HD-DVD audio formats question

Re: HD-DVD audio formats question

I assume you mean the RX-V496 since the RX-496 is only a stereo receiver and the RX-V496 is a 5.1 receiver.

In short, the RX-V496 will take advantage of the new formats of HD-DVD using its 6 channel external decoder input. The Toshiba HD-A1 takes some, but not all, advantage of these formats at this point in time though this may change with firmware upgrade.

The new sound formats available on HD-DVD include Dolby Digital Plus, Dolby Digital TrueHD, and DTS-HD. Dolby Digital Plus is lossy but can have bitrates up to 3mbps while DD TrueHD and DTS-HD are lossless.

What can the Toshiba HD-A1 do?

Dolby Digital Plus - The Toshiba can read and fully decode this format in full to 5.1 channels which can be sent via the 5.1 analog outputs to your RX-V496. Dolby Digital Plus can have up to twice the bitrate of the highest bitrate audio seen on DVD (1.5mbps used by DTS). Dolby Digital Plus is mandatory for every disc, so on every disc you have the ability to hear sound with bitrate significantly greater than anything on standard DVD. With that being said, studios can encode at lower bitrates with Dolby Digital Plus as well if they so choose; word has it that for most titles Warner currently is encoding their DD+ soundtracks at 640kbps while Universal is encoding them at 1.5mbps. Again, all HD-DVDs have Dolby Digital Plus soundtracks, so in the end the Toshiba HD-A1 will provide you with 5.1 sound on all HD-DVDs for the lifetime of the format.

Dolby Digital TrueHD - The Toshiba can currently only decode 2-channel Dolby Digital TrueHD making its decoding of this format limited in use. However, many believe Toshiba will enable full 5.1 decoding of Dolby Digital TrueHD in future firmware updates for the HD-A1; this is not guaranteed of course, so if it this is a make-or-break feature you might want to wait. Then again, only two discs I know of actually have a Dolby Digital TrueHD soundtrack on disc (Phantom of the Opera, Constantine). Remember though that Dolby Digital Plus is still required to be on disc in addition to DD TrueHD if it is included, so you will never have an issue where you cannot get 5.1 even with your older RX-V496.

DTS-HD - The Toshiba can read lossless DTS-HD soundtracks but only can decode the lossy backwards-compatible DTS portion of these soundtracks, meaning that at this point in time you won't be able to get the full fidelity of DTS-HD with the Toshiba HD-A1. No discs currently have DTS-HD soundtracks, but when they do the Toshiba will be able to read and decode them in 5.1 - but the result will be no better than standard DTS. Like Dolby Digital TrueHD this could change with a firmware upgrade; also like Dolby Digital TrueHD, if a disc does feature DTS-HD it must also feature Dolby Digital Plus.

So, in summary, using the 5.1 analog output to your RX-V496, you will be able to get excellent 5.1 audio out of every HD-DVD that will be made as the HD-A1 does full decoding of the format's mandatory Dolby Digital Plus codec. However, at this point in time you cannot get the highest fidelity 5.1 lossless sound with the Toshiba - though this very well can and may change with a future firmware upgrade. While it may be disappointing that it cannot do lossless (yet), think of it this way - the upcoming $1000 Sony Blu-Ray player cannot even decode Dolby Digital Plus or TrueHD for twice the price of the HD-A1, and there are no receivers that can decode DD+ or DD TrueHD either! Therefore you are getting cutting edge audio technology on the HD-A1 that more expensive competitors and state of the art digital receivers cannot even compete with.

On a side note, if you wanted to hook up your receiver to the Toshiba HD-A1 digitally via optical or coaxial out of convenience, you could do that as well and still get 5.1 on all HD-DVDs even though your receiver does not support Dolby Digital Plus decoding. The reason being is that over the digital coax/optical outputs the HD-A1 decodes the Dolby Digital Plus soundtrack internally then re-encodes it to DTS5.1 @ 1.5mbps for optical/coax output; meaning that hooking the receiver up digitally will result in your receiver being fed a full bitrate DTS signal from the HD-DVD's decoded Dolby Digital Plus soundtrack. Though hooking the receiver up digitally will not take "full advantage" of Dolby Digital Plus as hooking it up via analog 5.1 does, it will still get a high quality 5.1 soundtrack as 1.5mbps DTS is excellent fidelity.

Re: HD-DVD audio formats question

It is, but due to bandwidth and copy protection, the newest formats (DD+,DDTHD,DTS-HD) can only be output via analog 5.1 or HDMI 1.3 digital output. Also, since current receivers don't support DD+/DDTHD/DTS-HD, outputting them via optical/coax would do no one any good anyway. The Toshiba has very good DACs which means the quality of the decoding is excellent.

