Patent ID: 8484018

Claim:
A data converting apparatus, which divides input data into plural frames and partially overlaps the divided frames, thereby producing output data, the apparatus comprising: an input buffer for storing input data of a first frame size; an output buffer for storing output data of a second frame size decided in accordance with a reproducing speed ratio, wherein the reproducing speed ratio indicates a ratio of a reproducing speed of the output data to the input data; a controlling unit for deciding an overlapping rate based on the reproducing speed ratio indicating the ratio of a reproducing speed of the output data to the input data, and for deciding a first hopsize based on the first frame size of the input data and the decided overlapping rate; a data converting unit for producing the output data of the second frame size from the input data stored in the input buffer, wherein the data converting unit comprises: an input-frame data producing unit for producing from the input data stored in the input buffer input frames each having the first hopsize and including a predetermined number of sub-frames, wherein the predetermined number of sub-frames corresponds to the overlapping rate; a window function executing unit for executing a window function on the input frames produced by the input-frame data producing unit; a frame processing unit for shifting the input frames subjected to the window function by the first hopsize and overlapping the shifted input frames, thereby obtaining data of output frame, wherein the obtaining data of output frame has a second hopsize defined based on the first hopsize and the reproducing speed ratio and includes sub-frames; and an output buffer data producing unit for storing in the output buffer the data of output frame as the output data each having the second hopsize and including the predetermined number of sub-frames, and the controlling unit sets the first hopsize and the overlapping rate in a slow speed reproduction different from the first hopsize and the overlapping rate in a high speed reproduction and vice versa, wherein the slow speed reproduction is set when the reproducing speed ratio has been set lower than “1” and the high speed reproduction is set when the reproducing speed ratio has been set higher than “1”, wherein the controlling unit, based on an effect of a comb filter, sets the first frame size of the input data smaller in the slow speed reproduction than in the high speed reproduction based on a sampling frequency and the reproducing speed ratio and an overlapping rate.