Abstract: A system for managing user-generated content (UGC) and professionally generated content (PGC) is disclosed. The system is programmed to receive digital audio data having two channels from a social media platform. The system is programmed to extract spatial features that capture differences in the two channels from the digital audio data. The system is programmed to also extract temporal features, spectral features, and background features from the digital audio data. The system is programmed to then use the extracted features to determine whether to process the digital audio data as UGC or PGC before playback.

Abstract: Methods for generating an object based audio program, renderable in a personalizable manner, and including a bed of speaker channels renderable in the absence of selection of other program content (e.g., to provide a default full range audio experience). Other embodiments include steps of delivering, decoding, and/or rendering such a program. Rendering of content of the bed, or of a selected mix of other content of the program, may provide an immersive experience. The program may include multiple object channels (e.g., object channels indicative of user-selectable and user-configurable objects), the bed of speaker channels, and other speaker channels. Another aspect is an audio processing unit (e.g., encoder or decoder) configured to perform, or which includes a buffer memory which stores at least one frame (or other segment) of an object based audio program (or bitstream thereof) generated in accordance with, any embodiment of the method.

Abstract: Many portable playback devices cannot decode and playback encoded audio content having wide bandwidth and wide dynamic range with consistent loudness and intelligibility unless the encoded audio content has been prepared specially for these devices. This problem can be overcome by including with the encoded content some metadata that specifies a suitable dynamic range compression profile by either absolute values or differential values relative to another known compression profile. A playback device may also adaptively apply gain and limiting to the playback audio. Implementations in encoders, in transcoders and in decoders are disclosed.

Abstract: A system includes one or more processors and memory. The memory stores instructions for execution by the one or more processors, including instructions for: obtaining a configuration request for a communications network; configuring a network of models (e.g., oscillators or oscillators' settings) into an initial configuration representing the configuration request for the communications network; reading out a final configuration of the network of models, the final configuration representing a solution to the configuration request for the communications network; and providing information over the communications network according to the configuration request.

Abstract: An audio processing method may involve receiving output signals from each microphone of a plurality of microphones in an audio environment, the output signals corresponding to a current utterance of a person. The method may involve determining, responsive to the output signals and based at least in part on audio device location information and echo management system information, one or more audio processing changes to apply to audio data being rendered to loudspeaker feed signals for two or more audio devices in the audio environment. The audio processing changes may involve a reduction in a loudspeaker reproduction level for one or more loudspeakers in the audio environment. The method may involve causing one or more types of audio processing changes to be applied. The audio processing changes may have the effect of increasing a speech to echo ratio at one or more microphones.

Abstract: Some disclosed methods involve causing one or more loudspeakers in an audio environment to emit sound and receiving microphone signals from one or more microphones in the audio environment corresponding to an acoustic response of the audio environment to the emitted sound. Some disclosed methods involve detecting, by the control system, a change of the acoustic response of the audio environment. Some disclosed methods involve changing one or more aspects of media processing for media played back by one or more devices in the audio environment based, at least in part, on the change of the acoustic response of the audio environment. Alternatively, or additionally, some disclosed methods may involve changing the lighting in the environment, changing a gain of one or more microphone signals, locking or unlocking one or more devices, or combinations thereof, based at least in part on the change of the acoustic response.

Abstract: Described is a method of processing a media stream.

Abstract: Decoding of Ambisonics representations for a stereo loudspeaker setup is known for first-order Ambisonics audio signals. But such first-order Ambisonics approaches have either high negative side lobes or poor localisation in the frontal region. The invention deals with the processing for stereo decoders for higher-order Ambisonics HOA. The desired panning functions can be derived from a panning law for placement of virtual sources between the loudspeakers. For each loudspeaker a desired panning function for all possible input directions at sampling points is defined. The panning functions are approximated by circular harmonic functions, and with increasing Ambisonics order the desired panning functions are matched with decreasing error. For the frontal region between the loudspeakers, a panning law like the tangent law or vector base amplitude panning (VBAP) are used. For the rear directions panning functions with a slight attenuation of sounds from these directions are defined.

