What's the use of a 192 kHz sample rate?

Started by Green Xenon [Radium] May 3, 2008
On May 6, 9:53 am, rajesh <getrajes...@gmail.com> wrote:
> On May 5, 10:33 pm, dpierce.cartchunk....@gmail.com wrote: > > > > > On May 5, 10:09 am, rajesh <getrajes...@gmail.com> wrote: > > > > On May 5, 7:05 pm, Oli Charlesworth <ca...@olifilth.co.uk> wrote: > > > > If we can, then of course a higher sampling rate will sound better. > > > > But that goes against the premises of the OP, and is nothing to do > > > > with the ECC or interpolation that you've been going on about! > > > > > -- > > > > Oli > > > > I said we cant percieve, but i didnt say they arent there.. > > > Again, true but irrelevant. > > > > i will continue the dicussion on ECC tomorrow. > > > Hopefully, you will be much better prepared. > > > As a hint: the issue of proper sampling vs bandwidth > > is a topic COMPLETELY separate from ECC. You > > might want to keep that in mind during your preparations. > > take for example h.264 video > Apart from having many sophisticated techniques it also > recommends simple one like repeating packets.
Correction its not packets , its slices
> This is not rocket science. The differences may not be audible to > you, but they exist and they are well understood. I'll give you a > hint; do you know what phase distortion is?
The 20KHz low-pass FIR filters that they use in all modern CD/DVD players are phase linear.
> Also, I would like you to explain what is wasteful about a 192 kHz > sample rate. How much money does it cost to use 192 kHz instead of 96 > kHz or 44.1 kHz. What time is involved? How much extra energy does > the higher sample rate use? Are you aware that there are virtually > infinite amounts of bandwidth not being used every second? What > difference does it make if DVDs underutilize a bit more?
The only reason to use anything higher than 44.1KHz for consumer playback is marketing, and evidently, they have bandwidth (storage) to burn, so it doesn't cost them much.
> I am working on a circuit that uses a 192 kHz CODEC to process 1 kHz > signals. Of course I am not using it at 192 kHz, so am I wasting > bandwidth still? Or by using an 8 kHz sample rate, am I conserving > bandwidth and deserve recognition? I like the idea of being "pink" (as > in noise) by conserving precious bandwidth. Actually, I can't wait to > get the thing out on the open road and open it up! I want to put the > pedal to the metal and sample at the full 192 kHz to see just what > sort of analog bandwidth these CODECs really have! I'm not actually > sure they will produce higher than about 40 kHz at the analog output. > I'll have to hack away the 1 pole filter I added to the input and > output. It limits the frequency range to a paltry 30 kHz or so. I > may not hear the difference, but my scope can "see" it!
Okay, if you are still working with analog filters, then you need more room for the transition band. Digital FIR filters get you much closer to the theoretical limits much more easily and predictably. And they stay in spec with temperature and age.
> BTW, if you aren't looking at your monitor or you aren't sitting close > enough to see every pixel, are you wasting bandwidth on your video > signal? Actually, that is an excellent analogy. If you limit the > video bandwidth to half the pixel rate, what difference will you see > on a CRT display?
The difference here is, video bandwidth is chosen for a particular viewing distance, and if you are within (or nearer) the optimal distance, higher bandwidth is easily perceptible. Not so with excessive audio sample rates.
> Finally, why do you see the advantage of using 96 kHz sample rate and > not 192 kHz? Isn't 96 kHz wasting bandwidth?
Yes, very much so. I daresay you won't find a lot of 96 or 192KHz sample rates where bandwidth is at a premium (broadcast, satellite or streaming media). Quite the reverse; they'll be looking for ways of reducing the bit rate. But if you have bandwidth (storage) to burn, and a lot of unsophisticated consumers who think bigger is better, then 96 or 192KHz it is. Not because good engineering demands it, but because marketing departments know consumers are gullible. The original CD spec was pretty much optimal from an engineering perspective. It delivers just as much as it needs to, and not much beyond. It was beautifully engineered. Many of the original CD players (and recorders) did not actually meet the spec very well, nor did recording engineers and producers understand how to work with the new medium, which gave CDs a bit of a black eye. But the theoretical design was quite optimal.
