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Re: Re: again about compression

Subject: Re: Re: again about compression
From: Walter Knapp <>
Date: Mon, 01 Apr 2002 18:26:56 -0500
richpeet wrote:
> 
> Sony has made a large effort to make unavailable computer emulation
> of atrac. 

I would say it's more the case that it's just not necessary to have
computer emulation. And even if you did, note that word emulation, it
would only be like the hardware ATRAC system, not identical.

Actually atrac is available in computer form. Real Audio is now Atrac as
I understand it. But, note it's not the same compression rate as minidisc.

 If you want to test a few specific files I would be happy
> to convert a wave file to atrac and back to PC wave and send it back
> to you to look at.  I would make the transfer from wave to atrac all
> digital but I only have an ablility to make the atrac back to wave
> via line level analog. It would still be pretty clean but you may
> want to use someone with a digital out on their Minidisc.

If you want to examine ATRAC itself, use all digital. Or at least be
very careful blaming ATRAC for what you get.

Even using all digital, there are some issues with clock sync that can
trip you up as the clock in the recorder will not be exactly the same as
the computer. Unless you are extremely lucky. In addition make sure your
digital system is not resampling the digital stream. Like a digital
soundcard that's running internally at 48khz will do.

And, if you look through the nature recordist's binary page, the test I
organized that had a analog step is still there. Though the key is right
there too. That was based on the older ATRAC 4.

Walt



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