High-definition surround sound explained
Blu-ray and HD DVD don’t just offer awesome pictures – thay can also offer substantially better sound quality too. We’ve written a great deal about compression formats, usually when discussing the pros and cons of MP3. But it’s equally an issue in home cinema: in order to maximise disc space (especially with the rather more memory-starved traditional DVD), some form of compression of the soundtrack is usually necessary.
But things are changing. It’s now possible to store an uncompressed PCM soundtrack on a Blu-ray or HD DVD disc, while the new compressed formats include two ‘lossless’ formats – Dolby True HD and DTS Master Audio. This means exactly what it says: a lossless signal, when decoded, should replicate exactly the original uncompressed signal.
As you can see in the diagram above, the bitrates of these lossless formats are much bigger than traditional data rates: at a maximum bitrate of 24.5 mbps, DTS Master Audio delivers roughly 50 times as much information, per second, to your receiver as a standard Dolby Digital soundtrack on DVD.
Data rates tell their own story: the more information you have, the better it can sound. We’ve listed the tech specs of all the current high-definition players in the panel below. So with Blu-ray and HD DVD, you’re in for a sonic treat as well as great pictures.