Decorrelation of signals in audio data processing system

FIELD: data processing.

SUBSTANCE: invention relates to signal processing. Method of processing audio data includes receiving from a bit stream audio data, corresponding to a row of audio channels, application of decorrelation process to some of audio data, wherein decorrelation process involves using a decorrelation algorithm, active completely on real-valued coefficients.

EFFECT: reduced complexity of coding and decoding algorithms owing to decorrelation of only real-valued coefficients.

16 cl, 37 dwg

 



 

Same patents:

FIELD: physics, acoustics.

SUBSTANCE: invention relates to audio processing and particularly to decomposing audio signals into different components. A device for decomposing an input signal, having at least three input channels, comprises a downmixer for downmixing the input signal to obtain a downmixed signal having fewer channels, an analyser for analysing the downmixed signal to obtain an analysis result which is forwarded to a signal processor for processing the input signal or the signal derived from the input signal in order to obtain a decomposed signal.

EFFECT: high accuracy of reproducing stereo sound.

15 cl, 16 dwg

FIELD: physics, acoustics.

SUBSTANCE: invention relates to audio processing, particularly to decomposition of audio signals into different components, for example, differently detectable components. An apparatus for decomposing a signal having at least three channels comprises an analyser (16) for analysing a similarity between two channels of an analysed signal related to the signal having at least two analysed channels, wherein the analyser is configured to use a pre-calculated frequency-dependent similarity curve as a reference curve to determine the analysis result. The signal processor (20) processes the analysed signal or a signal derived from the analysed signal or a signal, from which the analysed signal is derived using the analysis result to obtain a decomposed signal.

EFFECT: decomposing a signal using a pre-calculated frequency-dependent similarity curve as a reference curve.

15 cl, 16 dwg

FIELD: physics.

SUBSTANCE: invention discloses perfected tools for author development and presentation of sound playback data. Some said tools allow combine said data for wide range of playback means. Playback data can be individually developed by creation of metadata for audio objects. Said metadata can be created with reference to zones of loudspeakers. Data of audio playback can be reproduced in compliance with loudspeakers arrangement for particular playback medium.

EFFECT: simplified computer processing of 3D sound.

42 cl, 47 dwg

FIELD: physics, acoustics.

SUBSTANCE: invention relates to encoding and decoding an audio signal in which audio samples for each object audio signal may be localised in any required position. In the method and device for encoding an audio signal and in the method and device for decoding an audio signal, audio signals may be encoded or decoded such that audio samples may be localised in any required position for each object audio signal. The method of decoding an audio signal includes extracting from the audio signal a downmix signal and object-oriented additional information; generating channel-oriented additional information based on the object-oriented additional information and control information for reproducing the downmix signal; processing the downmix signal using a decorrelated channel signal; and generating a multichannel audio signal using the processed downmix signal and the channel-oriented additional information.

EFFECT: high accuracy of reproducing object audio signals.

7 cl, 20 dwg

FIELD: physics, acoustics.

SUBSTANCE: invention relates to means of encoding audio signals and related spatial information in a format which is independent of the playback scheme. A first set of audio signals is assigned to a first group. The first group is encoded as a set of mono audio tracks with associated metadata describing the direction of the signal source of each track relative to the recording position and the initial playback time thereof. A second set of audio signals is assigned to a second group. The second group is encoded as at least one set of ambisonic tracks of a given order and a mixture of orders. Two groups of tracks comprising the first and second sets of audio signals are generated.

EFFECT: providing a technique capable of presenting spatial audio content independent of the exhibition method.

26 cl, 11 dwg

FIELD: physics, acoustics.

