Dolby TruHD and DTS HD decoding
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Keep in mind...
As more source components deliver HD along w/Dolby Digital +..
Does it make sense to have multiple decoders for Dolby Digital + such as....
1 in the HD DVD player..
1 in the cable box..
1 in the sat tuner..
1 in the game console..
1 in the Tivo..
The situation is similar to what happened with SD/HD sources and Dolby Digital..
Originally..
Each source component had its own Dolby Digital decoder..
But then as the market matured and costs became more crucial and competitive, the respective's source components began to delete the on-board Dolby Digital decoder..
To use the decoder within the AVR..
Just my $.02 worth...
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As more source components deliver HD along w/Dolby Digital +..
Does it make sense to have multiple decoders for Dolby Digital + such as....
1 in the HD DVD player..
1 in the cable box..
1 in the sat tuner..
1 in the game console..
1 in the Tivo..
The situation is similar to what happened with SD/HD sources and Dolby Digital..
Originally..
Each source component had its own Dolby Digital decoder..
But then as the market matured and costs became more crucial and competitive, the respective's source components began to delete the on-board Dolby Digital decoder..
To use the decoder within the AVR..
Just my $.02 worth...
But unless somehow the control of the interactive part of those new audio formats can be managed over HDMI control, I don't see how any HDDVD/Bluray player can eliminate the internal decoding/remixing and still call itself a full fledged HDDVD/Bluray player.
Does DD+ have "on the fly remixing" concepts, and was he asking about DD+?
And before, the alternative was multichannel analog. There would be quality loss going analog too early. Made much more sense to delay moving to the analog domain at the last possible time. And so not only did you eliminate the cost of decoders, but the cost of DACs, which now you only needed one set of nice DACs. And a couple of digi coax connectors is a lot cheaper in parts and real estate than many multichannel analog inputs, even using DB25.
Maybe there were products which used 3xSPDIF and that's what you are referring to. I don't remember those products. I think HDMI vs. multichannel analog makes this round quite different than what happened before with DD/DTS and DVD.
Just thoughts.
Does DD+ have "on the fly remixing" concepts, and was he asking about DD+?
And before, the alternative was multichannel analog. There would be quality loss going analog too early. Made much more sense to delay moving to the analog domain at the last possible time. And so not only did you eliminate the cost of decoders, but the cost of DACs, which now you only needed one set of nice DACs. And a couple of digi coax connectors is a lot cheaper in parts and real estate than many multichannel analog inputs, even using DB25.
Maybe there were products which used 3xSPDIF and that's what you are referring to. I don't remember those products. I think HDMI vs. multichannel analog makes this round quite different than what happened before with DD/DTS and DVD.
Just thoughts.
Yes, at this point the decoding really has to be done within the HD format disc player, because there is mixing of audio from disparate sources (film soundtrack, menu sounds, commentaries, downloaded content, extras, widgets, gizmos, all sorts of stuff) that must be performed before the audio is output. AV receivers don't do that, it's done in the player. At this point, I'm not sure how valuable Dolby TrueHD and DTS-HD MA decoding in an AVR will be.
Eric
Eric
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Which means the mixing can't be done at all since there is no way to send the multiple streams of mixable audio to the AVR.
And this loss of features gains you precisely what? The decoding in the AVR can't be any better then the decoding in the player because both are "lossless". You can't GET any better than lossless.
Either the "advanced content" feature set offered by the new formats will win in the market or not. If it wins, decoding in the AVR is irrelevant.
--Bob
Which means the mixing can't be done at all since there is no way to send the multiple streams of mixable audio to the AVR.
And this loss of features gains you precisely what? The decoding in the AVR can't be any better then the decoding in the player because both are "lossless". You can't GET any better than lossless.
Either the "advanced content" feature set offered by the new formats will win in the market or not. If it wins, decoding in the AVR is irrelevant.
--Bob
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what's the limitation here? your response will probably be more technical that i can digest, but i'm curious nonetheless
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is it possible/probable that future players could send multiple streams of mixable audio to the AVR?
what's the limitation here? your response will probably be more technical that i can digest, but i'm curious nonetheless
is it possible/probable that future players could send multiple streams of mixable audio to the AVR?
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37,688 Posts
The player mixes audio from several different streams that are read/generated essentially simultaneously from the disc. To do this, it has to decode any of the "zipped up" new formats, such as TrueHD, to extract all the individual channels of audio, i.e., to get it into a form where it can be mixed with other audio streams.
If you send the undecoded TrueHD (or whatever) bitstream to the AVR to decode instead, the AVR doesn't have access to any of the other audio streams and thus can't do the mixing. You'd need to run the equivalent of several HDMI cables from the player to the AVR for the AVR to have all that and to be able to do the mixing. There's no path to get all of that into the AVR.
