Movie Maker is first rendering your video from your project files which
takes time.
Then Sonic MyDVD imports the video created by Movie Maker and converts it to
DVD format which takes time.
Then Sonic has to actually burn and test the DVD which once again takes
time.
45 minutes is not that long actually.
If you are burning more than one copy of the same DVD then you are better
off saving the video to your computer and manually importing it into MyDVD
to create the DVD. You will then have the option of burning the same movie
again and it will take far less time.