Extending STL BASOPs Used in 3GPP Codecs to Leverage Features of Modern DSP Architectures

All 3GPP reference speech, audio and hybrid codecs are implemented using a basic set of operators standardized previously by ITU-T and part of the software tools library (STL). The last major update to the basic operators (BASOPs) was made in 2009. Since then modern DSP architectures with features such as VLIW, SIMD, and 64-bit wide accumulators have become prevalent. Over the years, DSP architectures and processing algorithms have evolved to provide better precision at lower bit-rates and to handle increased coding complexities that have resulted in improved speech and audio quality. To keep in sync with these trends, We contributed to the 3GPP SA4 standards committee with a proposal to update the STL BASOPs. To demonstrate the impact of STL update, reference c-code of EVS codec was implemented using updated STL BASOPs. With the proposed EVS implementation, we are able to achieve 1.25x improvement in cycles, 1.1x improvement in WMOPS along with 100 KBytes reduction in memory footprint.