Posted by Toby on 07/15/06 01:07

I've done a bit of digging, and I can't find any controlled studies which
quantify unrecoverable dropouts on DV. This is interesting in itself, since
almost all the DV and professional video sites that I visited acknowledge
that they do exist, and adam wilt even has frame grabs showing them.

I've come to the following conclusion. Direct bitstream copying of DV does
not suffer from generational degradation, *if* one defines that term as
meaning relatively predictable degradation of the image over multiple copies
based on loss of data due to inherent limitations in the ability to copy
identically. This would include the introduction of noise, for instance, and
frequency bandwidth limitations, or the introduction of relatively constant
distortions, such as wow and flutter in analog audio. I'm sure there are
many more that I am missing. These occur even if the recording medium is
perfect and the means of transferring a signal from it to the machine is
perfect.

However this does not mean that DV does not suffer losses over multiple
generations, this being due to the accumulation of non-recoverable errors,
given that such do indeed exist, even if their number is relatively low.

In another realm, we are here precisely because the digital copying of DNA
is not perfect. The instances of copying errors is low enough to ensure
relative stability in the genotype, while at the same time being high enough
to allow for change. DNA copying should be perfect, given its mechanism, but
it isn't, just as DV copying is not perfect.

Toby

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