What is HDMI?
HDMI (High-Definition Multimedia Interface) is an uncompressed, all-digital audio/video interface. It provides a connection between any audio/video source, such as a set-top box, DVD player, and AV receiver and an audio and/or video monitor, such as a digital television (DTV). It supports standard, enhanced, or high-definition video, plus multi-channel digital audio on a single cable. HDMI transmits all ATSC HDTV standards and supports 8-channel digital audio, with bandwidth to spare to accommodate future enhancements and requirements.
How do users benefit from HDMI?
HDMI digital interconnect provides:
- Superior, uncompressed digital video and audio quality
- Simple, user-friendly connector that replaces the maze of cabling behind the entertainment centre
- Integrated remote control
- A popular interface enabling the transmission of high-definition content.
When was the HDMI specification released?
The first HDMI specification (1.0) was released in December 2002. The latest version of HDMI is 1.3.
What is the life expectancy of HDMI?
HDTV uses less than half of HDMI's available 5 Gbps bandwidth. With capacity to spare, HDMI can incorporate new technology advancements and capabilities long into the foreseeable future.
Does HDMI provide a secure interface?
HDMI, when used in combination with HDCP (High Definition Digital Content Protection), provides a secure audio/video interface that meets the security requirements of content providers and systems operators.
What are the advantages of HDMI over existing analogue interfaces such as composite, S-Video and component video?
- Quality HDMI transfers uncompressed digital audio and video for the highest, crispest image quality
- All Digital HDMI ensures an all-digital rendering of video without the losses associated with analogue interfaces and their unnecessary digital-to-analogue conversions
- Low-cost HDMI provides the quality and functionality of a digital interface while also supporting uncompressed video formats in a simple, cost-effective manner
- Audio HDMI supports multiple audio formats, from standard stereo to multi-channel surround-sound
- Ease-of-use HDMI combines video and multi-channel audio into a single cable, eliminating the cost, complexity, and confusion of multiple cables currently used in A/V systems
- Intelligent HDMI supports communication between the video source (such as a DVD player) and the DTV, enabling new functionality
Is HDMI backward compatible with DVI (Digital Visual Interface)?
Yes, HDMI is fully backward compatible with DVI using the CEA-861 profile for DTVs. HDMI DTVs will display video received from existing DVI-equipped products, and DVI-equipped TVs (provided they are equipped with HDCP decoding) will display video from HDMI sources.
What types of video does HDMI support?
HDMI has the capacity to support existing high-definition video formats (720p, 1080i, and even 1080p). It also has the flexibility to support enhanced definition formats such as 480p and 576p, as well as standard definition formats such as NTSC or PAL. Multiple frame rates are also supported.
What types of audio does HDMI support?
The specification allows for up to 8 channels of audio with 24 bits at sampling rates for up to 192 kHz. It will therefore support all current forms of PCM audio including DVD-Audio, and compressed audio formats such as Dolby Digital™ and DTS™.
As HDMI has developed its audio capabilities have increased. It now includes transmission of DSD data (for SACD in its native form, V1.2 on). HDMI V1.3 also includes support for the very latest Dolby Digital+, Dolby TrueHD, DTS High Definition and DTS Master Audio formats in their native bitstreams.
Does HDMI accommodate long cable lengths?
Yes. HDMI technology has been designed to use standard copper cable construction at long lengths. In order to allow cable manufacturers to improve their products through the use of new technologies, HDMI specifies the required performance of a cable but does not specify a maximum cable length. In practice the maximum length an HDMI cable will work at is dependant on the amount of data being sent. A standard definition (480 or 576 line) TV picture is often able to travel 15m or more. At higher resolutions (such as 720 or 1080 line) maximum cable lengths can be shorter. As semiconductor technology improves, even longer stretches can be reached with fibre optic cables, and with active cable technologies such as amplifiers or repeaters.
Where can I find more information about HDMI?
The very latest information about HDMI, its adopters and standards are available at the HDMI Organisations website.