Pardon me, if these matters has already be addressed in a previous thread. The number of threads and posts in this forum is becoming quite large and a few searches found nothing in this area. I have read all the pages in the DVDScan thread and many of the pages in the OHT thread.
All the latest drives are employing “calibration events” in an attempt to correct “problems” occuring during a burn, IMO aimed primarily at average to poor quality media or media not supported in the firmware’s media table. This is all intended to improve the quality of the burn on that media. Exactly which type of “problem” is trying to be improved during any recalibration event is unclear.(PIE, PIF, Jitter, Beta, etc.)
It appears that these events often have an impact on Jitter Levels as indicated by DVDScan v.0.04beta, my LH-20A1P 487C KL05, and a spindle of relatively good Verbatim MCC 004 media. The following posts suggest there is often a strong correlation between these events and abrupt changes in jitter levels reported. The posts also indicate that Lite-On’s HyperTuning and Online HyperTuning may have an adverse affect on jitter levels if used on “good” media" already supported in the firmware–when compared to results obtained using SmartBurn only(i.e., No Calibration Events.) But much more testing needs to be done in this area.
I have cropped & resized portions of DVDScan’s jitter tests and CD-DVD Speed’s Create Disc or Disc Quality tests to show this correlation and to save space. I can post the full images if anyone asks.