Since your receiver doesn't have HDMI digital input, using the analog 5.1 outputs on the Toshiba HD-A1 is what you'd need to do - and the quality of the DACs in the Toshiba is excellent so you need not worry about quality loss.


No, the analog should give you the best quality since the source is 640/1.5/3.0/whatever DD+ and that is exactly what you get with analog 5.1. With optical/coax you are getting that same source decoded and then re-encoded at 1.5mbps DTS. This doesn't mean it can make the bitrate of the soundtrack on the HD-DVD higher, it just means that you are getting a decent representation of that soundtrack at whatever bitrate because 1.5mbps DTS sounds pretty good. In other words, a 640kbps DD+ soundtrack can only get worse, not better, by being decoded then re-encoded at DTS 1.5mbps.

Some analogies
To draw a parallel, if you took an 128kbps MP3 file on the computer, decoded it to a WAV file and then re-encoded the resulting WAV file to a 320kbps MP3 (i.e. created a 320kbps mp3 using a 128kbps mp3 as the source), you would not have a 320kbps quality MP3 - instead you'd have an MP3 that played back at 320kbps but was similar in quality to a 128kbps MP3 because the 128kbps mp3 was essentially the original source it was made from. Yet another way to think of it is if you take a 16 color picture and resave it as a 256 color picture, the picture will still look like a 16 color picture since that is what the source was; so if you took a 640kbps DD+ soundtrack and converted it to DTS 1.5mbps for optical/coax output, it could not possibly sound any better than the original 640kbps DD+ soundtrack since that was the source for the DTS track. Likewise, if you take a 65,536 color picture and saved it as a 256 color picture, it may look noticably worse; similarly, if you take a 3.0mbps DD+ soundtrack and convert it to 1.5mbps DTS for optical/coax output, it could sound worse than the original DD+ soundtrack because the DTS soundtrack uses half the bitrate. With the optical/coax out on the HD-A1 you are still using the DD+ soundtrack as the source, its just converted to DTS so receivers without 5.1 analog input can decode it. Therefore you can't really lose with the analog 5.1 output, because you get the actual original source directly rather than a never better quality and possibly lower quality re-encoded version of the original source as you would with optical/coax.

Think of it this way. You can either have:

Option A:
ORIGINAL DD+ SOUNDTRACK (640kbps/1.5mbps/3.0mbps) -> DECODED -> output via analog 5.1 or digital HDMI.

Option B:
ORIGINAL SOUNDTRACK (640kbps/1.5mbps/3.0mbps) -> DECODED -> RE-ENCODE DECODED RESULT to 1.5mbps DTS -> output via digital coax/optical.

In other words with the HD-A1, you can have Option A for the best quality signal or you can have Option B if your receiver doesn't have a 5.1 analog input. The optical/coax DTS option does not increase quality, it only increases compatibility for cheaper/older receivers.


Yep, the Toshiba HD-A1 essentially has higher quality innards for high definition audio than any receiver currently available and can decode formats that no receiver can - so you are right, its left up to the HD DVD player to do the decoding at least until Spring 2007 likely.


No prob, but I'd definitely hold off on a new receiver until next spring if possible, because that is likely when receivers that support HDMI 1.3, Dolby Digital Plus, Dolby Digital TrueHD, DTS-HD will come out. Until then the Toshiba HD-A1 paired with your RX-V496 5.1 analog input will do you just fine

Re: HD-DVD audio formats question

Sure. One last caveat though. While the Toshiba HD-A1 does support DD+ 5.1 decoding right now and most likely will support DDTHD 5.1 lossless decoding in a future firmware upgrade, one thing it likely won't be able to do is transmit these actual undecoded bitstreams to a future receiver for decoding. Reason being is because you need to have HDMI 1.3 support for that, and the Toshiba only supports HDMI 1.1 since HDMI 1.3 won't be ready to go in products until late 2006/early 2007.

So it gets a bit more complex and confusing here. If you do buy a receiver in mid/late 2007 that supports DD+, etc, and hooked the Toshiba HD-A1 up to it via HDMI, the decoding would still take place in the Toshiba since the Toshiba cannot transmit the digital bitstream via HDMI due to the limitations of the HDMI 1.1 spec employed by the HD-A1; this is unlike traditional DVD players which can transmit the actual DD/DTS bitstream to the receiver to decode. What instead would happen is that the signal still gets decoded at the HD-A1 and is then re-encoded with lossless 5.1 channel 24bit/96khz PCM sound at 13.8mbps (!) that is then transmitted to your receiver. This is different than the conversion made on the optical/coaxial outputs because 13.8mbps 24bit/96khz PCM is lossless unlike 1.5mbps DTS and hence the original soundtrack quality would still be preserved by this conversion. So, with the HD-A1 you will most likely never be able to have the sound be decoded at the receiver end - but it doesnt have to be because the HDMI digital output is lossless and the 5.1 analog outputs are top notch.

