Coding device, decoding device, coding method, and decoding method for audio signals
First Claim
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.
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Abstract
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.
21 Citations
12 Claims
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1. A coding device comprising:
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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. - View Dependent Claims (2, 3, 4)
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5. A decoding device comprising:
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a demultiplexer which demultiplexes a coded audio signal and a coded time warping parameter from a bitstream, the coded audio signal being obtained by coding a pitch-corrected audio signal, the coded time warping parameter being obtained by coding a first time warping parameter for correcting pitches, the bitstream being obtained by multiplexing the coded audio signal and the coded time warping parameter; a first decoding unit configured to decode the coded time warping parameter to generate a second time warping parameter including information indicating the number of pitch nodes, a pitch change position, and a pitch change ratio, the number of pitch nodes being the number of pitches detected within a period, the pitch change position being a position where a change in pitch occurs in pitches of the number of pitch nodes, the pitch change ratio being a ratio of the change at the pitch change position; a second decoding unit configured to decode the coded audio signal to generate a pitch-corrected audio signal obtained by correcting pitch to approximate the pitches of the number of pitch nodes to a predetermined reference value; and a time warping unit configured to transform, using the second time warping parameter, the pitch-corrected audio signal into an audio signal before correction by changing at least one pitch included in the pitches of the number of pitch nodes to restore the pitches of the number of pitch nodes to pitches before correction. - View Dependent Claims (6)
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7. A coding method comprising:
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detecting a pitch contour of an input audio signal, the pitch contour being information indicating a change in pitch within a period; analyzing the detected pitch contour; and
determining, based on a result of the analyzing, the number of pitch nodes that is an optimal number of pitches detected within the period, to 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 at the pitch change position;coding the generated first time warping parameter to generate a coded time warping parameter; correcting, 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; coding the input audio signal having the pitch corrected in the correcting to generate a coded audio signal; and multiplexing the coded time warping parameter generated in the coding of the generated first time warping parameter and the coded audio signal generated in the coding of the input audio signal, to generate a bitstream. - View Dependent Claims (9)
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8. A decoding method comprising:
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demultiplexing a coded audio signal and a coded time warping parameter from a bitstream, the coded audio signal being obtained by coding a pitch-corrected audio signal, the coded time warping parameter being obtained by coding a first time warping parameter for correcting pitches, the bitstream being obtained by multiplexing the coded audio signal and the coded time warping parameter; decoding the coded time warping parameter to generate a second time warping parameter including information indicating the number of pitch nodes, a pitch change position, and a pitch change ratio, the number of pitch nodes being the number of pitches detected within a period, the pitch change position being a position where a change in pitch occurs in pitches of the number of pitch nodes, the pitch change ratio being a ratio of the change at the pitch change position; decoding the coded audio signal to generate a pitch-corrected audio signal obtained by correcting pitch to approximate the pitches of the number of pitch nodes to a predetermined reference value; and transforming, using the second time warping parameter, the pitch-corrected audio signal into an audio signal before correction by changing at least one pitch included in the pitches of the number of pitch nodes to restore the pitches of the number of pitch nodes to pitches before correction. - View Dependent Claims (10)
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11. An integrated circuit comprising:
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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.
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12. An integrated circuit comprising:
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a demultiplexer which demultiplexes a coded audio signal and a coded time warping parameter from a bitstream, the coded audio signal being obtained by coding a pitch-corrected audio signal, the coded time warping parameter being obtained by coding a first time warping parameter for correcting pitches, the bitstream being obtained by multiplexing the coded audio signal and the coded time warping parameter; a first decoding unit configured to decode the coded time warping parameter to generate a second time warping parameter including information indicating the number of pitch nodes, a pitch change position, and a pitch change ratio, the number of pitch nodes being the number of pitches detected within a period, the pitch change position being a position where a change in pitch occurs in pitches of the number of pitch nodes, the pitch change ratio being a ratio of the change at the pitch change position; a second decoding unit configured to decode the coded audio signal to generate a pitch-corrected audio signal obtained by correcting pitch to approximate the pitches of the number of pitch nodes to a predetermined reference value; and a time warping unit configured to transform, using the second time warping parameter, the pitch-corrected audio signal into an audio signal before correction by changing at least one pitch included in the pitches of the number of pitch nodes to restore the pitches of the number of pitch nodes to pitches before correction.
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Specification