(RFC 4337 published March 2006, RFC 6381 published August 2011, subtype last updated August 2011) MIME media type name: audio MIME subtype name: mp4 Required parameters: none Optional parameters: none Encoding considerations: base64 IS generally preferred; files are binary and should be transmitted without CR/LF conversion, 7-bit stripping, etc. Security considerations: See section 5 of RFC 4337. Interoperability considerations: A number of interoperating implementations exist within the ISO/IEC 14496 community, and that community has reference software for reading and writing the file format. Published specification: ISO/IEC 14496-1:2001. Applications: Multimedia Additional information: Magic number(s): none File extension(s): mp4 and mpg4 are both declared at . Macintosh File Type Code(s): mpg4 is registered with Apple. Person to contact for info: David Singer, singer&apple.com Intended usage: Common Author/Change controller: David Singer, ISO/IEC 14496 file format chair.