If youâ€™ve taken the plunge and invested in a high definition TV, youâ€™re probably keen to make the most of your shiny new screen. Itâ€™s hard to believe that only a year ago, the only high definition source that was easily available was the Xbox 360, and that didnâ€™t even make use of that lovely, digital HDMI port that was laying dormant at the back of your TV. In fact it wasnâ€™t until May last year, when Sky launched its HD box that there was actually something to plug into your HDMI port, which is probably why there are masses of HDTVs out there with only one HDMI input.
Of course having only one HDMI input wasnâ€™t too much of a problem when there was nothing to plug into it, but things have changed and now youâ€™re spoiled for choice. As well as the Sky HD box, you can now pick up a Blu-ray player, or an HD DVD player and in a few weeks, youâ€™ll be able to add a PlayStation 3 to that list. Now, if youâ€™ve only got a single HDMI port, youâ€™re in for a lot of reaching behind your TV and swapping cables every time you want to watch a different source.
The answer to the above problem is an HDMI switcher box â€“ a unit that will accept multiple sources and then switch between them, while outputting to the single HDMI port on your TV. This concept is nothing new and weâ€™ve been using switcher boxes for some time in the AV world. In fact I reviewed the excellent AV-5831 Component Video switcher from AV Tool last August, but things are a little more complicated with an HDMI switcher.
With an analogue switcher box like the Component Video unit I looked at previously, the big challenge is making sure that there is no signal degradation caused by the added impedance. Although both the AV Tool unit and the Joytech Component Video switcher that Andy reviewed recently, produced a pleasingly clean and sharp image that was almost impossible to discern from a direct connection. Obviously with a digital connection, signal degradation is far less of an issue, but HDMI does bring with it the problem of HDCP.
HDCP is the protocol that is used to protect digital content from copyright infringement. For example, if you connect a Sky HD box to a screen that isnâ€™t HDCP compliant it will refuse to display an image â€“ it will actually just present you with a large window telling you to disconnect your HDMI cable to be precise. A PlayStation 3 on the other hand, will down scale content to standard definition if it isnâ€™t connected via an HDCP compliant HDMI connection. So HDCP compliance is paramount for any company attempting to produce an HDMI switcher.
Luckily for all those HDTV owners with multiple HDMI envy, there are a couple of companies who have cracked the HDMI switcher problems and have products that offer both multiple input switching and HDCP compliance.