This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
JMF (Java Multimedia Framework) provides very limited functionality around this sort of thing. I'd personally recommend finding an existing tool to perform this conversion. You may find some help in this thread.