I’ve noticed this on DVDs and BluRays but also with games on any console. I’ve rented a movie and the disk is riddled with scratches and I’m sure it’s not going to read, but it somehow does. However, sometimes it hitches. But playing it back on a different DVD player presents no issues at all. What’s happening here?
In: 6
CDs and DVDs have huge amounts of error correction built into the data stream. Each packet of data contains multiple backups, and then there are backups to the backups with different data in between.
The error correction on an audio CD is so strong, that you could drill a 2.5 mm diameter hole through a CD, and there should be no data loss at all. CD-ROMs have even stronger error correction. DVDs even stronger again.
The biggest problem with scratched discs is that the laser beam gets blurred out or distorted, and the laser is unable to see the line of data clearly. A series of lenses and sensors keep the laser perfectly aligned onto a thin spiral line of data. However, if the laser focus isn’t good enough, it may not be able to keep track, and it may jump to a different track, causing the sound to skip – or it may struggle to read a piece of data. Locking back onto a track can take long enough that the laser goes way past any backup copies of the data.
Latest Answers