SUBSTANCE: invention relates to a surround sound system. multi-channel spatial signal comprising at least one surround channel is received. Ultrasound is emitted towards a surface to reach a listening position via reflection of said surface. The ultrasound signal may specifically reach the listening position from the side, above or behind of a nominal listener. A first drive unit generates a drive signal for the directional ultrasound transducer from the surround channel. The use of an ultrasound transducer for providing the surround sound signal provides an improved spatial experience while allowing the speaker to be located, for example, in front of the user. An ultrasound beam is much narrower and well defined than conventional audio beams and can therefore be better directed to provide the desired reflections. In some scenarios, the ultrasound transducer may be supplemented by an audio range loudspeaker.

EFFECT: high quality of reproducing audio and high efficiency of the surround sound system.

12 cl, 11 dwg

FIELD: physics, acoustics.

SUBSTANCE: binaural rendering of a multi-channel audio signal into a binaural output signal is described. The multi-channel audio signal includes a stereo downmix signal (18) into which a plurality of audio signals are downmixed; and side information includes downmix information (DMG, DCLD), indicating for each audio signal, to what degree the corresponding audio signal was mixed in the first channel and second channel of the stereo downmix signal (18), respectively, as well as object level information of the plurality of audio signals and inter-object cross correlation information, describing similarity between pairs of audio signals of the plurality of audio signals. Based on a first rendering prescription, a preliminary binaural signal (54) is computed from the first and second channels of the stereo downmix signal (18). A decorrelated signal (Xdn,k) is generated as an perceptual equivalent to a mono downmix (58) of the first and second channels of the stereo downmix signal (18) being, however, decoded to the mono downmix (58).

EFFECT: improved binaural rendering while eliminating restrictions with respect to free generation of a downmix signal from original audio signals.

11 cl, 6 dwg, 3 tbl

FIELD: physics, acoustics.

SUBSTANCE: invention relates to processing signals in an audio frequency band. The apparatus for generating at least one output audio signal representing a superposition of two different audio objects includes a processor for processing an input audio signal to provide an object representation of the input audio signal, where that object representation can be generated by parametrically guided approximation of original objects using an object downmix signal. An object manipulator individually manipulates objects using audio object based metadata relating to the individual audio objects to obtain manipulated audio objects. The manipulated audio objects are mixed using an object mixer for finally obtaining an output audio signal having one or multi-channel signals depending on a specific rendering setup.

EFFECT: providing efficient audio signal transmission rate.

14 cl, 17 dwg

FIELD: radio engineering, communication.

SUBSTANCE: described is a device for generating a binaural signal based on a multi-channel signal representing a plurality of channels and intended for reproduction by a speaker system, wherein each virtual sound source position is associated to each channel. The device includes a correlation reducer for differently converting, and thereby reducing correlation between, at least one of a left and a right channel of the plurality of channels, a front and a rear channel of the plurality of channels, and a centre and a non-centre channel of the plurality of channels, in order to obtain an inter-similarity reduced combination of channels; a plurality of directional filters, a first mixer for mixing output signals of the directional filters modelling the acoustic transmission to the first ear canal of the listener, and a second mixer for mixing output signals of the directional filters modelling the acoustic transmission to the second ear canal of the listener. Also disclosed is an approach where centre level is reduced to form a downmix signal, which is further transmitted to a processor for constructing an acoustic space. Another approach involves generating a set of inter-similarity reduced transfer functions modelling the ear canal of the person.

EFFECT: providing an algorithm for generating a binaural signal which provides stable and natural sound of a record in headphones.

33 cl, 14 dwg

FIELD: information technology.

SUBSTANCE: method comprises estimating a first wave representation comprising a first wave direction measure characterising the direction of a first wave and a first wave field measure being related to the magnitude of the first wave for the first spatial audio stream, having a first audio representation comprising a measure for pressure or magnitude of a first audio signal and a first direction of arrival of sound; estimating a second wave representation comprising a second wave direction characterising the direction of the second wave and a second wave field measure being related to the magnitude of the second wave for the second spatial audio stream, having a second audio representation comprising a measure for pressure or magnitude of a second audio signal and a second direction of arrival of sound; processing the first wave representation and the second wave representation to obtain a merged wave representation comprising a merged wave field measure, a merged direction of arrival measure and a merged diffuseness parameter; processing the first audio representation and the second audio representation to obtain a merged audio representation, and forming a merged audio stream.