Abstract: Described is a method of performing automatic audio enhancement on an input audio signal including at least one speech-articulation noise event. The method comprises: segmenting the input audio signal into a number of audio frames; obtaining at least one feature parameter from the audio frames; and determining, based at least in part on the obtained feature parameter, a respective type of the speech-articulation noise event and a respective time-frequency range associated with the speech-articulation noise event within the input audio signal.

Abstract: An audio processing method may involve receiving audio signals and associated spatial data, listener position data, loudspeaker position data and loudspeaker orientation data, and rendering the audio data for reproduction, based, at least in part, on the spatial data, the listener position data, the loudspeaker position data and the loudspeaker orientation data, to produce rendered audio signals. The rendering may involve applying a loudspeaker orientation factor that tends to reduce a relative activation of a loudspeaker based, at least in part, on an increased loudspeaker orientation angle. In some examples, the rendering may involve modifying an effect of the loudspeaker orientation factor based, at least in part, on a loudspeaker importance metric. The loudspeaker importance metric may correspond to a loudspeaker's importance for rendering an audio signal at the audio signal's intended perceived spatial position.

Abstract: In some embodiments, a pitch filter for filtering a preliminary audio signal generated from an audio bitstream is disclosed. The pitch filter has an operating mode selected from one of either: (i) an active mode where the preliminary audio signal is filtered using filtering information to obtain a filtered audio signal, and (ii) an inactive mode where the pitch filter is disabled. The preliminary audio signal is generated in an audio encoder or audio decoder having a coding mode selected from at least two distinct coding modes, and the pitch filter is capable of being selectively operated in either the active mode or the inactive mode while operating in the coding mode based on control information.

Abstract: The present disclosure relates to a method of processing audio content including directivity information for at least one sound source, the directivity information comprising a first set of first directivity unit vectors representing directivity directions and associated first directivity gains. The disclosure further relates to corresponding methods of encoding and decoding audio content including directivity information for at least one sound source.

Abstract: Methods and apparatus for estimating metadata for images having absent metadata or unusable form of metadata. According to an example embodiment, a method of estimating metadata includes accessing first and second images of a scene, the first and second images having a first dynamic range (DR) and a different second DR, respectively. The method also includes: generating a third image of the scene having the second DR by applying a mapping function to the first image, the mapping function being configured using an applicable metadata set; generating a sequence of updated metadata sets by iteratively updating the applicable metadata set based on a cost function quantifying a difference between the second image and the third image; and computing values of the cost function to select an output metadata set from the sequence, the output metadata set having estimated metadata for the second image.

Abstract: Several embodiments of scalable image processing systems and methods are disclosed herein whereby color management processing of source image data to be displayed on a target display is changed according to varying levels of metadata.

Abstract: Described herein is a method for training a machine learning algorithm. The method may comprise receiving a first input multichannel audio signal. The method may comprise generating, using the machine learning algorithm, an intermediate audio signal based on the first input multichannel audio signal. The method may comprise rendering the intermediate audio signal into a first output multichannel audio signal. Further, the method may comprise improving the machine learning algorithm based on a difference between the first input multichannel audio signal and the first output multichannel audio signal. Described herein are further an apparatus for generating an intermediate audio format from an input multichannel audio signal as well as a respective computer program product comprising a computer-readable storage medium with instructions adapted to carry out said method when executed by a device having processing capability.

Abstract: Some examples involve rendering received audio data by determining a first relative activation of a set of loudspeakers in an environment according to a first rendering configuration corresponding to a first set of speaker activations, receiving a first rendering transition indication indicating a transition from the first rendering configuration to a second rendering configuration and determining a second set of speaker activations corresponding to a simplified version of the second rendering configuration. Some examples involve performing a first transition from the first set of speaker activations to the second set of speaker activations, determining a third set of speaker activations corresponding to a complete version of the second rendering configuration and performing a second transition to the third set of speaker activations without requiring completion of the first transition.

