Abstract: A method of down-mixing a multi-channel audio signal is provided. The method including restoring sub-band Pulse Coded Modulation (PCM) samples for each channel of the multi-channel audio signal by decoding the multi-channel audio-signal and then dequantizing a sub-band coded multi-channel audio signal, scaling the restored sub-band PCM samples for each channel with a coefficient corresponding to a down-mixing configuration, generating sub-band PCM samples corresponding to predetermined channels by down-mixing the scaled sub-band PCM samples for each channel into the predetermined channels, and performing inverse sub-band filtering on the generated sub-band PCM samples corresponding to the predetermined channels.

Abstract: A device for processing an audio signal, wherein the device comprises a detection unit adapted for detecting a widening state of the audio signal, and a widening modification unit adapted for modifying a widening characteristic of the audio signal depending on the detected widening state of the audio signal.

Abstract: A system and a method for coding by principal component analysis (PCA) of a multi-channel audio signal comprising the following steps: decomposing at least two channels (L, R) of said audio signal into a plurality of frequency sub-bands (I(b1), . . . , I(bN), r(b1), . . . , r(bN)), calculating at least one transformation parameter (?(b1), . . . , ?(bN)) as a function of at least some of said plurality of frequency sub-bands, transforming at least some of said plurality of frequency sub-bands into a plurality of frequency sub-components as a function of said at least one transformation parameter (?(b1), . . . , ?(bN)), said plurality of frequency sub-components comprising principal frequency sub-components (CP(b1), . . . , CP(bN)), combining at least some of said principal frequency sub-components (CP(b1), . . . , CP(bN)) in order to form a principal component (CP), and defining a coded audio signal (SC) representing said multi-channel audio signal (C1, . . .

Abstract: Provided is an apparatus and method for coding and decoding multi-object audio signals with various channels and providing backward compatibility with a conventional spatial audio coding (SAC) bitstream. The apparatus includes: an audio object coding unit for coding audio-object signals inputted to the coding apparatus based on a spatial cue and creating rendering information for the coded audio-object signals, where the rendering information provides a coding apparatus including spatial cue information for audio-object signals; channel information of the audio-object signals; and identification information of the audio-object signals, and used in coding and decoding of the audio signals.

Abstract: A system for decoding a stereo multiplex signal, including one or more devices operable to convert the stereo multiplex signal into a sum signal (L+R) and a difference signal (L?R). The sum signal and the difference signal may be derived from a left stereo signal (L) and right stereo signal (R). The system may also be operable to determine a first transfer function HL(f) and a second transfer function (HR(f)) from the sum signal (L+R) and the difference signal (L?R). Further, the system may be operable to filter the sum signal (L+R) according to the first transfer function to provide the left stereo signal (L), and filter the sum signal (L+R) according to the second transfer function to provide the right stereo signal (R).

Abstract: The invention provides methods and devices for stereo encoding and decoding using complex prediction in the frequency domain. In one embodiment, a decoding method, for obtaining an output stereo signal from an input stereo signal encoded by complex prediction coding and comprising first frequency-domain representations of two input channels, comprises the upmixing steps of: (i) computing a second frequency-domain representation of a first input channel; and (ii) computing an output channel on the basis of the first and second frequency-domain representations of the first input channel, the first frequency-domain representation of the second input channel and a complex prediction coefficient. The upmixing can be suspended responsive to control data.

Abstract: The present invention relates to a signal processing apparatus and a signal processing method, an encoder and an encoding method, a decoder and a decoding method, and a program capable of reproducing music signal having a better sound quality by expansion of frequency band. An encoder sets an interval including 16 frames as interval section to be processed, outputs high band encoded data for obtaining the high band component of an input signal and low band encoded data obtained by encoding the low band signal of the input signal for each section to be processed. In this case, for each frame, a coefficient used in estimation of the high band component is selected and the section to be processed is divided into continuous frame segments including continuous frames from which the coefficient with the same section to be processed is selected.

Abstract: There is provided a playback method for decode-processing and playing back coded audio data which is transmitted with necessary stereo process information required for a stereo process intermittently multiplexed into coded information of a monaural audio signal. The playback method includes a first step of outputting stereo audio signals using the monaural audio signal if the necessary stereo process information is not supplied; a second step of starting updating stereo variables within filters, and outputting the stereo audio signals using the monaural audio signal until all the state variables are updated, if the necessary stereo process information is supplied; and a third step of performing the stereo process based on stereo process information acquired by the necessary stereo process information, on the monaural audio signal to generate and output stereo audio signals, if all the state variables within the filters are updated.

