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In Reply to: No - Charles is just plain wrong, or at least very self serving posted by Christine Tham on December 18, 2005 at 12:08:43:
...obviously you didn't breath deep enough.> Of the dozen or so HDCDs I have in my collection, this additional
> compression is clearly audible on at least half of them.Merely your opinion, not fact. Fact is, very few manufacturers bother with HDCD anymore. That says alot.
Give it a rest.
ps: I don't own any of Charles' products and have no affiliation with him.
Follow Ups:
maybe the person who needs to "give it a rest" is yourself. your posts hasn't exactly been full of sweetness and tolerance you know. first you misinterpreted what i say, and then you accuse me of missing the point, and now your best response is "blah blah blah"?this is the fact: if you have an HDCD disc, and it's encoded with Peak Extend, then playing it on a non-HDCD player will not give optimal results.
over half of my HDCD discs have Peak Extend. Again, that is fact, not opinion.
scaling down peaks by 6dB is the equivalent of halving their amplitude. is this audible? what do you think?
if you want to listen to HDCD discs with their peaks chopped down by half, go right ahead. but don't try and justify it as charles did.
Christine, you are wrong on several points.1) You wrote, "[Without HDCD decoding] you are not getting the benefit of dynamic filter switching, and the filter is probably not compensating for the specialised dithering algorithm."
Both claims are incorrect. The HDCD playback filter does not have dynamic filter switching -- only the encode side does. Also, there is nothing in an HDCD playback filter that "compensates" for dithering on the encode side.
2) You claim that I am anti-HDCD because the Ayre players do not have HDCD filters. This is also incorrect. The Ayre players do not have HDCD filters because I am anti-HDCD. Here's why:
When it was still run by Pacific Microsonics, they indulged in deceptive marketing. The most egregious example of this was when they released their sampler that allegedly compared non-HDCD against HDCD. What they negelected to tell you was that the non-HDCD was made using a Sony 1630 A/D converter and the HDCD was made with a Keith Johnson A/D converter. I don't do business with companies that behave this way.
When Microsoft purchased Pacific Microsonics, they doubled the licensing fee (from $5,000 to $10,000). Furthermore, they terminated the licenses of the existing licensees, forcing them to pay twice. Then they stopped making HDCD playback filters. I don't do business with companies that behave this way.
3) The only area where HDCD playback filters offer an advantage is when the dynamic compression features of HDCD were enabled during encoding. The problem is that one has no way of knowing when this happens. In other words, what percentage of HDCD discs are recorded with these features turned on?
You claim, "over half of my HDCD discs have Peak Extend. Again, that is fact, not opinion."
In the first place this is a pretty meaningless claim, as in an earlier post you wrote, "[Joni Mitchell and Mike Oldfield] are the only two artists I have on HDCD". Your sample size is so small that it is ludicrous to make claims such as you did. I'd also be curious as to how you know for a "fact" which HDCD discs have the Peak Extend enabled and which ones don't.
There is one place where I agree with you -- if all else is equal, playback of an HDCD disc *that was encoded with the dynamic range compression features enabled* will sound better if the dynamic range is restored via an HDCD decoder.
The problem lies in two areas:
a) "If all else is equal" -- When we designed our DVD player, the only HDCD decoder available was the PMD-100. A fine filter for CD, but it offered no support of higher sample rates. Given the choice between supporting HDCD or the then-new 96/24 discs, we chose the latter.
When we designed our CD player, both the PMD-100 and the newly released PMD-200 had been discontinued. At that time there was no way to offer HDCD decoding except with the inferior performing Burr-Brown PCM1732. Given the choice of using a good DAC chip without HDCD decoding and a mediocre DAC chip with HDCD decoding, the decision wasn't too difficult.
Since that time about the only people that still offer HDCD are Cary and Denon. I honestly don't know how they are able to implement HDCD decoding, as all available decoding chips have been long discontinued. One possibility is that they are using NOS (New Old Stock) from discontinued PMD-100 and/or PMD-200 chips. The other possibility is that Microsoft has licensed the HDCD code for implementation in a custom programmed DSP chip. (They didn't allow this in the past, but they may have changed their policy since then. I really don't keep up with Microsoft and their policies regarding HDCD.)
b) I (and I would assert you, as well) have no way of knowing what percentage of HDCD discs are actually encoded with the compression features turned on. I have spoken with mastering engineers who use the Model Two because they like the sound, but do not use the compression features.
So one has to weigh the costs and benefits when deciding to include an expensive feature such as HDCD. I would assert that the percentage of HDCD discs is relatively small, and further that the percentage of those that also use the compression features is even smaller. Given an unlimited budget, it would make sense to include HDCD decoding, even if it only benefits a very small fraction of the available discs. But in the real world we have to decide whether to use that money in other places (such as improved parts quality) that benefits the sonic performance of *all* discs. We've made our decision with our existing products, and I am not dissatisfied with that decision.
Really Charles, before you accuse someone of being wrong, it would help if you actually knew what you were talking about. Perhaps if you actually read the HDCD technical literature you wouldn't be making posts like this (I tried to search for the link to the PDF document, but it's disappeared so you'll have to get this yourself).*** Both claims are incorrect. The HDCD playback filter does not have dynamic filter switching -- only the encode side does. Also, there is nothing in an HDCD playback filter that "compensates" for dithering on the encode side. ***
No, it is you who is incorrect. As I've stated before, HDCD encodes command packets in the LSB of the sample stream. There are commands for filter selection, all this is fully documented.
And there is also compensation of the loss of resolution created by the command packets taking up 1 bit. The filter implementation also needs to be sensitive to the dithering algorithm. All this is fully documented.
Rather than accusing me of being incorrect, how about if you actually read the documentation? All I am doing is paraphrasing the technical documentation.
*** You claim that I am anti-HDCD because the Ayre players do not have HDCD filters. ***
No, I never claimed that. But your anti-HDCD bias is fairly obvious, and given you don't manufacture HDCD players, I was simply asking the question.
*** In the first place this is a pretty meaningless claim ***
You need to understand the context. I said the effects of Peak Extend were clearly audible on half the discs in my collection. He said this was mere "opinion", but it's not - I *do* know that at least half the discs in my collection have Peak Extend enabled.
*** I'd also be curious as to how you know for a "fact" which HDCD discs have the Peak Extend enabled and which ones don't. ***
Microsoft Windows Media Player *will* recognise and decode HDCD - including Peak Extend (they bought the technology, remember?). By comparing the output of WMP on HDCD discs against the raw digital samples prior to decoding, the effect of Peak Extend is then visible.
*** There is one place where I agree with you -- if all else is equal, playback of an HDCD disc *that was encoded with the dynamic range compression features enabled* will sound better if the dynamic range is restored via an HDCD decoder. ***
That was ALL I was trying to say in my original post. Remember? So when you accused me of "missing the point", perhaps it was you that missed *my* point?
*** "If all else is equal" -- When we designed our DVD player, the only HDCD decoder available was the PMD-100. A fine filter for CD, but it offered no support of higher sample rates. Given the choice between supporting HDCD or the then-new 96/24 discs, we chose the latter. ***
TI and Cirrus Logic have DSPs that support HDCD decoding, along with higher sample rates for normal PCM. Maybe you should have done more research. Rotel, Cary, Sherwood, Denon, Harman Kardon all have no problems offering HDCD support along with high sample rates.
