Disc Quality Tests
Having recorded the maximum amount possible onto the Verbatim 4x DVD-R Dual Layer media at its rated recording speed of 4x to our review drives with CD Speed, the next stage of our review will concentrate on Disc Quality.
Now normally it is here where we would show you the PI Error and PI Failure scans using KProbe with a Liteon writer such as the 1693S to scan all recorded media and gain an average recording. We would then follow up with advanced tests such as Beta/Jitter/TA and Peak shift tests on the average recording with the Plextor PX-716A and the excellent PXScan. But during testing we found that the Liteon 1693S with firmware KS04 was having very bad difficulties in seeking or spinning up the media. We also discovered that this left a scratch like effect on the beginning of the media from where it had been trying to seek and spin up which was being pikcked up as very high PI Failures.
Thankfully this was noticed on the disc upon further examination after seeing such high errors and then we switched the Plextor PX-716A to do the PI Error and PI Failure tests which we would normally show with KProbe. The basics for PI Error and PI Failure scanning are the same for the Plextor as with the Liteon whith one added avantage to using the Plextor for these tests - we are able to show the PIE/PIF results for each layer of the recording which we could not normally display with KProbe and the Liteon drive.
Sounds like a lot to read but basically in our new 2 tier Disc Quality structure here is a brief explanation of what each test can tell us:
The PI Error and PI Failure results we can show us how many potential errors a playback device may need to correct. PI Errors should not exceed 280 and PI Failures not exceeding 4 for a quality recording. Single PI Failure spikes of upto 32 can still remain correctable but would most definitley cause slowdowns in transfer and very possible bad areas of pixelation on DVD Video playback
The beta and jitter tests tell us how well balanced a recording is at any given speed.
The TA and peak shift tests tell us how well the actual recording pit of the media has been produced at 3 measured stages during the recording.
Further information on Plextor scanning can be found at the home of PXScan and Here at the official Plextor website. We really do recomend taking some time to have a read of these links to help you better understand our review results.
Results of these tests are shown below:
"We thank Alex Noe for his very informative website and very useful PXScan software on behalf of ourselves and any readers that may benefit from the information provided by his Free software. PXScan enables us to do all our required tests just the way we would like them for free without having to pay the premium required to do the same with Plextors own (and not free ) PlexTools XL."
Overview of Disc Quality results:
The Disc Quality results show that the NEC based review recording devices seemed to handle the recording of the Verbatim 4x DVD-R Dual Layer media as well if not better than any other of the drives with the most pleasing results in the Disc Quality tests carried out for this review under present firmware. The Plextor PX-716 and Pioneer 109 XL results where satisfactory but we believe their is room for improvement. After doing so well with 16x media, the Liteon-IT 1693S was actually our worst result with very uneven beta and poor TA/Peak shift results which seemed very squashed in appearance on the second layer. The PI Error and PI Failure are low enough that transfer should be very good and playback at 1x should be fine too, but it really could do with a tweak.
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