Conversion device

1. A conversion device, comprising:

a segment processing unit operable to (a) select at least one pair of segments from a plurality of segments constituting original audio data and (b) perform segment processing so as to overlap playback periods of the selected pair of segments; and

a generation unit operable to generate after-conversion audio data by arranging the overlapped segments and unoverlapped segments in playback order, the unoverlapped segments being remainders of the plurality of segments, wherein

along a time axis of the original audio data, a positional relationship between the overlapped segments and the unoverlapped segments is non-linear,

one of the overlapped segments is a base segment while the other is a subsidiary segment,

the base segment is included in the plurality of segments that are positioned at certain time intervals throughout the original audio data,

the subsidiary segment is positioned away from the base segment by a maximum time lag to a minimum time lag, and

each of the certain time intervals is greater than the minimum time lag.

2. The conversion device of claim 1 , further comprising:

a calculation unit operable to (a) generate all possible pairs of the plurality of segments and (b) calculate a degree of similarity pertaining to each possible pair of the plurality of segments, wherein

the overlapped segments are one of the all possible pairs of the plurality of segments that holds the highest degree of similarity, and

the unoverlapped segments are included in remainders of the all possible pairs of the plurality of segments.

3. The conversion device of claim 2 , wherein

the segment processing unit includes a selection subunit operable to (a) obtain a time difference between each of the at least one pair of segments to be overlapped and (b) accumulate the time difference, and

the selection subunit selects, one by one, the at least one pair of segments to be overlapped, as long as the following condition is satisfied: the accumulated time difference is equal to or smaller than a target time length, which is a time length of the after-conversion audio data.

4. The conversion device of claim 3 , wherein

under an assumption that a ratio between a time length of the original audio data and the target time length is α,

when the after-conversion audio data is shorter than the original audio data, the target time length is the time length of the original audio data×(1−α), and

when the after-conversion audio data is longer than the original audio data, the target time length is the time length of the original audio data×(α−1).

5. The conversion device of claim 1 , wherein

the minimum time lag approximates a time length of a minimum cycle of an input signal, and the maximum time lag approximates a time length of a maximum cycle of the input signal,

in the original audio data, there is a gap of time between the base segment and the subsidiary segment when the following conditions are satisfied: (a) a time length of the base segment is an intermediate value between the minimum time lag and the maximum time lag; and (b) the subsidiary segment is positioned away from the base segment by the maximum time lag, and

in the original audio data, the base segment and the subsidiary segment overlap when the following conditions are satisfied: (a) the time length of the base segment is the intermediate value between the minimum time lag and the maximum time lag; and (b) the subsidiary segment is positioned away from the base segment by the minimum time lag.

6. The conversion device of claim 1 , wherein

when the after-conversion audio data is shorter than the original audio data, the subsidiary segment is positioned behind the base segment along the time axis of the original audio data, and

when the after-conversion audio data is longer than the original audio data, the subsidiary segment is positioned ahead of the base segment along the time axis of the original audio data.

7. The conversion device of claim 1 implemented as an audio conversion device into a playback device that plays back and outputs video and audio, wherein

the playback device includes a video conversion device that converts a playback speed of the video, and

the video conversion device converts the playback speed of the video by freezing or skipping a part of a plurality of frames constituting video data.