(RFC 3555 published July 2003, subtype last updated March 2007 per RFC4856)

Type name: audio

Subtype name: L16

Required parameters:
	rate: number of samples per second -- For non-RTP transport,
	the permissible values for rate are 8000, 11025, 16000, 22050,
	24000, 32000, 44100, and 48000 samples per second.  For RTP
	transport, other values are permissible but the aforementioned
	values are RECOMMENDED.  For RTP, the rate parameter indicates
	the RTP timestamp clock rate, which is equal to the sample
	rate.

Optional parameters:
	channels: how many audio streams are interleaved -- defaults
	to 1; stereo would be 2, etc.  Interleaving takes place
	between individual two-byte samples.  The channel order is as
	specified in RFC 3551 unless a channel-order parameter is also
	present.

	emphasis: analog preemphasis applied to the signal before
	quantization.  The only emphasis value defined here is
	emphasis=50-15 to indicate the 50/15 microsecond preemphasis
	used with Compact Discs.  This parameter MUST be omitted if no
	analog preemphasis was applied.  Note that this is a stream
	property parameter, not a receiver configuration parameter.
	Thus, if parameters are negotiated, it may not be possible for
	the sender to comply with a receiver request for a particular
	setting.

	channel-order: specifies the sample interleaving order for
	multiple-channel audio streams (see RFC 3190 [7], Section 7).
	Permissible values are DV.LRLsRs, DV.LRCS, DV.LRCWo,
	DV.LRLsRsC, DV.LRLsRsCS, DV.LmixRmixTWoQ1Q2,
	DV.LRCWoLsRsLmixRmix, DV.LRCWoLs1Rs1Ls2Rs2, DV.LRCWoLsRsLcRc.
	For interoperation with DV video systems, only a subset of
	these channel combinations is specified for use with 20-bit
	linear encoding in the DV video specification [9]; those are
	DV.LRLsRs, DV.LRCS, DV.LmixRmixTWoQ1Q2.  This parameter MUST
	be omitted when the AIFF-C channel order convention (see RFC
	3551) is in use.

	For RTP, ptime: RECOMMENDED duration of each packet in
	milliseconds.

	For RTP, maxptime: maximum duration of each packet in
	milliseconds.

Encoding considerations:
	Audio data is binary data, and must be encoded for non-binary
	transport; the Base64 encoding is suitable for Email.  Note
	that audio data does not compress easily using lossless
	compression.

Security considerations:
	Audio/L16 data is believed to offer no security risks.  This
	media type does not carry active content.  The encoding is not
	compressed.  See Section 4 of RFC 4856.

Interoperability considerations:
	This type is compatible with the encoding used in the WAV
	(Microsoft Windows RIFF) and Apple AIFF union types, and with
	the public domain "sox" and "rateconv" programs.

Published specification:
	RFC 2586 for non-RTP transports, RFC 3551 for RTP

Applications that use this media type:
	The public domain "sox" and "rateconv" programs accept this
	type.

Additional information:
	Magic number(s): none
	File extension(s): WAV L16
	Macintosh file type code: AIFF

Person to contact for further information:
	James Salsman <jps-L16&bovik.org>

Intended usage:
	Common

	It is expected that many audio and speech applications will
	use this type.  Already the most popular platforms provide
	this type with the rate=11025 parameter, referred to as "radio
	quality speech".

Restrictions on usage:
	In addition to file-based transfer methods, this type is also
	defined for transfer via RTP (RFC 3550).

Author:
	James Salsman for non-RTP transports.
	Stephen Casner for RTP transport.

Change controller:
	James Salsman for non-RTP transports.
	For RTP transport, IETF Audio/Video Transport working group
	delegated from the IESG.