Abstract: The present invention relates to transposing signals in time and/or frequency and in particular to coding of audio signals. More particular, the present invention relates to high frequency reconstruction (HFR) methods including a frequency domain harmonic transposer. A method and system for generating a transposed output signal from an input signal using a transposition factor T is described. The system comprises an analysis window of length La, extracting a frame of the input signal, and an analysis transformation unit of order M transforming the samples into M complex coefficients. M is a function of the transposition factor T. The system further comprises a nonlinear processing unit altering the phase of the complex coefficients by using the transposition factor T, a synthesis transformation unit of order M transforming the altered coefficients into M altered samples, and a synthesis window of length Ls, generating a frame of the output signal.

Abstract: A projection display system comprises a light source configured to emit a light in response to a content data; an optical modulator configured to modulate the light; and a controller configured to adjust a light level of the projection display system based on the content data and a metadata relating to a future frame, thereby to reduce a perceptibility of a visual artifact.

Abstract: In a method to improve the coding efficiency of high-dynamic range (HDR) images, a decoder parses sequence processing set (SPS) data from an input coded bitstream to detect that an HDR extension syntax structure is present in the parsed SPS data. It extracts from the HDR extension syntax structure post-processing information that includes one or more of a color space enabled flag, a color enhancement enabled flag, an adaptive reshaping enabled flag, a dynamic range conversion flag, a color correction enabled flag, or an SDR viewable flag. It decodes the input bitstream to generate a preliminary output decoded signal, and generates a second output signal based on the preliminary output signal and the post-processing information.

Abstract: Enclosed are embodiments for multisource methods and systems for coded media. In some embodiments, a method comprises: at a first device: receiving media data representing a media asset; obtaining a first plurality of data elements including at least one of bitstream identification data, content-specific encode data and media segment data; encoding at least a portion of the media data in accordance with a first coding process into coded data corresponding to the media asset; generating a second plurality of data elements different from the first plurality of data elements based on information associated with the first coding process; combining the first plurality of data elements and the second plurality of data elements into one or more coded bitstreams representing the media asset; and transmitting the one or more coded bitstreams to one or more second devices using one or more network paths.

Abstract: Methods and apparatus for compressing and decompressing MPI videos. According to an example embodiment, a method of compressing an MPI video includes splitting the MPI video into first and second frame sequences including texture and alpha frames of multiplane images, respectively. The method further includes applying sets of preprocessing operations to convert the first frame sequence into a third frame sequence and to convert the second frame sequence into a fourth frame sequence. Example preprocessing operations include, but are not limited to, applying a fill process, thresholding RGB channels based on the corresponding alpha channel, blurring images, computing pixelwise difference values of frames, and computing pixelwise product values of frames. The method also includes applying video compression to the second frame sequence and to the fourth frame sequence.

Abstract: Several embodiments of scalable image processing systems and methods are disclosed herein whereby color management processing of source image data to be displayed on a target display is changed according to varying levels of metadata.

Abstract: Systems and methods are described for controlling adaptive filtering components. A far end signal may be filtered by each of a foreground filter and a background filter, where both filters are adaptive echo cancellation filters that output echo estimations. Control logic may halt adaptation by the background filter based on a deviation signal. To determine the deviation signal, cross-correlation coefficients for the echo estimations produced by both filters may be determined for each frequency bin of the far end signal. The determined cross-correlation coefficients may be summed across a plurality of the frequency bins. A hysteresis function may then be applied to the sum associated with the filter associated with the echo estimation used to generate a filtered result. The deviation signal may be activated in response to the hysteresis function outputting a high value, which the control logic uses to turn off adaptation by the background filter.

