Abstract: The embodiments of the present invention improves conventional attenuation schemes by replacing constant attenuation with an adaptive attenuation scheme that allows more aggressive attenuation, without introducing audible change of signal frequency characteristics.

Abstract: Methods and arrangements in a codec for supporting bandwidth extension, BWE, of an harmonic audio signal. The method in the decoder part of the codec comprises receiving a plurality of gain values associated with a frequency band b and a number of adjacent frequency bands of band b. The method further comprises determining whether a reconstructed corresponding frequency band b? comprises a spectral peak. When the band b? comprises a spectral peak, a gain value associated with the band b? is set to a first value based on the received plurality of gain values; and otherwise the gain value is set to a second value based on the received plurality of gain values. The suggested technology enables bringing gain values into agreement with peak positions in a bandwidth extended frequency region.

Abstract: Methods and arrangements in a codec for supporting bandwidth extension, BWE, of an harmonic audio signal. The method in the decoder part of the codec comprises receiving a plurality of gain values associated with a frequency band b and a number of adjacent frequency bands of band b. The method further comprises determining whether a reconstructed corresponding frequency band b? comprises a spectral peak. When the band b? comprises a spectral peak, a gain value associated with the band b? is set to a first value based on the received plurality of gain values; and otherwise the gain value is set to a second value based on the received plurality of gain values. The suggested technology enables bringing gain values into agreement with peak positions in a bandwidth extended frequency region.

Abstract: A frame error concealment method based on frames including transform coefficient vectors including the following steps: It tracks sign changes between corresponding transform coefficients of predetermined sub-vectors of consecutive good stationary frames. It accumulates the number of sign changes in corresponding sub-vectors of a predetermined number of consecutive good stationary frames. It reconstructs an erroneous frame with the latest good stationary frame, but with reversed signs of transform coefficients in sub-vectors having an accumulated number of sign changes that exceeds a predetermined threshold.

Abstract: The embodiments of the present invention improves conventional attenuation schemes by replacing constant attenuation with an adaptive attenuation scheme that allows more aggressive attenuation, without introducing audible change of signal frequency characteristics.

Abstract: The embodiments of the present invention improves conventional attenuation schemes by replacing constant attenuation with an adaptive attenuation scheme that allows more aggressive attenuation, without introducing audible change of signal frequency characteristics.

Abstract: A frame error concealment method based on frames including transform coefficient vectors including the following steps: It tracks (S11) sign changes between corresponding transform coefficients of predetermined sub-vectors of consecutive good stationary frames. It accumulates (S12) the number of sign changes in corresponding sub-vectors of a predetermined number of consecutive good stationary frames. It reconstructs (S13) an erroneous frame with the latest good stationary frame, but with reversed signs of transform coefficients in sub-vectors having an accumulated number of sign changes that exceeds a predetermined threshold.

Abstract: An encoder for encoding frequency transform coefficients of a harmonic audio signal include the following elements: A peak locator configured to locate spectral peaks having magnitudes exceeding a predetermined frequency dependent threshold. A peak region encoder configured to encode peak regions including and surrounding the located peaks. A low-frequency set encoder configured to encode at least one low-frequency set of coefficients outside the peak regions and below a crossover frequency that depends on the number of bits used to encode the peak regions. A noise-floor gain encoder configured to encode a noise-floor gain of at least one high-frequency set of not yet encoded coefficients outside the peak regions.

Abstract: Methods and arrangements in a codec for supporting bandwidth extension, BWE, of an harmonic audio signal. The method in the decoder part of the codec comprises receiving a plurality of gain values associated with a frequency band b and a number of adjacent frequency bands of band b. The method further comprises determining whether a reconstructed corresponding frequency band b? comprises a spectral peak. When the band b? comprises a spectral peak, a gain value associated with the band b? is set to a first value based on the received plurality of gain values; and otherwise the gain value is set to a second value based on the received plurality of gain values. The suggested technology enables bringing gain values into agreement with peak positions in a bandwidth extended frequency region.

Abstract: A spectrum filler for filling non-coded residual sub-vectors of a transform coded audio signal includes a sub-vector compressor configured to compress actually coded residual sub-vectors. A sub-vector rejecter is configured to reject compressed residual sub-vectors that do not fulfill a predetermined sparseness criterion. A sub-vector collector is configured to concatenate the remaining compressed residual sub-vectors to form a first virtual codebook. A coefficient combiner is configured to combine pairs of coefficients of the first virtual codebook to form a second virtual codebook. A sub-vector filler is configured to fill non-coded residual sub-vectors below a predetermined frequency with coefficients from the first virtual codebook, and to fill non-coded residual sub-vectors above the predetermined frequency with coefficients from the second virtual codebook.

Abstract: A frame error concealment method based on frames including transform coefficient vectors including the following steps: It tracks (S11) sign changes between corresponding transform coefficients of predetermined sub-vectors of consecutive good stationary frames. It accumulates (S12) the number of sign changes in corresponding sub-vectors of a predetermined number of consecutive good stationary frames. It reconstructs (S13) an erroneous frame with the latest good stationary frame, but with reversed signs of transform coefficients in sub-vectors having an accumulated number of sign changes that exceeds a predetermined threshold.