*** I (and I would assert you, as well) have no way of knowing what percentage of HDCD discs are actually encoded with the compression features turned on. ***
Your assertion would be wrong. I've even posted the exact process for decoding HDCD using WMP a few months ago on this very forum.
*** So one has to weigh the costs and benefits when deciding to include an expensive feature such as HDCD. I would assert that the percentage of HDCD discs is relatively small, and further that the percentage of those that also use the compression features is even smaller. Given an unlimited budget, it would make sense to include HDCD decoding, even if it only benefits a very small fraction of the available discs. But in the real world we have to decide whether to use that money in other places (such as improved parts quality) that benefits the sonic performance of *all* discs. We've made our decision with our existing products, and I am not dissatisfied with that decision. ***
No one is questioning your decision, but I am calling out your pathetic attempts at rationalising the value of doing HDCD decoding, which borders on unethical behaviour since you are misleading consumers from making informed decisions.
And by the way, other manufacturers obviously do not see any problems offering HDCD implementations. They obviously see the value doing so.
Your assertions about the percentage of HDCD discs with or without Peak Extend is completely unfounded. Now that I've taught you how to find out for yourself, why don't you gather some facts before making such assertions.
It's similar to your assertion that the additional compression does not matter since the recordings may be already compressed. If you have any experience doing digital recordings, you would realise how silly your assertion is. Compression material that is already compressed is a big NO NO. It creates even worse artefacts.
1) Christine, you claim that "HDCD encodes command packets in the LSB of the sample stream. There are commands for filter selection, all this is fully documented."I have looked at the data sheets for the PMD-100 and PMD-200, as well as the AES paper. They make no mention of this feature in the data sheets, and only a vaguely worded (and possibly misleading) mention in the AES paper. If there are multiple digital filters inside the PMD-100 selectable by sub-code commands, this is news to me. Please refer me to the "document" that supports your claim.
2) It's really swell that "TI and Cirrus Logic have DSPs that support HDCD decoding, along with higher sample rates for normal PCM" now. I can assure you that they did not in 1998 when we were developing the Ayre D-1 DVD player.
Furthermore, the *only* way to decode HDCD when we were developing the CX-7 was the Burr-Brown PCM1732 (now discontinued), which is a decidedly mediocre sounding part. The PMD-100 had been discontinued as it was developed on a 0.6 micron (IIRC) process that was no longer supported by the fab house that Pacific Microsonics chose. They announced the PMD-200, but never shipped more than sample quantities before discontinuing it.
3) "I've even posted the exact process for decoding HDCD using WMP a few months ago on this very forum." I searched for posts by "Christine Tham" with the terms "HDCD" or "WMP" on this very forum since May 1 and found nothing relevant. If you have a link, I would be interested to read about your method.
> > Furthermore, the *only* way to decode HDCD when we were developing the CX-7 was the Burr-Brown PCM1732 (now discontinued) < <Charles, according to my 'comprehension', I assume by the above that you are referring to a "commercially available hardware chip" as distinct from "custom software" (i.e. 'DSP') implementations of HDCD code -- such as I presume was implemented in the Mark Levinson's proprietary "no. 360" DAC using "software" (as mentioned in Racer's post below)?
If so, then your rationale would indeed seem logical.
Charles, I own your latest player, and I'm a big supporter of Ayre, but you are way wrong in much of what you've said in this thread. Christine is right.> > Furthermore, the *only* way to decode HDCD when we were developing the CX-7 was the Burr-Brown PCM1732 (now discontinued), which is a decidedly mediocre sounding part. < <
This is completely wrong. Mark Levinson implemented HDCD decoding completely in software in their No. 360 DAC, which was developed in 1998 and released in 1999. IIRC, the CX-7 was released by you in 2002.
I looked up the details on the No 360, and you are correct. The HDCD decdoding was implemented in Analog Devices DSP chips. I was not aware that this was possible at that time. (It is relatively commonplace now.) Following is the chronology of our development work on the CX-7:- When we first began development work, we were considering using the PMD-100 decoder chip. However, its discontinuance was announced early on in our project's lifespan.
- The successor PMD-200 was then announced. We considered using it also, but before we could get samples they announced it was also being discontinued.
- Resolution Audio is an HDCD licensee. They use a Motorola DSP chip to perform their digital filtering functions. Jeff Kalt told me at the time that Pacific Microsonics/Microsoft would not release the HDCD code to him for incorporation in his DSP chip.
I understood that to mean that they would not release the code at all, but obviously that was not the case. Apparently they released the code to Analog Devices who could then offer a DSP chip with HDCD decoding to Levinson.
Thank you for clarifying these facts. If there are other incorrect statements I've made in this thread, I would be glad to have them also corrected.
Well, what can I say, I did a search for all posts with HDCD authored by myself and immediately found my previous post - see belowThere was a technical paper on HDCD available on the web that described the HDCD encoding and decoding process - unfortunately this no longer seems to be available but it was previously on http://www.hdcd.com/partners/proaudio/articles.html
Sorry - unfortunately I did not save a copy of this paper. Perhaps you can try and get a copy by contacting Microsoft directly.
For reference, this is what I posted in April, which is a summary of my conclusions from reading that paper:
my understanding is that an HDCD encoded CD differs from a "normal" CD in at least three different ways:
1. a proprietary dithering algorithm that supposedly gives a "perceived" extra 3 bits of resolution
2. plus a way of encoding an extra bit, or 6dB of dynamics
3. plus a way of encoding dynamic switching between multiple filters on playback (which is why HDCD players are equiped with a special digital filter chip)if you play an HDCD on a player with no HDCD support, you still get the benefit of (1) but not the next two. You also get the music automatically "compressed" by a factor of 2:1 due to the "missing" 6dB of dynamics (that's why HDCD often sound louder than normal CDs when played back without HDCD decoding)
i think the Microsoft HDCD decodes (2), not sure if it properly decodes (3). Presumably (3) is done by requantizing into 24-bits, but an even better process is to upsample 2x or 4x at the same time (which the Microsoft HDCD decoder unfortunately does not do).
*** It's really swell that "TI and Cirrus Logic have DSPs that support HDCD decoding, along with higher sample rates for normal PCM" now. I can assure you that they did not in 1998 when we were developing the Ayre D-1 DVD player. ***
But we are living in 2005 (soon to be 2006), not 1998, so what's your point?
By the way, last I checked, nearly all the major manufacturers support HDCD on their flagship processors/receivers and/or players: Denon, Pioneer, Rotel, Harman Kardon, Panasonic, Sherwood, ...
Very few of these implementations are based on the Pacific Microsonics chip, so if you think the only way to implement HDCD today is to use Pacific Microsonics, you should look further.
Essentially HDCD these days is implemented as software on a DSP and no longer relies on hardware. Think of it as a proprietary upsampler based on hints (the HDCD command set) supplied by the encoder.
Given that it's just software, there is no "cost" or engineering constraint to implementing it, apart from paying the license fee. Your objections to HDCD are out of date, you should really catch up and live in 2006 rather than 1998.
