HD DVD High-Res Audio Connections
Robert Harley -- Tue, 06/13/2006 - 11:09
Dear Mr. Harley
I have a great deal of respect for you and The Perfect Vision. I have subscribed to your publication for several years now and look forward to reading each and every issue. Your publication has influenced the upgrading my home system. I have recently purchased and new Sony KDS-R50XBR1, Rotel RSP-1068, and a Rotel RMB-1075. These purchases were guided by the reviews and buying guides that I have read in The Perfect Vision.
I am emailing you because I have some questions about the new disc formats that I am unable to answer through my normal research and thought maybe you could help. First, it is my understanding that next generation of disc players will be able to pass uncompressed audio through their multi channel outputs. Does this mean the new audio formats(i.e True HD, DTS HD) will be passed through the multi channel outputs? I have heard that this is true and I have also heard that the new audio formats will only be passed through HDMI. Second, if the new players are capable of passing the new audio formats through multi channel outputs, why do the pictures of the new Sony Blu Ray player and the Pioneer Blu Ray player only have 5.1 multi channel outs instead of 7.1? I thought the new audio formats supported 7.1.
I look forward to your response and appreciate your time.
A loyal reader,
Neil J. Regitz
Dear Mr. Regitz:
The audio formats have been standardized, but the way in which the players (HD DVD, Blu-ray Disc) and AV receivers handle the formats is still in transition.
Here's the situation at the moment: the players output conventional Dolby Digital or DTS on the familiar coaxial or TosLink outputs. This makes them compatible with the existing base of AVRs and controllers. The new players also output multichannel analog decoded from the Dolby Digital Plus, Dolby TrueHD, DTS-HD, or DTS-HD Master Audio formats. The player's six analog outputs feed a six-channel analog input on your receiver. All decoding takes place in the HD DVD or Blu-ray player. To hear the high-res formats at the moment, you must use this multichannel analog connection.
The next generation of hardware (disc players and AVRs) will connect via the HDMI v1.3 interface. HDMI v1.3 will carry high-resolution multichannel digital audio from the player to AV receiver. HDMI v1.3 is expected later this year.
Although the new high-resolution audio formats support 7.1-channel surround sound, the first generation of players is based on 5.1-channel. Moreover, the Toshiba HD DVD machines support Dolby TrueHD (high-resolution lossless encoding) only in 2-channel mode, not multichannel.
The first-generation of HD DVD players is also not compatible with DVD-Audio.
In other words, early adopters will end up with hardware that isn't fully realized. But once you see and hear HD DVD, you won't want to watch standard-definition.
We have a full report on HD DVD, including a review of the Toshiba player, in Issue 69 of The Perfect Vision (which mails from the printer later this week).
Best regards,
Robert Harley
Will the signal transfered over the HDMI cable be a digital data stream in the proprietary uncoverted format or will the signal be converted inside the high-res player and be transmitted as high bit rate PCM?
I'm curious because I have a receiver (Sony STR-DA7100ES) that has HDMI and can (allegedly) play multichannel PCM and was sold as "forward compatible."
Thanks.
Reports suggest that decoding will be performed in the HD DVD and Blu-ray player---the HDMI output will be high-resolution PCM. This technique obviates the need for additional decoding in the AVR. However, it makes sense to eventually perform decoding in the AVR rather than in the HD DVD or Blu-ray player; the AVRs DSP can integrate Dolby DIgital Plus and DTS-HD decoding more cheaply than a dedicated decoder in the player.
Also, don't expect products with HDMI v1.3 until the middle of 2007. Although the specification was finalized a few weeks ago, it takes a full year for chip makers to create the transmitting and receiving chips and for manufacturers to incorporate those chips into products.
Robert Harley
Editor-in-Chief
The Absolute Sound
The Perfect Vision
Dear Mr. Harley:
I may have misunderstood your explanation of HDMI pass-through of the new audio formats available from the new hi-def DVD formats. Since you did not say anything about the capability of earlier versions of the HDMI spec to carry the new audio formats, I assumed that earlier versions would not be capable of passing these formats. I have since learned that this is incorrect.