EFFECT: high quality of a merged audio stream.

15 cl, 7 dwg

FIELD: physics, acoustics.

SUBSTANCE: invention relates to encoding an audio signal. An encoding method for encoding a sample sequence in a frequency domain which is derived from an audio signal in frames, the method comprising: an interval determination step of determining an interval T between samples from a set S of candidates for the interval T, the interval T corresponding to a periodicity of the audio signal or to an integer multiple of the fundamental frequency of the audio signal; an additional information generating step of encoding the interval T determined at the interval determination step to obtain additional information; and a sample sequence encoding step of encoding a rearranged sample to obtain a code sequence.

EFFECT: high quality of encoding an audio signal with a low bit-rate with less processing.

22 cl, 10 dwg

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to bandwidth expansion devices. An excitation signal based on an acoustic signal is generated; with that, the acoustic signal includes a variety of frequency components. A feature vector is distinguished out of the acoustic signal; with that, the feature vector includes at least one feature of a component in a frequency domain and at least one feature of a component in a time domain. At least one parameter of the spectrum shape is determined based on the feature vector; with that, at least one parameter of the spectrum shape corresponds to a sub-range signal containing frequency components that belong to an additional variety of frequency components. A signal of the sub-range is generated by the filtration of an excitation signal by means of a filter bank and weighing of a filtered excitation signal using at least one parameter of the spectrum shape.

EFFECT: technical result consists in the improvement of perception of an expanded acoustic signal.

21 cl, 10 dwg

FIELD: physics, acoustics.

SUBSTANCE: invention relates to systems for encoding audio signal sources. Provided is subband block-based harmonic transposition, where the time block of complex discrete values of subbands is processed by common phase modification. Superposition of multiple modified discrete values yields the resultant effect of limiting undesirable cross products, making it possible to use coarser frequency resolution and/or lesser degree of oversampling. In one embodiment, the invention further includes a window function suitable for use with cross product-enhanced, subband block-based HFR. A hardware embodiment may include an analysing filter unit (101), a control data-configurable subband processing module (102) and a synthesising filter unit (103).

EFFECT: efficient implementation of high-frequency reconstruction (HFR) through enhancement with cross products, where a new component with frequency QΩ+rΩ0 is generated based on existing components with frequencies Ω and Ω+Ω0.

63 cl, 9 dwg

FIELD: physics, computer engineering.

SUBSTANCE: present invention relates to signal processing means. An encoder sets an interval including 16 frames as interval section to be processed, outputs high-frequency band encoded data to obtain the high-frequency band component of an input signal and low-frequency band encoded data obtained by encoding the low-frequency 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-frequency 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. In addition, high-frequency band encoded data are produced which include data including information indicating the length of each continuous frame segment, information indicating the number of continuous frame segments included in the section to be processed and a coefficient index indicating the coefficient selected in each continuous frame segment.

EFFECT: improved sound quality with frequency band expansion.

23 cl, 51 dwg

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to signal processing means. The system receives an encoded low-frequency band signal and encoded energy information used for frequency shift of the encoded low-frequency band signal. The low-frequency band signal is decoded and energy suppression of the decoded signal is smoothed. The smoothed low-frequency band signal is frequency shifted to generate a high-frequency band signal. The low-frequency band signal and the high-frequency band signal are then merged and output.

EFFECT: high quality of the decoded signal.

20 cl, 14 dwg

FIELD: physics, computer engineering.

