I don't know why I keep trying. Since Yosemite and now El Capitan I have not once succeeded in burning a single DVD without some kind of problem turning up with either the creation process (freezing) or the final product itself - jittery video, audio not matching picture, not completing the burn because of an error. Even tried a competitor (DVD Creator) and got the same results so Toast isn't alone. I have a feeling as the use of DVD diminishes so does the software to create them receive less attention.
No question - just letting off stream. What does always work however is creation of a data disk. Never had problems with that. I can't speak about music because I usually end up making music CDs from iTunes since I am there anyway.
If anyone knows of a full-proof DVD creator/burner I would be happy to give it a try. In the past Toast was always the reliable one!