I am truly sorry that you have such trouble with reading comprehension. I am even more sorry that you persist in arguing points that are factually incorrect.1) Thanks for the link to the "technical paper on HDCD". Even though Micro$oft deleted it from their website, it still exists in cyberspace courtesy of "The Wayback Machine" at www.archive.org. In the paper "HDCD Decoder FAQ" you will find the following information:
"The HDCD decoder uses an interpolation filter complementary to the anti-alias filters used in the A/D filter switching process."
I know that reading comprehension is not your strong suit (again, I'm sorry about that), but please note that they use the *plural* form when talking about the encoding filters and the *singular* form when describing the decoding filter.
Now it's not quite clear to me how a *single* decoding filter could somehow be "complementary" to *multiple* encoding filters, but that is the kind of marketing fluff that I have encountered from Pacific Microsonics. (NB -- From a technical standpoint I have no beef with HDCD, nor its implementation. I just don't like the approach whereby they intentionally mislead with their marketing. Which by the way, seems to have fooled you quite well.)
2) Thanks for your link to your previous posting. (I missed it by two weeks in my previous search as you had specified "a few months ago". I erroneously thought that a 7-month window would have encompassed "a few months", but I actually should have used an 8-month window.)
Please note however, that your claim that "the max peak level [of the decoded HDCD signal] is under -6dBFS which means the bit is never used" is incorrect. In the first place, there is not some separate 'extra bit' used for "peak extend". In the second place, the max peak level does not tell you one way or the other whether "peak extend" was used during the encoding process. All it tells you is that the signal level never exceeded -6 dBFS during the A/D conversion process, regardless of whether "peak extend" was used or not.
(If you are unclear about this last point, please read the AES preprint from Johnson and Pflaumer also available from The Wayback Machine. Refer especially to Figure 6.)
3) If you think Ayre should design a DVD player using DSP chips designed for surround-sound processors (that will only be available five years after the player has been designed), then I think you may have a more than just an issue with reading comprehension. I really don't know what to tell you, except that maybe you should start your own audio company and build the products the way you think they should be built. Best of luck.
I think you may have misinterpreted the following line: "The HDCD decoder uses an interpolation filter complementary to the anti-alias filters used in the A/D filter switching process."I think if you read this as "The HDCD decoder [dynamically selects] an interpolation filter [that matches] the anti-alias filters used in the A/D filter switching process", you will find that your confusion over singular vs plural and the use of the word complementary resolves itself. Hey, the sentence now makes complete sense!
*** All it tells you is that the signal level never exceeded -6 dBFS during the A/D conversion process, regardless of whether "peak extend" was used or not. ***
Again, this is rather fanciful. How many CDs have you encountered where the signal never exceeds -6dBFS in the mastering stage? Hmmm?
You seem to be resorting to tortured justifications to support your points. Isn't is easier just to admit you are wrong?
*** If you think Ayre should design a DVD player using DSP chips designed for surround-sound processors (that will only be available five years after the player has been designed), then I think you may have a more than just an issue with reading comprehension. ***
Why do you keep referring to a DVD player you designed in 1998? Surely we are talking about today, when such chips are easily available and at low cost? Again, maybe it is you who has an issue with reading comprehension. No one (except perhaps yourself) is referring to what you may or may not have done in 1998, we are talking about your incorrect statements about HDCD *today*.
You are correct that the line I quoted can be interpreted in two different ways, thereby reaching two different conclusions. However, I am confident that my interpretation is the correct one, based on the following facts:a) There was absolutely no reason for them to be ambiguous with these claims. In fact it would have been a great marketing advantage for them to say "The PMD-100 has three different digital filters -- two that dynamically switch when playing back HDCD-encoded discs, and a separate one for playing standard CDs." But instead they chose to put a very vague and ambiguous reference in *one* single document, and leave out all mention of this feature in all other literature, data sheets, marketing materials, technical presentations, et cetera. Given Pacific Microsonics' known track record of misleading marketing, this is pretty damning evidence.
b) At the time the PMD-100 was introduced, there was a practical limit as to how much circuitry could be stuffed into a single chip. A digital filter consumes a lot of hardware resources, and the one digital filter known to be inside the PMD-100(that is detailed in the datasheet) was by far the biggest one used at that time. (It's specs were far superior to other similar parts of that time, with greater stop-band rejection and a larger number of taps.) It is extremely unlikely that Pacific Microsonics could have fit *three* digital filters, plus the sub-code detection circuitry and associated timers, plus the expansion circuitry, plus all of the other housekeeping circuitry required to run the lights and gain scaling, et cetera.
Now I realize that neither of the above facts represent incontrovertible proof. (Which is why we are still having this argument.) One needs to examine the facts and draw conclusions. While it is possible that I have made an incorrect conclusion, I don't think this is the case. However in the absence of some additional evidence surfacing, I don't think we are likely to make much headway in this scenario. Perhaps it is best to agree to disagree.
Regarding the signal level issue, you are simply wrong. If you understood the compansion process used in HDCD a little better, you would realize your error. I will try to explain this to you.
If "peak extend" is turned on during the mastering process, then the overall signal level is increased by 6 dB. To avoid digital "clipping", the top 9 dB of the incoming audio signal is squeezed into the top 3 dB of space on the disc. During playback, the overall signal level is reduced by 6 dB (hence the requirement for gain scaling of discs encoded using "peak extend") and the upper 3 dB on the disc is unsqueezed back to the original upper 9 dB of audio signal.
Please note that the above compansion process is (almost) completely transparent. (There is a negligible increase in the quantization error of high level signals.) If you have found a disc with the restored audio signal having nothing above -6 dBFS, all that means is there was nothing above -6 dBFS in the original audio signal. The exact same would be true if the disc were recorded and played without any HDCD processing. So your claim of being able to identify discs that use "peak extend" based on the peak signal level is simply incorrect.
As far as designing equipment today, your claim that "[HDCD] chips are easily available and at low cost" is also incorrect. There are *no* stand-alone HDCD decoder chips available today, and there haven't been for many years. If we discount the possibility of finding a limited stash of NOS chips in some back alley, the only choice is to use a DSP chip.
A DSP chip that decodes HDCD is not "easily available". In other words, one cannot just purchase it from Digikey or as an off-the-shelf part from a distributor as one can with a non-HDCD digital filter. Instead one has to purchase an HDCD license from Microsoft, which $10,000 plus pages of forms. (I've never applied for an HDCD license, but for example a Dolby license requires a complete financial statement of the company. Just filling out the paperwork for a Dolby license takes about a week.) Once you are licensed, then you can buy DSP chips with the HDCD decoding algorithm. Of course then you need to write the program for the other functions that the chip will perform, such as digital filtering. Then the chips themselves need to be programmed. So, yes, HDCD decoding chips are "available", but not "easily".
A DSP chip that decodes HDCD is also not a "low cost" item. These chips are designed for surround-sound processors, not CD players. They are *much* more powerful than is required for HDCD decoding. They will add significantly to the bill of materials of a CD player.
The above should be self-evident, based on the fact that so few CD players offer HDCD decoding. In the '90s, most high-end CD players *did* offer HDCD decoding precisely because the HDCD chip *was* "readily available at low cost". The only barrier to entry back then was the license fee (which was $5,000 then).
