rfc2361.txt

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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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   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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   "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
   value. These codecs may be referenced within the IANA namespace as
   "video/vnd.avi; codec=XXX", where XXX represents a valid AVI Codec ID
   (e.g., the WAVE Format ID of "SCRN" is referenced within the IANA
   namespace by "video/vnd.avi; codec=SCRN").

   Appendix A is an authoritative list of the complete set of audio
   codecs that have been registered (as of January 1998) within the WAVE
   Registry. Appendix B is an authoritative list of the complete set of
   video codecs that have been registered (as of January 1998) within
   the AVI registry.

4 Mapping Codec IDs to GUID Values

   Direct mappings exist between WAVE Format IDs and GUIDs and between
   FourCC codec values and GUIDs [5]. [Note: GUIDs are Globally Unique
   Identifiers that are also known as Universally Unique Identifiers
   (UUIDs). UUIDs have been standardized within the Open Software
   Foundation's (OSF) Distributed Computing Environment (DCE).] These
   mappings enable GUID-oriented software to directly refer to these
   historic codec values. For example, the Advanced Streaming Format
   (ASF) [6] uses GUID values to refer to codecs, and the following
   mechanism is used to convert the historic WAVE and AVI codec values
   into the appropriate GUID value for use within ASF.

   WAVE Format IDs are converted to GUIDs by inserting the hexadecimal
   value of the WAVE Format ID into the XXXXXXXX part of the following
   template: {XXXXXXXX-0000-0010-8000-00AA00389B71}. For example, a WAVE
   Format ID of 123 has the GUID value of {00000123-0000-0010-8000-
   00AA00389B71}.

   FourCC values are converted to GUIDs by inserting the FourCC value
   into the XXXXXXXX part of the same template: {XXXXXXXX-0000-0010-
   8000-00AA00389B71}. For example, a conversion of the FourCC value of
   "H260" would result in the GUID value of {30363248-0000-0010-8000-
   00AA00389B71}. [Note: the 32-bit FourCC value of "H260" is converted
   into hexadecimal 32-bit value (i.e., 30363248) because the initial
   XXXXXXXX of the GUID is defined as a DWORD and thus takes a 32-bit
   hexadecimal value. Endian considerations account for the apparent
   re-ordering of the original ASCII text.]





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5  Security Considerations

   This document merely registers a set of formats. It does nothing to
   address the security considerations of these formats.  The format
   itself must be investigated for security issues with each format.

Author's Address

   Eric Fleischman
   Microsoft Corporation
   One Microsoft Way
   Redmond, WA 98052-6399 USA

   EMail: [e-mail]
   http://www.microsoft.com/asf/

   Subsequent to this submittal the author has changed employers. He now
   can be reached at:

   The Boeing Company
   PO Box 3707, MS 7M-FM
   Seattle, WA 98124-2207

   Phone: [phone]
   EMail: [e-mail]


























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References

   [1] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson,"RTP:
       A Transport Protocol for Real-Time Applications", RFC 1889,
       January 1996.

   [2] Schulzrinne, H., "RTP Profile for Audio and Video Conferences
       with Minimal Control", RFC 1890, January 1996.

   [3] Schulzrinne, H., Rao, A., and R. Lanphier, "Real Time Streaming
       Protocol (RTSP)", RFC 2326, April 1998.

   [4] Handley, M., and V. Jacobson, "SDP: Session Description
       Protocol", RFC 2327, April 1998.

   [5] "ASF Codec GUIDs", http://www.microsoft.com/asf/guids.htm

   [6] Microsoft Corporation, "Advanced Streaming Format (ASF)
       Specification", September 1997,
       http://www.microsoft.com/asf/specs.htm.

   [7] Freed, N., Klensin, J., and J. Postel, "Multipurpose Internet
       Mail Extensions (MIME) Part Four: Registration Procedures", RFC
       2048, November 1996.



























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Appendix A      Audio Codecs from the Microsoft WAVE Registry

  A.1     Microsoft Unknown Wave Format

  WAVE form Registration Number (hex):    0x0000
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=0
  WAVE form wFormatTag ID:                WAVE_FORMAT_UNKNOWN
  Contact:
  Terri Hendry, 425-936-2069
  Microsoft Corporation
  One Microsoft Way
  Redmond, WA 98052-6399 USA

  A.2     Microsoft PCM Format

  WAVE form Registration Number (hex):    0x0001
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=1
  WAVE form wFormatTag ID:                WAVE_FORMAT_PCM
  Contact:
  Terri Hendry
  425-936-2069
  Microsoft Corporation
  One Microsoft Way
  Redmond, WA 98052-6399 USA