SUBSTANCE: present invention relates to means of encoding and decoding. An envelope predistortion link predistorts an envelope. A noise shaping link divides the predistorted envelope formed by envelope predistortion by a value greater than 1 and subtracts from the division result a noise shaping signal determined by information. A sampling link sets the subtraction result as a number of sampling bits and, based on said number of sampling bits, samples a normalised spectrum formed by spectrum normalisation. A multiplexing link multiplexes the information, sampled spectrum, formed by sampling the normalised spectrum, and the envelope. The present invention can applied, for example, to an encoding device which encodes an audio signal.

EFFECT: improved audio quality due to encoding audio signals.

14 cl, 31 dwg

FIELD: physics, computer engineering.

SUBSTANCE: present invention relates to means of encoding and decoding. An envelope predistortion link predistorts an envelope. A noise shaping link divides the predistorted envelope formed by envelope predistortion by a value greater than 1 and subtracts from the division result a noise shaping signal determined by information. A sampling link sets the subtraction result as a number of sampling bits and, based on said number of sampling bits, samples a normalised spectrum formed by spectrum normalisation. A multiplexing link multiplexes the information, sampled spectrum, formed by sampling the normalised spectrum, and the envelope. The present invention can applied, for example, to an encoding device which encodes an audio signal.

EFFECT: improved audio quality due to encoding audio signals.

14 cl, 31 dwg

FIELD: physics, computer engineering.

SUBSTANCE: invention relates to radio engineering and is intended for controlling an audio signal, including a transient event. The device comprises a unit for replacing a transient signal, configured to replace the transient part of a signal, which includes a transient event of an audio signal, with part of a replacement signal adapted to energy characteristics of the signal of one or more transient parts of the audio signal, or to the energy characteristic of the signal of the transient part of the signal to obtain an audio signal with a shorter transient process. The device also includes a signal processor configured to process an audio signal with a shorter transient process to obtain a processed version of the audio signal with a shorter transient process. The device also includes a transient signal inserting unit configured to merge the processed version of the audio signal with a shorter transient process with the transient signal, representing in the original or processed form the transient content of the transient part of the signal.

EFFECT: high accuracy of reproducing the signal.

14 cl, 20 dwg

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to communication engineering. An audio decoder for providing decoded audio information based on encoded audio information includes a window application-based signal converter formed to map a frequency-time presentation, which is described by the encoded audio information, to a time interval presentation. The window application-based signal converter is formed to select one of a plurality of windows, which include windows of different transition inclinations and windows of different conversion lengths based on window information. The audio decoder includes a window selector formed to evaluate window information of a variable-length code word for selecting a window for processing said part of the frequency-time presentation associated with said audio information frame.

EFFECT: eliminating artefacts arising when processing time-limited frames.

15 cl, 23 dwg

FIELD: physics, computer engineering.

SUBSTANCE: group of inventions relates to means of encoding and decoding a signal. The encoder comprises a first layer encoding section which encodes an input signal in a low-frequency range below a predetermined frequency. First encoded information is generated. The first encoded information is decoded to generate a decoded signal. The input signal is broken down in a high-frequency range above a predetermined frequency into a plurality of frequency subbands. A spectrum component is partially selected in each frequency subband. An amplitude adjustment parameter is calculated, which is used to adjust the amplitude of the selected spectrum component in order to generate second encoding information.

EFFECT: high efficiency of encoding spectral data of a high-frequency part and high quality of the decoded signal.

14 cl, 15 dwg

FIELD: physics, computer engineering.

SUBSTANCE: present invention relates to methods and devices for forward time-domain aliasing cancellation in a coded signal transmitted from an encoder to a decoder. The technical result is facilitating cancelling of aliasing effects at the switching point between encoding modes. The decoder receives the bit stream and cancels the time-domain aliasing in the encoded signal in response to the information contained in the bitstream. The information may be representative of a difference between a frame of the audio signal to be encoded in a first encoding mode and a decoded signal from the frame including time-domain aliasing effects.

EFFECT: information related to correction of the time-domain aliasing in the encoded signal is calculated at the encoder and added to a bit stream sent from the encoder to the decoder.

34 cl, 17 dwg

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