When we design a product, we make the decisions that we feel will create the best product we can make, balancing all relevant factors. The decisions we make are based upon the actual situation at that time. If we were to design a CD player today we might reach a different decision than we would have four years ago, as the circumstances have changed. But even in a cost-no-object design, we might not choose to implement HDCD decoding. For example, one problem is that DSP chips operate with extremely high internal clock speeds. For example, the current generation of SHARCs run at 400 MHz. This creates problems with internally radiated RFI inside the player, and can degrade the sonic performance of the unit. All engineering is a series of tradeoffs and compromises. Each designer will reach a different conclusion. The consumer is the one who gets to decide which design best suits their needs. If you think that another manufacturer has made the best decision by including HDCD decoding in their products, then you should purchase their products.
Regardless of how you choose to interpret one statement in an FAQ, the facts are these: an invention ("HDCD") is legally described by the patent, not by the implementation. The patent clearly spells out the mechanism for playback filter switching. Whether or not this is implemented is immaterial, and you have absolutely no proof (other than a distrust of Pacific Microsonics) that what was described in the patent has not been implemented.*** Regarding the signal level issue, you are simply wrong. If you understood the compansion process used in HDCD a little better, you would realize your error. I will try to explain this to you. ***
I think it is you that doesn't understand. The Microsoft implementation of HDCD automatically attenuates the digital signal by 1 bit (or approximately 6dB). If Peak Extend is engaged, the top 3 dB in the digital signal is expanded to 9dB. If Peak Extend is not engaged, no expansion occurs, therefore the result does not exceed -6dB.
Therefore, if the digital samples stored on the CD has signals between 0 and -3dB, and if on the output of WMP these signals are reproduced as -6 to -9 dB, then clearly that particular album/track does NOT have Peak Extend. Otherwise these signals will be expanded to 0 to -9 dB. Understand?
*** A DSP chip that decodes HDCD is also not a "low cost" item. ***
Not to you, perhaps. But to a large manufacturer, a DSP *is* a low cost item. Last time I checked, the pricing of these things in bulk is quite reasonable.
No one is forcing you to support HDCD. But your comments on what it is and isn't are wrong. Please don't mislead potential customers from thinking they are getting optimal performance listening to HDCDs on non-HDCD players, because they are not.
Christine wrote, "You have absolutely no proof that what was described in the patent has not been implemented." Just as you have no proof that it was implemented. Without further information, we will have to agree to disagree.On your second point, you stubbornly persist in being flat-out wrong. You wrote, "The Microsoft implementation of HDCD automatically attenuates the digital signal by 1 bit (or approximately 6dB)."
This is incorrect. Here is the text from the Microsoft document explaining gain scaling:
A key feature of the HDCD process is Peak Extend. Peak Extend increases the dynamic range of
Redbook CDs by 6dB. The Peak Extend feature is selectable on the Model 1 (or Model 2) HDCD
encoder - the recording or mastering engineer has the ability to set Peak Extend ON or OFF on
the Model 1 HDCD encoder. So it is possible to have HDCD recordings with, or without Peak Extend.
Because Peak Extend adds 6dB of dynamic range to the top end, the “average” decoded
signal level will be 6dB lower than an HDCD recording without Peak Extend, or a non-HDCD
recording. Unless the decoded level of Peak Extended and non-Peak Extended recordings are
matched using Gain Scaling, Peak Extended Recordings will be 6dB quieter than non-Peak
Extended recordings and this is not acceptable. All HDCD decoders must either 1) lower the gain
of non-HDCD recordings and HDCD recordings without Peak Extend by 6dB, or 2) raise the gain
of the Peak Extended recording 6dB. This is a requirement of the HDCD license agreement.So contrary to your unfounded assertion, the signal is *only* attenuated during playback if it was recorded with "peak extend" enabled. Therefore you *cannot* determine if a recording was recorded with "peak extend" enabled simply by examining the peak signal level of the decoded output.
However, I just realized that there actually *is* a relatively simple way to tell if a recording was made with "peak extend". Pin 5 on the PMD-100 goes "high" when the recording employs "peak extend". (At least this is the case when analog gain scaling is employed in the DAC. Tying pin 19 low on the PMD-100 enables internal digital gain scaling, but the datasheet doesn't say if this disables the output of pin 5 or not.)
So if one had a DAC with the PMD-100 (it may need to use analog gain scaling for this to work), then it would be easy to tell what percentage of HDCD discs use "peak extend".
*** Christine wrote, "You have absolutely no proof that what was described in the patent has not been implemented." ***My point was I don't need to prove it, since an invention is described by the patent, not the implementation. You on the other hand is clearly wrong, since your interpretation of an admittedly badly written sentence does not correlate with what's described in the patent. What is or isn't implemented is completely irrelevant, since when we are talking about HDCD we are talking about the technology, NOT a specific implementation.
*** On your second point, you stubbornly persist in being flat-out wrong. You wrote, "The Microsoft implementation of HDCD automatically attenuates the digital signal by 1 bit (or approximately 6dB)." ***
Charles, I am describing what WMP does when playing HDCD. If you don't believe me, check it out yourself. Would you like me to send you the actual WAVE files as output by WMP vs what's stored on the CD so you can clearly see this 6dB attenuation for yourself? I can send you an example of a disc showing Peak Extend in action, and other without Peak Extend.
Again, before you call someone wrong, it helps if you actually know what you are talking about.
PS - The MediaTek all in one "DVD player on a chip" does HDCD decoding. This is used in $50 made in China DVD players.
On the first point, either you are being taken in by deliberately misleading marketing fluff, or I am being cynical about their lack of forthrightness. I can provide *lots* of evidence for my position, but none of it is out-and-out proof.The only additional thing I've found since yesterday is the block diagram from the datasheet for the PMD-200. The section in question is labeled "2xFs Interpolation Filter" (note the use of the singular once again). Like every other reference to the decoding filter, it leans toward the idea that there is one single filter. I suppose it is possible that this filter has variable coefficients, but that seems quite a stretch to me. Again, we won't know until we have some additional facts.
On your second point, I'm not sure I'm following you. Your idea of comparing undecoded data with decoded data is a good one. This will clearly show if the level is being changed by -6 dB. According to the HDCD specification, this will be done only to those HDCD discs that employ "peak extend".
If I understand you correctly, you are saying that WMP lowers the level of *all* HDCD discs by -6 dB. If this is correct, I have two questions for you:
a) Why would WMP not follow the HDCD specification?
b) How do you then tell the difference between an HDCD disc that uses "peak extend" and one that does not?
On your third point, I'm afraid you don't understand the situation. Just because MediaTek (a Taiwanese semiconductor foundry) sells MPEG decoder chips for a low price to high-volume Chinese manufacturers doesn't mean that it is even *available* to Western-based low-volume manufacturers. If you don't believe me, try to get a lowly datasheet or even a sample chip. And even if you could somehow get a hold of the chip in small production quantities, it would be nearly impossible to use one in a CD player. MPEG decoder chips represent a monumental programming task. For example, Madrigal spent five man-years developing the Proceed PMDT DVD player. When they released it (a year behind schedule) it was so bug-ridden that they wouldn't even submit it for review.
So we at Ayre certainly wouldn't go down the path of using a MediaTek MPEG decoder as a way to provide HDCD playback on a CD player. But there is certainly more than one way to skin a cat, and you are more than welcome to design and sell your own CD player.
