Along with its new glasses-free 3D technology, Dolby is bringing an updated version of its Digital Plus surround sound technology to NAB this year. Dolby Digital Plus is the current incarnation of the company's discrete surround technology, where each audio channel is delivered separately rather than decoded from a stereo stream. Normally, the bare minimum bit rate used by broadcasters to deliver Dolby Digital Plus is around 384kbps, but Dolby says that through tweaking the codec it has been able to reduce this down to just 192kbps.
This means that the audio stream would need to take up only half as much bandwidth, allowing broadcasters and streaming providers to add extra commentary or languages, more surround channels (allowing for 7.1 surround), or even to use the freed-up bandwidth for more TV channels. The best part of this is that current Dolby Digital Plus decoders will support the lower bit rate streams, so your cable box, Xbox 360, and PS3 will still work fine. Whether you'll notice the reduction in quality or not is a different matter.