Disc Quality tests
Having recorded the maximum amount possible onto the Verbatim 16x DVD-R media at its rated recording speed of 16x to our review drives with CD Speed, the next stage of our
review will concentrate on Disc Quality.
As CDR-Zone.COM have found it to give accurate results and great support for Liteon-IT writers, CD Speed was used to check the media for any unexceptably high error levels using the Liteon-IT 1653S at its recommended scanning speed of 4x. So all the the Disc Quality test results shown here are from the Create CD tests recorded earlier in this review.
"Please note that you will need a compatible drive for doing these scans such as the
Liteon-IT 1653S we have used. Other drives you could try include BenQ, NU TECH, Plextor and ASUS branded writers."
"The less PI/PIF errors that are found on a media then in theory the better the chances
are of longer archival life for the media without data loss becoming a problem". Different
scanning devices scan slightly differently but basic guidelines are that PI errors should
not exceed 280 for sustained periods and PI failures should not exceed 4 for sustained
periods. Single spikes are usually ignorable due to a bug in the Liteons Mediatek chipset
but we will confirm this with our transfer tests."
Overview of Disc Quality Results:
All the Verbatim 16x DVD-R media reported PI Errors and PI Failure rates that are well within set specifications. All of the review recording devices used in these tests reported pretty similar total PI Failures if you take into account the 'single spike bug' that the Liteon-IT is renowned to have when scanning recordings made with certain writers such as our NEC writers used.
Understanding the results:
CDR-Zone.COM really do try to make the understanding of the official specifications as simple as possible so this is how best we can decribe the PI Error and PI failure levels.
A DVD has two levels of error correction. Any errors that make it through the first level
are reported as PI Errors and any that make it past the second level are reported as PI Failures. PI Failures are what your DVD playback device will potentially have to correct to achieve perfect DVD Video playback or Data transfer at high speeds.
As long as PI Error levels stay under 300 then the recorded disc should be readable in any device at speeds upto 16x. Single 'Spikes' above this limit can be ignored. Reported PI Error levels of upto 1000 can still be read by some devices, but we would question their long term archival life.
When reading the CD Speed Quality results for PIF values, please pay special notice to
the bottom graph which we have nicknamed the 'safety zone'. As long as the PIF errors stay
below 4 then the disc should be perfectly readable also with again single 'Spikes' ignorable
but sustained areas above the safety zone would often reflect as skipping on DVD Video playback.
Different drives scan differently but staying within the 4 PIF 'safety zone' is always a
good indication of a good quality recording.
These are to be used as a basic guideline to the quality of the recorded media only and
our scans at 4x may be considered as such. DVD players only read at 1x whilst playing a
movie and so if the media passes our Quality tests at 4x scanning speed and passes the
following transfer tests then we are safe to assume compatiable DVD devices will not have
any problems playing this media.
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