Posted by Richard Crowley on 01/12/61 11:52

"PTravel" wrote ...
> Yep. Good examples of drop out that results in uncorrectable errors.
> I've never, ever had that happen, and I've not heard reports from anyone
> else saying its anything but highly unusual.

I hope so. Unfortunately, I have seen three of them in the last
two months. Keep your fingers crossed. :-(

> The question remains how often this happens. If it is so rare that it
> happens once in 10,000 hours then, for all intents and purposes, it's
> zero.

You must have missed the reference provided by Mr. Heffels...
http://www.creativevideo.co.uk/public/pdf/sony_dvcam_2005-6_inc_xdcam.pdf
Page 4, middle of left column: "100 counts/minute" for DV.
(50/minute for DVCAM). Having seen the RF envelope
from the rotating heads on my oscilloscope, and the "eye-
pattern" from the resulting bitstream, those numbers seem
quite plausible. Likely 99.99% of these are completely and
accurately correctable using ECC.

We have really done a good job of making digital look perfect
from the POV of the end user. Most people really have no
appreciation for the complexity of what is happening under
the hood. (Or for their automobiles, either, for that matter.)

> Then tell me what the uncorrectable error rate is for DV tape.

There is no single number. It depends on a great many factors.
For ANY media, analog or digital; audio, video, or data.
Magnetic, optical, holographic, etc. For our DV recordings,
many of these factors we can keep at bay by using new tapes,
not switching brands, keeping everything clean, keeping the
equipment properly aligned for interchange, avoiding the long-
playing modes, etc.etc.etc.

If you held a gun to my head, I would guess that on average,
under good conditions, there is an uncorrectable error every
10-30 minutes. Fortunately most of them are so small (<8
pixels) and so short (<2 frames) that we don't notice them.
Its good enough for me. Sounds like it is good enough for
you, also.

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