How should I deal with Jitter?

vbimport

#1

Hi,
My I ask someone to explain about Jitter testing?
What’s jitter and how should I deal with it?
I hope someone can help me in this case.
Best Regards,
GuyNoir.


#2

Explaining jitter would take several pages, so the best you can do, if you really want to understand what it is, is read articles on the net.

For DVDRs and CDRs, you can picture “jitter” as a relative deviation of the “pits and lands” from their ideal location, shape and/or lenght. This is definitly not a really correct explanation, but it’s sufficient for the purpose of understanding why jitter is a concern with optical media.

Standards limit acceptable jitter to 9% (DVDR), but the problem is, you don’t know exactly what the drives report (Benq, Plextor and LiteOn) and if the values are reported in a way that is compliant with the standards, so you can’t really rely on these standards to appreciate your burns. :frowning:

There are questions, though, about the Benq’s jitter reporting, as some discs showing very high jitter in these drives don’t show such high jitter in other testing drives. This is a complex and controvesial subject, just as PIE/PIF scanning relevance. :doh: (probably even more so :bigsmile: ).

I only have experience with Benq jitter reporting. I’ve come to consider (from cross-checking behaviour in other drives/players) that jitter levels reported > 10% (in @8X Benq scans) are an indication of a lesser burn or media, as such discs are less widely compatible with full 16X reading in several drives (some of my drives show a slowdown near the end with such discs if the > 10% jitter is reported in this area). But that’s [I]my [/I]book, from my own experience with my own discs and hardware.

The can of worms is opened. :stuck_out_tongue: Bring it on. :bigsmile:


#3

Here is a nice explanation of Jitter:

Jitter what it is and how to measure it [PDF format]


#4

I second that!
All the burns with jitter >10 % (as reported by the benQ) show some reading troubles in my Aopen DVD-ROM. My DVD-burners read them just fine.
So I would never burn my media with a LiteOn, maybe only for testing purposes.

Here’s an example of what I mean:






#5

[ot] Is it just me or does the the Lite-on 165p6s seem like a very forgiving scanner?


#6

Less forgiving than my LiteOn SHW-1635S. At least with my 165P6S I can get it to show some problems when scanning at 16x that my 1635S doesn’t show at any speed, and which are also shown in some of my other scanning drives.

There can also be significant differences between individual drives of the same model.

BenQ drives OTOH are notorious for showing bad scans of discs burned in certain other drives, so I don’t consider the BenQ scans to be more “correct” than the LiteOn scans.


#7

I think it’s more the BenQ being pickier. :wink:

But I have to second [B]DrageMester[/B] with the individual drives and the BenQ scans… :slight_smile:


#8

Not to keep this thing too much OT, but the fact that the Benqs would be “correct” or not is, in my book, not very important. I have a different approach.

I consider that if a disc/burner combination can be scanned in different drives with OK results (in my case NEC 3540, Benq 1650 and Liteon 16P1S, all being drives with huge quirks for scans), it’s a better disc/burn that another one showing excellent figures in a given scanner and problematic figures in another.

So I go for discs and burning methods that look OK in scans from my three scanners, rather than trying to figure out which scanner is more “correct”. I like to think that it’s a sounder approach, but [I]YMMV [/I]of course.

When I scanned with a LiteOn 1693S, all discs looked good in it. Even discs that refused to play in my Pioneer DV-535.


#9

Franck, you speak directly out of my soul! :bow: :flower:


#10

:iagree: I also want scans at different speeds to be OK and Transfer Rate Tests to be OK.


#11

I agree wholeheartedly. I like to do a Quality Scan with BOTH Lite-On and BENQ drives, atleast with a new batch, and a TRT as well ofcourse.
Hope you still don’t have “Where have all the good Verbs gone…” playing in your head, Francksoy!


#12

Aaaaargh! Naughty you, now it’s back! :doh: LOL


#13

I kinda left that part out cause I’m trying to write shorter posts these days (lol), but you know that I’m of course on the same wavelenght, specially for TRTs… :wink: :iagree:


#14

a good one!? (burned w/pio @ 8x)





#15

It sure does look like a good scan.
But I thought BenQ and LiteOn measure different kinds of jitter (one does DD and the other does DC jitter)? :confused:


#16

That’s so horrible it will make you go blind, kill your pets and halve the value of your house. You need to immediately send that batch of MCC004 to my dragon cave in Denmark, where it will be safely disposed of! :bigsmile:

J/K that’s an excellent scan.


#17

Hmmm, IIRC that sounds like something [B]muchin[/B] once mentioned in relation to DVDscan’s Jitter reporting being much different to the BenQ results on CD-DVD Speed. Under CD-DVD Speed, it [I]seems[/I] [B]Erik Deppe[/B] has managed to report DC Jitter for Lite-ON drives. (Maybe he could confirm what type of Jitter BenQ/Lite-ON are actually reporting)


#18

It seems so, at least. There is not [I]much[/I] difference in CDSpeed, from what I’ve seen o nthe board, between LiteOn and Benq jitter reports (about 1 to 1.5%, the Benq reporting the higher values), and I guess that if it was not the same kind of jitter that is reported, the differences would be far more pronounced? :confused: Can’t be sure, though.