Abstract: A method performed in an audio decoder for reconstructing an original audio signal having a lowband portion and a highband portion is disclosed. The method includes receiving an encoded audio signal and extracting reconstruction parameters from the encoded audio signal. The method further includes decoding the encoded audio signal with a core audio decoder to obtain a decoded lowband portion and regenerating the highband portion based at least in part on a cross over frequency and the decoded lowband portion to obtain a regenerated highband portion. The method also includes creating a synthetic sinusoid with a level based at least in part on a spectral envelope value for the particular subband and a noise floor value for the particular subband and adding the synthetic sinusoid to the regenerated highband portion in the particular frequency band specified by the location information.

Abstract: The present invention relates to a new method and apparatus for improvement of High Frequency Reconstruction (HFR) techniques using frequency translation or folding or a combination thereof. The proposed invention is applicable to audio source coding systems, and offers significantly reduced computational complexity. This is accomplished by means of frequency translation or folding in the subband domain, preferably integrated with spectral envelope adjustment in the same domain. The concept of dissonance guard-band filtering is further presented. The proposed invention offers a low-complexity, intermediate quality HFR method useful in speech and natural audio coding applications.

Abstract: A method performed in an audio decoder for reconstructing an original audio signal having a lowband portion and a highband portion is disclosed. The method includes receiving an encoded audio signal and extracting reconstruction parameters from the encoded audio signal. The method further includes decoding the encoded audio signal with a core audio decoder to obtain a decoded lowband portion and regenerating the highband portion based at least in part on a cross over frequency and the decoded lowband portion to obtain a regenerated highband portion. The method also includes creating a synthetic sinusoid with a level based at least in part on a spectral envelope value for the particular subband and a noise floor value for the particular subband and adding the synthetic sinusoid to the regenerated highband portion in the particular frequency band specified by the location information.

Abstract: The document relates to modulated sub-sampled digital filter banks, as well as to methods and systems for the design of such filter banks. In particular, the present document proposes a method and apparatus for the improvement of low delay modulated digital filter banks. The method employs modulation of an asymmetric low-pass prototype filter and a new method for optimizing the coefficients of this filter. Further, a specific design for a 64 channel filter bank using a prototype filter length of 640 coefficients and a system delay of 319 samples is given. The method substantially reduces artifacts due to aliasing emerging from independent modifications of subband signals, for example when using a filter bank as a spectral equalizer. The method is preferably implemented in software, running on a standard PC or a digital signal processor (DSP), but can also be hardcoded on a custom chip.

Abstract: An apparatus and method are disclosed for filtering an audio signal. The apparatus includes an analysis filter bank, a phase shifter, a high frequency reconstructor or parametric stereo processor, and a synthesis filter bank. The analysis filterbank receives real-valued time domain input audio samples and generates complex valued subband samples. The phase shifter shifts a phase of the complex-valued subband samples by an amount. The high frequency reconstructor or parametric stereo processor modifies at least some of the complex valued subband samples. A phase shifter then unshifts a phase of the modified complex-valued subband samples by the amount. The synthesis filter bank receives the modified complex valued subband samples and generates time domain output audio samples.

Abstract: An apparatus and method are disclosed for filtering an audio signal. The apparatus includes a high frequency reconstructor or parametric stereo processor, a phase shifter, and a synthesis filter bank. The high frequency reconstructor or parametric stereo processor generates modified complex-valued subband samples. A phase shifter unshifts a phase of the modified complex-valued subband samples by an amount. The synthesis filter bank receives the modified complex valued subband samples and generates time domain output audio samples.

Abstract: A method performed in an audio decoder for reconstructing an original audio signal having a lowband portion and a highband portion is disclosed. The method includes receiving an encoded audio signal and extracting reconstruction parameters from the encoded audio signal. The method further includes decoding the encoded audio signal with a core audio decoder to obtain a decoded lowband portion and regenerating the highband portion based at least in part on a cross over frequency and the decoded lowband portion to obtain a regenerated highband portion. The method also includes creating a synthetic sinusoid with a level based at least in part on a spectral envelope value for the particular subband and a noise floor value for the particular subband and adding the synthetic sinusoid to the regenerated highband portion in the particular frequency band specified by the location information.