*** On the first point, either you are being taken in by deliberately misleading marketing fluff, or I am being cynical about their lack of forthrightness. I can provide *lots* of evidence for my position, but none of it is out-and-out proof. ***No Charles, you can download the patent from the US Patents Office web site. It is a *legal* document that describes what HDCD is, and not "deliberately misleading marketing fluff".
As for your evidence, you haven't actually given any, apart from you misreading a sentence, and irrelevant material/guesses concerning one particular *implementation* of HDCD.
*** If I understand you correctly, you are saying that WMP lowers the level of *all* HDCD discs by -6 dB. ***
Actually, it lowers the level of ALL CDs (HDCD encoded or not) by 6dB (when you select the 24-bit output mode, which is required for HDCD decoding). More precisely, it maps the 16-bit digital signal into a 24-bit word just below the most significant bit. This is to allow for Peak Extend encoded discs to expand into the most significant bit.
I'll attach four graphs to illustrate, taken from two HDCDs (one encoded with Peak Extend, one without). As you can see from the graphs, the presence or absence of Peak Extend is fairly obvious.
The non-decoded ones are digital rips from the CD, done using EAC in secure mode.
The decoded ones are the output of WMP playing these CDs, exactly as WMP would send to a WDM driver for an audio card (these waveforms were captured by the WDM rerouting the output into a WAV recording). No editing have been done on the output - ie. they are exactly what comes out of WMP.
*** Just because MediaTek (a Taiwanese semiconductor foundry) sells MPEG decoder chips for a low price to high-volume Chinese manufacturers doesn't mean that it is even *available* to Western-based low-volume manufacturers. ***
The MediaTek decoder is used on the Oppo DVD player, which is designed by a (smallish) US company. It is also used in many DVD players from boutique manufacturers such as NAD (Canada/UK) and Arcam (UK). I think all three companies qualify as "Western-based low-volume manufacturers."
It's not a bad decoder, and can certainly be used as the basis for a good DVD player (eg. the Oppo).
PS - I don't understand why you think it would be difficult for the original PMD chip to support multiple filters. Again, if you had actually read the patent, you would realise the filters only differ by three parameters. It would be very easy to build a chip that essentially has one filter, but allow the parameters to be dynamically reloaded.
This is an HDCD disc without Peak Extend, by the same artist (Joni Mitchell), taken from her album "Both Sides Now". This is track 3 (Comes Love).Not the extreme peak limiting on this track. It looks like it's clipping, but when you zoom in, you realise it's not - all the peaks have been limited to just under 0dBFS.
As you can clearly see, on a disc that has no Peak Extend, WMP does not expand the peaks, so the entire track does not have any peaks exceeding -6dBFS.
This is what Adobe Audition reports for the digitally rip (non-decoded) wave file:
Left Right
Min Sample Value: -32425 -32418
Max Sample Value: 32399 32416
Peak Amplitude: -.09 dB -.09 dB
Possibly Clipped: 0 0
DC Offset: 0 0
Minimum RMS Power: -89.95 dB -89.84 dB
Maximum RMS Power: -4.54 dB -5.32 dB
Average RMS Power: -17 dB -17.27 dB
Total RMS Power: -15.63 dB -15.85 dB
Actual Bit Depth: 16 Bits 16 BitsUsing RMS Window of 50 ms
By contrast, this is the statistics for the WMP decoded output:
Left Right
Min Sample Value: -16212.5 -16209
Max Sample Value: 16199.5 16208
Peak Amplitude: -6.11 dB -6.11 dB
Possibly Clipped: 0 0
DC Offset: 0 0
Minimum RMS Power: -95.57 dB -95.55 dB
Maximum RMS Power: -10.56 dB -11.34 dB
Average RMS Power: -23.03 dB -23.3 dB
Total RMS Power: -21.65 dB -21.88 dB
Actual Bit Depth: 24 Bits 24 BitsUsing RMS Window of 50 ms
As you can see, even for an HDCD disc that is NOT encoded with Peak Extend, the output of WMP is not identical to the non-decoded data.
In particular, if you zoom in on both files, you will find the low level information have been subtly altered, which is consistent with what the patent describes as "low level gain manipulation".
I think this is sufficient evidence to completely destroy your theory that there is no benefit or material difference to HDCD decoding on non-Peak Extend discs.
So, bottom line is HDCD decoding does make a difference, regardless of whether the discs are flagged with Peak Extend or not.
So let's review what we've learned here:1) Microsoft's implementation of HDCD decoding is different in WMP than it is for stand-alone CD players. I had no idea that this was the case, and I have no idea why they would do this.
2) By comparing the non-decoded output of an HDCD disc versus the decoded output, you can tell if "peak extend" was used in the recording. I hadn't thought of this method before, and this is a useful tool. (This method cannot be used with stand-alone CD players.)
On these points, the facts are self-evident and there is no room for disagreement.
Next you claim that by comparing the non-decoded output of an HDCD disc versus the decoded output, you can *probably* tell if "low level extension" was used in the recording. In this case the evidence is not quite as clear as with "peak extend", so I will reserve judgement on this. The statistical analysis you posted clearly shows a 6 dB shift in levels (as noted in point #1 above). Once this is compensated for, the biggest difference between the files is less than 0.5 dB (for "minimum RMS power"). Without further information, I don't think we can say one way or the other. In theory this method should work, but it is likely to be tedious, and I'm not clear that you've correctly identified a disc employing "low level extension".
And finally we return to the reading comprehension issue. You claim to "destroy [my] theory", but the problem is that you are setting up a straw man. I never said what you claim.
The HDCD encoder has two compansion schemes that are optionally engaged by the mastering engineer -- "peak extend" and "low level extension". (Furthermore, there are two varieties of "low level extension".) However if BOTH of these are *not* engaged, then there is no need for HDCD decoding.
I will recap one more time, in hopes that this will sink in:
1) When HDCD was introduced, it represented a true sonic breakthrough for the CD format. This was because the HDCD encoder was head and shoulders superior to the only other widely available choice at that time -- the horrible sounding Sony 1630. However, most of the gains found with HDCD were due to the encoder's features that DO NOT require decoding:
a) Dithering.
b) Switchable on-the-fly anti-alias filters.
c) Keith Johnson's discrete analog circuitry, excellent power supplies, and low-jitter clocks.
Nowadays there are many great sounding A/D converters available (none of them with HDCD encoding), but 10 years ago it was a completely different story. And while there are still many HDCD encoders in use, there are none available for sale today.
2) Unless an HDCD disc was recorded with "peak extend" and/or "low level extension", there is nothing for an HDCD playback machine to decode. Hence there is no advantage to using an HDCD-capable player with these discs.
You and I have both described methods to distinguish HDCD discs using "peak extend" from HDCD discs that do not use "peak extend". It may be possible that your method is also able to distinguish discs that use "low level extension". What is yet to be determined is what percentage of HDCD discs use "peak extend" and/or "low level extension" and would therefore benefit from HDCD decoding.
Please note that I never said that these type of discs *wouldn't* benefit from HDCD decoding. Instead, what I said was that HDCD decoding didn't provide the full benefits commonly ascribed to it for two reasons:
a) Much of the sonic benefit from HDCD discs does not derive from the HDCD process per se.
b) Many (we don't know how many) HDCD discs are not encoded in such a way as to require decoding.
