
Date: Thu, 21 Nov 96 10:19:00 PST
From: Vineet Kumar <Vineet_Kumar@ccm.jf.intel.com>
To: gary_shirk@ccm.jf.intel.com, iana@isi.edu
Subject: need payload type assigned to G.723.1 audio codec


G.723.1 is an audio codec used in ITU's H.323 and H.324. It is being
widely used for Internet Telephony. Intel's own Internet Phone product
has over 300,000 (three-hundred-thousand) downloads. Microsoft's
Netmeeting also implements H.323 with G.723.1 and is expected to reach
millions of consumers. Due to such a demand it makes a lot of sense to
have a static payload type assigned to G.723.1.

-------------------------------------------------------------------- 
About G.723.1
---------------
G.723.1 is specified in ITU recommendation G.723.1. Reference 
implementations for G.723.1 are available as part of the CCITT/ITU-T 
Software Tool Library (STL) from the ITU General Secretariat, Sales 
Service, Place du Nations, CH-1211 Geneve 20, Switzerland. The library

is covered by a license.

This Recommendation specifies a coded representation that can be used 
for compressing the speech or other audio signal component of 
multi-media services at a very low bit rate. A G.723.1 frame can be 
one of three sizes: 24 bytes (6.3 kb/s frame), 20 bytes (5.3 kb/s 
frame), or 4 bytes.  These 4-byte frames are called SID frames 
(Silence Insertion Descriptor) and are used to specify comfort noise 
parameters. There is no restriction on how 4, 20, and 24 byte frames 
are intermixed. The first two bits in the frame determine the frame 
boundary. It is possible are                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  