In article 
<b86829fe-0a50-4bc5-8c2b-4274cfff7035@q27g2000prf.googlegroups.com>,
 rajesh <getrajeshin@gmail.com> wrote:

> On May 6, 9:53 am, rajesh <getrajes...@gmail.com> wrote: > > On May 5, 10:33 pm, dpierce.cartchunk....@gmail.com wrote: > > > > > > > > > On May 5, 10:09 am, rajesh <getrajes...@gmail.com> wrote: > > > > > > On May 5, 7:05 pm, Oli Charlesworth <ca...@olifilth.co.uk> wrote: > > > > > If we can, then of course a higher sampling rate will sound better. > > > > > But that goes against the premises of the OP, and is nothing to do > > > > > with the ECC or interpolation that you've been going on about! > > > > > > > -- > > > > > Oli > > > > > > I said we cant percieve, but i didnt say they arent there.. > > > > > Again, true but irrelevant. > > > > > > i will continue the dicussion on ECC tomorrow. > > > > > Hopefully, you will be much better prepared. > > > > > As a hint: the issue of proper sampling vs bandwidth > > > is a topic COMPLETELY separate from ECC. You > > > might want to keep that in mind during your preparations. > > > > take for example h.264 video > > Apart from having many sophisticated techniques it also > > recommends simple one like repeating packets. > > Correction its not packets , its slices
Slice repeat is not for handling errors; it's an efficient encoding technique. Instead of sending all the data a second time whwnever two slices are nearly identical (and that happens fairly often), just say "remember that slice I just sent you? Well, use it again, but make these minor changes to it." Isaac
On May 7, 8:53 am, isw <i...@witzend.com> wrote:
> In article > <b86829fe-0a50-4bc5-8c2b-4274cfff7...@q27g2000prf.googlegroups.com>, > > > > rajesh <getrajes...@gmail.com> wrote: > > On May 6, 9:53 am, rajesh <getrajes...@gmail.com> wrote: > > > On May 5, 10:33 pm, dpierce.cartchunk....@gmail.com wrote: > > > > > On May 5, 10:09 am, rajesh <getrajes...@gmail.com> wrote: > > > > > > On May 5, 7:05 pm, Oli Charlesworth <ca...@olifilth.co.uk> wrote: > > > > > > If we can, then of course a higher sampling rate will sound better. > > > > > > But that goes against the premises of the OP, and is nothing to do > > > > > > with the ECC or interpolation that you've been going on about! > > > > > > > -- > > > > > > Oli > > > > > > I said we cant percieve, but i didnt say they arent there.. > > > > > Again, true but irrelevant. > > > > > > i will continue the dicussion on ECC tomorrow. > > > > > Hopefully, you will be much better prepared. > > > > > As a hint: the issue of proper sampling vs bandwidth > > > > is a topic COMPLETELY separate from ECC. You > > > > might want to keep that in mind during your preparations. > > > > take for example h.264 video > > > Apart from having many sophisticated techniques it also > > > recommends simple one like repeating packets. > > > Correction its not packets , its slices > > Slice repeat is not for handling errors; it's an efficient encoding > technique. Instead of sending all the data a second time whwnever two > slices are nearly identical (and that happens fairly often), just say > "remember that slice I just sent you? Well, use it again, but make these > minor changes to it." > > Isaac
I didnt get how repetition can be used for efficient encoding?