Abstract: In a method to improve backwards compatibility when decoding high-dynamic range images coded in a wide color gamut (WCG) space which may not be compatible with legacy color spaces, hue and/or saturation values of images in an image database are computed for both a legacy color space (say, YCbCr-gamma) and a preferred WCG color space (say, IPT-PQ). Based on a cost function, a reshaped color space is computed so that the distance between the hue values in the legacy color space and rotated hue values in the preferred color space is minimized. HDR images are coded in the reshaped color space. Legacy devices can still decode standard dynamic range images assuming they are coded in the legacy color space, while updated devices can use color reshaping information to decode HDR images in the preferred color space at full dynamic range.

Abstract: The present invention relates to transposing signals in time and/or frequency and in particular to coding of audio signals. More particular, the present invention relates to high frequency reconstruction (HFR) methods including a frequency domain harmonic transposer. A method and system for generating a transposed output signal from an input signal using a transposition factor T is described. The system comprises an analysis window of length La, extracting a frame of the input signal, and an analysis transformation unit of order M transforming the samples into M complex coefficients. M is a function of the transposition factor T. The system further comprises a nonlinear processing unit altering the phase of the complex coefficients by using the transposition factor T, a synthesis transformation unit of order M transforming the altered coefficients into M altered samples, and a synthesis window of length Ls, generating a frame of the output signal.

Abstract: In an embodiment, a method comprises: receiving bands of power spectra of an input audio signal and a microphone covariance, and for each band: estimating, using a classifier, respective probabilities of speech and noise; estimating, using a directionality model, a set of means for speech and noise, or a set of means and covariances for speech and noise, based on the microphone covariance for the band and the probabilities; estimating, using a level model, a mean and covariance of noise power based on the probabilities and the power spectra; determining a first noise suppression gain based on the directionality model; determining a second noise suppression gain based on the level model; selecting the first or second noise suppression gain or their sum based on a signal-to-noise ratio of the input audio signal; and scaling a time-frequency representation of the input signal by the selected noise suppression gain.

Abstract: The present document describes a method (600) for encoding a multi-channel input signal (101) which comprises N different channels. The method (600) comprises, for a current frame of a sequence of frames, determining (601) whether the current frame is an active frame or an inactive frame using a signal and/or a voice activity detector, and determining (602) a downmix signal (103) based on the multi-channel input signal (101), wherein the downmix signal (103) comprises N channels or less. In addition, the method (600) comprises determining (603) upmixing metadata (105) comprising a set of parameters for generating, based on the downmix signal (103), a reconstructed multi-channel signal (111) comprising N channels, wherein the upmixing metadata (105) is determined in dependance of whether the current frame is an active frame or an inactive frame. The method (600) further comprises encoding (604) the upmixing metadata (105) into a bitstream.

Abstract: A method of audio processing includes receiving user-generated content having two audio sources, extracting audio objects and a residual signal, adjusting the audio objects and the residual signal according to the listener's head movements, and mixing the adjusted audio signals to generate a binaural audio signal. In this manner, the binaural signal adjusts according to the listener's head movements without requiring perfect audio objects.

Abstract: In a method to improve backwards compatibility when decoding high-dynamic range images coded in a wide color gamut (WCG) space which may not be compatible with legacy color spaces, hue and/or saturation values of images in an image database are computed for both a legacy color space (say, YCbCr-gamma) and a preferred WCG color space (say, IPT-PQ). Based on a cost function, a reshaped color space is computed so that the distance between the hue values in the legacy color space and rotated hue values in the preferred color space is minimized. HDR images are coded in the reshaped color space. Legacy devices can still decode standard dynamic range images assuming they are coded in the legacy color space, while updated devices can use color reshaping information to decode HDR images in the preferred color space at full dynamic range.

Abstract: A method (200) of processing audio in an immersive audio format comprising at least one height audio channel, comprising: obtaining (250) two height audio signals from at least a portion of the at least one height audio channel: modifying (270) a relative phase between the two height audio signals in frequency bands in which phase differences are predominantly out of phase to obtain two phase modified height audio signals: and playing back (290) the processed audio comprising the two phase modified height audio signals with at least two audio loudspeakers. The phase differences occur as a result of having monaural signals emanated from two audio loudspeakers at one or more listening positions symmetrically off-center with respect to the at least two loudspeakers, laterally spaced with respect to each of said one or more listening positions. The method allows perception of sound height/elevation without using overhead speakers.

