The better quality burner apps can convert most mp3 type's themselves. But on occasions they can't. One stumbling block seems to be Ogg Vorbis. Another way is to use an audio app called
Audacity (a free audio editor) which can open all types of mp3s & save them as any type of mp3 or as aiff or wav. Can also obviously do a lot more such as edit, equalise, filter, etc. All the things programs worth $500 can do. It's just a little slower but heh, it's for free!!!

When you dwnld it, you also need to dwnld not only the app but also the manual, & also the plug-in whatever it's called, Just dwnld all thats n that page! You'll be glad you did.