[EMAIL PROTECTED] wrote:
>
> Ralph Smeets <[EMAIL PROTECTED]> writes:
>
> > You're correct here. But the error correction system only accepts
> > single bit errors... Ie, guessing mode is entered very quicly. (A
> > dust particle is sufficient!)
>
> Hardly, it accepts long spans of errors, as you would see with a scratch
> on the disc.
Data is organized in a interleaved format. As long as the scratch is not in a
circular form, the affected sectors will not have a direct connection with each
other.
I've got 2 CD's that became un-usable/playable due to some circular scratches.
> > AFAIK, the ATRAC error correction takes place before 'decompression'. If
> > I understood the IEEE-ATRAC document correctly (Eric please help me out),
>
> The error correction takes place with the data that is read/written to
> the disc (i.e. compressed data).
Thanks!
> > MD has no guessing mode. Ie, It can either correct the error or you get
> > a moment without sound.
>
> The Error Concealment scheme for MD and CD is different. You may be
> right, that the only concealment for MD is muting, though I seem to
> remember something about a fallback arrangement when part of the
> soundgroup data is recoverable. IIRC, the original MD soundgroup
> stored the "sound parameter bytes" (quantization bit lengths)
> redundantly (see the diagram in the IEEE paper). This was later
> dropped however, in favor of using those extra bits to improve overall
> coding accuracy.
>
> Rick
I've had dustparticles on a MD. When I played this MD, I would get muted sound
at some parts. After cleaning the MD, everything sounded fine. I remember
other reports to this list in the same style.
Cheers,
RalphI
--
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Ralph Smeets Functional Verification Centre Of Competence - CMG
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