Abstract: A method performed in an audio decoder for reconstructing an original audio signal having a lowband portion and a highband portion is disclosed. The method includes receiving an encoded audio signal and extracting reconstruction parameters from the encoded audio signal. The method further includes decoding the encoded audio signal with a core audio decoder to obtain a decoded lowband portion and regenerating the highband portion based at least in part on a cross over frequency and the decoded lowband portion to obtain a regenerated highband portion. The method also includes creating a synthetic sinusoid with a level based at least in part on a spectral envelope value for the particular subband and a noise floor value for the particular subband and adding the synthetic sinusoid to the regenerated highband portion in the particular frequency band specified by the location information.

Abstract: An apparatus and method are disclosed for filtering an audio signal. The apparatus includes a high frequency reconstructor or parametric stereo processor, a phase shifter, and a synthesis filter bank. The high frequency reconstructor or parametric stereo processor generates modified complex-valued subband samples. A phase shifter unshifts a phase of the modified complex-valued subband samples by an amount. The synthesis filter bank receives the modified complex valued subband samples and generates time domain output audio samples.

Abstract: An apparatus and method are disclosed for filtering an audio signal. The apparatus includes an analysis filter bank, a phase shifter, a high frequency reconstructor or parametric stereo processor, and a synthesis filter bank. The analysis filterbank receives real-valued time domain input audio samples and generates complex valued subband samples. The phase shifter shifts a phase of the complex-valued subband samples by an amount. The high frequency reconstructor or parametric stereo processor modifies at least some of the complex valued subband samples. A phase shifter then unshifts a phase of the modified complex-valued subband samples by the amount. The synthesis filter bank receives the modified complex valued subband samples and generates time domain output audio samples.

Abstract: A method performed in an audio decoder for reconstructing an original audio signal having a lowband portion and a highband portion is disclosed. The method includes receiving an encoded audio signal and extracting reconstruction parameters from the encoded audio signal. The method further includes decoding the encoded audio signal with a core audio decoder to obtain a decoded lowband portion and regenerating the highband portion based at least in part on a cross over frequency and the decoded lowband portion to obtain a regenerated highband portion. The method also includes creating a synthetic sinusoid with a level based at least in part on a spectral envelope value for the particular subband and a noise floor value for the particular subband and adding the synthetic sinusoid to the regenerated highband portion in the particular frequency band specified by the location information.

Abstract: An apparatus and method are disclosed for filtering an audio signal are disclosed. The apparatus includes an analysis filter bank, a high frequency reconstructor or a parametric stereo processor, and a synthesis filter bank. The analysis filterbank receives real-valued time domain input audio samples and generates complex valued subband samples. The high frequency reconstructor or parametric stereo processor modifies at least some of the complex valued subband samples. The synthesis filter bank receives the modified complex valued subband samples and generates time domain output audio samples. The analysis filter bank comprises analysis filters that are complex exponential modulated versions of a prototype filter.

Abstract: The present disclosure provides methods, devices and computer program products for non-uniform quantization of parameters relating to parametric spatial coding of audio signals. The disclosure further relates to a method and apparatus for reconstructing an audio object in an audio decoding system taking the non-uniformly quantized parameters into account. According to the disclosure, such an approach renders it possible to reduce bit consumption without substantially reducing the quality of the reconstructed audio object.

Abstract: An apparatus and method are disclosed for filtering an audio signal are disclosed. The apparatus includes an analysis filter bank, a high frequency reconstructor or a parametric stereo processor, and a synthesis filter bank. The analysis filterbank receives real-valued time domain input audio samples and generates complex valued subband samples. The high frequency reconstructor or parametric stereo processor modifies at least some of the complex valued subband samples. The synthesis filter bank receives the modified complex valued subband samples and generates time domain output audio samples. The analysis filter bank comprises analysis filters that are complex exponential modulated versions of a prototype filter.