Abstract: A system and a method for the scalable coding of a multi-channel audio signal comprising a principal component analysis (PCA) transformation of at least two channels (L, R) of the audio signal into a principal component (CP) and at least one residual sub-component (r) by rotation defined by a transformation parameter (?), comprising the following steps: formation of a frequency subband-based residual structure (Sfr) on the basis of the at least one residual sub-component (r), and definition of a coded audio signal (SC) comprising the principal component (CP), at least one residual structure (Sfr) of a frequency subband and the transformation parameter (?).

Abstract: The following coding scenario is addressed: A number of audio source signals need to be transmitted or stored for the purpose of mixing wave field synthesis, multi-channel surround, or stereo signals after decoding the source signals. The proposed technique offers significant coding gain when jointly coding the source signals, compared to separately coding them, even when no redundancy is present between the source signals. This is possible by considering statistical properties of the source signals, the properties of mixing techniques, and spatial hearing. The sum of the source signals is transmitted plus the statistical properties of the source signals which mostly determine the perceptually important spatial cues of the final mixed audio channels. Source signals are recovered at the receiver such that their statistical properties approximate the corresponding properties of the original source signals. Subjective evaluations indicate that high audio quality is achieved by the proposed scheme.

Abstract: Soundfield signals such as e.g. Ambisonics carry a representation of a desired sound field. The Ambisonics format is based on spherical harmonic decomposition of the soundfield, and Higher Order Ambisonics uses spherical harmonics of at least 2nd order. However, commonly used loudspeaker setups are irregular and lead to problems in decoder design, A method for improved decoding an audio soundfield representation for audio playback comprises calculating a panning function using a geometrical method based on the positions of a plurality of loudspeakers and a plurality of source directions, calculating a mode matrix from the loudspeaker positions, calculating a pseudo-inverse mode matrix and decoding the audio soundfield representation. The decoding is based on a decode matrix that is obtained from the panning function and the pseudo-inverse mode matrix.

Abstract: Disclosed is an object based audio contents generating/playing apparatus. The object based audio contents generating/playing apparatus may include an object audio signal obtaining unit to obtain a plurality of object audio signals by recording a plurality of sound source signals, a recording space information obtaining unit to obtain recording space information with respect to a recording space of the plurality of sound source signals, a sound source location information obtaining unit to obtain sound location information of the plurality of sound source signals, and an encoding unit to generate object based audio contents by encoding at least one of the plurality of object audio signals, the recording space information, and the sound source location information, thereby enabling the object based audio contents to be played using at least one of a WFS scheme and a multi-channel surround scheme regardless of a reproducing environment of the audience.

Abstract: An apparatus for processing a media signal and method thereof are disclosed, by which the media signal can be converted to a surround signal by using spatial information of the media signal. The present invention provides a method of processing a signal, the method comprising of extracting a downmix signal from a bitstream; generating a decorrelated downmix signal by applying a decorrelator to the downmix signal; and generating a surround signal by applying rendering information for generating a surround signal to the downmix signal and the decorrelated downmix signal.

Abstract: A frequency domain method for phase-amplitude matrixed surround decoding of 2-channel stereo recordings and soundtracks, based on spatial analysis of 2-D or 3-D directional cues in the recording and re-synthesis of these cues for reproduction on any headphone or loudspeaker playback system.

Abstract: A first matrix (W(k)) indicating frequency characteristics of a separation filter is calculated from input signals of a plurality of channels. A second matrix (Ws(k)) is calculated by using the restriction coefficients (Ci(k)) for restricting the separation filter and the first matrix, and separation filter coefficients (wsij(s)) are calculated by using the second matrix. With use of the separation filter coefficients, separation signals (ysi(t)) are then calculated from the input signals. A third matrix (Ws?1(k)) is then calculated by transforming the second matrix into an inverse matrix at each frequency, and reproduction filter coefficients (a?I1(s), a?I2(s)) are calculated by using the third matrix. With use of the reproduction filter coefficients, the synthesized signal of each channel is calculated by using the separation signals.

