Well if you have gone ahead and bought a new HDTV wouldn't you want HD sound? Today we discuss the two audio formats that bring even more life to what you see on the screen. 

 

 

High Definition Audio

Thanks to HD-DVD and Blu-ray we can see the our home movies in high definition - and thanks to Dolby and DTS we can hear them like never before.  There is a lot of information out there surrounding the next generation audio formats.  And with that information comes a ton of questions, most of which have landed in our inbox.  We've taken some time to compile as much information as we can on the new, competing high-definition audio formats.  Hopefully this will help to clear up the confusion.  At least a little.

DTS

We'll begin with DTS, since the transition from DTS to DTS HD is pretty simple.  While the standard DTS digital surround (2 channel) format is mandated by both the HD-DVD and Blu-ray specifications, DTS digital 5.1 and DTS ES digital 6.1 are also available as optional formats.  In addition DTS has three new audio formats available for the next generation movie discs.  They are DTS Encore, DTS-HD High Resolution, and DTS-HD Master Audio. 

DTS Encore is essentially the same thing as the standard DTS digital format, it just adds twice the resolution by increasing sample rates and sizes to 96 and 24 respectively.  That's a fancy way to say that it will sound a lot better and your current DTS enabled receiver should have no problem decoding it. 

DTS-HD High Resolution is a new 7.1 channel format that delivers thae same 96 kHz / 24 bit audio at significantly higher bitrates, delivering compressed audio that is almost exactly what was mixed.  It allows the movie studio to include audio that is very close to uncompressed, without taking up all the space an uncompressed audio track would need.  At it's core it holds a DTS digital track, with extensions for the additional information, so there's no duplication of data.

DTS does not claim, on their website at least, that DTS-HD Master Audio is a lossless codec.  Instead they say that there is so much audio information in the soundtrack, and that it uses such a high bitrate, that it delivers exactly, bit for bit, what was mixed in the recording studio.  Bit for bit seems to infer lossless, but the word doesn't appear on their site.  They claim it delivers sound that is clear, pure and uncompromised.  It appears that Master Audio also uses a 5.1 track at its core, with extensions for the additional information.

A description of the DTS formats.

Dolby

Dolby is doing its own thing.  For next generation audio formats Dolby is offering Dolby Digital Plus and Dolby TrueHD.  Dolby Digital Plus  is roughly analogous to the DTS-HD High Resolution format.  It includes a Dolby Digital track at its core, with extensions for the additional information.  While it is capable of more than 8 channels of audio, both Blu-ray and HD-DVD have limited the number of available channels to 8.  This makes DD Plus essentially a 7.1 format.  It supports data rates up to 6 Mbps.

Dolby TrueHD promises a lossless experience, according to the website it is a 100 percent lossless coding technology.  Like DTS-HD Master Audio, Dolby TrueHD provides 8 full-range channels of 96 kHz / 24 bit audio.  From what we can tell, the Dolby TrueHD stream is actually two stream in one.  One carries the Dolby Digital track for backward compatibility, another carries a stream very similar to their lossless DVD Audio format called MLP.  Whether or not this causes redundancy in the data is undetermined.

Support in HD-DVD

Currently the HD-DVD spec requires support for LPCM, DTS 5.1, Dolby Digital 5.1 and 2 channel Dolby TrueHD.  HD-DVD gets DTS 5.1 by mandating support for DTS-HD, but only the "core" 5.1 track, so you may see that DTS-HD is mandated, but in truth, it's just the 5.1 core DTS Digital track (at 1.5 Mbps).  The players internally decode all audio formats to an uncompressed Linear PCM format compatible with most current receivers.  This PCM is transmitted to the receiver via HDMI.  For non-HDMI receivers, the same audio is converted to analog and output via 6.1 analog outputs to your receiver.  If you want to stick with the legacy digital audio cables (optical or digital coax), the player will re-encode the audio to DTS 5.1 for your receiver to playback.  All of the other formats are included in the spec as optional.  HD-DVD supports DTS-HD High Res up to 3 Mbps and DTS-HD Master Audio up to 18 Mbps.  It supports Dolby Digital plus up to 3 Mbps and Dolby TruHD up to 18 Mbps.

Support in Blu-ray

The Blu-ray spec requires support for LPCM, DTS 5.1 and Dolby Digital 5.1.  All the other formats are optional.  The current player on the market, the Samsung BDP-1000, supports Dolby Digital, Dolby Digital Plus and DTS.  The HD formats are nowhere in sight.  It appears that the player also decodes everything to LPCM for output on the HDMI line, converts it to analog for the 6.1 outputs and also sends it out the legacy digital ouptus.  Blu-ray supports DTS-HD High Res up to 6 Mbps and DTS-HD Master up to 24.5 Mbps, due to Blu-ray's higher bandwidth capabilities.  Fos some, unknown reason, Blu-ray only supports Dolby Digital Plus up to 1.7 Mbps, but supports Dolby TrueHD up to the maximum 18 Mbps.

Both players decode everything to PCM to allow the player itself to mix, merge and modify soundtracks on the fly.  For this reason, Receivers may never have the HD audio format decoding built-in.  We'll have to wait and see what happens.