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DTS-HD Master Audio output -- plus TrueHD, DD+ and DSD
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FunkyMonkey



Joined: 09 Nov 2007
Posts: 77

PostPosted: Thu Apr 17, 2008 2:04 pm    Post subject: Reply with quote

krzysop1 wrote:
BTW: PCM=Analog. Since the DTS HD signal is converted to PCM in the PS3 what we are trying to grapple with is making the digital sound as close to a smooth and perfect analog master. Ironic eh???


Don't understand this. Confused
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krzysop1



Joined: 13 Apr 2008
Posts: 28

PostPosted: Thu Apr 17, 2008 2:28 pm    Post subject: Reply with quote

I may be wrong but from my reading, sampling rates and sound frequencies ARE the same thing.

Here:
"Audio sampling

[edit] Sampling rate

When it is necessary to capture audio covering the entire 2020,000 Hz range of human hearing, such as when recording music or many types of acoustic events, audio waveforms are typically sampled at 44.1 kHz (CD) or 48 kHz (professional audio). The approximately double-rate requirement is a consequence of the Nyquist theorem.

There has been an industry trend towards sampling rates well beyond the basic requirements; 96 kHz and even 192 kHz are available.[1] This is in contrast with laboratory experiments have failed to show that ultrasonic frequencies are audible to human observers, however in some cases ultrasonic sounds do interact with and modulate the audible part of the frequency spectrum (intermodulation distortion). It is noteworthy that intermodulation distortion is not present in the live audio and so it represents an artificial coloration to the live sound.[2]

One advantage of higher sampling rates is that they can relax the low-pass filter design requirements for ADCs and DACs, but with modern oversampling sigma-delta converters this advantage is less important."

Source: http://en.wikipedia.org/wiki/Sampling_(signal_processing)

See also: http://www.ambisonic.net/sacdvdada.html

I
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krzysop1



Joined: 13 Apr 2008
Posts: 28

PostPosted: Thu Apr 17, 2008 2:36 pm    Post subject: PCM Digital Copy of Analog Reply with quote

"PCM is a digital representation of an analog signal where the magnitude of the signal is sampled regularly at uniform intervals, then quantized to a series of symbols in a digital (usually binary) code."


"http://en.wikipedia.org/wiki/PCM"
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krzysop1



Joined: 13 Apr 2008
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PostPosted: Thu Apr 17, 2008 2:55 pm    Post subject: Reply with quote

See this as well about sample rates and the human ear Smile

http://www.musiq.com/recording/digaudio/intro2.html
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FunkyMonkey



Joined: 09 Nov 2007
Posts: 77

PostPosted: Thu Apr 17, 2008 3:46 pm    Post subject: Re: PCM Digital Copy of Analog Reply with quote

krzysop1 wrote:
"PCM is a digital representation of an analog signal where the magnitude of the signal is sampled regularly at uniform intervals, then quantized to a series of symbols in a digital (usually binary) code."


"http://en.wikipedia.org/wiki/PCM"


You've got the wrong idea from that statement. PCM in no way is like the original analogue wafeform. PCM is a coding method. DSD - what SACD uses IS close the original waveform. This is why many people think SACD is better than DVD-A. I think they difference is negligible so it depends on how godd the original mastering and recording is.
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PS3SACD
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Joined: 17 Aug 2007
Posts: 316

PostPosted: Thu Apr 17, 2008 6:13 pm    Post subject: Re: PCM Digital Copy of Analog Reply with quote

FunkyMonkey wrote:
You've got the wrong idea from that statement. PCM in no way is like the original analogue wafeform. PCM is a coding method. DSD - what SACD uses IS close the original waveform.


Correct, basically. Of course, the PCM signal (when converted back to analog) can be made to resemble the original analog signal well, simpy by choosing the sampling frequency and the resolution (very) high. That's the difference between CD's PCM and DVD-Audio's PCM. Still, PCM is a very abstract way of representing an analog signal in digital form -- much more abstract than DSD which is so simple and elegant the bitstream can almost be used as an analog signal.
See the SACD FAQ at http://www.ps3sacd.com/sacdfaq.html#_Toc168933213.

