I had to convert a mov file into an mp4 recently and looked all around for the right converter to use. I started using one that charged a $5 fee, but learned pretty quickly that the conversion wasn’t always accurate – meaning some programs will say they converted your file to a particular audio bitrate but when you actually test the converted file you’ll find the bitrate is off, etc.
The service that ultimately ended up working for me was actually free. You can check it out here. Happy converting!