Sunday, March 17, 2013

Blu-Ray High Definition Audio Formats

Blu-ray is rapidly increasing in sales and it's hard not to be impressed by high definition video when you see it. However Blu-ray does more than just add better pictures, it also adds high definition audio that surpasses that on DVD.

Blu-ray discs have more storage capacity than DVDs (DVDs are roughly 8GB, Blu-rays can be 25GB to 50GB) and as well as using this for better pictures there's also capacity to increase the audio quality.

DVD audio quality is very good already and was a quantum leap in comparison to VHS Video quality (which was stereo encoding and at best could create poor 3 speaker surround sound effects). Most DVDs were encoded in Dolby Digital (aka AC3) and for the majority of "modern" titles this presented them in 5.1 audio - meaning that you have 2 speakers infront of you on the left and right, another in the centre, and two speakers to the left and right behind you - and to increase the bass power a subwoofer (the ".1" part of 5.1) could be used. There was also DTS audio which was again 5.1 but was generally considered to sound better by experts. Later on the two standards were expanded to support up to 7 speakers and a subwoofer ("7.1") however this wasn't universally provided.

All formats on DVD were "compressed" and "glossy" so sound quality was lost during encoding and playback, this is in contrast to CDs which are uncompressed (and thus are universally agreed to have a higher sound quality and sound better).

Blu-ray provides a number of formats (in order of current quality):

Dolby Digital (aka AC3) - This is the minimum standard and provides audio in the same format as current DVDs (up to 5.1 channel surround sound). "DTS" - The same format as provided on some DVDs today gives up to 5.1 channel audio with higher quality than Dolby Digital (DD). Dolby Digital Plus - Provides up to 7.1 channel surround sound with less loss of quality than standard Dolby Digital "DTS-HD": The high definition form of DTS allowing up to 8 channels of digital audio with a higher quality than standard DTS encoding "Linear PCM" ("LPCM") - up to 8 channels of uncompressed audio, providing perfect "CD" quality audio without any loss Dolby "TrueHD" - compressed but loss less audio for up to 8 channels of audio

If you have a current surround sound amplifier/system then it's unlikely that you will be able to enjoy the new HD Audio capabilities of Blu-ray, and in the same way that you've had to buy a Blu-ray player to watch new blu-ray movies you'll have to do the same with your surround sound system to enjoy Blu-ray quality audio. However, it does sound amazing so if you're upgrading your system I highly recommend that you get a demonstration of HD audio and consider upgrading your system.

No comments:

Post a Comment