Abstract: Audio encoding method and device comprising the transmission, in addition to the data representing a frequency-limited signal, of information relating to a temporal filter that is to be applied to the entire enhanced signal, both in its transmitted low-frequency part and in its reconstituted high-frequency part. The application of this filter for reshaping the reconstituted high-frequency part and the correction of compression artefacts present in the transmitted low-frequency part. In this way, the application of the temporal filter, simple and inexpensive, to all or part of the reconstituted signal, makes it possible to obtain a signal of good perceived quality.

Abstract: In summary, this application describes a psycho-acoustically motivated, parametric description of the spatial attributes of multichannel audio signals. This parametric description allows strong bitrate reductions in audio coders, since only one monaural signal has to be transmitted, combined with (quantized) parameters which describe the spatial properties of the signal. The decoder can form the original amount of audio channels by applying the spatial parameters. For near-CD-quality stereo audio, a bitrate associated with these spatial parameters of 10 kbit/s or less seems sufficient to reproduce the correct spatial impression at the receiving end.

Abstract: A binaural cue coding scheme involving one or more object-based cue codes, wherein an object-based cue code directly represents a characteristic of an auditory scene corresponding to the audio channels, where the characteristic is independent of number and positions of loudspeakers used to create the auditory scene. Examples of object-based cue codes include the angle of an auditory event, the width of the auditory event, the degree of envelopment of the auditory scene, and the directionality of the auditory scene.

Abstract: An system, method, and method of encoding/decoding a multi-channel audio signal, including a decoding level generation unit producing decoding-level information that helps a bitstream including a number of audio channel signals and space information to be decoded into a number of audio channel signals, wherein the space information includes information about magnitude differences and/or similarities between channels, and an audio decoder decoding the bitstream according to the decoding-level information. Accordingly, even a single input bitstream can be decoded into a suitable number of channels depending on the type of a speaker configuration used. Scalable channel decoding can be achieved by partially decoding an input bitstream. In the scalable channel decoding, a decoder may set decoding levels and outputs audio channel signals according to the decoding levels, thereby reducing decoding complexity.

Abstract: An apparatus for extracting a direct and/or ambience signal from a downmix signal and spatial parametric information, the downmix signal and the spatial parametric information representing a multi-channel audio signal having more channels than the downmix signal, wherein the spatial parametric information has inter-channel relations of the multi-channel audio signal, is described. The apparatus has a direct/ambience estimator and a direct/ambience extractor. The direct/ambience estimator is configured for estimating a level information of a direct portion and/or an ambient portion of the multi-channel audio signal based on the spatial parametric information. The direct/ambience extractor is configured for extracting a direct signal portion and/or an ambient signal portion from the downmix signal based on the estimated level information of the direct portion or the ambient portion.

Abstract: A digital audio interface may include two signal inputs to transmit audio data. A first signal line may carry digital serial audio data. The second signal line may carry a word clock signal to differentiate the serial audio data transmitted over the first signal line. In the case of stereo audio data, the word clock signal may correspond to a left-right clock signal and may differentiate audio data intended for a right channel from that intended for a left channel. The audio data may also be differentiated differently depending on the configuration, such as in the case that the transmitted audio data include audio for more than two channels. The word clock signal may be scaled to regenerate a bit clock signal used to encode the serial audio data over the first signal line. The encoding bit clock signal need not be transmitted.

Abstract: A method of encoding a multi-channel 3-dimensional (3D) audio signal mixed with a multi-channel 3D object signal is provided. The method includes: obtaining a location parameter indicating a virtual location of the multi-channel 3D object signal on a multi-channel speaker layout based on a gain value of the multi-channel 3D object signal for each channel; and encoding the multi-channel 3D audio signal and the location parameter.

Abstract: In summary, this application describes a psycho-acoustically motivated, parametric description of the spatial attributes of multichannel audio signals. This parametric description allows strong bitrate reductions in audio coders, since only one monaural signal has to be transmitted, combined with (quantized) parameters which describe the spatial properties of the signal. The decoder can form the original amount of audio channels by applying the spatial parameters. For near-CD-quality stereo audio, a bitrate associated with these spatial parameters of 10 kbit/s or less seems sufficient to reproduce the correct spatial impression at the receiving end.

