Audio upmixer operable in prediction or non-prediction mode
First Claim
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1. An apparatus for outputting a stereo audio signal having a left channel and a right channel, the apparatus comprising:
- a demultiplexer configured to receive an audio bitstream and extract therefrom a prediction coefficient for each of a plurality of frequency bands;
a decoder configured to generate a downmix signal and a residual signal from the encoded audio bitstream; and
an upmixer configured to operate in either a prediction mode or a non-prediction mode based on a parameter encoded in the audio bitstream, and to output the left channel and the right channel as the stereo audio signal,wherein, when the upmixer operates in the prediction mode, the residual signal represents a difference between a side signal and a predicted version of the side signal, and the upmixer generates the left channel and the right channel from a combination of the downmix signal, the residual signal, and the prediction coefficients for each of the plurality of frequency bands, andwherein, when the upmixer operates in the non-prediction mode, the residual signal represents the side signal, the upmixer generates the left channel based on a sum of the downmix signal and the residual signal passed through from the decoder, and the upmixer generates the right channel based on a difference of the downmix signal and the residual signal passed through from the decoder.
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Abstract
The invention provides methods and devices for outputting a stereo audio signal having a left channel and a right channel. The apparatus includes a demultiplexer, decoder, and upmixer. The upmixer is configured operate either in a prediction mode or a non-prediction mode based on a parameter encoded in the audio bitstream.
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Citations
18 Claims
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1. An apparatus for outputting a stereo audio signal having a left channel and a right channel, the apparatus comprising:
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a demultiplexer configured to receive an audio bitstream and extract therefrom a prediction coefficient for each of a plurality of frequency bands; a decoder configured to generate a downmix signal and a residual signal from the encoded audio bitstream; and an upmixer configured to operate in either a prediction mode or a non-prediction mode based on a parameter encoded in the audio bitstream, and to output the left channel and the right channel as the stereo audio signal, wherein, when the upmixer operates in the prediction mode, the residual signal represents a difference between a side signal and a predicted version of the side signal, and the upmixer generates the left channel and the right channel from a combination of the downmix signal, the residual signal, and the prediction coefficients for each of the plurality of frequency bands, and wherein, when the upmixer operates in the non-prediction mode, the residual signal represents the side signal, the upmixer generates the left channel based on a sum of the downmix signal and the residual signal passed through from the decoder, and the upmixer generates the right channel based on a difference of the downmix signal and the residual signal passed through from the decoder. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 16, 17, 18)
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14. A method for outputting a stereo audio signal having a left channel and a right channel, the method comprising:
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receiving an audio bitstream and extract therefrom a prediction coefficient for each of a plurality of frequency bands; generating in a decoder a downmix signal and a residual signal from the encoded audio bitstream; upmixing in either a prediction mode or a non-prediction mode based on a parameter encoded in the audio bitstream; and outputting the left channel and the right channel as the stereo audio signal, wherein, when the upmixing operates in the prediction mode, the residual signal represents a difference between a side signal and a predicted version of the side signal, and the upmixing generates the left channel and the right channel from a combination of the downmix signal, the residual signal, and the prediction coefficients for each of the plurality of frequency bands, and wherein, when the upmixing operates in the non-prediction mode, the residual signal represents the side signal, and the upmixing generates the left channel based on a sum of the downmix signal and the residual signal passed through from the decoder, and generates the right channel based on a difference of the downmix signal and the residual signal passed through from the decoder. - View Dependent Claims (15)
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Specification