Dolby True HD Upsampling for Blu Ray releases

[Bleedink]

High Definition Digest has an article on Dolby's recent "Fidelity Forum 2.0" event where 96k Upsampling and Dolby Atmos were showed off for the Audio Press and Bloggers.

See http://bluray.highdefdigest.com/new...and_Dolby_TrueHD_Advanced_96K_Upsampling/9450

Thanks. Informative but I truly wish that those who write articles have a good grasp of grammar and lacking that, spell check. I digress!

 

[leevitalone1]

Thanks. Informative but I truly wish that those who write articles have a good grasp of grammar and lacking that, spell check. I digress!

I agree that really cleared it up, theaters will be back in the money with atmos

 

[neil wilkes]

I don't see how you can put back, or put in (by up-res-ing to 96/24) what wasn't already there (original being 44.1/16 or 24) in the first place?!?

I'm sure I've heard counter-arguments that all you do is add a load of noise beyond the upper frequency limits of 44.1khz when you upsample..!!

Curious as to how Norah Jones' new album (or indeed any of her studio recorded output) can be aided by SACD/DSD if they're all at 44.1/16 or 44.1/24?!?

We shall have to wait and see I guess?

I'd love to be proven wrong.. but unless the first time around the CD mastering was wonky for all these Norah albums, what's the point?!?

Let's have some more gorgeous analogue recordings in real high res (preferably 5.1, or 4.0/4.1 if they're quad masters, of course!) instead, please..!!

(sigh).
Here we are yet again with people who seem to think the whole point of 24/96 is extended frequency responses.
It is not. Nobody can hear anything above 23kHz at any point in any time, and this degrades with age.
The point is to move the transition band from the audible to the ultrasonic, where aliasing, pre-ringing & other problems caused by steep slopes to nyquist & poor filter design will no longer be audible - which is sadly not the case on most CD because it is cheaper to make a bad DAC and a bad DAC causes issues at low sample rates.
If you fancy some homework (research it properly - it may stick) check out Peter Craven's excellent paper "Controlled pre respone anti-alias filters for use at 96kHz and 192kHz" (AES 114th convention) where he shows that adding a properly configured gentle slope anywhere in the reproductiob chain will eliminate these issues.
As Bob Katz says, this alone is justification for upsampling even a digital source from 44.1 to 96.

As for adding noise, you are actually shifting it from the audible band to the ultrasonic.

Finally, IMHO nothing is ever helped by SACD. It is a terrible format, as all that ever existsabove 23kHz at the very, very best is noise, and lots of it too - the ultrasonic crap from DSDIFF encoding goes to a whopping -55dB at 40kHz, so even if your speakers can actually reproduce anything above 20kHz (and most cannot) or your amplifier can output it (again, most cannot) all you would get is an irritating noise like a mosquito in the room right on the edge of your hearing. When we play any SACD or decoded DSD in the studio, the cats leave immediately. PCM they remain.

Spectral analysis will not tell you how a record sounds either. You need to play it, not look at pictures of it.

 

[fredblue]

well, you need sigh and be weary no longer, Neil Wilkes!

I get it now, thanks to your excellent response.

Nowhere before had I seen it all explained so clearly.
So, sincerely, thank you for taking the time and trouble here.

I can now see the point of upsampling (even 44.1 CD!) and understand its not just about stuff like freq. resp.

Plus very interested to hear your thoughts on SACD -- and how terrible it is!

I've often felt my DVDA's sounded better than the SACD's (of the same album) but thought it must be the old ears/mind playing tricks wimme! Probably still is, as I'd imagine my setup & hearing couldn't reveal SACD's ultrasonic shortcomings but still, fascinating to hear your findings on the subject all the same.

Cheerio!

 

[Ge Someone]

I personally didn't see a downside--it actually looked like it cleaned up what they used as reference material (Dolby's own paper) ..]

In that source you're not gonna find a downside of course.
One downside is that upsampled PCM takes a lot more space. Another (more technical) is that with resampling you choose a tradeof between some pre-echo (also called pre-ringing) or non-linear phase. Dolby chooses non-linear phase (with more post-echo) here. The general idea is that the amount of pre-echo in lossless audio with sample rates above 40kHz goes unnoticed. Don't let those images fool you, that is not what your speakers produce. Those are usually schematics of an (unfiltered) digital test signal at a certain frequency and volume.
I think it makes much more sense to handle upsampling at the playback stage, in or just before the DAC. In that way all audio will benefit. BTW most CD players from around 1985 to about 2000 did oversampling in hardware already.

 

[Bleedink]

In that source you're not gonna find a downside of course.
One downside is that upsampled PCM takes a lot more space. Another (more technical) is that with resampling you choose a tradeof between some pre-echo (also called pre-ringing) or non-linear phase. Dolby chooses non-linear phase (with more post-echo) here. The general idea is that the amount of pre-echo in lossless audio with sample rates above 40kHz goes unnoticed. Don't let those images fool you, that is not what your speakers produce. Those are usually schematics of an (unfiltered) digital test signal at a certain frequency and volume.
I think it makes much more sense to handle upsampling at the playback stage, in or just before the DAC. In that way all audio will benefit. BTW most CD players from around 1985 to about 2000 did oversampling in hardware already.

With all I know about digital audio dolby could tell me it invented something to get rid of the bacteria in digital audio and I'd probably be hmmm didn't know there was bacteria in audio...One thing that came to me a bit later was this: if the optical playback device upsamples, then the receiver conceivably upsamples, and if you add an upsampled recording to the chain...well, what do you end up with? Obviously some of this is already happening. Is pre echo and stuff THAT much of an issue? I honestly don't recall ever hearing it. Has it been sufficiently filtered already before it reaches my ears? If so, then what's the point of another filter to do this? If not, I guess I have other things to worry about eh?!

 

[0tto]

With all I know about digital audio dolby could tell me it invented something to get rid of the bacteria in digital audio and I'd probably be hmmm didn't know there was bacteria in audio...One thing that came to me a bit later was this: if the optical playback device upsamples, then the receiver conceivably upsamples, and if you add an upsampled recording to the chain...well, what do you end up with? Obviously some of this is already happening. Is pre echo and stuff THAT much of an issue? I honestly don't recall ever hearing it. Has it been sufficiently filtered already before it reaches my ears? If so, then what's the point of another filter to do this? If not, I guess I have other things to worry about eh?!

honestly i believe that main reason for Dolby Lab. to step up with this invention laid in declining
of demand at present for their True HD format from industry. we all know that previously Dolby
was mandatory on DVD thus have received royalties or whatever other incentives for usage of
their coding system.
not the case with blu-ray. seems like very few utilize True HD, so probably some bright corporate
geniuses came with this idea but perhaps releases of several really good titles with stunning sound,
catchy surround mixes and printed in bold sort of "this sound was delivered to you by inovative
advanced Dolby True HD format" could do more for less

 

[Bleedink]

I thought about that when I heard they were offering Dolby TrueHD music downloads. In defense of DTS, in every album that contains both I inevitably prefer the DTS to the Dolby. I am very impressed with what I have heard for music in DTS-HD MA (what marketing genius came up with the name...). And oddly DTS from what I know doesn't do any of this dolby stuff does it? Or did they already try to corner the market on pre-ringing?