  A.3     Microsoft ADPCM Format

  WAVE form Registration Number (hex):    0x0002
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=2
  WAVE form wFormatTag ID:                        WAVE_FORMAT_ADPCM
  Contact:
  Terri Hendry
  425-936-2069
  Microsoft Corporation
  One Microsoft Way
  Redmond, WA 98052-6399 USA

  A.4     IEEE Float

  WAVE form Registration Number (hex):    0x0003
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=3
  WAVE form wFormatTag ID:                        WAVE_FORMAT_IEEE_FLOAT
  Contact:
  Terri Hendry
  425-936-2069
  Microsoft Corporation
  One Microsoft Way
  Redmond, WA 98052-6399 USA



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  A.5     Compaq Computer's VSELP

  WAVE form Registration Number (hex):    0x0004
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=4
  WAVE form wFormatTag ID:        WAVE_FORMAT_VSELP
  Additional information:         VSELP codec for Windows CE 2.0 devices
  Contact:
  Doug Stewart
  713-374-7925
  Compaq Computer Corporation
  20555 SH 249
  Houston, TX 77269-2000 USA

  A.6     IBM CVSD

  WAVE form Registration Number (hex):    0x0005
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=5
  WAVE form wFormatTag ID:                WAVE_FORMAT_IBM_CVSD
  Contact:
  IBM Corporation

  A.7     Microsoft ALAW

  WAVE form Registration Number (hex):    0x0006
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=6
  WAVE form wFormatTag ID:                WAVE_FORMAT_ALAW
  Contact:
  Terri Hendry
  425-936-2069
  Microsoft Corporation
  One Microsoft Way
  Redmond, WA 98052-6399 USA

  A.8     Microsoft MULAW

  WAVE form Registration Number (hex):    0x0007
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=7
  WAVE form wFormatTag ID:                WAVE_FORMAT_MULAW
  Contact:
  Terri Hendry
  425-936-2069
  Microsoft Corporation
  One Microsoft Way
  Redmond, WA 98052-6399 USA







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  A.9     OKI ADPCM

  WAVE form Registration Number (hex):    0x0010
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=10
  WAVE form wFormatTag ID:                WAVE_FORMAT_OKI_ADPCM
  Contact:
  Oki

  A.10    Intel's DVI ADPCM

  WAVE form Registration Number (hex):    0x0011
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=11
  WAVE form wFormatTag ID:                WAVE_FORMAT_DVI_ADPCM
  Contact:
  Intel Corporation
  5200 NE Elam Young Parkway
  Hillsboro, OR 97124
  503-696-2448

  A.11    Videologic's MediaSpace ADPCM

  WAVE form Registration Number (hex):    0x0012
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=12
  WAVE form wFormatTag ID:                WAVE_FORMAT_MEDIASPACE_ADPCM
  Contact:
  Videologic
  Home Park Estate
  Kings Langley England WD4 8LZ
  Telephone: [phone]

  A.12    Sierra ADPCM

  WAVE form Registration Number (hex):    0x0013
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=13
  WAVE form wFormatTag ID:                WAVE_FORMAT_SIERRA_ADPCM
  Contact:
  Stuart Goldstein
  [e-mail]
  Sierra Semiconductor Corp
  2075 North Capitol Avenue
  San Jose, California 95132 USA
  408-263-9300









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  A.13    G.723 ADPCM

  WAVE form Registration Number (hex):    0x0014
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=14
  WAVE form wFormatTag ID:                WAVE_FORMAT_G723_ADPCM
  Contact:
  Bob Bauman
  310-532-3092
  Antex Electronics Coporation
  3184-H Airway Ave.
  Costa Mesa, California 92627 USA

  A.14    DSP Solution's DIGISTD

  WAVE form Registration Number (hex):    0x0015
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=15
  WAVE form wFormatTag ID:                WAVE_FORMAT_DIGISTD
  Contact:
  DSP Solutions, Inc
  2464 Embarcadero Way
  Palo Alto, California 94303 USA
  415-494-8086

  A.15    DSP Solution's DIGIFIX

  WAVE form Registration Number (hex):    0x0016
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=16
  WAVE form wFormatTag ID:                WAVE_FORMAT_DIGIFIX
  Contact:
  DSP Solutions, Inc
  2464 Embarcadero Way
  Palo Alto, California 94303 USA
  415-494-8086

  A.16    Dialogic OKI ADPCM

  WAVE form Registration Number (hex):    0x0017
  Codec ID in the IANA Namespace:         audio/vnd.wave;codec=17
  WAVE form wFormatTag ID:        WAVE_FORMAT_DIALOGIC_OKI_ADPCM
  WAVEFORMAT use:                 for OKI ADPCM chips or firmware
  Contact:
  Dialogic Corporation
  300 Littleton Road
  Parsippany, NJ 07054 USA
  201-334-1268






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