On May 7, 9:35 am, rajesh <getrajes...@gmail.com> wrote:
> On May 7, 8:53 am, isw <i...@witzend.com> wrote: > > > > > In article > > <b86829fe-0a50-4bc5-8c2b-4274cfff7...@q27g2000prf.googlegroups.com>, > > > rajesh <getrajes...@gmail.com> wrote: > > > On May 6, 9:53 am, rajesh <getrajes...@gmail.com> wrote: > > > > On May 5, 10:33 pm, dpierce.cartchunk....@gmail.com wrote: > > > > > > On May 5, 10:09 am, rajesh <getrajes...@gmail.com> wrote: > > > > > > > On May 5, 7:05 pm, Oli Charlesworth <ca...@olifilth.co.uk> wrote: > > > > > > > If we can, then of course a higher sampling rate will sound better. > > > > > > > But that goes against the premises of the OP, and is nothing to do > > > > > > > with the ECC or interpolation that you've been going on about! > > > > > > > > -- > > > > > > > Oli > > > > > > > I said we cant percieve, but i didnt say they arent there.. > > > > > > Again, true but irrelevant. > > > > > > > i will continue the dicussion on ECC tomorrow. > > > > > > Hopefully, you will be much better prepared. > > > > > > As a hint: the issue of proper sampling vs bandwidth > > > > > is a topic COMPLETELY separate from ECC. You > > > > > might want to keep that in mind during your preparations. > > > > > take for example h.264 video > > > > Apart from having many sophisticated techniques it also > > > > recommends simple one like repeating packets. > > > > Correction its not packets , its slices > > > Slice repeat is not for handling errors; it's an efficient encoding > > technique. Instead of sending all the data a second time whwnever two > > slices are nearly identical (and that happens fairly often), just say > > "remember that slice I just sent you? Well, use it again, but make these > > minor changes to it." > > > Isaac > > I didnt get how repetition can be used for efficient encoding?
I think a new thread has to be started on H.264. As this thread appears to be very dangerous.
On May 3, 9:25 pm, rickman <gnu...@gmail.com> wrote:
> On May 3, 12:14 pm, nos...@nospam.com (Don Pearce) wrote: > > I thought we were having a conversation. But I don't appreciate being > called names. Would you speak to me this way if I were standing in > front of you? Either way you come across as being rude. > > Rick
There is no two way communication between encoder and decoder... they just repeat the slices marking one as duplicate....this done especially for I slices (other key pictures which are considered important).
In rec.audio.tech Green Xenon [Radium] <glucegen1@excite.com> wrote:
> Hi:
> Why does DVD-Audio use 192 kHz sample rate? What's the advantage over > 44.1 kHz? Humans can't hear the full range of a 192 kHz sample rate?
> On average, what is the minimum sample rate for a guy in his early to > mid 20s who likes treble?
> I agree there are a small percentage of humans who can hear above 20 > kHz. However, DVD-audio uses a sample-rate of 192 kHz which allows a > maximum frequency of 96 kHz. There is no known case of any human being > able to hear sounds nearly as high as 96 kHz. I can agree with 48 kHz > sample rate and even 96 kHz sample-rate [maybe], but 192 kHz is just stupid.
True, but by no means all DVD-Audio uses 192 kHz. Many use 96kHz...which arguably is also 'stupid'. -- -S maybe they wanna rock. maybe they need to rock. Maybe it's for the money? But That's none of our business..our business as fans is to rock with them.
In rec.audio.tech Dave Platt <dplatt@radagast.org> wrote:
> In article <481becfe$0$5141$4c368faf@roadrunner.com>, > Green Xenon [Radium] <glucegen1@excite.com> wrote: > >Hi: > > > >Why does DVD-Audio use 192 kHz sample rate? What's the advantage over > >44.1 kHz? Humans can't hear the full range of a 192 kHz sample rate? > > > >On average, what is the minimum sample rate for a guy in his early to > >mid 20s who likes treble?
> In my personal opinion, a rate of 192 kilosamples/second (allowing a > passband of DC to 96 kHz) is indeed overkill as an audio delivery > standard.
