Patent ID: 7472056
Filing Date: 2008-12-30
Classification: G10L

Abstract:
1. A transcoder for converting an input Code-Excited Linear Prediction (CELP) codec stream of one format into an output CELP codec stream of another format, comprising: a decoding unit of an input CELP codec, which converts a bitstream encoded in an input CELP codec format into a speech signal; a transcoding filter, which performs filtering of the speech signal decoded in the decoding unit of the input CELP codec with filter characteristics calculated by adapting an optimum weight to minimize spectral distortion based on a reference filter; a transcoding filter design unit, which extracts the optimum weight to minimize spectral distortion of the transcoding filter from a weight set, and then supplies the optimum weight to the transcoding filter, the transcoding filter design unit to: an encoding unit of an output CELP codec, which generates a bitstream in an output CELP codec format by encoding the speech signal filtered in the transcoding filter.