BBC brings back test card for HD

The BBC is transmitting a test card in high definition to help viewers optimise their TV and home theatre settings.

The card, much anticipated by Digital Spy forum users, airs for 90 seconds once every two hours in the BBC HD channel's preview loop. A second test signal, which airs later in the loop, is designed to ensure that viewers with home theatre audio setups are able to precisely synchronise sound with video.

In a BBC Internet Blog post, Andy Quested - principal technologist, HD at BBC Future Media and Technology explained: "Many of you have been asking for a test signal to help line up your own HD TVs, we have been listening but it's taken a while to get it sorted."

Quested's post offers a detailed guide to using the two test signals, which when used correctly offer optimisations for brightness, contrast, colour and sharpness. Audio-video sync, which has been problematic on BBC HD's surround sound output in the past, is also adjustable by users who connect their set top boxes to AV systems with delay controls.

Because the signals air at different times - 1 hour into the preview reel for the test card and 1 hour 50 minutes for the sync signal, Quested suggested that viewers set a manual recording on set top boxes starting an hour after the last programme of the day on BBC HD airs.