Title :
Source signal based rate adaptation for GSM AMR speech codec
Author :
Makinen, J. ; Vainio, J.
Author_Institution :
Audio & Visual Syst. Lab., Nokia Res. Center, Espoo, Finland
Abstract :
Adaptive multirate (AMR) codec was standardised for GSM in 1999. AMR offers substantial improvement over previous GSM speech codecs in error robustness by adapting speech and channel coding depending on channel conditions. However, current standard do not exploit the multirate capability of AMR codec in source signal based adaptation that would optimise the average bit-rate vs. quality trade-off. This paper presents a source signal based rate adaptation algorithm for AMR codec in GSM system. Together with fast power control, it can be used to increase the system capacity and further increase the robustness of GSM AMR codec.
Keywords :
adaptive codes; error statistics; source coding; speech codecs; speech coding; variable rate codes; GSM AMR codec; adaptive multirate codec; channel coding; source signal based rate adaptation; speech codec; speech processing functions; Automatic speech recognition; Bit rate; GSM; Knowledge based systems; Laboratories; Robustness; Speech codecs; Speech coding; Switches; Visual system;
Conference_Titel :
Information Technology: Coding and Computing, 2004. Proceedings. ITCC 2004. International Conference on
Print_ISBN :
0-7695-2108-8
DOI :
10.1109/ITCC.2004.1286652
