Dynamic data compression algorithms in speech coding

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Speech coding is to use a series of bits to encode speech signals, such that it is much easier and more efficient to digitally transmit or store speech signals. Bit rate is the number of bits required for every second of speech signal.

Based upon parametric descriptions of speech signals, the linear prediction analysis provides a successful method for low bit rate speech coding. Due to the high redundancy among the parameters of adjacent speech signal frames, further data compression becomes possible. In this paper, various data compression techniques and algorithms are studied and two sets of variable frame rate linear predictive vocoders are developed based on frame interpolation and frame repeating concepts, respectively. Simulation results indicate that almost identical speech quality can be achieved even when the bit rate is reduced from 2,400 bps to 1,200 bps.