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TS 26.204 (SA4)
Speech codec speech processing functions –
Adaptive Multi-Rate - Wideband (AMR-WB) speech codec –
ANSI-C code

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(P) V13.1    2016/03    21 p.
(P) V12.1    2015/03    21 p.
(P) V11.0    2012/09    21 p.
(P) V10.0    2011/04    21 p.
(P) V9.0    2009/12    21 p.
(P) V8.0    2008/12    21 p.
(P) V7.1    2007/10    21 p.
(P) V6.1    2007/10    21 p.
(P) V5.4    2007/10    21 p.

Rapporteur:  Dr. Bruhn, Stefan
See also:  AMR-WB-related TS/TR    

This TS contains an electronic copy of the ANSI-C code for the Floating-point Adaptive Multi-Rate Wideband codec. This floating-point codec specification is mainly targeted to be used in multimedia applications or in packet-based applications. The bit-exact fixed-point ANSI-C code in TS 26.173 remains the preferred implementation for all applications, but the floating-point codec may be used instead of the fixed-point codec when the implementation platform is better suited for a floating-point implementation. It has been verified that the fixed-point and floating-point codecs interoperate with each other without any artifacts.

The floating-point ANSI-C code in this TS is the only standard conforming non-bit-exact implementation of the Adaptive Multi-Rate Wideband speech transcoder (TS 26.190), Voice Activity Detection (TS 26.194), comfort noise generation (TS 26.192), and source controlled rate operation (TS 26.193). The floating-point code also contains example solutions for substituting and muting of lost frames (TS 26.191).

The fixed-point specification in TS 26.173 shall remain the only allowed implementation for the 3G AMR-WB speech service and the use of the floating-point codec is strictly limited to other services.

The floating-point encoder in this TS is a non-bit-exact implementation of the fixed-point encoder producing quality indistinguishable from that of the fixed-point encoder. The decoder in this TS is functionally a bit-exact implementation of the fixed-point decoder, but the code has been optimized for speed and the standard fixed-point libraries are not used as such.


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