I thought that the CATS DVD analyser would give an "absolute" measurement of recordable DVD quality. But that may not be the case.
Based on the below white paper from Audiodev, who make the CATS equipment, it looks like they recommend calibrating the machine with a DVD-R master from the same dye lot if you're testing DVD-R (for example).
http://www.audiodev.com/filearchive/2/2 ... %20DVD.pdf
Sounds like they don't recommend testing DVD-R to a single "absolute" standard, but only relative to similar discs?
To quote from the PDF:
“To ensure playability, it is essential to measures as closely as possible to the reference labs. This can be achieved by calibrating the CATS analyzer with a disc using the same process and dye technology as the discs being manufactured”, says Magnus Wikstrand, AudioDev’s Measurement Development Manager. [...]
Phase-change materials are fairly similar, but if a test system for DVD-RW/DVD+R is calibrated with a disc using one phase-change material and pre-groove design, and then used to measure discs using another phase-change material and pre-groove design, the measurement accuracy will be affected, thus the ability to give a true picture of disc quality and playability. For DVD-R/DVD+R the differences can be even larger as pre-groove designs are optimized for each individual dye technology.
I really don't understand this. The first sentence says you have to calibrate to an absolute standard. The second sentence says you have to calibrate to a local (non-absolute) standard, and the next paragraph says each type of disc is different and there is no one standard.
It strikes me that ultimately there is only ONE standard if you want all your DVD, DVD+/-R, DVD whatever discs to play on the same set-top-box... right?