*** On these points, the facts are self-evident and there is no room for disagreement. ***I think you will now agree that previously when you were asserting that I was not able to distinguish between discs that have peak extend or not, you were wrong. Also, when you persisted in calling me wrong in my description of what WMP does, you were also wrong.
Again, perhaps an apology would be in order?
*** Once this is compensated for, the biggest difference between the files is less than 0.5 dB (for "minimum RMS power"). Without further information, I don't think we can say one way or the other. ***
I've already said: further information is there, by inspecting and comparing the actual shape of the waveforms. You are more than welcome to repeat what I've done, and evaluate the differences yourself. What you will find is that these differences are on every HDCD disc (or at least in my case every single HDCD I own).
*** The HDCD encoder has two compansion schemes that are optionally engaged by the mastering engineer -- "peak extend" and "low level extension". (Furthermore, there are two varieties of "low level extension".) However if BOTH of these are *not* engaged, then there is no need for HDCD decoding. ***
No, you are still wrong. Unlike Peak Extend, the low level manipulations are NOT optional. Again, read the patent.
*** I will recap one more time, in hopes that this will sink in ***
Your recap is still wrong, and is not consistent with what the patent says.
*** Much of the sonic benefit from HDCD discs does not derive from the HDCD process per se. ***
This is debatable, since it is merely your opinion, and you have not provided any substantiation for this statement. Any it is clearly wrong for discs with Peak Extend, but we can argue about whether the benefits of dynamic filter switching and low level gain manipulation is "substantial."
*** Many (we don't know how many) HDCD discs are not encoded in such a way as to require decoding. ***
You are wrong, because the low level gain manipulation is NOT optional. It's related to the way HDCD does dithering.
You are amazing in your persistence in being wrong. You must love to be wrong. Repeat after me:THE PATENT IS NOT THE PRODUCT.
THE PATENT IS NOT THE PRODUCT.
THE PATENT IS NOT THE PRODUCT.
Please refer to the operating manual for the Pacific Microsonics Model Two HDCD encoder:
==========
Low Level Extension is an average signal level based low level compression / expansion
system used on HDCD 16-bit amplitude encoded recordings which very gradually raises
gain a preset amount when the average signal level drops below a preset threshold. During
HDCD 16-bit decoded playback the compression curve is expanded back to linear gain by
the HDCD decoder using a precisely mapped inverse of the compression curve controlled by
a hidden code, producing a dynamic range and resolution floor beyond 16-bit. During
undecoded playback low level information normally lost by standard 16-bit players is preserved,
providing more accurate timbral and spatial reproduction.
There are two modes of Low Level Extension, “Normal” and “Special”. Normal mode begins
to affect the input signal 45 dB below peak level, gradually raising the gain 4 dB as the
level drops over an 18 dB range. Special mode begins to affect the input signal 39 dB
below peak level, and gradually raises the gain 7.5 dB over a 26 dB range.Use of Low Level Extension is optional in the HDCD 16-bit encoding process.
==========Since you apparently have a problem with reading compehension, I will repeat this last point:
USE OF LOW LEVEL EXTENSION IS OPTIONAL IN THE HDCD 16-BIT ENCODING PROCESS.
Remember Christine, THE PATENT IS NOT THE PRODUCT.
You seem to have a real aversion to reading the patent, but prefer to quote from a specific implementation.If you did read the patent, you may realise what the patent refers to as "low level gain manipulation" refers a broad number of things, including low level extension. It is not a synonym for low level extension.
Anyway, the proof is in the empirical results, which you have ignored. Again, based on my experience, the WMP HDCD decoder seems to manipulate all HDCD content, regardless of whether specific features are engaged or disengaged.
If you can find a specific HDCD disc that passes through the WMP HDCD decoder unscathed, then perhaps you may have a point. But I'm willing to bet you can't.
Christine wrote, "HDCD is defined by the patent, not the implementation."Yep, I'm pretty sure that's the way it works in real life.
There they are in the mastering studio, getting ready to create the master for their new album. The band is there, the producer is there, and the mastering engineer there, all working hard to make the best product they can. The studio is equipped with a Pacific Microsonics Model Two A/D converter (which along with the Model One is the only way there is to make an HDCD disc).
They are debating which settings to use, and then someone shouts, "STOP! We have to check with the patent!"
So they go on-line and download the patent. They discuss it for a while and then agree, that even though there are menu options for turning "low level extension" on and off, and even though these options are explained in the manual, that they MUST NOT turn off "low level extension". After all, that's what it says in the patent.
Yep, I'm pretty sure that's the way it works in real life.
Tell me something, Charles, have you ever been in a recording studio? Have you been involved in mastering any recordings? Do you actually have any idea at all what constitutes "real life" in a studio?Hint: I *do* have first hand experience.
One of my best friends (whom I have known for over 30 years) is a well-established recording engineer. His credits include Alanis Morissette, Ringo Starr, and Dada. I have sat in on several recording sessions with him.I have also sat in on mastering sessions with George Marino (Sterling Sound), David Glasser (Airshow Mastering), and Gus Skinas (Super Audio Center). If you haven't heard of these guys, do a Google search and see what you find out.
So yes, I do have an idea of what constitutes "real life" in a studio. And I must say that not once in all my times in a studio has someone been concerned about looking up a patent, even though in some cases these people were actually using an HDCD encoder. Funny, that.
This is "Black Crow", from Joni Mitchell's "Shadows and Light" (Disc 2, Track 1), ripped via EAC in secure mode.This is what a non-HDCD player would play. As you can see, the waveform is peak-limited (all the peaks are suspiciously the same height) - this is due to Peak Extend in action.
This is how WMP has decoded the track. Note the attenuation of the entire waveform by -6dB, followed by expansion of peaks, which are now clearly of different heights (louder than -6dB).
As I have personally talked to Prof. Johnson, Gene Pope II and others in the music business. And have read all the details on how HDCD works. It is an endode/decode process and "un-decoded" you get the advantage of the subtractive processes to reduce some of the ills of PCM. But you need the extra musical information encoded in the LSB for the additive information which not only includes an extra 6dB of dynamic range but overtones beyond 20kHz and resolution to 20 Bits.Sorry Charles to play HDCD correct you NEED an HDCD decoder.
Hope this helps,
Teresa
It would seem that Christine's problem with reading comprehension is contagious.I would agree with you that to correctly play HDCDs *that are encoded with peak extend and/or low level extension* an HDCD decoder is required. I never said otherwise. What I did say were two things. I will say them again in a slightly different way, in hopes they will sink in this time.
1) Contrary to Christine's assertion. There are NOT multiple filters that switch on-the-fly in an HDCD decoder. This means that one of Christine's claims for the benefits of HDCD decoding does not actually exist.
2) If an "HDCD" disc is recorded without the mastering engineer activating the "peak extend" and "low level extension" features, THEN THERE IS ABSOLUTELY NO ADVANTAGE TO USING AN HDCD DECODER.
This is because there are only three things added by the HDCD encoder in this situation:
a) Dither during the A/D conversion.
b) Multiple digital filters that are selected on-the-fly.
c) Good sounding circuitry and power supplies designed by Keith Johnson.
Please note that there is NO advantage to using an HDCD decoder in this situation because an HDCD decoder does NOTHING different in this situation than does any other playback circuit.