Abstract: A method, an apparatus, and a system for encoding and decoding multi-channel signals are disclosed. The method for encoding multi-channel signals includes: determining the category of an index corresponding to a channel level difference (CLD) which needs to be quantized in a current frame; quantizing the CLD of at least one frequency band whose index category is the same as the determined category of the index in the current frame, and obtaining quantized data.

Abstract: An encoder and encoding method for use in a surround sound system wherein at least four audio input signals representing an original sound field are encoded into two channel signals and the encoded two channel signals are decoded into at least four audio output signals corresponding to the four audio input signals. The encoder includes matrix structure connected to receive the four audio input signals for encoding the four input signals into two channel output signals. The matrix structure is responsive to the four input signals for producing L and R output signals as follows: L=FL+kFR+jRL+jkRR R=FR+kFL?jRR?jkRL wherein k denotes a transformation or matrix constant having a value approximately 0.207 and j denotes a 90 degree phase shift.

Abstract: Embodiments of the present invention provide a stereo signal down-mixing method, encoding/decoding apparatus and system. The down-mixing method includes: converting a first channel time-domain signal and a second channel time-domain signal into a first channel frequency-domain signal and a second channel frequency-domain signal; obtaining a frequency-domain channel signal level difference and a frequency-domain channel signal phase difference between the two channel frequency-domain signals; for each frequency bin in each frequency band, using a function based on the frequency-domain channel signal level difference and frequency-domain channel signal phase difference to obtain a down-mixed signal phase that is located between phases of the two channel frequency-domain signals, and obtaining a down-mixed signal amplitude through calculation; and obtaining a frequency-domain down-mixed signal according to the phase and amplitude.

Abstract: A multi-channel signal decoding method is provided. A down-mixed signal representative of a multi-channel signal is decoded, and parameters representing characteristic relations between channels of the multi-channel signal are decoded. An additional parameter is estimated by using the decoded parameters, and the decoded down-mixed signal is up-mixed by using the decoded parameters and the estimated parameter so as to decode the multi-channel signal.

Abstract: An apparatus and method for encoding/decoding a multi-channel signal may be provided. The apparatus of encoding a multi-channel signal may insert information about whether to encode a phase parameter indicating phase information of a plurality of channels, included in the multi-channel signal, in a bitstream of the multi-channel signal. The apparatus of decoding a multi-channel signal may determine whether to up-mix a mono signal using the phase parameter based on the information about whether to encode.

Abstract: The present research relates to controlling rendering of multi-object or multi-channel audio signals. The present research provides a method and apparatus for controlling rendering of multi-object or multi-channel audio signals based on spatial cues in a process of decoding the multi-object or multi-channel audio signals. To achieve the purpose, the method suggested in the research controls rendering in a spatial cue domain in the process of decoding the multi-object or multi-channel audio signals.

Abstract: Provided are a method and apparatus for multi-channel de-correlation processing for cancelling a multi-channel acoustic echo. The method includes: dividing an input multi-channel audio signal into units of frames to form multi-channel audio signals in units of frames; analyzing eigen values and eigen vectors related to the multi-channel audio signals by using the multi-channel audio signals in units of frames every time contents are modified; and separating the multi-channel audio signals in units of frames into a plurality of signal component spaces by using the analyzed eigen values and eigen vectors.

Abstract: A method for processing an audio signal, comprising: receiving a downmix signal in time domain; if the downmix signal corresponds to a mono signal, bypassing the downmix signal; if the number of channel of the downmix signal corresponds to at least two, decomposing the downmix signal into a subband signal, and processing the subband signal using a downmix processing information, wherein the downmix processing information is estimated based on an object information and a mix information is disclosed.

Abstract: A method, medium, and apparatus encoding and/or decoding an audio signal to surround data. While encoding spatial information, which can up-mix an audio signal to a surround signal, to extension data, a length of a payload corresponding to the spatial information is encoded and a payload of the spatial information is decoded using the length of the payload. Accordingly, compatibility of the spatial information can be provided, and the spatial information can be transmitted by effectively embedding the spatial information.

Abstract: Disclosed is an apparatus and method for encoding and decoding a multichannel audio signal. The encoding apparatus may compute a weight matrix from a multichannel audio signal to be encoded, and may extract a base signal from the multichannel audio signal using the computed weight matrix.

