a comparative analysis of digital audio encoders: lpc, celp, and melp, evaluating quality and complexity of transmitted content

This article compares the quality and complexity of lpc, celp, and melp standard audio encoders. these standards are based on linear predictive and are used in sound (speech) processing. these standards are powerful high-quality speech coding methods that provide highly accurate estimates of audio parameters and are widely used in the commercial (mobile) and military (nato) communications industries. to compare lpc, celp, and melp audio encoders in two male and female voice modes and four voice models: quiet, audio recorded without sound by the microphone, mce, office, and two noise models 1% and 05% were used. the simulation results show the complexity of melp is higher than lpc and celp in terms of both processor and memory requirements. the melp analyzer requires 72% of its total processing time. this additional memory is, due to the vector quantization tables melp uses for the linear spectral frequencies (lsfs) and the fourier magnitude. also, according to the quality comparison test using the mos index, melp has the highest score, followed by celp and lpc