Patent ID: 8706506
Filing Date: 2014-04-22
Classification: G10H,G10L

Abstract:
1. A waveform compressing apparatus for converting data of an original waveform signal into a compressed data with a given compression rate, the compressed data having a plurality of frames of a predetermined format, the waveform compressing apparatus comprising: a trial mode selecting device that selects a trial mode having the highest compression rate from a plurality of candidate modes that have not been previously selected as a trial mode for generating a residue code, the selected trial mode comprising a scalar quantization mode or a vector quantization mode; a compressing device that compresses the sample data of the original waveform signal according to the selected trial mode so as to generate the residue code corresponding to the selected trial mode, an amount of the sample data of the original waveform signal to be compressed being specified by the selected trial mode; a waveform signal generating device that generates a sample data of a restored waveform signal using the generated residue code and the selected trial mode; a determining device that determines an evaluation value that indicates a quantization error contained in the sample data of the restored waveform signal by comparing the sample data of the restored waveform signal relative to the sample data of the original waveform signal, and that determines whether the evaluation value is equal to or smaller than a predetermined allowable value; a mode change instructing device that outputs a mode change instruction for instructing the trial mode selecting device to select another trial mode when the determining device determines that the evaluation value is not equal to or smaller than the predetermined allowable value; and a frame storing device that stores the generated residue code and sub information specifying the selected trial mode as the compressed data corresponding to the sample data of the original waveform signal in a frame corresponding to the sample data of the original waveform signal when the determining device determines that the evaluation value is equal to or smaller than the predetermined allowable value, the compressed data being stored for use in generation of a timbre of a musical tone.