Abstract: An apparatus and method are disclosed for filtering and performing high frequency reconstruction of an audio signal. The apparatus includes an analysis filter bank, a phase shifter, a high frequency reconstructor, and a synthesis filter bank. The analysis filterbank receives real-valued time domain input audio samples and generates complex valued subband samples. The phase shifter shifts a phase of the complex-valued subband samples by an arbitrary amount. The high frequency reconstructor modifies at least some of the complex valued subband samples. A phase shifter unshifts a phase of the modified complex-valued subband samples by the arbitrary amount. The synthesis filter bank receives the modified complex valued subband samples and generates time domain output audio samples. The analysis filter bank comprises analysis filters that are complex exponential modulated versions of a prototype filter with an arbitrary phase shift.

Abstract: The document relates to modulated sub-sampled digital filter banks, as well as to methods and systems for the design of such filter banks. In particular, the present document proposes a method and apparatus for the improvement of low delay modulated digital filter banks. The method employs modulation of an asymmetric low-pass prototype filter and a new method for optimizing the coefficients of this filter. Further, a specific design for a 64 channel filter bank using a prototype filter length of 640 coefficients and a system delay of 319 samples is given. The method substantially reduces artifacts due to aliasing emerging from independent modifications of subband signals, for example when using a filter bank as a spectral equalizer. The method is preferably implemented in software, running on a standard PC or a digital signal processor (DSP), but can also be hardcoded on a custom chip.

Abstract: An apparatus and method are disclosed for filtering and performing high frequency reconstruction of an audio signal. The apparatus includes an analysis filter bank, a phase shifter, a high frequency reconstructor, and a synthesis filter bank. The analysis filterbank receives real-valued time domain input audio samples and generates complex valued subband samples. The phase shifter shifts a phase of the complex-valued subband samples by an arbitrary amount. The high frequency reconstructor modifies at least some of the complex valued subband samples. A phase shifter unshifts a phase of the modified complex-valued subband samples by the arbitrary amount. The synthesis filter bank receives the modified complex valued subband samples and generates time domain output audio samples. The analysis filter bank comprises analysis filters that are complex exponential modulated versions of a prototype filter with an arbitrary phase shift.

Abstract: An apparatus and method are disclosed for filtering and performing high frequency reconstruction of an audio signal. The apparatus includes an analysis filter bank, a phase shifter, a high frequency reconstructor, and a synthesis filter bank. The analysis filterbank receives real-valued time domain input audio samples and generates complex valued subband samples. The phase shifter shifts a phase of the complex-valued subband samples by an arbitrary amount. The high frequency reconstructor modifies at least some of the complex valued subband samples. A phase shifter unshifts a phase of the modified complex-valued subband samples by the arbitrary amount. The synthesis filter bank receives the modified complex valued subband samples and generates time domain output audio samples. The analysis filter bank comprises analysis filters that are complex exponential modulated versions of a prototype filter with an arbitrary phase shift.

Abstract: An apparatus and method are disclosed for filtering and performing high frequency reconstruction of an audio signal. The apparatus includes an analysis filter bank, a phase shifter, a high frequency reconstructor, and a synthesis filter bank. The analysis filterbank receives real-valued time domain input audio samples and generates complex valued subband samples. The phase shifter shifts a phase of the complex-valued subband samples by an arbitrary amount. The high frequency reconstructor modifies at least some of the complex valued subband samples. A phase shifter unshifts a phase of the modified complex-valued subband samples by the arbitrary amount. The synthesis filter bank receives the modified complex valued subband samples and generates time domain output audio samples. The analysis filter bank comprises analysis filters that are complex exponential modulated versions of a prototype filter with an arbitrary phase shift.

Abstract: An apparatus and method are disclosed for filtering and performing high frequency reconstruction of an audio signal. The apparatus includes an analysis filter bank, a phase shifter, a high frequency reconstructor, and a synthesis filter bank. The analysis filterbank receives real-valued time domain input audio samples and generates complex valued subband samples. The phase shifter shifts a phase of the complex-valued subband samples by an arbitrary amount. The high frequency reconstructor modifies at least some of the complex valued subband samples. A phase shifter unshifts a phase of the modified complex-valued subband samples by the arbitrary amount. The synthesis filter bank receives the modified complex valued subband samples and generates time domain output audio samples. The analysis filter bank comprises analysis filters that are complex exponential modulated versions of a prototype filter with an arbitrary phase shift.