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Re: That would be you

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.

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