In addition, the user interface for determining when such mixing should take place is in THE PLAYER. So the player would also have to send control info to the AVR to tell it which things to mix and when.
The bottom line is that the "advanced content" features have no practical implementation if the AVR is expected to do the decoding.
As for quality, decoding the TrueHD (or whatever) produces the same set of lossless PCM digital audio channels that went into the encoder in the studio in the first place. That's what we mean by saying TrueHD and the other new formats are lossless. So if the player does the decode, mixes other audio as necessary, and sends the resulting set of PCM channels over one HDMI cable to the receiver the quality is as good as it can get. The AVR could not decode the TrueHD any better, nor can it do the mixing.
--Bob
Quote:
Originally Posted by leftheaded /forum/post/0
what's the limitation here? your response will probably be more technical that i can digest, but i'm curious nonetheless![]()
is it possible/probable that future players could send multiple streams of mixable audio to the AVR?
The player mixes audio from several different streams that are read/generated essentially simultaneously from the disc. To do this, it has to decode any of the "zipped up" new formats, such as TrueHD, to extract all the individual channels of audio, i.e., to get it into a form where it can be mixed with other audio streams.
If you send the undecoded TrueHD (or whatever) bitstream to the AVR to decode instead, the AVR doesn't have access to any of the other audio streams and thus can't do the mixing. You'd need to run the equivalent of several HDMI cables from the player to the AVR for the AVR to have all that and to be able to do the mixing. There's no path to get all of that into the AVR.
In addition, the user interface for determining when such mixing should take place is in THE PLAYER. So the player would also have to send control info to the AVR to tell it which things to mix and when.
The bottom line is that the "advanced content" features have no practical implementation if the AVR is expected to do the decoding.
As for quality, decoding the TrueHD (or whatever) produces the same set of lossless PCM digital audio channels that went into the encoder in the studio in the first place. That's what we mean by saying TrueHD and the other new formats are lossless. So if the player does the decode, mixes other audio as necessary, and sends the resulting set of PCM channels over one HDMI cable to the receiver the quality is as good as it can get. The AVR could not decode the TrueHD any better, nor can it do the mixing.
--Bob
The point was that decoding in the AVR could actually be used if desired. Personally I could do without commentary, etc. if that's what the "advanced content" is. Another point was that future satellite or downloadable content could used TrueHD and decoding in the AVR could be done then too. Seems like a lot could change before this is ever available but the point seemed to be that HDMI 1.3 will not be totally useless.
The point was that decoding in the AVR could actually be used if desired. Personally I could do without commentary, etc. if that's what the "advanced content" is. Another point was that future satellite or downloadable content could used TrueHD and decoding in the AVR could be done then too. Seems like a lot could change before this is ever available but the point seemed to be that HDMI 1.3 will not be totally useless.
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It's not exactly useless. It's just being oversold.
Most people are being led to believe that it will provide some really nifty stuff right away for HD-DVD and Blue Ray users, and that's just not the case.
The "advanced content" feature set is basically part of the intended user experience for any given disc. The studios are being assured that all players will play "advanced content" discs as intended, and thus they can design the way their disc is supposed to work DEPENDING upon those features working -- so long as the disc is properly marked as having been authored for "advanced content".
If the player disregards that, it is hard to guess exactly how things will work. For one thing, the disc authoring tools used by the studios are not likely to have been tested under the assumption that some players will simply ignore the "advanced content" marker.
But again, the unknown here is whether buyers will eagerly seek out "advanced content" discs. Based on the ease with which studios have convinced average buyers that the "best" standard DVD discs "must be" the ones with the most extras crammed on them, the odds look good for "advanced content".
So far, everyone I've heard who has looked into this has agreed that "advanced content" discs will rapidly drive "basic" disks out of the market.
We'll know soon. Virtually all HD-DVD titles are already "advanced content" TODAY, and the expectation is that as soon as this summer the same will be true for Blue Ray.
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Changes to television delivery formats could happen, of course, but it aint going to be any time soon. In many cases broadcasters are still trying to get the hang of Dolby Digital 5.1.
The new AVRs will find *SOME* use for these new decoders. Its just not likely it is going to be part of playing or watching any of the important, mass market content.
--Bob
It's not exactly useless. It's just being oversold.
Most people are being led to believe that it will provide some really nifty stuff right away for HD-DVD and Blue Ray users, and that's just not the case.
The "advanced content" feature set is basically part of the intended user experience for any given disc. The studios are being assured that all players will play "advanced content" discs as intended, and thus they can design the way their disc is supposed to work DEPENDING upon those features working -- so long as the disc is properly marked as having been authored for "advanced content".
