Posted by Toby on 07/13/06 02:41

"PTravel" <ptravel@ruyitang.com> wrote in message
news:4hg0kbF1rcksaU1@individual.net...
>
> "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).
>>
>
> More sloppy typing by me -- that should read "gross drop out errors that
> CAN'T be fixed by conventional ECC . . . "

You mean "can't be fixed LOSELESSLY by conventional ECC"? I would bet that
almost all ECC in DV is lossy.

Toby

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