Posted by Toby on 07/13/06 02:37

"PTravel" <ptravel@ruyitang.com> wrote in message
news:4hfsbtF1rcvsvU1@individual.net...
>
> "Richard Crowley" <richard.7.crowley@intel.com> wrote in message
> news:e8ucis$8o5$1@news01.intel.com...
>> "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".
>
> Can you site me to something that says how often this happens? I've never
> heard of DV video transfers being described as anything other than
> lossless.
>
>>
>>> 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.
>
> I meant that the resulting data is not the same as the original, hence
> there is data lost. But how often does this happen?

This reminds me of a story. How often do you think earthquakes happen in
Japan? Once a month? Once a week? We recently did a doco about earthquakes
here and visited one of their seismo centers. It turns out that the rate of
measurable earthquakes is about 100 an hour.

Do you see what I am getting at?

Toby

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