Using Tmpgenc plus, there is a option of converting to DVD Low Resolution. It gives an option of "Linear PCM Audio " or "MP2 Audio". Choosing the mp2 audio can get 495 minutes onto a dvdr , instead of the 245 minutes with the linear audio.
But is says if the Authoring software converts the mp2 to linear pcm audio, you can only get the 245 minutes.

My question is does TMPGEnc DVD Author convert it to Linear PCM or will it leave it at MP2 audio?
thanks.

If you use the wizard it will keep it at the format it is in already. If you want to change it you must cancel the wizard and adjust the setting manualy.