Advanced Audio Codecs via HDMI only?

Robert Crawford

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Is processing all of the advanced audio options from both the BR and HD players restricted to outputing from HDMI only?





Crawdaddy
 

Tony Kwong

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No. If the source device have the necessary decoders and a multichannel output you could go analog rca's.
For BD PCM no decoders are needed and you could just use the multichanel out.
 

Neil Joseph

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Can you not also pass dtsHDlossless and ddtrueHD via hdmi 1.1, 1.2 or 1.3 if the player has onboard capabilities to handle the lossless audio codecs?
 

Neil Joseph

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Another question.... If your blu-ray or hd dvd player can output lossless audio, either dts HD master or dd true hd, then will your receiver be able to fully decode it via hdmi if the version of hdmi is only 1.1? Does the receiver have to be hdmi version 1.3? If the receiver is not hdmi 1.3 then can the same lossless audio be decoded properly using the 5.1 analog audio inputs on the receiver? I realize that using the analog inputs limits you to 5.1 unless both the receiver and player have 7.1 I/O's.
 

Shawn Perron

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There are no receivers at the moment that can process a raw TrueHD or DTS-MA stream. But the players can output 7.1 LPCM over HDMI 1.1. Just look for a player that will decode any formats you are interested in and it should be equivalent to your receiver processing the sound.
 

DaViD Boulet

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HDMI is needed to transfer lossless audio to your reciever in digital form.

If your BD or HD DVD player had advanced audio decoding built in, and provided d/a conversion for it as well, you could send it via 5.1 or 7.1 RCA connections to your receiver if your receiver had 5.1 or 7.1 analog input.

Regarding going digital to your receiver with advanced audio...

YES, you do need HDMI.

If you have HDMI 1.1 or HDMI 1.3 (on both ends), then you'd need a BD or HD DVD player that has "advanced audio decoding" to decode (decompress) the Dolby True HD/DTS-HD to linear PCM. Then you could ship this "decoded" lossless PCM signal to your receiver if it was equipped to handle the input... as most HDMI 1.1 receviers are.

If you had HDMI 1.3 on both ends, then you could ship the "raw" compressed bitstream to your receiver directly without decoding. This would make for cheaper players though they'd have to have HDMI 1.3 as would your receiver. Presumably future HDMI 1.3 receivers will recognize and decode Dolby True HD and DTS-HD etc.

But you're getting full lossless quality going HDMI 1.1 (or 1.3) in LPCM form and letting the player do the decoding so nothing is lost (except there could be some minor issues with some HD DVD discs that instruct the player to do audio manipulation like mixing streams or adjusting level... but that's a different discussion).

Does that help or did I confuse everyone more?

dave
 

Neil Joseph

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So when I (and others) get the firmware upgrade for the panasonic blu-ray player that allows it to play the lossless audio then I will be able to play them even though my receiver is hdmi 1.1 only, right?
 

DaViD Boulet

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That's exactly right.

When the Panny gets upgraded it will decode/extract the advanced audio (Dolby True HD, DTS-HD etc) to LPCM and send it over HDMI 1.1 to your receiver in "unpacked" form.

 

Robert Crawford

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For some of us, talking about myself, I wonder if they can even hear a distinctive difference in what they're missing out on. I'm sure a lively debate can take place about that possibility.
 

Neil Joseph

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Probably depends on the bitrate used. Reminds me of the 1/2 bitrate vs full bitrate dts at 1.5Mbps, or dolby digital vs dolby digital plus which is at a higher bitrate. dts HD master can go as high as 24Mbps although that is for 7.1 and they probably won't go that high for some time if ever.
 

DaViD Boulet

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Hey Neil,

Lossless is lossless... there's no bit-rate to choose when you do lossless: you just tell the encoder to compress it and it does so at the most efficient (lossless) rate that it can. This can result in a variable bit-rate as well.

If it turns out that the bit-rate needed for lossless encoding it too high to fit the bandwidth available, then what would happen is that the producer would lower the resolution of the master PCM file being encoded. That may be why the Dolby True HD tracks on the early HD DVD titles were only 16/48 resolution... not 24/48 or 24/96 like we had hoped they'd be.

Looks like Fox is set on providing *high resolution* lossless audio. Otherwise, you're just getting CD quality... which is better than lossy 16/48, but not exactly the holy-grail of audio.



One thing that could affect that would be the quality of the d/a conversion in the player. If one didn't have HDMI thru-put and had to run analog, you're now hearing the d/a conversion from your player. Some receivers have a "bypass" mode so you don't force the audio signal through another a/d/a cycle for DSP which would also be harmful to the sound.

But if the recevier has a bypass and the d/a conversion in the player is as good as what's in the recevier, then it could be a close race.
 

Neil Joseph

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I read somewhere about the "bitrate" of the various lossless audio formats, by bitrate I mean the actual amount of data being sent as a result of the audio, same as the video has its own bitrate and the total of the audio and video being the total bitrate of the disk. I also vaguely remember for blu-ray, the bitrate max is around 57 Mbps, someone correct me on that number.
 

Dave_P.

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Quick question on the this full-bitrate DTS thing: is this the same type of DTS that was on those few early Dreamworks DTS DVD's like Small Soldiers & THe Peacemaker that were supposed to be 1.5mbps?
 

Tim Glover

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I'll say this, the Dolby Digital Plus which I guess is "downmixed" to a full bitrate DTS on the Bourne Supremacy HD-DVD sounds about as good as I have EVER heard in terms of impact, subtle ambient sounds, dialogue....absolutely cannot fathom this thing sounding any better. I guess it's possible but I will need to be a dog to hear it.
 

