WAVE and AVI Codec Registries
RFC 2361

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Network Working Group                                      E. Fleischman
Request for Comments: 2361                         Microsoft Corporation
Category: Informational                                        June 1998

                     WAVE and AVI Codec Registries

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (1998).  All Rights Reserved.

Abstract

   Internet applications may reference specific codecs within the WAVE
   and AVI registries as follows:
   * video/vnd.avi; codec=XXX identifies a specific video codec (i.e.,
     XXX) within the AVI Registry.
   * audio/vnd.wave; codec=YYY identifies a specific audio codec
     (i.e., YYY) within the WAVE Registry.

   Appendix A and Appendix B provides an authoritative reference for the
   interpretation of the required "codec" parameter. That is, the
   current set of audio codecs that are registered within the WAVE
   Registry are enumerated in Appendix A. Appendix B enumerates the
   current set of video codecs that have been registered to date within
   the AVI Registry.

1 Introduction

   Internet-oriented multimedia applications reference multimedia
   content via predefined mechanisms (e.g., [2]). In the general case,
   this content was created primarily for the use of these Internet-
   oriented applications. Unfortunately, this Internet-oriented
   multimedia content represents a small minority of the total amount of
   multimedia content that has been created to date.

   For this reason, a growing interest is forming in establishing
   mechanisms by which the repertoire of multimedia content available to
   Internet-oriented applications(e.g., for RTSP [3]) may be greatly
   extended to include multimedia content that has been created outside
   of distinctly Internet contexts. For this to occur, a mechanism must

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RFC 2361             WAVE and AVI Codec Registries             June 1998

   be created for Internet protocols (e.g., [1], [3], [4]) to be able to
   identify the codecs by which this so-called "traditional" multimedia
   content has been encoded.

   Unfortunately, several distinct encoding systems exist for
   traditional multimedia content. Each system has its own registry to
   ensure unique and stable codec identifications within that system.
   Perhaps the best known of these registries are Microsoft (for WAVE
   and AVI content) and Apple (for QuickTime content).

   The purpose of this paper is to establish a mechanism by which codecs
   registered within Microsoft's WAVE and AVI Registries may be
   referenced within the IANA Namespace by Internet applications.

2 References to Registries within the IANA Vendor Tree

   Reference [7] specifies that the IANA Namespace encompasses several
   trees. Discussions within the IETF-Types mailing list concluded that
   the most appropriate tree in which to reference codecs, which had
   already been registered by non-IANA Registries, is the Vendor Tree.

   As a result, the non-IANA registry is identified within the IANA
   Vendor tree by vnd.RegistryName. A specific codec, which has been
   registered within that registry, is identified by a required codec
   parameter as specified by Section 2.2.3 of [7].

3 WAVE and AVI Registries

   Both the WAVE and AVI Registries are historic databases that have
   been maintained by Microsoft as a free service. The Registries sought
   to assist developers of WAVE and AVI content and to standardize WAVE
   and AVI content by
   1) avoiding conflict and/or duplication with current definitions, and
   2) providing the registered information in a standard document and
      format that is publicly available.
   The historic nature of these databases implies that unless the
   original registrants informed the registrar of a change of status
   (e.g., company acquired, new contact, new location, new phone), the
   contact information has generally not been updated from the
   originally registered values.

   Audio codecs within the WAVE Registry are identified by WAVE Format
   IDs. The (audio) WAVE Format ID is officially known as "WAVE form
   Registration Number". The WAVE Format ID is a hexadecimal integer
   value. These codecs may be referenced within the IANA namespace as

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RFC 2361             WAVE and AVI Codec Registries             June 1998

   "audio/vnd.wave; codec=XXX", where XXX represents a valid WAVE Format
   ID (e.g., the WAVE Format ID of "123" is referenced within the IANA
   namespace by "audio/vnd.wave; codec=123").

   Video codecs within the AVI Registry are identified by AVI Codec IDs.
   The AVI Codec ID value is a FourCC encoding. A FourCC is 32-bits long
   and represents a (case-sensitive) four-character (i.e., ASCII) code