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| Editorial by: Josh Lehman 26 Apr 2006 The Sound and the Furious: The Next Generation
| | New formats, new sound schemes, new headaches. With the advent and implantation of HD-DVD and Blu-Ray Disc, we are once again hit with not only having to upgrade our optical disc players, but now we are going to have to upgrade our current preamps, receivers or processors to enjoy the latest and greatest the folks at Dolby Labs and DTS have to offer. Here’s a breakdown of the new sound technologies:
Dolby TrueHD
Features
* 100 percent lossless coding technology.
* Up to 18 Mbps bit rate.
* Supports up to eight full-range channels of 24-bit/96 kHz audio.*
* Supported by High-Definition Media Interface (HDMI‚Ñ¢), the new single-cable digital connection for audio and video.
* Supports extensive metadata including dialogue normalization and dynamic range control.
*Dolby TrueHD can support more than eight audio channels. HD DVD and Blu-ray Disc standards currently limit their maximum number of audio channels to eight.
Benefits
* Delivers enthralling studio-master-quality sound that unlocks the true high-definition entertainment experience on next-generation discs.
* Offers more discrete channels than ever before for impeccable surround sound.
* Compatible with the A/V receivers and home-theaters-in-a-box (HTIBs) of today and tomorrow.
* Dialogue normalization maintains the same volume level when you change to other Dolby Digital and Dolby TrueHD programming.
* Dynamic range control (Night mode) enables you to customize audio playback to reduce peak volume levels (no loud surprises) while experiencing all the details in the soundtrack, enabling late-night viewing of high-energy surround sound without disturbing others.
* Selected as the mandatory format for HD DVD and as an optional format for Blu-ray Disc.
Dolby Digital Plus
Features
* Mulitchannel sound with discrete channel output.
* Channel and program extensions can carry multichannel audio programs of up to 7.1 channels* and support multiple programs in a single encoded bitstream.
* Outputs a Dolby Digital bitstream for playback on existing Dolby Digital systems.
* Supports data rates as high as 6 Mbps.
* Bit rate performance of at least 3 Mbps on HD DVD and up to 1.7 Mbps on Blu-ray Disc.
* Accurately reproduces what the director and producer intended.
* Interactive mixing and streaming capability in advanced systems.
* Supported by HDMI‚Ñ¢, the new single-cable digital connection for high-definition audio and video.
Benefits
* Can deliver 7.1 channels and beyond* of enhanced-quality audio at up to 6 Mbps.
* Allows multiple languages to be carried in a single bitstream.
* Offers audio professionals new creative power and freedom.
* Compatible with the millions of home entertainment systems equipped with Dolby Digital.
* No latency or loss of quality in the conversion process.
* Maintains high quality at more efficient broadcast bit rates (<320 kbps for 5.1-channel audio).
* Selected by the Advanced Television Systems Committee (ATSC) as the standard for future broadcast applications; named as an option by the Digital Video Broadcasting (DVB) Project for satellite and cable TV.
* Selected as the mandatory audio format for HD DVD and as an optional audio format for the Blu-ray Disc.
*Dolby Digital Plus can support more than eight audio channels. HD DVD and Blu-ray Disc standards currently limit their maximum number of audio channels to eight.
DTS-HD Master Audio
*7.1 Discrete Channels
*Bit for Bit Identical to the Original Master
*Optional for Both Blu-Ray Disc and HD-DVD
So what does all this mean? Let’s take a step back: remember the leap in sound from Dolby 5.1 to DTS? Remember the leap from Dolby and DTS to SACD and DVD-Audio? SACD and DVD-Audio both delivered 5.1 soundtracks at roughly 96/24 5.1, with bit rates up to 3Mbps. Dolby Digital Plus is basically a smaller step-up from SACD and DVD-Audio, but offering up to 7.1 Discrete channels (and the capability to do more, although BD and HD-DVD will only currently support a maximum of 7.1 discrete channels).
Although the exact specs for DTS-HD Master Audio is not known, it appears to be relatively the same as Dolby True HD, and therefore will be up to 18Mpbs and 192/24 up to 7.1 channels. This means roughly twice the “resolution” of SACD or DVD-Audio, with zero compression at a much-higher bit rate. Think of this as what Superbit did for DVD, this will do for HD discs.
Many are complaining that HD-DVD simply does not blow away DVD; that may be true on smaller sets, but it certainly does on bigger screens. What is for certain though, these new soundtracks, even the ones that are choosing just Dolby Digital Plus for now, are certainly to blow away their DVD counterparts as Dolby 5.1 is limited to 640kbps and DTS is limited to 1509 kbps on DVD. Twice the resolution of DVD at the minimum for audio, with dramatically better clarity. So can’t we enjoy this now? Yes and no.
Dolby Digital Plus, yes, but only 5.1 soundtracks, and we only have two ways to enjoy it currently: through the 5.1 analog outs (for 7.1, you are screwed as all the first gen BD and HD-DVD players only offer 5.1 analog outs), or, if your processor supports it, as LPCM 5.1 (raw digital data) via HDMI. Unfortunately, there are only a handful of pieces that support HDMI Audio currently, and even less that support multi-channel PCM playback. Halcro Logic will most likely be the first high-end preamp to support LPCM 5.1 or 7.1, and, more importantly, the first to implement HDMI 1.3 and all three new formats natively. For Dolby TrueHD, however, we are again toasted currently as the Toshiba HD-A1 only supports 2-channel decoding of TrueHD, so soundtracks like the TrueHD 5.1 track on Phantom of the Opera is currently a waste.
Wait a minute? Did I say HDMI 1.3? What the hell is that, do you say? Well, HDMI 1.3 is the mojo for both HD-DVD and BD. It allows your next-gen disc player to pass the TrueHD, Plus or HD Master Audio directly to your receiver or preamp, and be decoded and processed using your preamp or receivers DACs, etc. And, hey, we won’t be limited to a craptastic 2-channel mix of a 5.1 track, either. The wait is on, as no one currently knows when this will implemented, but dare I say, I would think sometime in May or June we will see pieces emerge that meet the standard and have built-in decoders for the new formats.
But what does the guy do who has only digital coax or digital optical cable, with no HDMI in for audio? Unfortunately, you are in for an experience not much better than you are getting now. On the current Toshiba HD-A1, the sound is decoded from Dolby Digital Plus or DTS-HD, and then re-encoded as DTS and passed to your receiver. Why? The unit only has a DTS encoder, so that’s what it passes. A lot of people are unhappy they are selecting Dolby on the disc menu and their preamp or receiver says “DTS,” but this is the way it is as DTS is the better choice for re-encoding as it can handled 1509kbps, which is much closer to the rate of Dolby Digital Plus.
Confused? Don’t worry, folks, it will only get worse; but that’s why you have us to help you out and only confuse you further.
*Dolby specifications courtesy of Dolby Labs
*DTS specifications courtesy of DTS | About Josh | | Besides being the Publisher of Digital Audio Video.com, Josh Lehman is the co-author of McGraw-Hill Osborne's How to Do Everything with TiVo. He also is one of the top ISF/HAA technicians in the US, and is regarded as one of the best home theater designers available today. Since 1997, Josh has been "DocDVD" beginning on the Digital Bits and then on DVD.com, providing 24-hour-a-day free technical support for Home Theater products. If you would like to contact Josh with a comment or you would like to setup a calibration or consultation appointment, click here. |
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Copyright (c) 2007 Rock Star Media Works, Inc. All rights reserved.
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