What is HDMI?
HDMI (High-Definition Multimedia Interface) is the first and only industry-supported, uncompressed, all-digital audio/video interface. By delivering crystal-clear, all-digital audio and video via a single cable, HDMI dramatically simplifies cabling and helps provide consumers with the highest-quality home theater experience. HDMI provides an interface between any audio/video source, such as a set-top box, DVD player, or A/V receiver and an audio and/or video monitor, such as a digital television (DTV), over a single cable.
HDMI supports standard, enhanced, or high-definition video, plus multi-channel digital audio on a single cable. It transmits all ATSC HDTV standards and supports 8-channel, 192kHz, uncompressed digital audio and all currently-available compressed formats (such as Dolby Digital and DTS), HDMI 1.3 adds additional support for new lossless digital audio formats Dolby® TrueHD and DTS-HD Master Audio™ with bandwidth to spare to accommodate future enhancements and requirements.
HDMI is the de facto standard digital interface for HD and the consumer electronics market: More than 700 companies have become adopters, and nearly 200 million devices featuring HDMI are expected to ship in 2008, with an installed based of nearly one billion HDMI devices by 2010 (conservative estimates by In-Stat).
Convergence – HDMI is the interface for convergence of PC and consumer electronics devices: HDMI enables PCs to deliver premium media content including high definition movies and multi-channel audio formats. HDMI is the only interface enabling connections to both HDTVs and digital PC monitors implementing the DVI and HDMI standards.
Evolving standard – HDMI is continually evolving to meet the needs of the market: Products implementing new versions of the HDMI specification will continue to be fully backward compatible with earlier HDMI products.
What is the difference between HDMI 1.3 and HDMI 1.3a, or 1.3b?
For consumers, there is no difference between HDMI version 1.3 and 1.3a or 1.3b. These minor revisions to the specification typically relate to manufacturing or testing issues and do not impact features or functionality. In addition, HDMI Licensing, LLC is actively working with manufacturers to reduce confusion for consumers by de-emphasizing version numbers and focusing instead on product features and functionality.
For Adopters, the latest HDMI Specification is v1.3a and the latest HDMI Compliance Test Specification (CTS) is 1.3c.
What is the difference between DVI and HDMI?
HDMI is DVI with the addition of:
Audio (up to 8-channels uncompressed)
Support for YUV Color Space
CEC (Consumer Electronics Control)
What is HDCP?
High-bandwidth Digital Content Protection (HDCP) is a form of digital copy protection developed by Intel Corporation to prevent copying of digital audio and video content as it travels across DisplayPort, Digital Visual Interface (DVI), High-Definition Multimedia Interface (HDMI), Gigabit Video Interface (GVIF), or Unified Display Interface (UDI) connections, even if such copying would be permitted by fair use laws. The specification is proprietary, and implementing HDCP requires a license.
For DVI interfaces, HDCP is optional.
HDCP is licensed by Digital Content Protection, LLC, a subsidiary of Intel. In addition to an annual fee, licensed adopters agree to the conditions set forth in the HDCP License Agreement. For example, high-definition digital video sources must not transmit protected content to non-HDCP-compliant receivers. Additionally, DVD-Audio content is restricted to CD-audio quality or less on non-HDCP-digital audio outputs (analog audio outputs have no quality limits). Licensed adopters cannot allow their devices to make copies of content, and must design their products in ways that "effectively frustrate attempts to defeat the content protection requirements." The technology sometimes causes handshaking problems, especially with older high-definition displays.
What are the differences between HDMI Versions?
A 36-bit support is mandatory for Deep Color compatible CE devices with 48-bit support being optional.
B Maximum resolution is based on CVT-RB blanking which is a VESA standard for non-CRT based displays. Using CVT-RB blanking 1920x1200 would have a video bandwidth of 3.69 Gbit/s and 2560x1600 would have a video bandwidth of 8.12 Gbit/s.
C Using CVT-RB blanking would have a video bandwidth of 8.12 Gbit/s.
D Using CVT-RB blanking would have a video bandwidth of 7.91 Gbit/s.
E Using CVT-RB blanking would have a video bandwidth of 7.39 Gbit/s.
