Coding device, decoding device, coding method, and decoding method for audio signals

摘要

A coding device includes: a pitch contour detection unit which detects a pitch contour of an input audio signal; a dynamic time warping unit which determines the number of pitch nodes based on the pitch contour and generates a first time warping parameter including information indicating the determined number of pitch nodes, a pitch change position, and a pitch change ratio; a first encoder which codes the first time warping parameter; a time warping unit which corrects pitch, using the information obtained from the first time warping parameter, to approximate the pitches of the number of pitch nodes to a predetermined reference value; a second encoder which codes the input audio signal at the corrected pitch; and a multiplexer which multiplexes the coded time warping parameter and the coded audio signal to generate a bitstream.

主权项

1. A coding device comprising:
a pitch contour detection unit configured to detect a pitch contour that is information indicating a change in pitch of an input audio signal within a period; a dynamic time warping unit configured to: analyze the detected pitch contour; and determine, based on a result of the analysis, the number of pitch nodes that is an optimal number of pitches detected within the period; and generate a first time warping parameter including information indicating the determined number of pitch nodes, a pitch change position, and a pitch change ratio, the pitch change position being a position where the change in pitch occurs in pitches of the number of pitch nodes, the pitch change ratio being a ratio of the change in pitch at the pitch change position; a first encoder which codes the generated first time warping parameter to generate a coded time warping parameter; a time warping unit configured to correct, using the information obtained from the generated first time warping parameter, at least one pitch included in the pitches of the number of pitch nodes, to approximate the pitches of the number of pitch nodes to a predetermined reference value; a second encoder which codes the input audio signal at the pitch corrected by the time warping unit to generate a coded audio signal; and a multiplexer which multiplexes the coded time warping parameter generated by the first encoder and the coded audio signal generated by the second encoder to generate a bitstream.