A vocoder and method transcodes Mixed Excitation Linear Prediction (MELP) encoded data for use at different speech frame rates. Input data is converte (100) into MELP parameters such as used by a first MELP vocoder. These parameters are buffered (102) and a time interpolation (104) is performed on the parameters with quantization to predict spaced points. An encoding function (106) is performed on the interpolated data as a block to produce a reduction in bit-rate as used by a second MELP vocoder at a different speech frame rate than the first MELP vocoder.
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