dbpoweramp should work for this. Seems that it does about any amount of batch converting you need done.
I recall someone having some kind of playlist problem with it though,something like that. I have never had any problems myself
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The impossible takes more time,and costs more money.
The link worked for me. I have this on my other 'puter. Just went to see if the link would work and found they have a new version so I got it. It works good ,easy too