InstaPort Reduces Painful Lag in HDMI Switching

If you have multiple HDMI sources connected to a single TV, you know the lag time when switching sources can be painful – maybe four to seven seconds.

Silicon Image, developer of HDMI technology, now has a solution called InstaPort that can "reduce switching time to under one second," says Lew Pacely, DTV marketing director for the company.

"It works at least five times faster, and sometimes a little bit more."

The reason for the lag in the first place is that, because of HDCP content protection requirements, says Pacely, "We must authenticate the link before we can distribute content. It just takes some time."

Currently, HDCP authentication takes place only when an HDMI source is actively switched on.

With InstaPort, a new piece of technology allows inactive devices to begin the authentication process, and InstaPort "holds them in ready, even though they are not selected by the TV," Pacely says.

InstaPort can be implemented in a single chip and does not require extra processing power from the device itself.

"It adds processing power, but it is self-contained in our devices," says Pacely. "It operates autonomously from the processor in the TV."

The technology does not in any way alter the content or communications, Pacely says. For example, EDID (Extended Display Identification Data) and CEC (Consumer Electronics Control) operate the same as before. "The source is unaware of InstaPort operation," he says.

InstaPort technology will be incorporated into three new Silicon Image semiconductor products, including the SiI9287 port processor and the SiI9251/SiI9261 input processors, all which will be sampling in July. The first compliant products should be available in the first half of 2009.

The technology cannot be retrofitted into existing TVs.


This figure shows a TV without Instaport. While one source is active, the TV locks out the other sources. Only when another device is switched on, does the TV authenticate that source for transmission. That can take up to seven seconds. The illustration at the top of the page shows how InstaPort can authenticate the unused devices while they are inactive, so they stand "at the ready" to transmit when called upon.

What Took So Long?

When HDMI emerged many years ago, we just didn't have a lot of sources that connected to the TV.

"Either an internal tuner inside the TV or a settop box is where we've gotten most of our content," says Pacely.

Today, however, "the consumer is getting more and more of their channels outside of the box," he adds. "They should have the ability to get the same experience whether it [source] is inside or outside the box."

Silicon Image plans to have a licensable logo program (great another logo) to support InstaPort.

Pacely suggests, however, that participating manufacturers may "bring their own brands," as they do, for example, with HDMI's Consumer Electronics Control (CEC).