Abstract: A method for encoding and decoding a digital audio signal composed of an original right-hand signal (SDO) and an original left-hand signal (SGO). The method combines the original right-hand signal (SDO) and the original left-hand signal (SGO) to obtain a single combined signal (SC), encodes the combined signal (SC) using a standard encoder to obtain a compressed combined signal (SCC), and decodes the compressed combined signal (SCC) using a standard decoder (8) to obtain a decompressed combined signal (SCD). After decoding, the method generates a reconstructed right-hand signal (SDR) and a reconstructed left-hand signal (SGR) from the decompressed combined signal (SCD), which are de-correlated from each other. Also, a treble-generating module enables the high-frequency component (SHF) of the right-hand (SDR) or left-hand (SGR) signals to be recreated, which signals had been deleted as a result of the compression.

Abstract: Provided are a multi-object audio encoding and decoding method and an apparatus thereof. The multi-object encoding method includes generating a down-mix signal and a residual signal by down-mixing a foreground audio object and a background audio object, and generating a bitstream including the down-mix signal and the residual signal.

Abstract: The present document relates to audio decoding and/or audio transcoding. In particular, the present document relates to a scheme for efficiently decoding a number M of audio channels from a bitstream comprising a higher number N of audio channels. In this context a method and system for merging a first and a second source set of spectral band replication (SBR) parameters to a target set of SBR parameters is described. The first and second source set comprise a first and second frequency band partitioning, respectively, which are different from one another. The first source set comprises a first set of energy related values associated with frequency bands of the first frequency band partitioning. The second source set comprises a second set of energy related values associated with frequency bands of the second frequency band partitioning. The target set comprises a target energy related value associated with an elementary frequency band.

Abstract: A method and circuit for deriving a set of multichannel audio signals from a conventional monaural or stereo audio signal uses an auxiliary multichannel spectral mapping data stream. Audio can be played back in stereo and multichannel formats from a conventional stereo signal on compact discs, FM radio, or other stereo or monaural delivery systems. The invention reduces the data rate needed for the transmission of multichannel digital audio.

Abstract: An audio signal decoder for providing an upmix signal representation on the basis of a downmix signal representation and an object-related parametric information and in dependence on a rendering information has an object parameter determinator. The object parameter determinator is configured to obtain inter-object-correlation values for a plurality of pairs of audio objects. The object parameter determinator is configured to evaluate a bitstream signaling parameter in order to decide whether to evaluate individual inter-object-correlation bitstream parameter values to obtain inter-object-correlation values for a plurality of pairs of related audio objects, or to obtain inter-object-correlation values for a plurality of pairs of related audio objects using a common inter-object-correlation bitstream parameter value.

Abstract: A decoding method of audio data is applied to an electronic device. The method includes: calculating difference values of the left and right channel audio signal values; determining time slots, wherein each of the first difference values exceeds a threshold value and a time length of the time slots exceeds a preset time; respectively multiplying the time slots with the left channel audio signal values and the right channel audio signal values to obtains and then making subtraction to obtain DM1˜n; finding a U shaped pattern or an inverse U shaped pattern which meets proportionality from the waveform of DM1˜n; and decoding the written symbol “0” or “1” according to the found U shaped pattern or inverse U shaped pattern.

Abstract: An encoding method and apparatus and a decoding method and apparatus are provided. The decoding method includes extracting a compatible down-mix signal optimized for a first multi-channel decoder from the input bitstream, converting the compatible down-mix signal to be optimized for a second multi-channel signal by performing a compatibility processing operation on the compatible down-mix signal, and generating a three-dimensional (3D) down-mix signal by performing a 3D rendering operation on the converted down-mix signal. Accordingly, it is possible to efficiently encode multi-channel signals with 3D effects and to adaptively restore and reproduce audio signals with optimum sound quality according to the characteristics of an audio reproduction environment.

Abstract: An apparatus for providing one or more adjusted parameters for a provision of an upmix signal representation on the basis of a downmix signal representation and a parametric side information associated with the downmix signal representation has a parameter adjuster. The parameter adjuster is configured to receive one or more parameters and to provide, on the basis thereof, one or more adjusted parameters. The parameter adjuster is configured to provide the one or more adjusted parameters in dependence on an average value of a plurality of parameter values, such that a distortion of the upmix signal representation caused by the use of non-optimal parameters is reduced at least for parameters deviating from optimal parameters by more than a predetermined deviation.