> There may be _some_ justification for it, as it eliminates the need to > place the knee of the anti-aliasing filter anywhere near the range of > frequencies that one _can_ hear. One of the criticisms made against > CD is that the sharp filtering which must be done at around 20 kHz can > cause artifacts which may be audible to some listeners, either due to > "pre-ringing" (with a symmetric FIR low-lass filter) or a frequency- > dependent delay and "smearing" of transients (with an IIR filter).
> These effects can be moved up to higher frequencies, and prevented > from having effects in the human hearing passband, by increasing the > sampling rate.
> My own personal guess is that a rate of 96 ksamples/second is probably > high enough to move any phase-affecting artifacts up well out of the > human hearing range, and that there are few if any benefits to going > to a rate higher than this.
Dan Lavry and others have estimated that you're already in to the 'theoretical benefit zone' by 60 kHz. So if one feels the need for that, seems to me 88.2 kHz is the most sensible common choice. -- -S maybe they wanna rock. maybe they need to rock. Maybe it's for the money? But That's none of our business..our business as fans is to rock with them.
In rec.audio.tech rickman <gnuarm@gmail.com> wrote:
> On May 3, 3:28 am, Randy Yates <ya...@ieee.org> wrote: > > rickman <gnu...@gmail.com> writes: > > > If it really is a waste of time and money to use 192 kHz ADC and DAC, > > > why do you think they would do it? > > > > Greed. They think that the general public is dumb enough to buy into > > the lie that they really need such a system and would then spend lots of > > money repurchasing what they already have.
> I'm curious, how do you know what unnamed people are thinking? My > understanding is that regardless of what frequencies acoustic testing > says that people can hear, audiophiles can hear the difference between > many of these "wasteful" features and otherwise adequate audio > systems.
> I have known people who worked on professional equipment. The > extremes that they have design in are all audible to the buyers of > such systems.
And people will judge wine's quality on the basis of its price.
> I am not going to try to tell someone else what they can and can't > hear.
Do you need to be told the conditions that might confuse you into thinking you heard a difference, when you didn't? -- -S maybe they wanna rock. maybe they need to rock. Maybe it's for the money? But That's none of our business..our business as fans is to rock with them.
In rec.audio.tech rickman <gnuarm@gmail.com> wrote:
> On May 3, 8:22 am, nos...@nospam.com (Don Pearce) wrote: > > On Sat, 3 May 2008 05:11:53 -0700 (PDT), rickman <gnu...@gmail.com> > > wrote: > > > > >On May 3, 3:28 am, Randy Yates <ya...@ieee.org> wrote: > > >> rickman <gnu...@gmail.com> writes: > > >> > If it really is a waste of time and money to use 192 kHz ADC and DAC, > > >> > why do you think they would do it? > > > > >> Greed. They think that the general public is dumb enough to buy into > > >> the lie that they really need such a system and would then spend lots of > > >> money repurchasing what they already have. > > > > >I'm curious, how do you know what unnamed people are thinking? My > > >understanding is that regardless of what frequencies acoustic testing > > >says that people can hear, audiophiles can hear the difference between > > >many of these "wasteful" features and otherwise adequate audio > > >systems. > > > > Utter nonsense - unless of course you can cite some proper tests.
> And what do you base this statement on? I don't have any "proper" > studies. I am referring to a conversation with a friend who worked in > the field.
Not nearly good enough.
> You can poo-poo this sort of evaluation. But that doesn't make you > right. Do you have any "proof" that no one can hear the difference? > Do you even know what the differences are that I was talking about?
You can't prove negatives to 100% empirical certaintly. You can determine likelihoods, and that's what science is really about -- finding the models of reality that are most likely to be accurate. It seems extremely likely, for example, that no one can actually *hear* frequencies above the mid-20 kHz. They can be perceived via bone conduction, if the signal is generated right at the skin surface. -- -S maybe they wanna rock. maybe they need to rock. Maybe it's for the money? But That's none of our business..our business as fans is to rock with them.