, the immediate predecessor to HDMI offers digital video, but likewise cannot transmit audio.
Command and Control
Consumer Electronics Control, or CEC, sends a constant stream of communications information through all devices that support the feature. Since you might want to watch something without your surround system on, CEC allows audio and video to pass to your display without your A/V receiver activated. CEC is often known by proprietary names, such as "SimpleLink" or "CE-Link." The feature allows you to control all compatible devices through one remote, typically included with your television.
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