Abstract: An input multi-channel representation is converted into a different output multi-channel representation of a spatial audio signal, in that an intermediate representation of the spatial audio signal is derived, the intermediate representation having direction parameters indicating a direction of origin of a portion of the spatial audio signal; and in that the output multi-channel representation of the spatial audio signal is generated using the intermediate representation of the spatial audio signal.

Abstract: A binaural decoder for an MPEG surround stream, which decodes an MPEG surround stream into a stereo 3D signal, and a decoding method thereof. The method includes dividing a compressed audio stream and head related transfer function (HRTF) data into subbands, selecting predetermined subbands of the HRTF data divided into subbands and filtering the HRTF data to obtain the selected subbands, decoding the audio stream divided into subbands into a stream of multi-channel audio data with respect to subbands according to spatial additional information, and binaural-synthesizing the HRTF data of the selected subbands with the multi-channel audio data of corresponding subbands.

Abstract: A signal processing device includes a generation unit that generates a second signal from a first signal that is obtained by down mixing two signals; a mixing coefficient determination unit that determines, based on a value L and a value ?, a mixing degree for mixing the first signal and the second signal; and a mixing unit that mixes the first signal and the second signal based on the mixing degree determined by the mixing coefficient determination unit. The generation unit includes a first filter that generates a low frequency band signal in the second signal, from a low frequency band signal in the first signal; and a second filter that generates a high frequency band signal in the second signal, from a high frequency band signal in the first signal. The first filter is a filter unit which, for a complex-number signal, de-correlates an input signal and adds a reverberation component by using a delay unit and an all pass filter, and the processing unit is a filter unit different from the first filter.

Abstract: The processing efficiency of a process used to decode frames of an enhanced AC-3 bit stream is improved by processing each audio block in a frame only once. Audio blocks of encoded data are decoded in block order rather than in channel order. Exemplary decoding processes for enhanced bit stream coding features such as adaptive hybrid transform processing and spectral extension are disclosed.

Abstract: An apparatus for providing an upmix signal representation on the basis of a downmix signal representation and an object-related parametric information, which are included in a bitstream representation of an audio content, and in dependence on a rendering information, has a distortion limiter configured to adjust upmix parameters using a distortion control scheme to avoid or limit audible distortions which are caused by an inappropriate choice of rendering parameters. The distortion limiter is configured to obtain a distortion limitation control parameter, which is included in the bitstream representation of the audio content, and to adjust a distortion control scheme in dependence on the distortion limitation control parameter.

Abstract: A wireless earphone device capable of providing balanced stereo. The wireless headset includes a Bluetooth earphone device, an audio adaptor, and a stereo earphone device for giving balanced sounds on both left and right channels. When the Bluetooth earphone device and the stereo earphone device are connected with the audio adaptor respectively, an audio switching module of the Bluetooth earphone device determines to transmit stereo audio signal with first channel signal and second channel signal to the stereo earphone device through the audio adaptor. Otherwise, only one channel of the stereo audio signal is transmitted from the audio switching module to a mono speaker unit on the Bluetooth earphone device.

Abstract: A method, an apparatus, a computer readable storage medium configured with instructions for carrying out a method, and logic encoded in one or more computer-readable tangible medium to carry out actions. The method is to decode audio data that includes N.n channels to M.m decoded audio channels, including unpacking metadata and unpacking and decoding frequency domain exponent and mantissa data; determining transform coefficients from the unpacked and decoded frequency domain exponent and mantissa data; inverse transforming the frequency domain data; and in the case M<N, downmixing according to downmixing data, the downmixing carried out efficiently.

Abstract: A method, medium, and apparatus encoding and/or decoding an audio signal to surround data. While encoding spatial information, which can up-mix an audio signal to a surround signal, to extension data, a length of a payload corresponding to the spatial information is encoded and a payload of the spatial information is decoded using the length of the payload. Accordingly, compatibility of the spatial information can be provided, and the spatial information can be transmitted by effectively embedding the spatial information.

Abstract: Embodiments of systems and methods are described for providing backwards compatibility for legacy devices that are unable to natively render non-channel based audio objects. These systems and methods can also be beneficially used to produce a reduced set of audio objects for compatible object-based decoders with low computing resources.