If the player disregards that, it is hard to guess exactly how things will work. For one thing, the disc authoring tools used by the studios are not likely to have been tested under the assumption that some players will simply ignore the "advanced content" marker.
But again, the unknown here is whether buyers will eagerly seek out "advanced content" discs. Based on the ease with which studios have convinced average buyers that the "best" standard DVD discs "must be" the ones with the most extras crammed on them, the odds look good for "advanced content".
So far, everyone I've heard who has looked into this has agreed that "advanced content" discs will rapidly drive "basic" disks out of the market.
We'll know soon. Virtually all HD-DVD titles are already "advanced content" TODAY, and the expectation is that as soon as this summer the same will be true for Blue Ray.
------------------------------------------------------
Changes to television delivery formats could happen, of course, but it aint going to be any time soon. In many cases broadcasters are still trying to get the hang of Dolby Digital 5.1.
The new AVRs will find *SOME* use for these new decoders. Its just not likely it is going to be part of playing or watching any of the important, mass market content.
--Bob
Who's overselling it? I've not seen any company anywhere plugging it at all. It's just lots of misinformed muppet users on internet forums like this going round and round in circles.
All the companies that comment at all, as far as I can see, try patiently to explain to these knuckleheads that 1.1 is fine.
I honestly don't see how anyone can blame the industry for the 1.3 confusion. People just seem to be being willfully stupid, from where I'm sitting.
Now, if we want to blame industry for stuff, let's blame them for caving in and adding copy protection, and mixing video and audio in the same signal...
Who's overselling it? I've not seen any company anywhere plugging it at all. It's just lots of misinformed muppet users on internet forums like this going round and round in circles.
All the companies that comment at all, as far as I can see, try patiently to explain to these knuckleheads that 1.1 is fine.
I honestly don't see how anyone can blame the industry for the 1.3 confusion. People just seem to be being willfully stupid, from where I'm sitting.
Now, if we want to blame industry for stuff, let's blame them for caving in and adding copy protection, and mixing video and audio in the same signal...
It might sound pointless to people who buy cheap disc players but for those in high end market separates are way to go which means they are looking for transports and converters in two pieces. You can also buy cheap disc player and then output digital audio to outboard processor and have great sound while using onboard DACs from cheap player will result in poor sound. I use Pioneer DVD/receiver combo connected via firewire connection. DACs in receiver are better than those in DVD player.
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Ravenx - is your player a Universal player?
if the DACs are better in the receiver - it shouldn't matter where the decoding is done, as long as the receiver converts those (decoded) digital signals to analog
DD/DTS -> (decoding) -> PCM -> (D/A conversion) -> sound
up till now the decoding process has been done in the receiver prior to the D/A stage
if the DACs are better in the receiver - it shouldn't matter where the decoding is done, as long as the receiver converts those (decoded) digital signals to analog
DD/DTS -> (decoding) -> PCM -> (D/A conversion) -> sound
up till now the decoding process has been done in the receiver prior to the D/A stage
Currently I like to verify with my receiver that I am actually decoding/getting the DTS track I selected on current DVDs. With new players converting everything to PCM will there be a way to tell what the source is? If my receiver indicates 5.1 PCM can I tell if it came from TrueHD, DD+, or just DD? Presumably the players would have some way to see what track is playing but I find it oddly comforting to see it on my receiver
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. I guess for me this would be a draw to having the decoding in the receiver, although a small one...
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I don't think you are correct. Every DVD player on the planet has a MPEG2 decoder, not a DD decoder. The DD bitstream can and most often is left intact (undecoded) and passed via SP/DIF to a receiver or pre/pro for proper decoding. Unless I am misunderstanding your post?
I don't think you are correct. Every DVD player on the planet has a MPEG2 decoder, not a DD decoder. The DD bitstream can and most often is left intact (undecoded) and passed via SP/DIF to a receiver or pre/pro for proper decoding. Unless I am misunderstanding your post?
I don't understand the strong desire to move audio decoding back into the receiver, other then familiarity with current practice. We have always decoded video in the player and it is arguably a much trickier conversion. With HDMI audio you are still working in the digital domain for BM, TA, and any other processing and you are using the receivers DACs.
All DVD players have at least a 2-channel analogue audio output (even portable ones have headphone jacks). Almost all DVDs have DD soundtracks. How could you hear those tracks if every player wasn't first decoding DD (to PCM) before converting to analogue?
Sanjay
All DVD players have at least a 2-channel analogue audio output (even portable ones have headphone jacks). Almost all DVDs have DD soundtracks. How could you hear those tracks if every player wasn't first decoding DD (to PCM) before converting to analogue?
Sanjay
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