(registered by RFC4348; optional parameters updated by RFC4424)

   Note, the receiver MUST ignore any unspecified parameter and use the
   default values instead.  Also note that if no input parameters are
   defined, the default values will be used.

Media Type name:      audio

Media subtype name:   VMR-WB

Required parameters:  none

Furthermore, if the interleaving parameter is present, the parameter
"octet-align=1" MUST also be present.

OPTIONAL parameters:

  mode-set:       Requested VMR-WB operating mode set.  Restricts
                  the active operating modes to a subset of all
                  modes.  Possible values are a comma-separated
                  list of integer values.  Currently, this list
                  includes modes 0, 1, 2, 3, and 4 
                  [3GPP2 C.S0052-A v1.0][RFC4424], but MAY be
                  extended in the future.  If such mode-set is
                  specified during session initiation, the encoder
                  MUST NOT use modes outside of the subset.  If not
                  present, all operating modes in the set 0 to 4 are
                  allowed for the session.

  channels:       The number of audio channels.  The possible
                  values and their respective channel order
                  is specified in Section 4.1 in [6].  If
                  omitted, it has the default value of 1.

  octet-align:    RTP payload format; permissible values are 0 and
                  1.  If 1, octet-aligned payload format SHALL be
                  used.  If 0 or if not present, header-free payload
                  format is employed (default).

  maxptime:       See RFC 3267 [4]


  interleaving:   Indicates that frame-block level
                  interleaving SHALL be used for the session.
                  Its value defines the maximum number of
                  frame-blocks allowed in an interleaving
                  group (see Section 6.3.1).  If this
                  parameter is not present, interleaving
                  SHALL NOT be used.  The presence of this
                  parameter also implies automatically that
                  octet-aligned operation SHALL be used.

  ptime:          See RFC2327 [5].  It SHALL be at least one
                  frame size for VMR-WB.

  dtx:            Permissible values are 0 and 1.  The default
                  is 0 (i.e., No DTX) where VMR-WB normally
                  operates as a continuous variable-rate
                  codec.  If dtx=1, the VMR-WB codec will
                  operate in discontinuous transmission mode
                  where silence descriptor (SID) frames are
                  sent by the VMR-WB encoder during silence
                  intervals with an adjustable update
                  frequency.  The selection of the SID update-rate
                  depends on the implementation and
                  other network considerations that are
                  beyond the scope of this specification.

Encoding considerations:

       This type is only defined for transfer of VMR-WB-encoded data
       via RTP (RFC 3550) using the payload formats specified in
       Section 6 of RFC 4348.

Security considerations:

       See Section 8 of RFC 4348.

Public specification:

       The VMR-WB speech codec is specified in
       3GPP2 specifications C.S0052-0 version 1.0.
       Transfer methods are specified in RFC 4348.

Additional information:

Person & email address to contact for further information:

       Sassan Ahmadi, Ph.D.        sassan.ahmadi&ieee.org

Intended usage: COMMON.

  It is expected that many VoIP, multimedia messaging and
  streaming applications (as well as mobile applications)
  will use this type.

Author/Change controller:

  IETF Audio/Video Transport working group delegated from the IESG