Internet Engineering Task Force M. Nilsson INTERNET DRAFT 6th April 1998 Document: draft-nilsson-audio-mpeg-00.txt Expires 6th October 1998 The audio/mpeg Media Type Status of this Memo This document is an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts as reference material or to cite them other than as "work in progress." To view the entire list of current Internet-Drafts, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), ftp.nordu.net (Northern Europe), ftp.nis.garr.it (Southern Europe), munnari.oz.au (Pacific Rim), ftp.ietf.org (US East Coast), or ftp.isi.edu (US West Coast). This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Abstract The audio layers of the MPEG-1 and MPEG-2 standards are in frequent use on the internet, but there is no uniform MIME type for these files. The intention of this draft is to standardize the use of audio/mpeg as its media type. 1. MPEG audio The audio compression defined as layer I, layer II and layer III in the MPEG-1 [MPEG-1] and MPEG-2 [MPEG-2] standards is a popular method of compressing audio with a low quality loss. The compressed audio is split into several small data frames, each containing a frame header and compressed audio data. The frame header is easy to find even if it is surrounded with non-MPEG data. To allow the use of MPEG audio compression over connections with lower bandwith, a non-ISO-approved standard called MPEG 2.5, has been invented as well. Nilsson [Page 1]
Internet DRAFT The audio/mpeg Media Type April 1998 2. Registration Information To: ietf-types@iana.org Subject: Registration of MIME media type audio/mpeg MIME media type name: audio MIME subtype name: mpeg Required parameters: none Optional parameters: none Encoding considerations: For use over internet it is assumed that lower layers take care of transmission errors, so the use of cyclic redundancy checks (CRC) in the MPEG frames is not needed. For easier recognition and to provide additional information about the file's content, extra information may be concatenated to the file. As long as the MPEG frames are unmodified and no concatenated data is recognized as an MPEG frame, this is not a problem for MPEG audio decoders. Security considerations: The concatenated data might contain executable code. This executable code can only be executed by a program that looks for it and is not executed by an MPEG audio decoder when it attempts to play the file. It's simply ignored. Interoperability considerations: MPEG audio has proven to be widely interoperable across computer platforms. Published specification: see [MPEG-1] and [MPEG-2] Applications which use this media type: MPEG audio is device-, platform- and vendor-neutral and is supported by a wide range of encoders and decoders (players). Additional information: Magic number(s): none File extension(s): .mp1, .mp2, .mp3 Macintosh File Type Code(s): MPEG Object Identifier(s) or OID(s): none Person & email address to contact for further information: The author of this draft. Nilsson [Page 2]
Internet DRAFT The audio/mpeg Media Type April 1998 Intended usage: COMMON Author/Change controller: 3. References [MPEG-1] ISO/IEC 11172-3:1993. Coding of moving pictures and associated audio for digital storage media at up to about 1,5 Mbit/s, Part 3: Audio. Technical committee / subcommittee: JTC 1 / SC 29 [MPEG-2] ISO/IEC 13818-3:1995 Generic coding of moving pictures and associated audio information, Part 3: Audio. Technical committee / subcommittee: JTC 1 / SC 29 and ISO/IEC DIS 13818-3 Generic coding of moving pictures and associated audio information, Part 3: Audio (Revision of ISO/IEC 13818-3:1995) 4. Full Copyright Statement Copyright (C) The Internet Society (1998). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implmentation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE." Nilsson [Page 3]
Internet DRAFT The audio/mpeg Media Type April 1998 5. Authors' Addresses Martin Nilsson Rydsvägen 246 C. 30 S-584 34 Linköping Sweden Email: martin.nilsson@bigfoot.com Nilsson [Page 4]