F Even for a compressed audio codec that a given HDMI version can not transport the source device may be able to decode the audio codec and transmit the audio as uncompressed LPCM.
G CEC has been in the HDMI specification since version 1.0 but only began to be used in CE products with HDMI version 1.3a.
H Playback of SACD may be possible for older HDMI versions if the source device (such as the Oppo 970) converts to LPCM.
I Large number of additions and clarifications for CEC commands. One addition is CEC command allowing for volume control of an AV receiver.
What Does HDMI Connections Look Like?
HDMI Shape & Pins:
HDMI Female (Output) Port Sample:
How does changing to an HDMI connection affect my entertainment systems?
The most tangible and immediate way that HDMI changes the way we interface with our components is in the set-up. One cable replaces up to 11 analog cables, highly simplifying the setting up of a home theater as well as supporting the aesthetics of new component design with cable simplification.
Next, when the consumer turns on the HDMI-connected system, the video is of higher quality since the signal has been neither compressed nor converted from digital to analog and back.
Lastly, because of the two-way communication capabilities of HDMI, components that are connected via HDMI constantly talk to each other in the background, exchanging key profile information so that content is sent in the best format without the user having to scroll through set-up menus. The HDMI specification also includes the option for manufacturers to include CEC functionality (Consumer Electronics Control), a set of commands that utilizes HDMI’s two- way communication to allow for single remote control of any CEC-enabled devices connected with HDMI. For example, CEC includes one-touch play, so that one touch of play on the DVD will trigger the necessary commands over HDMI for the entire system to power on and auto-configure itself to respond to the command. CEC has a variety of common commands as part of its command set, and manufacturers who implement CEC must do so in a way that ensures that these common command sets interoperate amongst all devices, regardless of manufacturer.
CEC is an optional feature, however, so consumer interested in this functionality must look for CEC in the product feature list. Also, it is important to know that some manufacturers are creating their own proprietary names for their implementation of the CEC command set.
What kind of devices use HDMI cables and other HDMI connection accessories?
In general, most of the newest home theater equipment, and audio/video equipment is adapting HDMI. Some devices include:
- New TVs - specifically HDTVs (LCD, Projector, Plasma)
- New DVD Players
- Blu-Ray & HD DVD Players
- Sony PlayStation 3 video game system
- Home Theater 5.1 systems
- A/V (Audio & Video) Receivers
- Digital / DVR Cable and Satelitte Boxes (check with your provider)
- Select models of digital Cameras and Camcorders
When buying a new TV or home theater electronic - what HDMI related questions should I ask?
Several questions are key to evaluating HDMI on a CE component.
- How many inputs/outputs do I need?
- We are seeing more and more inputs and outputs on components as more and more people are connecting with HDMI. It is common to see 3 and 4 inputs on an HDTV – many with one input on the side or front for connecting to game consoles or other portable devices such as digital still cameras or camcorders. Always think about the number of sources and displays (or projectors) that could become part of your home theater system, and make sure the device you are evaluating has the number of inputs and outputs to support your needs over the near and long term.
- For those who have existing systems with one or two inputs, and are finding they need more, there are HDMI switches in the market that switch from multiple inputs (sources) to one output (to your display).
- Think features rather than HDMI version number.
HDMI is constantly evolving to meet the needs of the marketplace. The standard is constantly adding more and more features that manufacturers can implement if they desire. But HDMI does not require manufacturers to implement everything that HDMI can do. HDMI provides a menu of capabilities and allows the manufacturer to choose which of those features make sense for its product line.
As a result, HDMI strongly recommends that consumers look for products with the features they want, rather than the version number of the HDMI components. Version numbers reflect capabilities, but do not correspond to product features. For example, if you want the new video features called Deep Color, look for Deep Color in the feature set rather than HDMI 1.3, the version of the specification that enabled Deep Color. Why? Because the version of the specification that enables Deep Color (1.3) does not mandate that Deep Color functionality be implemented.
However, it is important to also note that all HDMI versions are backwards compatible, so it does not matter what version of HDMI is in the component, all HDMI-enabled components will work together at the highest level of shared functionality.
resources: HDMI.org, Wikipedia