i have a 120 minute HD music video that i want to burn to DVD and have it as the best quality that i can so i wanted to burn as a double layer DVD and i can't get Pre10 to do that. when it go to burn to a file it shows the single layer and double layer DVD.s and i click on the DL and start the burn but when it's done it saves it as a SL DVD. i tried it twice with the same result.
Do you have Fit Contents to Available Space checked? By unchecking, you should then be able to use the Quality slider.
If so, then it is probably that your 120 Timeline can be Transcoded to a good quality DVD-5.
The DVD-specs. limit the Bit-Rate, so at a point, the Quality cannot be increaced (Bit-Rate increased), because of that upper limit.
Just thinking here, and good luck,