Now the truth can be revealed. What they don’t want you to know about jitter.
I wanted to do a little jitter testing so I stuck a mini DVD burned with a 600 MB file into my Liteon 165H6, and ran DVDscan. I intended to investigate how much more jitter DVDscan was reporting than CDspeed was reporting.
I had noticed previously that the jitter measurement was repeatable. Subsequent scans would show the same jitter. But not this time. Each time I scanned, the jitter increased. I thought I would see how high it would get but after 12 scans I realized this might take a lifetime.
So instead I decided to see what would happen if I re-loaded the DVD. I hit the “tray out” button and then the “tray in” button. This cured the problem. The jitter dropped to a normal level and stayed that way for 12 more scans. Apparently the disc didn’t get loaded correctly the first time. Maybe this only happens with mini DVDs, and I don’t know how ofter it happens, but I will be more suspicious of any scans in the future unless I verify the jitter doesn’t change between scans.
I made a movie for your viewing pleasure. Until it plays at a theater near you, you can click the link. Actually it’s a 260KB animated gif. You will see the jitter increase for 12 scans, then drop to a normal level and stay there. As I said earlier, I reloaded the disc after 12 scans.
I suppose the PIE/PIF scans were changing also as the jitter increased, but I didn’t record those. I have to leave something for the sequel, you know
I suppose now every time I go to burn a DVD I’m going to wonder if the disc is loaded cockeyed. Now I wish I had never run this test