According to the HDMI consortium, any version of HDMI can carry any currently available compressed audio format, including the new HD formats. According to Dolby Labs, any AVR capable of processing PCM audio over its HDMI 1.1 connection would have enough bandwidth to accept an HD video and a PCM multi-channel audio bitstream decoded by the hi-def DVD player. Initially it was thought that the only way to get the full bandwidth of the hi-def audio would be to use analog connections, but this was found to be false.
The only difference in the capabilites of an HDMI 1.1 AVR in this regard versus an HDMI 1.3 AVR is that the hi-def audio decoding would need to be done in the hi-def DVD player for the former, but could be done in the AVR for the latter.
Best regards,
Don Stimson
Having read about the new high definition video disc players and their enhanced sound capabilities, I am interested in learning about compatible integrated amplifiers and processors that will accept and process the new, improved digital audio these formats offer. I understand this will require compatibility with HDMI version 1.3, Dolby Digital Plus and True HD, and DTS- HD. Are there any processor/amplifier products available that support these new formats? If not, what is the timetable for introduction of such products? Other than the hassle of the additional cables to transfer multichannel audio, what, if anything, is lost in using the disc player to convert the audio to analog rather than having the integrated amp/processor convert the digital information to analog?
I have been a subscriber for many years and really appreciate your product reviews and news. Your July/August 2006 issue contains the best, most complete information on the audio aspects of the new high definition video disc that I have read among several A/V magazines to which I subscribe, but this is typical of you magazine and its content.
You are correct that HDMI 1.3 is required for digital connection of Dolby Digital Plus, TrueHD, DTS-HD, and DTS-HD Master Audio. No controllers or AVRs are now on the market with HDMI 1.3. We expect to see the first prototypes of HDMI 1.3 products at the CEDIA show in two weeks. We'll be reporting daily from the show floor on significant news and product introductions (including HDMI 1.3) starting September 13 on www.avguide.com.
There's no advantage in having the digital-to-analog conversion performed in the controller or AVR rather than in the disc player, unless the controller offers better-sounding DACs.
Thanks for your comments about the magazine.
Best regards,
Robert Harley
I wish Mr Harley would stop spreading the notion that the only way to hear the audio from the DD+ and DTS-HD streams is to hook up 6 analog cables. That's just not so. Mr Stimson in a previous post and Mr Hawthorne in his letter in TPV 71 have it right - at least for the Toshiba players. You can command those players to send your DD+ (for example) decoded audio to the HDMI interface and send 5.1 channels of hi-res PCM to your AVR for processing and D/A conversion. There is a handy chart showing all this on page 59 of the downloadable manual for the HD-A1.
By the way, there is a potential downside to having your AVR do the decoding, in that there is a decoding step that is already required inside the players in order to mix in button sounds, commentary, etc. There is a potential loss of quality by re-encoding an already perceptual-coded datastream which is avoided by keeping it in PCM until D/A conversion. But it's probably minimal, since those Dolby/DTS guys are pretty smart.
Love the magazine - great reviews.
I agree. I don't know why he keeps doing that. He did so again in answering a letter in the most recent issue of The Perfect Vision (Oct/Nov 2006). I sent an email "letter to the editor" espressingmy surprise and disappointment that he continues to mislead readers.
Don Stimson
Mr. Stimson is correct; earlier versions of HDMI (1.1 and 1.2) will pass high-resolution audio (Dolby Digital Plus and DTS-HD) between an HD DVD or Blu-ray player and an AVR. The Dolby Digital Plus and DTS-HD bitstreams are decoded in the player and sent over HDMI 1.1 or 1.2 as high-resolution PCM.
The next generation of hardware with HDMI 1.3 will permit transmitting the Dolby Digital or DTS-HD bitstreams from HD DVD or Blu-ray player to an AVR or controller. Decoding of these formats will occur in the AVR rather than in the player.
Thanks to Mr. Stimpson for bringing to my attention the error in my reply to the reader letter in Issue 71 of The Perfect Vision.
Robert Harley
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