A speech coding method using thinned-out residual

A new high-quality speech information compression method is developed. This method introduces techniques of eliminating unnecessary samples of prediction residual wave pulses to obtain a thinned-out residual. First, a thinning-out procedure which minimizes the quality degradation is formulated. Next, a procedure which simplifies this thinning-out procedure under several hypotheses is defined. Subjective evaluation of this procedure using preference tests confirms that almost no quality degradation occurs. Pitch information is utilized. Adding the process of repetitive use of the thinned-out residual to the procedure, preference tests are carried out at a bit-rate of 9.6 kb/s for purposes of comparison with the newest MPE which includes the pitch prediction process. The results are that our proposed method produces slightly higher quality speech than does the MPE method. The number of processing steps is less than one-third that of MPE.