But here is the kicker. Short of asking the original mastering engineer, I know of no way to know which HDCD discs use "peak extend" and/or "low level extension". This means that THERE IS NO WAY OF KNOWING WHICH "HDCD" DISCS REQUIRE HDCD DECODING FOR CORRECT PLAYBACK.
This is the point that I made to Christine in my first post in this thread. I have no idea what percentage of HDCD discs use "peak extend" and/or "low level extension". It could be 5% or 95% or anywhere in between. The point is that there is not as much benefit to HDCD decoding as one would think, based on the fact that not all so-called "HDCD" discs will benefit from HDCD decoding.
Charles Christine and my reading comprehension are fine, it is you that is having trouble grasping the concepts of HDCD. So I will try to help you.You said: If an "HDCD" disc is recorded without the mastering engineer activating the "peak extend" and "low level extension" features, THEN THERE IS ABSOLUTELY NO ADVANTAGE TO USING AN HDCD DECODER.
Sorry Charles your statement is very incorrect, see highlighted text below from HDCD.com FAQs:
Q: Why should I listen to HDCD-encoded CDs on a player with HDCD decoding?
A: HDCD recordings will always sound better than conventional CDs when played on any CD player. You hear fuller, richer sound on all types of players, from portables to high-end systems, which is why so many top artists and engineers use HDCD technology. To bring out the full bandwidth and superb fidelity of HDCD recordings, a player with HDCD decoding should be used . HDCD recordings have a dynamic range and resolution and, best of all, the HDCD decoder chip used in consumer products also contains the HDCD high-precision digital filter that improves the sound quality of all types of digital audio recordings. This means that any A/V receiver, CD player, DVD player, and MiniDisc player equipped with HDCD will produce significantly better sound from your entire collection of CDs, DVDs, and MDs.
from Spectral Audio.com
HDCD recordings are made from analog to digital conversions having more bits and faster sampling to provide a large amount of dynamic and resolution information. Digital signal processors then identify corrective actions or fixes to prevent losses and distortions when this information is reduced to the CD format. Some of these fixes are directly coded to the linear PCM data of the compact disc thereby improving performance from all players. Others are converted to a hidden code and sent through a buried information channel to the HDCD process chip in the SDR-2000. Upon processing, the normally lost micro level resolution signals are restored. This improved resolution requires conversion accuracy and jitter performance much better than traditional engineering and design practice. A very carefully and thoroughly executed process system is needed to fully utilize the HDCD filter technology.
Also from Reference Recordings.com:
However, the finest levels of resolution, imaging and spatial information will be revealed when these CDs are reproduced on players with HDCD decoding ...
You also said "Contrary to Christine's assertion. There are NOT multiple filters that switch on-the-fly in an HDCD decoder. This means that one of Christine's claims for the benefits of HDCD decoding does not actually exist.
For this I was unable to find a link, for some reason Microsoft has nixed most of the technical articles on the internet. I guess Bill Gates wants to make sure no one can copy the process? However I can assure you that HDCD does use multiple filters in the encoding process that are hidden in the LSB along with "extra" musical and ambient information. To retrieve it, you need an HDCD decoder to mirror the opposite of what the HDCD encoder did.
If you don't trust yourself to hear the extra 6dB of dynamic range "Peak Extend" affords, Christine has the equipment to measure it. BTW all of Reference Recordings HDCDs use both Peak Extend and low level Extend. But even without those two features you will miss the extra resolution of HDCD by not using an HDCD decoder prior to playback, all HDCDs, especially those from Reference Recordings, Linn Records, First Impression Music and Opus 3 need an HDCD decoder to get the full benefit of the extra resolution the process offers.
HDCD discs SHOULD use HDCD decoding every time to hear the recording as the engineer intended.
Hope this helps,
Teresa
The first half of your post comprises the repetition of meaningless marketing claims. I will not bother to rebut these.You claim you were unable to find a link to any evidence that supported Christine's claims. I will try to help you here. I already posted that www.archive.org keeps copies of old web pages. Apparently that wasn't enough information for you, so I will be more explicit.
The archived pages that contain technical information concerning the HDCD process can be found at:
http://web.archive.org/web/*/http://www.hdcd.com/partners/proaudio/articles.html
A specific archived web page from October 2004 that contains the now-deleted documents can be found at:
http://web.archive.org/web/20041012195600/http://www.hdcd.com/partners/proaudio/articles.html
The most relevant document that explains the HDCD decoding process can be found at:
http://web.archive.org/web/20020124175704/www.hdcd.com/partners/proaudio/DecoderFAQ.pdf
Additional technical information can be found in the AES pre-print at:
http://web.archive.org/web/20020124220637/www.hdcd.com/partners/proaudio/AES_Paper.pdf
Please read these documents (or any others you care to), and you will find that Christine's claim is untrue. Please remember that Pacific Microsonics was pretty good with misleading marketing claims, so you will need to read carefully to make sure you are not inferring something that isn't actually said. I think that is actually the source of Christine's confusion on this point.
If one adds a qualifier to your closing statement to instead read, "HDCD discs [utilizing "peak extend" and/or "low level extension"] SHOULD use HDCD decoding every time to hear the recording as the engineer intended", then this is accurate. However, HDCD discs recorded without these features enabled receive NO benefit by being played back via an HDCD decoder. All that it will do differently from any other playback circuit is light up the front panel indicator light. As far as I know, short of interviewing the mastering engineer, there is no way for one to know which HDCD discs will benefit from HDCD decoding.
I wonder why Microsoft deleted all the web pages that explain HDCD technology from www.hdcd.com and why they are no longer available on other "active" sites?The first set of articles are ones original appearing when Microsonics owned the technology. I am glad someone archived all of these links. I am sorry I missed the mention of these sites in one of the many of your previous posts in this very long thread. But I will read them all in time. Thanks!
So Pacific Microsonics has made claims that are untrue? It is often hard to seperate advertising from science.
Anyway I am quite pleased with HDCD recordings that originate from HDCD masters especially the Reference Recordings. Though the resolution is lower than DVD-Audio or SACD many are quite enjoyable and spectacular when decoded.
Teresa
Teresa wrote, "So Pacific Microsonics has made claims that are untrue?"I wouldn't say "untrue" as I don't know of any flat-out lies they made, but I would say definitely misleading. The most egregious example of this was when they released their sampler that allegedly compared non-HDCD against HDCD. What they negelected to tell you was that the non-HDCD track was made using the (atrocious sounding) Sony 1630 A/D converter and the HDCD track was made with the (excellent sounding) Keith Johnson A/D converter. This was an unfair, depceptive "comparison".
They could have chosen to make a valid comparison by simply turning the HDCD features on and off when using the Keith Johnson A/D converter. But they instead chose to sell by misleading the public.
Teresa wrote, "It is often hard to seperate advertising from science."
Agreed, which is what I've been attempting to do in this thread.
Teresa wrote, "Anyway I am quite pleased with HDCD recordings that originate from HDCD masters."
Also agreed. When first introduced, the HDCD A/D converter was head and shoulders above anything else on the market. It is still one of the best converters out there. (It was discontinued a couple of years ago, but is still used by many mastering houses.) The only thing I was trying to clarify was *why* HDCD recordings sound good in general.
