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Posted by Toby on 07/13/06 02:40
"PTravel" <ptravel@ruyitang.com> wrote in message
news:4hg0ejF1rh144U1@individual.net...
>
> "Richard Crowley" <richard.7.crowley@intel.com> wrote in message
> news:e8ueph$9p9$1@news01.intel.com...
>> "PTravel" wrote ...
>>> 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.
>>
>> There are some CD players and DAT recorders which display
>> the raw error rates while playing. I know that everyone who has
>> seen those numbers are astounded by them.
>
> Well, yes, but that's not what I'm asking for, i.e. a source for the
> number of uncorrectable errors that result in video data being "filled in"
> by extrapolation.
>
>>
>>> I meant that the resulting data is not the same as the original, hence
>>> there is data lost. But how often does this happen?
>>
>> It typically happens several times per second for your average
>> audio CD. I'd bet that it is roughly equivalent for DAT and DV
>> tape.
>
> Sorry, but that's not what I'm asking. The contention here is that there
> is generational loss in straight copies of digital video data, and I've
> never heard that anywhere else. For generational loss to occur, there
> have to be gross drop out errors that can be fixed by conventional ECC
> and, per you and Martin, are fixed by extrapolating based on prior or
> subsequent video data, i.e. pixels are filled in. I'll take your word
> that happens, but I don't believe it happens often enough to be a concern.
> I'd like to see some data that suggests that, notwithstanding every source
> I've ever seen that says digital video dupes are lossless, this isn't so
> (see the quote from Adobe in a post I made to Martin).
For most practical purposes they are loseless, and Adobe would probably win
in court with their fradulent claim. That doesn't mean that it is truly
loseless, for in that case *every* single instance of error correction would
have to be bit-perfect reconstruction based on redundancy, and it is not.
I think you'd better define what you mean by "gross drop out errors". At
what point do they become gross, counselor?
Toby
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