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TS 26.104 (SA4)
ANSI-C code for the floating-point Adaptive Multi-Rate (AMR) speech codec

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(P) V13.0    2015/12    25 p.
(P) V12.0    2014/09    25 p.
(P) V11.0    2012/09    25 p.
(P) V10.0    2011/04    25 p.
(P) V9.0    2009/12    25 p.
(P) V8.0    2008/12    25 p.
(P) V7.0    2007/06    25 p.
(P) V6.1    2004/04    25 p.
(P) V5.4    2004/04    25 p.
(P) V4.5    2003/06    25 p.
(P) V3.5    2003/04    25 p.

Rapporteur:  Mr. Usai, Paolino
See also:  AMR-related TS/TR    

This TS contains an electronic copy of the ANSI-C code for a floating-point implementation of the Adaptive Multi-Rate codec. This floating-point codec specification is mainly targeted to be used in multimedia applications such as the 3G-324M terminal specified in TS 26.110, or in packet-based (e.g., H.323) applications. The bit-exact fixed-point ANSI-C code in TS 26.073 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 artefacts.

The floating-point ANSI-C code in this TS is the only standard conforming non-bit-exact implementation of the Adaptive Multi Rate speech transcoder (TS 26.090), Voice Activity Detection (TS 26.094), comfort noise generation (TS 26.092), and source controlled rate operation (TS 26.093). The floating-point code also contains example solutions for substituting and muting of lost frames (TS 26.091).

The fixed-point specification in TS 26.073 shall remain the only allowed implementation for the 3G mandatory 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 fixedpoint libraries are not used as such.


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