Circulal track marks on dvd?

I was just wondering why I can clearly see the tracks where laser has burnt data on my dvd, how come not all other dvd that I get from friends have the same track marks after they have burnt in on their writer, is it the cd or their writer?

Could some one tell me?

Is this on your BURNT discs? Sounds like your DVD burner’s laser powers completely down between tracks or at shift points. Might need a firmware upgrade to sort that out - do these weird-looking discs play ok in your set-top box?

bostonflunkie the track marks can be the result of a write speed change, this is especially visible when the writer uses the so-called Z-CLV write method. Nothing to worry about as it’s normal and doesn’t affect the readability of the disc.

yup. ZCLV can causes banding marks. You’ll be able to see rings of a certain shade and rings of other shades.
like this…
Note: This is a fully burnt disc.