The goal for all the players is to create a new class of high definition home networks. They will let users play any content on a digital TV and use the TV and a remote to control any connected device. The efforts come at a time of increasing fragmentation in home networks.

The HDMI wannabes require new cables or connectors, some of them proprietary. They also require getting chips designed into next-generations TVs, Blu-Ray drives, PCs and other devices or using external connection boxes.

The newcomers compete with a relative giant. HDMI will appear in nearly 400 million systems this year, including nearly every new digital TV, and more than a dozen companies make chips supporting HDMI.

HDMI Licensing LLC is about to make its version 1.4 specification available to adopters. It includes support for 100 Mbit/second Ethernet, an audio return channel and support for higher resolution displays. Chips based on the new spec are expected to be released soon by companies including Silicon Image, parent of the HDMI licensing firm.

The 1.4 spec also builds in some basic capabilities to handle future stereo 3-D content, seen by some as the next big thing after HDTV. The new spec details how to pack and unpack stereo video content over the HDMI lines without taking a position on what should be the 3DTV broadcast or rendering formats, issues still being hotly debated.

A handful of former Silicon Image executives created Synerchip Inc. and launched a spec called Diiva in late April to compete with HDMI 1.4. The startup leveraged connections with China's TV makers to gain backing from them and the China's government, all eager to create their own standard and eliminate HDMI royalties. Backers include Changhong, Haier, Konka, Panda, and TCL in China as well as other top TV makers in Asia such as LG, Panasonic, Samsung and Sharp.

The Diiva spec is a serdes-based design that dedicates 13.5 Gbits/s bandwidth to video and has another 2 Gbits/s available for Ethernet, USB and audio functions. It supports the two leading content protection techniques, HDCP and DTCP-IP.

One downside to the approach is Synerchip requires a Category 6 cable to reach 25 meters and unique connectors to maintain signal integrity. Steve Yun, vice president of product marketing at Synerchip, gave a demo of the technology at the Connections conference here.