Abstract: An audio signal is processed to extract key information by selecting (102) tonal components from the audio signal. A mask is then applied (104) to the selected tonal components to discard at least one tonal component. Note values of the remaining tonal components are determined (106) and mapped (108) to a single octave to obtain chroma values. The chroma values are accumulated (110) into a chromagram and evaluated (112).

Abstract: An audio signal is processed to extract key information by selecting (102) tonal components from the audio signal. A mask is then applied (104) to the selected tonal components to discard at least one tonal component. Note values of the remaining tonal components are determined (106) and mapped (108) to a single octave to obtain chroma values. The chroma values are accumulated (110) into a chromagram and evaluated (112).

Abstract: An audio encoder in which two or more preferably different encoders cooperate to generate a joint encoded audio signal. Encoding parameters of the two or more encoders are optimized in response to a measure of distortion of the joint encoded audio signal in accordance with a predetermined criterion. The distortion. measure is preferably a perceptual distortion measure. In one encoder embodiment comprising a sinusoidal and a waveform encoder, a constant total bit rate for each audio frame is distributed between the two encoders so as to minimize perceptual distortion for both the first and the second encoder. Other embodiments consider a set of encoding parameters that is larger than only those that minimize the perceptual distortion of the first encoder. In some embodiments, perceptual distortion may be minimized by optimizing encoding via optimizing entire encoding templates, i.e. a complex set of encoding parameters, for the separate encoders.

Abstract: The invention relates to an audio encoder and decoder and methods for audio encoding and decoding. In a preferred encoder embodiment an audio signal is encoded by deterministic encoder means to form a first encoded signal part. A spectrum of the audio signal is determined and represented by an excitation pattern, i.e. spectral values corresponding to human auditory filters, as a second encoded signal part. A masking curve is also extracted based on the excitation pattern, thus improving encoding efficiency in terms of bit rate. In a preferred decoder the first encoded signal part is decoded by deterministic decoder means. A noise generator uses the decoded first signal part together with the second signal part, i.e. the excitation pattern for the original audio signal, to generate a noise signal. The noise signal is then added to the first decoded signal part to form an output audio signal. At the decoder side the masking curve is also extracted based on the second encoded signal part, i.e.

Abstract: Multi-channel audio signals are coded into a monaural audio signal and information allowing to recover the multi-channel audio signal from the monaural audio signal and the information. The information is generated by determining a first portion of the information for a first frequency region of the multi-channel audio signal, and by determining a second portion of the information for a second frequency region of the multi-channel audio signal. The second frequency region is a portion of the first frequency region and thus is a sub-range of the first frequency region. The information is multi-layered enabling a scaling of the decoding quality versus bit rate.

Abstract: The invention provides coding (11) of an at least two-channel audio signal (L,R) by determining common frequencies (fcom) in the at least two channels (L,R) of the audio signal, which common frequencies occur in at least two of the at least two channels of the audio signal, and by representing respective sinusoidal components in respective channels at a given common frequency by a representation of the given common frequency (fcom) and a representation of respective amplitudes (A,?A) of the respective sinusoidal components at the given common frequency.

Abstract: Described is a transmission system comprising a transmitter for transmitting a narrowband audio signal to a receiver via a transmission channel. The receiver comprises a bandwidth extender (18) for generating a wideband audio signal from the narrowband audio signal. The bandwidth extender (18) comprises spectral folding means (30) or generating a spectrally folded audio signal (33) by spectrally folding at least part of the narrowband audio signal. The transmission system according to the invention is characterized in that the bandwidth extender (18) comprises a noise shaper (32) for generating a shaped noise signal (35) by shaping a noise signal (31) in accordance with at least part of the spectrally folded audio signal (33), and in that the bandwidth extender (18) further comprises a combiner (34) for combining the shaped noise signal (35) and the spectrally folded audio signal (33) into the wideband audio signal.