As for the difference between sampling frequency (44.1 kHz for CD) and the maximum frequency of the sampled sound (20 kHz for CD) see http://en.wikipedia.org/wiki/Nyquist_frequency#The_aliasing_problem

FunkyMonkey wrote:
Another things, I think people are confused between old "lossy" codecs and the new lossless ones. The old lossy ones required DECODING and therefore differences occurred with how the bits were re-constructed.

Now my understanding (based on early discussions when the PS3 came out) is that the lossless codecs only need DECODING into PCM, and that is the same algorithm, be that in the player or the receiver. Please correct me if you know for certain that is wrong.


Not certain about the rest of the explanation, but certainly Dolby Digital Plus is a lossy codec, very much like Dolby Digital 'regular' and Dolby Digital EX, only with more channels and higher bit rates (i.e. lower compression). So why isn't that passed through (or is it)?
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Brandon B



Joined: 14 Oct 2007
Posts: 392

PostPosted: Sat Apr 19, 2008 1:09 am    Post subject: Re: DTS-HD Master Audio output -- plus TrueHD, DD+ and DSD Reply with quote

PS3SACD wrote:
Brandon B wrote:
Perhaps the "bitstreaming capabilities unknown" special PS3 HDMI chipset, as many surmise, lacks the ability.


That doesn't seem to make sense.
  • The drive does deliver the signal (DSD, DD+, TrueHD, DTS-HD MA) to the back end;
  • The HDMI output is capable of very high bitrates, after all 7.1-channel 24-bit 96 kHz PCM means a lot of bits;
  • The HDMI output must be capable of supplying the above standard because it's of version 1.3.

The only thing that has to happen is no processing instead of heavy processing (conversion to PCM), just transparent passthrough. It should be as simple as that, shouldn't it?


The HDMI chipset in the PS3 is an early version of a more widely used 1.3 chipset that can do bitstreaming, but no one has been able to point to a spec sheet that this PS3 version does, and the mfr is not talking. So the consensus, even among many pro PS3 people, is that this was an early version of the 1.3 chipset that may lack the full set of features of 1.3, including bitstreaming capabilities of the high rez audio formats like DSD, TrueHD, and DTS-MA. Not a bandwidth issue, as you point out, just a "get to market before standards are finalized" issue.

So no, it isn't quite that simple. Sort of the same boat as buying a wireless router with draft or "pre" standard compliance, it may not work if its hard coding is a bit different then what ends up in the approved standard. I'd bet that, if this is the case here, they needed to get the PS3 to market before all the standards for bitstreaming the new codecs were finalized, and their backup plan was what w are in fact getting, equivalent lossless audio through PCM conversion.

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Brandon B



Joined: 14 Oct 2007
Posts: 392

PostPosted: Sat Apr 19, 2008 1:16 am    Post subject: Reply with quote

On the PCM thing, DD, DTS, TrueHD, DTS-HD, DTS-MA, all come out as PCM. THe only one that is not PCM based is DSD. THe other codecs are all just compression algorithms for PCM, some with psycho-acoustic algorithms for discarding "less necessary" parts of the signal (lossy) and some not (lossless). None of it is analog.

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The Seventh Taylor



Joined: 17 Aug 2007
Posts: 401

PostPosted: Sat Apr 19, 2008 9:36 am    Post subject: Re: DTS-HD Master Audio output -- plus TrueHD, DD+ and DSD Reply with quote

Brandon B wrote:
The HDMI chipset in the PS3 is an early version of a more widely used 1.3 chipset that can do bitstreaming, but no one has been able to point to a spec sheet that this PS3 version does, and the mfr is not talking. So the consensus, even among many pro PS3 people, is that this was an early version of the 1.3 chipset that may lack the full set of features of 1.3, including bitstreaming capabilities of the high rez audio formats like DSD, TrueHD, and DTS-MA. Not a bandwidth issue, as you point out, just a "get to market before standards are finalized" issue.

So no, it isn't quite that simple. Sort of the same boat as buying a wireless router with draft or "pre" standard compliance, it may not work if its hard coding is a bit different then what ends up in the approved standard. I'd bet that, if this is the case here, they needed to get the PS3 to market before all the standards for bitstreaming the new codecs were finalized, and their backup plan was what w are in fact getting, equivalent lossless audio through PCM conversion.


Interesting theory, and it might explain the situation for the new lossless standards Dolby TrueHD and DTS-HD Master Audio, which were first supported in HDMI v1.3 but not DSD which was supported from v1.2 already.