Specifically, the primary sonic advantage of HDCD discs is due to the high performance of Keith Johnsons's circuitry. The compansion scheme optionally used on the encode side (and that is the *sole* basis of HDCD decoding) only provides an arguable sonic improvement, and one that is clearly smaller than KJ's circuitry. Finally, there is an unknown percentage of "HDCD" discs that are encoded without any compansion features enabled, and that there is no benefit *whatsoever* to playing back these discs on an HDCD-equipped playback machine.
Are you not man enough?I've quoted you the HDCD patent number. Based on this, you can download the patent yourself from the US Patents Office, which clearly describes the mechanism for dynamic filter selection that you don't believe exists.
In addition, it describes other mechanisms (such as low level gain manipulation, and waveform synthesis) which absolutely do show that an HDCD decoder is required for optimal HDCD playback, regardless of whether Peak Extend is present or not.
Really Charles, how arrogant or obtuse can you get? Calling out someone as being wrong when it is clear you do not know what you are talking about, and accusing myself and Teresa of having "reading comprehension issues" when it is clear you are the pot calling the kettle black ...
Charles, do yourself a favour and if you do not want to apologise, stop responding because your reputation on this forum is rapidly declining. You even have one of your customers (racerguy) basically telling you much of what you said is wrong. Are you willing to risk alienating your customers further?
Just because they patented a feature does not mean that it was implemented in the production version of the product. Please provide one written example where it is clearly stated that production HDCD decoders provide dynamic filter selection during *playback*.I don't think you can because I don't think such a document exists. I can hardly blame you for your perceptions, as much of the HDCD literature was written to be deliberately misleading. It's not surprising that you (and many others) have gained the wrong impression from their misleading claims.
But the thing that is puzzling to me is that when I point out the true facts, for some reason you take this personally and stoop to personal insults. You question my manliness and call me shameful, pathetic, and self-serving. I would instead suggest trying to find some factual evidence that supports your claims.
Charles, so far you've accused me of somehow "missing a point", being wrong, have reading comprehension issues, "confused" and who knows what else. So who's stooping to insults?Your suggestion that what's documented in a patent has not implemented is rather fanciful and contrived. Perhaps it is you who need to prove this assertion? Or is it simply because you can't bring yourself to admit you were wrong?
*** I would instead suggest trying to find some factual evidence that supports your claims. ***
Maybe you should follow your own advice?
W would have us believe that anyone who makes a valid inquiry as to his course of actions is unpatriotic. Similarly, Christine would have us believe that pointing out facts or questioning her assertions in somehow personally insulting.I don't buy either claim.
Well, at least you have two things in common in W: a belief that you are always right, even when its proven you are not. And the ability to make assertions (eg. WMD) on absolutely no basis whatsoever.
We apparently share a distaste of W.(Although you have certainly not "proven" I am wrong, and your assertion that my assertions have no basis has no basis.)
*** your assertion that my assertions have no basis has no basis ***Only according to you. Not according to your customer, racerguy. And also not according to a patent filed with the US Patent Office.
Not true. I have provide many bases for my assertions. You may disagree with my conclusion, but that doesn't negate the bases themselves.
No, your "bases" are irrelevant or wrong. They are irrelevant because they are essentially your unsubstantiated guesses relating to one specific implementation of HDCD. And you have made quite a few statements that are just flat out wrong.
Christine wrote, "your unsubstantiated guesses".You are wrong again. I have substantiated my reasoning in great detail in this thread. I will not bother to repeat myself here.
As far as "one specific implementation" goes, guess what? There have only ever been two ways to make an HDCD disc -- the Pacific Microsonics Model One and Model Two. The main difference between these two units is that the Model Two supports sample rates above 44.1 kHz. (I don't think there are any other substantive differences between these. If you know of any, please feel free to point them out.)
Everything I've posted pertains to these two units, and therefore to every HDCD disc ever made (unless there are some Reference Recordings discs made with a prototype encoder).
As far as your claims regarding Pacific Microsonics' patent, let me ask you a couple of questions.
a) Do you think that there have ever been patents granted that weren't turned into commercial products?
b) Do you think there were ever patents granted that were turned into commercial products, but in a slightly different form?
*** You are wrong again. I have substantiated my reasoning in great detail in this thread. I will not bother to repeat myself here. ***Well, at least you are consistent in that whenever you call me wrong, you are wrong.
You have definitely not substantiated your reasoning in the same way as I have - by referencing a patent that describes the invention, and actual graphs from an implementation by the current owner of the patent. Instead, you have a set of wild guesses, dubious inferences, incorrect interpretations and assertions that are not substantiated and many of them have been shown to be incorrect.
PS - I have no idea why you say the WMP implementation is not following the spec. Again, perhaps you have reading comprehension issues? According to my reading, it does.
*** As far as "one specific implementation" goes, guess what? There have only ever been two ways to make an HDCD disc ***
You definitely have a reading comprehension issue. We are talking about HDCD playback, not HDCD content creation. Even if there is only ONE way to make HDCD discs, so what? There are definitely multiple ways of HDCD playback - so your ramblings and guesses about the inner workings of the PMD 100 (which is a playback device by the way) are completely irrelevant.
Also we are talking about what HDCD is or isn't. That is purely defined by the patent, not the implementation. So when you say HDCD is this and HDCD is not this, you are basically flat wrong, regardless of what you think the implementation is or isn't.
*** As far as your claims regarding Pacific Microsonics' patent, let me ask you a couple of questions. ***
These questions are irrelevant. Actually, you don't need to have any commercial products for a patent to be valid (witness the case between NTP and RIM over wireless email). So, regardless of whether an invention is ever realised in a practical form, it is still described by the patent.
In the case of HDCD, however, there appears to be no evidence that what was implemented isn't EXACTLY what is documented in the patent. Again, if you have evidence to the contrary, I would like to see it.
...into something that would be beyond impolite to state.Christine wrote, "In the case of HDCD, however, there appears to be no evidence that what was implemented isn't EXACTLY what is documented in the patent. Again, if you have evidence to the contrary, I would like to see it."
I have already given this evidence many times in this thread. Since it didn't sink in any of the other many times I have said it, I won't bother to say it again.
I'm done with this one. Merry Christmas.
Let's face it, you can't. You just end up repeating the same incorrect and irrelevant phrases with no substantiation again and again, but somehow in your mind that constitutes "evidence". You yourself have admitted that much of what you say is suggestive rather than a definitive proof.Incidentally, it takes two to tango. Perhaps before you start referring to me with adjectives such as "obstinence" and "something that would be beyond impolite to state" - perhaps you could look at yourself in the mirror. So far you have not apologised for quite a number of things I said that you have called out as "wrong" but which you have later acknowledged are correct. Given the ferocity of your rebuttals, surely you could find some magnamity in you to acknowledge your mistakes?
A Merry Christmas to you too!
Extract from patent:"A fully decoding player, in accordance with the invention, retrieves the control signal and uses it to set up, operate and dynamically change a complementary process to recover the pre-computed high accuracy information and provide low distortion reproduction of the original analog signal. Operations to do this include fast peak expansion, averaged low level gain reductions, selecting complementary interpolation filters, waveform synthesis, and others."
If you read further, there is a whole section on how to do the filter selection on encoding, and filter switching on playback. The section on low level gain control is interesting as well.
If you had any grace at all, I would expect nothing less than an apology from you.
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