Interpreting Scan Data

vbimport

#1

It seems like the PI/PO test is the most important scan… if you have nice pi/po scans, is it even necessary to look at the TA or Beta-Jitter tests?

I’ve burned disc that have good PI/PO results, but the TA scans are bad. The Jitter is jittering quite a bit… The beta results look good. Any comments?


#2

What testing you do or do not do is up to you. Since you are not testing any hard and fast physical aspect of the disc, but it’s “readability in the given drive”, what works for you may not be what works for someone else. If you have reading issues in a DVD player, performing additional tests might help narrow down the issue.


#3

rdgrimes, thanks for the reply, but I guess, I did not make my question clear enough. What I was looking for is, what ramification each test has. For instance, having bad PI/PO scan might give you problems reading back the data. Especially if you are playing the disc in a DVD player, you might get skips etc… Good PI/PO scans suggest that you probably will be able to read the disc in fast and accuratly, due to the low number of read errors.

So, what does the other tests, like BETA-JITTER, TA tests suggests… they all seem to test the same thing in different ways.


#4

I would refer you to the various resources on what each test is measuring. A DVD player can balk at a disc for any number of reasons, high PI/PO is one of them. The underlying cause is often that the player simply does not like that particular media type or format. High jitter can bother some players, as can relatively low PI/PO levels if the player does not like the media type. We have seen very small increases in PI/PO affect some players.

The bottom line is always to try different media, or a different burn speed. And often, the shortest route is to replace a balky player.
But as you become familiar with what your player will and will not tolerate, you can use the tests to predict success.

Based on experience with CDR’s, it might be assumed that DVD’s with high PI or PO rates may be more likely to degrade over time, so there’s another reason to test. Demonstrating a progressively increasing error rate on a disc over a span of weeks or months is surely a predictor of impending failure.


#5

TA - is that the “humps” plot for the different Tn intervervals?
That, and jitter, are reading parameters of the burn - accuracy of.

PI/PO/PIF etc. are reading the result - and there lies one problem, a more capable reader will rate the disc better.

For several parameters, the point and amount at they relate is complicated, other than at the extremes of all bad or all good - and even burns that test like a dream, can read badly in some players, and unless replacing the player is the preferred option, then the player IS the final test!