See http://www.hdmi.org/learningcenter/faq.aspx#12

The only format I'm not sure about (which HDMI version you need for) is Dolby Digital Plus.
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krzysop1



Joined: 13 Apr 2008
Posts: 28

PostPosted: Sat Apr 19, 2008 12:11 pm    Post subject: Reply with quote

Hey here's a nice present for those without HDMI input into their AMPS but ext. analog inputs.


http://www.gefen.com/gefentv/gtvproduct.jsp?prod_id=5277


I'm in no rush to get one since only a handful of Blu-Rays can handle DTS-MA at present but it might be a nice tool for SACD listening. $399 is kind of stiff though.
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krzysop1



Joined: 13 Apr 2008
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PostPosted: Sat Apr 19, 2008 12:24 pm    Post subject: Reply with quote

If Sony wanted to they could make a cable with 5.1 or 7.1 analog connectors from the normal A/V extension on the PS3 and remap the settings via an update and wholla. The user could set the PS3 for LPCM 5.1 or 7.1 via A/V in the sound settings and you get 192/24 inputs into an amp which has a DAC to support it.

Without an update though this converter (see above) or others that will inevitably come to market are the only workaround.
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krzysop1



Joined: 13 Apr 2008
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PostPosted: Sat Apr 19, 2008 1:58 pm    Post subject: Reply with quote

[quote="krzysop1"]If Sony wanted to they could make a cable with 5.1 or 7.1 analog connectors from the normal A/V extension on the PS3 and remap the settings via an update and wholla. [/quote]

Or USB ?
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The Seventh Taylor



Joined: 17 Aug 2007
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PostPosted: Sat Apr 19, 2008 2:06 pm    Post subject: Reply with quote

krzysop1 wrote:
Hey here's a nice present for those without HDMI input into their AMPS but ext. analog inputs.


I was waiting for a product like this to be introduced. I'm surprised we haven't seen more of these yet. $399 is a little stiff indeed. You could buy an AV receiver for that money. Not an HDMI v1.3-compatible one perhaps but that shouldn't take too long. I guess until then they can get away with this price.

krzysop1 wrote:
If Sony wanted to they could make a cable with 5.1 or 7.1 analog connectors from the normal A/V extension on the PS3 and remap the settings via an update and wholla.


I doubt there are enough pins in the A/V extension port to do that. I could imagine a conversion cable from HDMI to 5.1 or 7.1 analog cinch (RCA) connectors though probably it would have to be an active (powered) device -- basically like the one advertised above.
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krzysop1



Joined: 13 Apr 2008
Posts: 28

PostPosted: Sat Apr 19, 2008 2:12 pm    Post subject: Reply with quote

There are at least five pins in the standard A/V output on the PS3, this can be deferred from the fact that they sell a component cable with A/V stereo plugs which has five cables. I would suspect that a 5.1 LPCM is feasible but SONY would have to do it because of re-mapping issues.
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Brandon B



Joined: 14 Oct 2007
Posts: 392

PostPosted: Sat Apr 19, 2008 4:45 pm    Post subject: Reply with quote

krzysop1 wrote:
If Sony wanted to they could make a cable with 5.1 or 7.1 analog connectors from the normal A/V extension on the PS3 and remap the settings via an update and wholla. The user could set the PS3 for LPCM 5.1 or 7.1 via A/V in the sound settings and you get 192/24 inputs into an amp which has a DAC to support it.

Without an update though this converter (see above) or others that will inevitably come to market are the only workaround.


Cool converter, I have several friends who can use that to get some more use out of nice but older receivers.

On the 5.1 or 7.1 analog cable out, also isn't going to happen. The PS3 only has two channels of DAC as I understand it, so you are only going to get 2 ch analog out of any models with that limitation.

So "if they wanted to" would mean if they want to release new models with different specs.

Or are you suggesting they make 6 or 8 channels of SPDIF coax out and send digital out to a DAC/DACs that way?

Taylor, didn't know/forgot DSD was part of 1.2. Now that you mention it, I recall maybe reading that somewhere. Perhaps Sony doesn't like the thought of their unprotected DSD stream being outside the box, as it tempts fate on the copy protection front, so they don't do it even if other do.

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