The transition from analog to digital in the video world has been quick and a key enabler of this has been HDMI, High Definition Multimedia Interface. Virtually all HD equipment utilizes HDMI to transport audio/video from the sources to the display. The original rendition of HDMI, HDMI 1.0 was released back in 2002 and has been the de facto standard for HD Video transmission. As the digital revolution has continued, HDMI has also evolved from 1.0, 1.1, 1.2 and mostly recently HDMI 1.3.

HDMI 1.0 -Single-cable digital audio/video connection with a maximum bit rate of 4.9 Gbps. Supports up to 165Mpixels/s video (1080p60 Hz or UXGA) and 8-channel/192 kHz/24-bit audio.

HDMI 1.1 - Added support for DVD audio

HDMI 1.2 -Added support for One Bit Audio, used on Super Audio CDs, up to 8 channels. Ability for PC sources to use native RGB color-space while retaining the option to support the YCbCr CE color space.

HDMI 1.3- Increases single-link bandwidth to 340 MHz (10.2 Gbps)

- Optionally supports 30-bit, 36-bit, and 48-bit xvYCC with Deep Color or over one billion colors, up from 24-bit sRGB or YCbCr in previous versions.

- Incorporates automatic audio syncing (lip sync) capability.

- Supports output of Dolby TrueHD and DTS-HD Master Audio streams for external decoding by AV receivers.

- Availability of a new mini connector for devices such as camcorders.

You will still get incredible HD picture quality with HDMI 1.1 and HDMI 1.2. HDMI 1.3 is backwards compatible with previous versions of HDMI. Getting HDMI 1.3 display and HDMI sources will enable you to take advantage of the extra feature enhancements available. If you are in the market for a new HDTV, then it would be advisable to get one with HDMI 1.3 support. However, you should look for the specific features that are supported.

On the physical layer level, all HDMI versions utilize Transmission Minimized Differential Signaling, TMDS and the physical connector looks identical. The major enhancements of HDMI 1.3 are:

HDMI 1.2 supports aggregate data rate of 4.95 Gbps.

In order to ensure that HDMI is the connectivity of the future, HDMI 1.3 has provisions to eventually double the bandwidth from 4.95 Gbps to 10.2 Gbps. For comparative purpose, USB 2.0 has a maximum data transfer rate of 480 Mbps, 1/20 of the data rate of HDMI 1.3.

Although, HDMI 1.3 has provision for up to 10.2Gbps, the transition will be gradual with the first devices available to achieve 6.75Gbps initially.

The increased bandwidth in HDMI 1.3 enables higher display resolutions beyond the typical 1920x1080P resolution and improved color depth. For example, HDMI 1.2 allows 8 bits/ pixel to be allocated for color information. In version 1.3, HDMI has provisions to support 10, 12 and 16 bit color/ pixel thus allowing for even improvement in picture quality.

The modern HDTV performs complex digital processing to the incoming video signal such as de-interlacing, format conversion, noise reduction and etc. The digital video processing takes finite time to execute and must be synchronized with the audio portion of the incoming signal to ensure that both video and audio are synchronized and no delay is perceived. Most HDTV have compensation to ensure that the audio and video are properly synchronized However, many consumers will likely process the audio separately in a surround sound system. HDMI 1.3's lip synch feature allows the audio and video signal to be synchronized to external HDMI devices.

HDMI 1.3 has also added an optional mini HDMI connectors so handheld HD video devices such as HD video cameras can also utilize HDMI for HD connectivity.

HDMI 1.3 is fully backwards compatible with previous versions of HDMI. So if your display supports 1.2 and your source is 1.3 capable. The source and display will arbitrate for the best available format. HDCP, although not required by HDMI 1.3, still enables HDCP to be implemented over the HDMI interface.