Abstract:
L'invention se rapporte à un procédé d'extension de bande de fréquence d'un signal audiofréquence lors d'un processus de décodage ou d'amélioration comportant une étape de décodage ou d'extraction, dans une première bande de fréquence dite bande basse, d'un signal d'excitation et des coefficients d'un filtre de prédiction linéaire. Le procédé comporte les étapes suivantes: - obtention d'un signal étendu (U HB2 (k), E403)) dans au moins une deuxième bande de fréquence supérieure à la première bande de fréquence à partir d'un signal d'excitation sur-échantillonné et étendu dans au moins une deuxième bande de fréquence (U HB1 (k), E401);- mise à l'échelle (E406) du signal étendu par un gain défini par sous-trame en fonction d'un ratio d'énergie d'une trame et d'une sous-trame; - filtrage (E404) dudit signal étendu mis à l'échelle par un filtre de prédiction linéaire dont les coefficients sont dérivés des coefficients du filtre de la bande basse. L'invention se rapporte également à un dispositif d'extension de bande de fréquence mettant en œuvre le procédé décrit et un décodeur comportant un tel dispositif.
Abstract:
The present invention provides methods and systems for narrow bandwidth digital processing of an input audio signal. Particularly, the present invention includes a high pass filter configured to filter the input audio signal. A first compressor then modulates the filtered signal in order to create a partially processed signal. In some embodiments, a clipping module further limits the gain of the partially processed signal. A splitter is configured to split the partially processed signal into a first signal and a second signal. A low pass filter is configured to filter the first signal. A pass through module is configured to adjust the gain of the second signal. A mixer then combines the filtered first signal and the gain-adjusted second signal in order to output a combined signal. In some embodiments, a tone control module further processes the combined signal, and a second compressor further modulates the processed signal.
Abstract:
A decoder for generating a frequency enhanced audio signal (120), comprises: a feature extractor (104) for extracting a feature from a core signal (100); a side information extractor (110) for extracting a selection side information associated with the core signal; a parameter generator (108) for generating a parametric representation for estimating a spectral range of the frequency enhanced audio signal (120) not defined by the core signal (100), wherein the parameter generator (108) is configured to provide a number of parametric representation alternatives (702, 704, 706, 708) in response to the feature (112), and wherein the parameter generator (108) is configured to select one of the parametric representation alternatives as the parametric representation in response to the selection side information (712 to 718); and a signal estimator (118) for estimating the frequency enhanced audio signal (120) using the parametric representation selected.
Abstract:
Eine Vorrichtung (100) zur Erzeugung eines frequenzverschobenen Audiosignals basierend auf einem Audioeingangssignal wird bereitgestellt. Die Vorrichtung (100) umfasst eine Schnittstelle (110) und eine Frequenzverschiebungseinheit (120). Die Schnittstelle (110) ist zum Empfang des Audioeingangssignals eingerichtet. Die Frequenzverschiebungseinheit (120) ist zur Erzeugung des frequenzverschobenen Audiosignals eingerichtet. Die Frequenzverschiebungseinheit (120) ist ferner dafür eingerichtet, einen der zweiten Subband- Werte basierend auf einem der ersten Subband- Werte so zu erzeugen, dass der zweite Phasenwinkel dieses zweiten Subband- Werts sich von dem ersten Phasenwinkel dieses ersten Subband- Werts um eine Phasenwinkel-Differenz unterscheidet, wobei die Phasenwinkel-Differenz von einer Frequenzinformation abhängt, die angibt, um welche Frequenzdifferenz das Audioeingangssignal zu verschieben ist, um das frequenzverschobene Audiosignal zu erhalten, und wobei die Phasenwinkel-Differenz von einer Frequenz- Bandbreite von einem der ersten Subbänder abhängt.
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:
대역폭 확장을 위한 고주파수 부호화/복호화 방법 및 장치가 개시된다. 대역폭 확장을 위한 고주파수 복호화방법은 가중치를 추정하는 단계; 및 랜덤 노이즈와 복호화된 저주파수 스펙트럼간에 상기 가중치를 적용해서 고주파수 여기신호를 생성하는 단계를 포함한다.
Abstract:
The present document relates to methods and systems for music information retrieval (MIR). In particular, the present document relates to methods and systems for extracting a chroma vector from an audio signal. A method (900) for determining a chroma vector (100) for a block of samples of an audio signal (301) is described. The method (900) comprises receiving (901) a corresponding block of frequency coefficients derived from the block of samples of the audio signal (301) from a core encoder (412) of a spectral band replication based audio encoder (410) adapted to generate an encoded bitstream (305) of the audio signal (301) from the block of frequency coefficients; and determining (904) the chroma vector (100) for the block of samples of the audio signal (301) based on the received block of frequency coefficients.
Abstract:
The present document relates to methods and systems for music information retrieval (MIR). In particular, the present document relates to methods and systems for extracting a chroma vector from an audio signal. A method (900) for determining a chroma vector (100) for a block of samples of an audio signal (301) is described. The method (900) comprises receiving (901) a corresponding block of frequency coefficients derived from the block of samples of the audio signal (301) from a core encoder (412) of a spectral band replication based audio encoder (410) adapted to generate an encoded bitstream (305) of the audio signal (301) from the block of frequency coefficients; and determining (904) the chroma vector (100) for the block of samples of the audio signal (301) based on the received block of frequency coefficients.