Whats the difference between mp3 and mp4?

MP3 is an MPEG standard used especially for digitally transmitting music over the Internet. A file containing a song or other audio data that is encoded using this standard: The band released its latest single as an MP3 on the Internet. MP4 refers to: MPEG-4 Part 14 or *.mp4, is a file format (a so called container) specified as a part of the ISO/IEC MPEG-4 international standard. It is used to store media types defined by the ISO/IEC Moving Picture Experts Group, and can be used to store other media types as well. It is, or will be, typically used to store data in files, though it will be used in data streams and possibly in other ways.  more