Stereo signal decoding device and stereo signal decoding method
First Claim
1. A decoding apparatus, comprising:
- a receiver that receives an encoded monaural signal obtained by encoding a monaural signal computed from first and second channel signals of a stereo signal and an encoded difference signal obtained by encoding a difference signal between the first and second channel signals;
a detector that detects a variation over time of the received encoded difference signal;
a decoder that decodes the received encoded monaural signal to obtain the decoded monaural signal and decodes the received encoded difference signal to obtain the decoded difference signal;
a smoothing section, including a processor, that smoothes the decoded difference signal by an operation of the decoded difference signal and a coefficient corresponding to the detected variation over time; and
a computation section, including a processor, that computes the decoded stereo signal from the decoded monaural signal and the decoded difference signal obtained by smoothing,wherein the detector detects, as the variation over time, that a frame including the encoded difference signal is changed to a frame not including the encoded difference signal or that a frame not including the encoded different signal is changed to a frame including the encoded difference signal.
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Abstract
A decoding device reduces abrupt changes in the number of channels in a decoded signal when transmission errors occur as a result of lost frames in an encoding/decoding system for multichannel signals. In the device, a demultiplexer receives an encoded monaural signal and an encoded differential signal and detects change over time in the received encoded differential signal. An M signal decoder decodes the encoded monaural signal and obtains a decoded monaural signal. An S signal decoder decodes the encoded differential signal and obtains a decoded differential signal. A smoothing unit performs smoothing on the decoded differential signal by means of a computation involving the decoded differential signal and coefficients corresponding to the change over time detected by the demultiplexer. An L/R signal computation unit computes a decoded stereo signal from the decoded monaural signal and the smoothed decoded differential signal.
17 Citations
10 Claims
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1. A decoding apparatus, comprising:
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a receiver that receives an encoded monaural signal obtained by encoding a monaural signal computed from first and second channel signals of a stereo signal and an encoded difference signal obtained by encoding a difference signal between the first and second channel signals; a detector that detects a variation over time of the received encoded difference signal; a decoder that decodes the received encoded monaural signal to obtain the decoded monaural signal and decodes the received encoded difference signal to obtain the decoded difference signal; a smoothing section, including a processor, that smoothes the decoded difference signal by an operation of the decoded difference signal and a coefficient corresponding to the detected variation over time; and a computation section, including a processor, that computes the decoded stereo signal from the decoded monaural signal and the decoded difference signal obtained by smoothing, wherein the detector detects, as the variation over time, that a frame including the encoded difference signal is changed to a frame not including the encoded difference signal or that a frame not including the encoded different signal is changed to a frame including the encoded difference signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A decoding method, comprising:
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receiving, using a receiver, an encoded monaural signal obtained by encoding a monaural signal computed from first and second channel signals of a stereo signal and an encoded difference signal obtained by encoding a difference signal between the first and second channel signals; detecting, using a detector, a variation over time of the received encoded difference signal; decoding, using a decoder, the received encoded monaural signal to obtain the decoded monaural signal and decoding the received encoded difference signal to obtain the decoded difference signal; smoothing, using a smoothing section including a processor, the decoded difference signal by an operation of the decoded difference signal and a coefficient corresponding to the detected variation over time; and computing, using a computing section including a processor, a decoded stereo signal from the decoded monaural signal and the decoded difference signal subjected to smoothing, wherein the detecting detects, as the variation over time, that a frame including the encoded difference signal is changed to a frame not including the encoded difference signal or that a frame not including the encoded different signal is changed to a frame including the encoded difference signal.
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Specification