Posted by Richard Crowley on 01/12/87 11:52

"PTravel" wrote ...
> We're still talking about apples and oranges -- data reconstructed using
> ECC is accurate and bit-for-bit what was recorded (or supposed to have
> been recorded).

No. That is the description of how ECC works for computer
data. There is another MAJOR error recovery layer used by
audio CDs, DVDs, DVD tape, etc. It is how they manage to
be cost effective.

Audio/video data that cannot be accurately *corrected* gets
*mitigated* by extrapolation. This is the factor that is present
in audio and video digital recording but NOT in computer data
recording. It probably comes into play more often than we think,
but if it is good enough we don't notice. But multiple repetitions
of it amount to something approaching "generation loss".

> Replacing pixels (or scan lines or averaging blocks) results in lost data.

I think you have that backwards. Replacing pixels, etc. is one
of the major migitating actions taken as a result of lost data.

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