DaViD Boulet

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Tim, just wait until you *do* finally hear the original lossless file. Yep. trust me. You'll hear the difference!

dave
 

Shawn Perron

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I assume that the sound track has a bit budget much like the video does on the main feature. Obviously if the lossless soundtrack needs more bits then it's been budgetted, they are going to have to compromise the sound quality to fit it within the allocated bit budget. If this is the case, then the term "lossless" seems fairly deceptive.
 

DaViD Boulet

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Can a "zip file" be compromised? Nope. If there aren't enough bits available to compress an audio stream losslessly then the decision has to be made to do one of two things:

1. forget lossless and go with lossy where you can specify a max bit-rate.
or
2. reduce the resolution of the LPCM signal so it needs less bits to compress. ie, you've got a 24/96 audio soundtrack and you dither it down to 24/48 or (sadly in the case of many lossless tracks on HD DVD) 16/48.

In that sense you're right... I don't personally consider a 16/48 "lossless" track to really be "lossless" in the sense that it's only bit-for-bit identical to the dumbed-down 16/48 LCPM track, NOT the *original* 24/48 master.

I'm not sure if it's because BD has more bandwith or what, but so far there studios seem to be going 24-bit lossless on BD most of the time whereas they're sticking with 16-bit on HD DVD for the most part.
 

RAF

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For some reason I got to this thread late but it happens to be about something recently near and dear to my heart - lossless (uncompressed) audio. I recently reconfigured my HT (once my PS3 arrived) and now I have the full capability to listen to all the codecs currently available on the various HD media (HD & BR).

Let me start by saying, HOLY CRAP!

As many of you know I have a pretty good home theater and have always prided myself in having some pretty good sound capabilities. But now that I have heard the comparison between "regular" 5.1 audio and lossless (uncompressed) 5.1 audio as offered on a lot of HD media I can say, without a doubt, that lossless audio sound much better than regular audio. It's almost as though a sonic veil has been lifted from my ears. And to answer the questions posed by others here (like the quote of my esteemed colleague, Crawdaddy, above) I can say "Yes, there is a distinctive difference." Or to put it another way, even though I haven't been overly motivated to purchase HD titles just for the video improvements (because I already receive a lot of HD content via Dish and my video processing of standard titles can be quite impressive at times) I now have a reason to purchase as many future titles as possible in the HD versions (HD or BR, take your choice) and that reason is: audio improvement. In other words, David Boulet is correct.

Those of you who have been following my "component approach to Digital A/V" thread already know where I have been headed in the past few months. And now that I have two HDMI sources that provide significant audio information beyond what "normal" toslink can provide (and wishing to avoid the analog out route) I decided to connect both my Toshiba XA-1 HD-DVD player (firmware 2.0) and my Blu-ray PS3 to the HDMI (1.1) inputs of my Denon 3806 to see what all the TrueHD, etc. fuss was about. In fact, I had to connect the PS3 to my Denon 3806 via HDMI because with all the equipment in my HT I was completely out of other audio and video connection options on the receiver!

Here's what I heard. The very first time I fired up the PS3 some amazing sound filled the air! Little did I know that the PS3 "intro" music or whatever is in 7.1 sound (as verified by the display on my 3806). In addition a lot of the game sounds are 7.1 so it caught my attention right away. I decided to test out the audio tracks of some Blu-ray titles and when presented with a choice between TrueHD (lossless) 5.1 and "regular" 5.1 the TrueHD blows it away every single time. Crisper, cleaner, clearer - pick an adjective - it fits. This is not an insignificant upgrade in the HT experience. As David said, "You'll hear the difference."

I then proceeded to go back to some of my HD-DVD discs and compared the TrueHD track to the "normal" audio track. Same thing. The TrueHD track was much clearer. Naturally, this was limited to my Toshiba HD-DVD player and not the XBox 360 HD-DVD player since the 360 lacks HDMI output at this point. (I'll be first on line when an HDMI 360 box is released.) I do have one question about the Toshiba XA-1's handling of TrueHD compared to the PS3. Maybe someone can provide an answer. I am finding that the TrueHD soundtrack is at a much lower volume level than the normal 5.1 soundtrack on the Toshiba. I literally have to crank up the volume about 10 units on the Denon 3806 to match the two outputs. For the record, once "cranked up" the TrueHD sounds just as good on the Toshiba as on the PS3. However, it doesn't make sense that there should be such a difference in the two sound levels - not to mention the inconvenience. I'm wondering if this is a problem with the XA-1 or what? Yes, I upgraded the firmware to allow TrueHD to pass through HDMI on the XA-1 but has anyone heard of volume level problems with this player in TrueHD or is that just the nature of HD-DVD TrueHD? It's happened on quite a few HD-DVD titles that I've checked. I'm ruling out the rest of my equipment as being the culprit here since both the PS3 and the XA-1 are connected to the Denon 3806 via HDMI and pass through the same audio chain from that point on. I've even swapped cables and HDMI ports to make sure that they weren't the problem (they're not.) Does anyone know if the 2nd generation Toshiba HD-DVD players address this? (I intend to see Robert Zohn after CES to see if he knows anything about this). Any clues as to what is going on would be greatly appreciated. I just don't look forward to wading through all the "mire" of that other forum.


Even with the TrueHD level quirk on my Toshiba (which I'm overcoming for now by cranking up the volume) I'm completely sold on uncompressed audio. And, from the little I've heard coming internally from my PS3 in the intro sounds and the games in 7.1 I can't wait until 7.1 source material comes to the HD media.

Bring it on. The audience is listening!



 

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