Without knowing whether you have this video on a card or that it was shot with this or that camera I will presume you just have the file on your desktop.
I would suggest using Mpeg Streamclip. It is a very useful free app.
We normally only work in PR422 (HQ for spots) so we convert everything before we start.
We usually do this through log and transfer in FC or Compressor but have found that Streamclip is considerably faster(especially for converting GoPro vs. Compressor.)
In theory Compressor should be the better app(with far more controls) but as far as just converting files to PR422 with the 422 preset we have been unable to see any difference. If time is not a factor I would use Compressor but I think even if you did a test with complex areas you will have hard time seeing the difference if there is any.
Starting with the best should ensure everything will look the best it can down the line but how well the footage looks for an SD DVD will most likely be determined by your compression settings when you make the DVD files more than whether you used Compressor or Streamclip to make your PR file.
I would suggest making sure your frame controls are set to best when you compress the final mpg-2 for DVD.