Well, firstly I am not really qualified to make a strong case about LG scanning, since this is the only drive I have and the only drive I've used for scanning. Obviously, this LG scanning is not directly comparable to other scanners. It behaves different in a few ways ... like the 'Jitter' . I have seen scans of discs burned with an H55 on other scanners helping to give an idea of what is a good/bad quality disc for burning. The only thing I'm concerned with is being able to compare the burns I have done with this drive and being able to tell which write speed provides the best quality .., with this drive.
Well most of the discs are showing that Avg. Jitter value of 16-19% but a couple were 20 and 21% I believe. Anyway its much higher than typical jitter readings so it is only useful in the local test environment. What is more important to me is PIE/PIF levels of the different recordings. Renting DVD movies and testing them show a very low PIE/PIF and those discs never skip or fail a TRT. Other burns that I have done on low quality media show a scattered line on the TRT and a very high PIF in the same area. Perhaps I can show you the TRT and DQ scan on that one.
All I'm saying is that I really don't trust the results at all. Setting a scan at 8x and it results in something in between 6x and 5x scanning speed may already be dubious, as well as a 4x scan which is actually done at 3x. Does the drive always do this on every disc scanned? Is there some sort of pattern that is followed with believable variances when multiple scans are made? I don't have that specific drive so I can't really test its scanning capability on my own although I understand your desire to test on this certain drive.
Yea, this was a little confusing to me at first. The firmware does not accept all speed selections. And I think data and DVD-Video are handled just a little different. A lot of my discs are burned with straight .mpg movie files which the firmware interpret as data.
Yes 8x shows the speed you mentioned and 4xCLV shows 3xCLV on the chart. The factor at play here is in the Advanced Button. In there you can scan at 1-ecc or 8-ecc intervals. You can change the test length from Speed to Accuracy in 5 different positions. Scanning at 1-ecc intervals is too slow for me to get a multiple of tests done. So my setting is 8-ecc intervals. I started at the full speed setting which is fast but faster than I need so I bumped it up one notch towards accuracy. Full accuracy is way too slow for my multiple testing at this time. I think Full Speed takes a little over a 1000 samples (4.7 gig discs) and one notch up takes a bit over 2000. The next one up is over 4000, the next 8000, and full accuracy around 16000 samples and is way too long for my purposes right now. I did a full speed and a full accuracy on one test and they were different, but not tremendously so.
What you see on the chart is a speed calculation of how fast your progressing through the position on the disc and calculated from the beginning to the end of the discs total size. There is no RPM indicator on these graphs. So yes the speed indicator drops as you move the Accuracy slider towards Accuracy because it has to take twice as many samples with each notch over. In those graphs you see the speed progress across the discs with a scan length set at about 2000 samples for a single layer disc and 4000 samples for a DL.
I'd really like to see scans of those discs you've already showed using other well-known DQ scanners just to support your case. I've had CMC MAG M01 that scans at a constant ~1M+ PIE and 4000+ PIF even on a tolerant scanner, imagine how it looked on a picky BenQ DW1640.
Disc scanning is incredibly unreliable but it does provide a few insights that help us to determine the best course of action in testing media batch qualities and deciding on write speeds and strategies so sometimes it's a necessary evil. Seeing how weird your scans look incomparable to other scans makes it even tougher to believe an already unreliable home-testing method (and also the reason why MediaTek/Nexperia/Sanyo chipsets are preferred due to their relative reliability in disc scanning).
Yes, I would too. But right now there is no way to get these discs to any other scans unless I mailed it to another scanner.
So far its working for me in showing me the relative quality of my burns, and that is all that is really important.
The following scans are of an .mpg movie file burned with Nero at 8x. The disc is a Maxell CMC MAG M01. The samples taken are about 2000 / 8-ecc intervals.
The first one is the TRT.
The second is the scan at 8x.
The third is at 4xCLV showing a little improvement. 2xCLV would probably look a little better still but the point is this disk has its better read ability at much slower speeds.
The fourth is this .mpg burned on at 16x with 'Create Disk' using the same type and batch, Maxell CMC MAG M01. This will pass the TRT smooth. The 16x burn showing much better quality than the 8X burn.
The Fifth is the same test as the fourth but at 4xCLV. As you can see the quality improves at the lower speed. But of course DVD movies in .vob or .mpg read very slowly anyway.
It appears that CMC MAG M01 burns better DQ at 16x than at 8x as far as using my drive to burn it, read it, and scan it. There were a couple that had high quality at 2x and 4x CLV but worse at DQ 8x scan when they were burned at 8x instead of 16x.
Anyway ... Great scanning Gurus ... teach me where I'm wrong and why I can't use this drive to measure quality. Teach me of the higher Jitter reading and where its useless and why it can't be used relatively.
I'm always up to pointers. :flower: