Upstream says this is fixed in
http://k3b.plainblack.com/news2#Z0ppUKH0LygJFwRA_dQeKQ
** Changed in: k3b (Ubuntu)
Importance: Untriaged => Medium
Status: Unconfirmed => Confirmed
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k3b will not burn video DVD compatible Disk
https://launchpad.net/bugs/48902