Dolby Laboratories have announced an extension to their Dolby 5.1 codec, called Dolby Digital Plus. The codec extension is of particular interest to television broadcasters because of the efficiency of its compression: if audio tracks take up less room, then it leaves more bandwidth for more channels.
Broadcasters are keen to deliver more channels to customers – particularly when they’re charging them – but need to keep picture quality up to, or even better than, current standards.The existing DD codec supports but rates from 320Kbps to 640Kbps for 5.1 audio – yet this new extension will reproduce 5.1-channel sound down to 192Kbps. Dolby Digital Plus has a new top end to – up to 6Mbps, which will no doubt be handy in the future.
Importantly, Digital Plus is backwardly-compatible with previous versions of the 5.1 codec.
Dolby have already come up with an interesting application for the new codec – a DVD could access a studio’s website and stream a live director’s commentary, or other interactive content, through the viewer’s TV.