Abstract: An encoder (20) for encoding frequency transform coefficients (Y(k)) of a harmonic audio signal include the following elements: A peak locator (22) configured to locate spectral peaks having magnitudes exceeding a predetermined frequency dependent threshold. A peak region encoder (24) configured to encode peak regions including and surrounding the located peaks. A low-frequency set encoder (26) configured to encode at least one low-frequency set of coefficients outside the peak regions and below a crossover frequency that depends on the number of bits used to encode the peak regions. A noise-floor gain encoder (28) configured to encode a noise-floor gain of at least one high-frequency set of not yet encoded coefficients outside the peak regions.

Abstract: Methods and arrangements in a codec for supporting bandwidth extension, BWE, of an harmonic audio signal. The method in the decoder part of the codec comprises receiving a plurality of gain values associated with a frequency band b and a number of adjacent frequency bands of band b. The method further comprises determining whether a reconstructed corresponding frequency band b? comprises a spectral peak. When the band b? comprises a spectral peak, a gain value associated with the band b? is set to a first value based on the received plurality of gain values; and otherwise the gain value is set to a second value based on the received plurality of gain values. The suggested technology enables bringing gain values into agreement with peak positions in a bandwidth extended frequency region.

Abstract: A spectrum filler for filling non-coded residual sub-vectors of a transform coded audio signal includes a sub-vector compressor (42) configured to compress actually coded residual sub-vectors. A sub-vector rejecter (44) is configured to reject compressed residual sub-vectors that do not fulfill a predetermined sparseness criterion. A sub-vector collector (46) is configured to concatenate the remaining compressed residual sub-vectors to form a first virtual codebook (VC1). A coefficient combiner (48) is configured to combine pairs of coefficients of the first virtual codebook (VC1) to form a second virtual codebook (VC2). A sub-vector filler (50) is configured to fill non-coded residual sub-vectors below a predetermined frequency with coefficients from the first virtual codebook (VC1), and to fill non-coded residual sub-vectors above the predetermined frequency with coefficients from the second virtual codebook (VC2).

Abstract: The embodiments of the present invention improves conventional attenuation schemes by replacing constant attenuation with an adaptive attenuation scheme that allows more aggressive attenuation, without introducing audible change of signal frequency characteristics.

Abstract: The embodiments of the present invention improves conventional attenuation schemes by replacing constant attenuation with an adaptive attenuation scheme that allows more aggressive attenuation, without introducing audible change of signal frequency characteristics.

Abstract: An audio classifier for frame based audio signal classification includes a feature extractor configured to determine, for each of a predetermined number of consecutive frames, feature measures representing at least the following features: auto correlation, frame signal energy, inter-frame signal energy variation. A feature measure comparator is configured to compare each determined feature measure to at least one corresponding predetermined feature interval. A frame classifier is configured to calculate, for each feature interval, a fraction measure representing the total number of corresponding feature measures that fall within the feature interval, and to classify the latest of the consecutive frames as speech if each fraction measure lies within a corresponding fraction interval, and as non-speech otherwise.

Abstract: A frame error concealment method based on frames including transform coefficient vectors including the following steps: It tracks (S11) sign changes between corresponding transform coefficients of predetermined sub-vectors of consecutive good stationary frames. It accumulates (S12) the number of sign changes in corresponding sub-vectors of a predetermined number of consecutive good stationary frames. It reconstructs (S13) an erroneous frame with the latest good stationary frame, but with reversed signs of transform coefficients in sub-vectors having an accumulated number of sign changes that exceeds a predetermined threshold.

Abstract: Methods and arrangements in a codec for supporting bandwidth extension, BWE, of an harmonic audio signal. The method in the decoder part of the codec comprises receiving a plurality of gain values associated with a frequency band b and a number of adjacent frequency bands of band b. The method further comprises determining whether a reconstructed corresponding frequency band b? comprises a spectral peak. When the band b? comprises a spectral peak, a gain value associated with the band b? is set to a first value based on the received plurality of gain values; and otherwise the gain value is set to a second value based on the received plurality of gain values. The suggested technology enables bringing gain values into agreement with peak positions in a bandwidth extended frequency region.

Abstract: An encoder (20) for encoding frequency transform coefficients (Y(k)) of a harmonic audio signal include the following elements: A peak locator (22) configured to locate spectral peaks having magnitudes exceeding a predetermined frequency dependent threshold. A peak region encoder (24) configured to encode peak regions including and surrounding the located peaks. A low-frequency set encoder (26) configured to encode at least one low-frequency set of coefficients outside the peak regions and below a crossover frequency that depends on the number of bits used to encode the peak regions. A noise-floor gain encoder (28) configured to encode a noise-floor gain of at least one high-frequency set of not yet encoded coefficients outside the peak regions.