An audio encoder comprises a multi-channel receiver which receives an M-channel audio signal where M>2. A down-mix processor down-mixes the M-channel audio signal to a first stereo signal and associated parametric data and a spatial processor modifies the first stereo signal to generate a second stereo signal in response to the associated parametric data and spatial parameter data for a binaural perceptual transfer function, such as a Head Related Transfer Function (HRTF). The second stereo signal is a binaural signal and may specifically be a (3D) virtual spatial signal. An output data stream comprising the encoded data and the associated parametric data is generated by an encode processor and an output processor. The HRTF processing may allow the generation of a (3D) virtual spatial signal by conventional stereo decoders. A multi-channel decoder may reverse the process of the spatial processor to generate an improved quality multi-channel signal.

Multiple virtual source locations may be defined for a volume within which audio objects can move. A set-up process for rendering audio data may involve receiving reproduction speaker location data and pre-computing gain values for each of the virtual sources according to the reproduction speaker location data and each virtual source location. The gain values may be stored and used during run time, during which audio reproduction data are rendered for the speakers of the reproduction environment. During run time, for each audio object, contributions from virtual source locations within an area or volume defined by the audio object position data and the audio object size data may be computed. A set of gain values for each output channel of the reproduction environment may be computed based, at least in part, on the computed contributions. Each output channel may correspond to at least one reproduction speaker of the reproduction environment.

Example techniques involve balancing bass response of a multiple driver playback device. An example playback device receives left and right channels of audio content and generates a center channel of the audio content by combining at least a portion of the left right channels. The playback device generates first and second side channels of the audio content by combining the center channel and a difference of the left channel and the right channel and combining the center channel and an inverse of the difference of the left channel and the right channel, respectively. The first and second side channels are attenuated by a filter with a given cutoff frequency. The center channel is amplified in proportion to the attenuation of the first side channel. The playback device plays back the first side channel, second side channel, and center channel according to respective radiation patterns having maximums aligned in respective directions.

Methods and systems encoding a stereo audio signal having a left channel and a right channel are disclosed. The system includes a downmixer for generating a downmix signal and a residual signal from the stereo audio signal in selected frequency bands representing only part of a used audio frequency range of the stereo audio signal, and a decision module for selecting, in a time variant manner, either left/right perceptual encoding or mid/side perceptual encoding. The system also includes a parameter estimator for estimating stereo parameters for reconstructing a stereo image of a portion of the stereo audio signal, and a perceptual encoder for performing either left/right perceptual encoding or mid/side perceptual encoding based on the selecting to generate an encoded output signal. Finally, the system includes a bitstream generator for creating a bitstream signal comprising the encoded output signal.

An encoding system encodes an N-channel audio signal (X), wherein N3, as a single-channel downmix signal (Y) together with dry and wet upmix parameters ({tilde over (C)}, {tilde over (P)}). In a decoding system, a decorrelating section outputs, based on the downmix signal, an (N1)-channel decorrelated signal (Z); a dry upmix section maps the downmix signal linearly in accordance with dry upmix coefficients (C) determined based on the dry upmix parameters; a wet upmix section populates an intermediate matrix based on the wet upmix parameters and knowing that the intermediate matrix belongs to a predefined matrix class, obtains wet upmix coefficients (P) by multiplying the intermediate matrix by a predefined matrix, and maps the decorrelated signal linearly in accordance with the wet upmix coefficients; and a combining section combines outputs from the upmix sections to obtain a reconstructed signal ({circumflex over (X)}) corresponding to the signal to be reconstructed.

An audio headset may receive a plurality of audio signals corresponding to plurality of surround sound channels. The headset may determine, via its audio processing circuitry, context and/or content of the audio signals. The audio processing circuitry may process the audio signals to generate stereo signals carrying one or more virtual surround channels, wherein the processing comprises automatically controlling, based on the context and the content of the audio signals, a simulated acoustic environment of the virtual surround channels.

An apparatus for generating one or more audio channels is provided. The apparatus includes a metadata decoder for receiving one or more compressed metadata signals. Each of the one or more compressed metadata signals includes a plurality of first metadata samples. The metadata decoder is configured to generate one or more reconstructed metadata signals and to generate each of the second metadata samples of each reconstructed metadata signal of the one or more reconstructed metadata signals depending on at least two of the first metadata samples of the reconstructed metadata signal. The apparatus includes an audio channel generator for generating the one or more audio channels depending on the one or more audio object signals and depending on the one or more reconstructed metadata signals. An apparatus for generating encoded audio information including one or more encoded audio signals and one or more compressed metadata signals is provided.

An apparatus for generating one or more audio channels is provided. The apparatus comprises a metadata decoder for generating one or more reconstructed metadata signals from one or more processed metadata signals depending on a control signal, wherein each of the one or more reconstructed metadata signals indicates information associated with an audio object signal of one or more audio object signals, wherein the metadata decoder is configured to generate the one or more reconstructed metadata signals by determining a plurality of reconstructed metadata samples for each of the one or more reconstructed metadata signals. The apparatus comprises an audio channel generator for generating the one or more audio channels depending on the one or more audio object signals and depending on the one or more reconstructed metadata signals. The metadata decoder is configured to receive a plurality of processed metadata samples of each of the one or more processed metadata signals. The metadata decoder is configured to receive the control signal.

Methods and systems are provided for audio devices with enhanced directional operations. A user of an audio system may be prompted to provide an audio input. Once received, the audio input may be processed, and based on processing of the audio input positioning related information associated with the user may be generated. Outputting of an audio output in the audio system may then be controlled based on the positioning related information. Controlling the outputting of the audio output may include configuring at least one audio output related parameter or function for optimizing directionality of the audio output based on the positioning related information.

An audio signal processing method. The audio signal processing method includes: acquiring a first stereo audio signal; splitting the first stereo audio signal into 5.1-channel audio signals; obtaining processed 5.1-channel audio signals by processing the 5.1-channel audio signals based on a speaker box parameter of a three-dimensional surround 5.1-channel virtual speaker box; and synthesizing the processed 5.1-channel audio signals into a second stereo audio signal.

An audio signal processing method. The audio signal processing method includes: acquiring a first stereo audio signal; splitting the first stereo audio signal into 5.1-channel audio signals; obtaining processed 5.1-channel audio signals by processing the 5.1-channel audio signals based on a speaker box parameter of a three-dimensional surround 5.1-channel virtual speaker box; and synthesizing the processed 5.1-channel audio signals into a second stereo audio signal.