7 Computational details and bit allocation

26.1923GPPAdaptive Multi-Rate - Wideband (AMR-WB) speech codecComfort noise aspectsRelease 17Speech codec speech processing functionsTS

A bit exact computational description of comfort noise encoding and generation in form of an ANSI-C source code is found in [1].

The detailed bit allocation and the sequence of bits in the comfort noise encoding is shown in Table 1.

Table 1: Source encoder output parameters in order of occurrence and bit allocation for comfort noise encoding

Bits (MSB‑LSB)	Description
s1 – s6	index of 1st ISF subvector
s7‑ s12	index of 2st ISF subvector
s13 – s18	index of 3nd ISF subvector
s19 – s23	index of 4th ISF subvector
s24 – s28	index of 5th ISF subvector
s29 – s34	index of logarithmic frame energy
s35	dithering flag

Annex A (informative):
Change history

Change history
Date	TSG #	TSG Doc.	CR	Rev	Subject/Comment	Old	New
03-2001	11	SP-010087			Version 2.0.0 presented for approval		5.0.0
12-2004	26				Version for Release 6	5.0.0	6.0.0
06-2007	36				Version for Release 7	6.0.0	7.0.0
12-2008	42				Version for Release 8	7.0.0	8.0.0
12-2009	46				Version for Release 9	8.0.0	9.0.0
03-2011	51				Version for Release 10	9.0.0	10.0.0
09-2012	57				Version for Release 11	10.0.0	11.0.0
09-2014	65				Version for Release 12	11.0.0	12.0.0
12-2015	70				Version for Release 13	12.0.0	13.0.0