So, in your case with the HD-A1 you'd do the following in your upgrade path:

Current setup w/ HD-A1:
ORIGINAL DD+ SOUNDTRACK (640kbps/1.5mbps/3.0mbps) -> DECODED -> output via analog 5.1 to RX-V496

Future setup w/ HD-A1 + digital HDMI input receiver:
ORIGINAL SOUNDTRACK (640kbps/1.5mbps/3.0mbps) -> DECODED -> RE-ENCODE DECODED RESULT to 13.8mbps lossless 24bit/96khz PCM -> output via digital HDMI 1.1 to future receiver for playback
(this can't be done for digital optical/coax outputs because of bandwidth restrictions and copy protection concerns)

A gen2 HD-DVD player available in Spring 2007 with HDMI 1.3 hooked up to an HDMI 1.3 receiver with DD+/etc would look something like this:
ORIGINAL SOUNDTRACK (640kbps/1.5mbps/3.0mbps) -> output bitstream via digital HDMI 1.3 to future receiver for decoding

Again, though, the decoding circuitry in the HD-A1 is top notch, so you should be fine no matter where you go in the future with it. I'd still wait on the receiver, though, since once you do your eventual hddvd player upgrade to gen3 or gen4 or whatever, you'll already have the hdmi 1.3/dd+/ddthd/dtshd receiver in place to use for audio decoding.

Re: HD-DVD audio formats question

So can you do TrueHD and DTS-HD over the 5.1 analog inputs when the discs (and firware) come? I'm confused.

Re: HD-DVD audio formats question

With the current firmware (1.4) you can only do 2-channel TrueHD and you can't do DTS-HD (it downconverts DTS-HD to standard DTS). However, with future firmware (2.x) its probable that TrueHD 5.1 will be made available and possible that DTS-HD could be made available as well.

Re: HD-DVD audio formats question

Correct.


It's likely a hardware thing. However, the Toshiba can actually output 5.1 channel audio via HDMI, just via a different technique. Instead of sending the dd+/ddthd bitstream digitally to the receiver to be decoded, the Toshiba decodes the dd+/ddthd bitstream internally then re-encodes it using lossless 24bit/96khz digital PCM 5.1 and outputs it via the HDMI 1.1 connection to the receiver. So, if you want to you will be able to connect the Toshiba via HDMI to your receiver - you just won't be able to have the receiver do the actual decoding of the bitstream.

For reference, as of current spec as per Sony the competition ($999 Sony BDP-S1 Blu-Ray player) downcoverts DD+/DDTHD/DTS-HD to standard DD/DTS for output over coaxial/optical and cannot decode or output true DD+/DDTHD via any method as it does not have analog 5.1 outputs nor an HDMI 1.3 connection. You are getting a lot more bang for your buck with the HD-A1.

Re: HD-DVD audio formats question

I can't guarantee that Toshiba is going to release firmware that decodes TrueHD 5.1 nor DTS-HD 5.1. I am just saying they are reportedly working on adding TrueHD 5.1 into 2.0 firmware - I don't work for toshiba/microsoft so I can't confirm it for a fact that it will be up and running.

Likewise, I can't guarantee that 2nd or 3rd gen players will have DD+/TrueHD/DTS-HD decoders builtin; therefore when you upgrade your HD-A1 to a future hddvd player you might be out of luck if you have an non-HDMI 1.3 compliant receiver.

In other words its best to stick with your current receiver and spend your current cash on the HD-A1 and movies for now. Once receivers with all the new codecs and HDMI 1.3 come out, that would be the wise time to invest in a new receiver.

Re: HD-DVD audio formats question

For reference, as of current spec as per Sony the competition ($999 Sony BDP-S1 Blu-Ray player) downcoverts DD+/DDTHD/DTS-HD to standard DD/DTS for output over coaxial/optical and cannot decode or output true DD+/DDTHD via any method as it does not have analog 5.1 outputs nor an HDMI 1.3 connection. You are getting a lot more bang for your buck with the HD-A1.


Correction: The Sony bdps1 does indeed have 5.1 analog outputs and with firmware version 3.60 the piece will decode Dolby True HD. The DACs in the peice are of decent quality and it does a great job of decoding the format. As a matter of fact it is one of the better Blu ray players on the market today and its 2 years old. I have never had the desier to own a Sony audio/video product, however I must say that I am totally pleased with the bdps1.

Re: HD-DVD audio formats question

Wow, that's what I call resurrecting a thread!