Performance of a single-chip low bit-rate voice transcoder

The objective of this research is to study the performance of a high quality speech compression in real-time on a single-chip system. Based on voice over Internet protocol (VoIP) requirements, we have decided to implement a high quality speech coding (with signal-to-noise ratio, SNR of more than 10 dB), at a low bit rate of 8 kbit/s or less. The coder must have delay not more than 100 ms. The development results have exceeded the requirements. The bit rates are as low as 5.3 kbit/s and 6.3 kbit/s, with SNR of 11.52 dB and 12.72 dB, respectively. Total delay time is 60.3 ms. The program requires 76 MIPS computation and 43 Kword memory, thus fit within a single chip of 100 MIPS TMS320C5409.