Abstract: Several embodiments of scalable image processing systems and methods are disclosed herein whereby color management processing of source image data to be displayed on a target display is changed according to varying levels of metadata.

Abstract: A method for encoding envelope information is provided. In some implementations, the method involves determining a first downmixed signal associated with a downmixed channel associated with an audio signal to be encoded. In some implementations, the method involves determining energy levels of the first downmixed signal for a plurality of frequency bands. In some implementations, the method involves determining whether to encode information indicative of the energy levels in a bitstream. In some implementations, the method involves encoding the determined energy levels. In some implementations, the method involves generating an energy control value indicating that energy levels are encoded. In some implementations, the method involves generating the bitstream, wherein the energy control value and the information indicative of the energy levels are usable by the decoder to adjust energy levels associated with the first downmixed signal.

Abstract: A method for decoding an encoded audio bitstream is disclosed. The method includes receiving the encoded audio bitstream and decoding the audio data to generate a decoded lowband audio signal. The method further includes extracting high frequency reconstruction metadata and filtering the decoded lowband audio signal with an analysis filterbank to generate a filtered lowband audio signal. The method also includes extracting a flag indicating whether either spectral translation or harmonic transposition is to be performed on the audio data and regenerating a highband portion of the audio signal using the filtered lowband audio signal and the high frequency reconstruction metadata in accordance with the flag. The high frequency regeneration is performed as a post-processing operation with a delay of 3010 samples per audio channel.

Abstract: Embodiments of a configurable loudspeaker using a user orientable routing card (120) that allows for multiple electrical drive modes in a non-powered loudspeaker system (122). The speaker has one or more drivers (126, 128) mounted in enclosure (124), an audio input interface configured to be coupled to an audio source (127) through one or more amplifiers (107, 127), and a connector interface configured to receive a routing card (120). The routing card is configured to be inserted in a first orientation to connect the audio input interface in a first operating mode with respect to driver selection and connection to the one or more amplifiers, and a second orientation to connect the audio input interface in a second operating mode with respect to driver selection and connection to the one or more amplifiers.

Abstract: Systems and methods to transmit data over multiple communication channels in parallel with forward error correction. Original packets are evenly distributed to the channels as the initial systematically channel-encoded packets. Subsequent channel-encoded packets are configured to be linearly independent of their base sets of channel-encoded packets, where a base set for a subsequent channel-encoded packet includes those scheduled to be transmitted before the subsequent packet in the same channel as the subsequent packet, and optionally one or more initial packets from other channels. The compositions of the sequences of the encoded packets can be predetermined without the content of the packets; and the channel-encoded packets can be generated from the original packets on-the-fly by the transmitters of the channels during transmission. When a sufficient number of packets have been received via the channels, a recipient may terminate their transmissions.

Abstract: A beam-steering projection system includes a light source configured to emit a light in response to image signal, a phase light modulator, and a spatial light modulator. The phase light modulator is configured to receive the light from the light source and to apply a spatially-varying phase modulation on the light, thereby to steer the light at an illumination angle and generate a first steered light. The spatial light modulator is configured to receive the first steered light, to apply a spatially-varying amplitude modulation on the light, to steer the light towards a projection optics system and to generate a second steered light. A plane of a secondary image constructed after the phase light modulator and before the spatial light modulator is parallel with the phase light modulator.

Abstract: A projection system and method includes a light source configured to emit a light in response to an image data; a phase light modulator configured to receive the light from the light source and to apply a spatially-varying phase modulation on the light, thereby to steer the light and generate a projection light; and a controller configured to dynamically determine, based on at least one of a user input or a sensor signal, a target geometry of a projection surface on which the projection light is projected, determine, based on the target geometry, a phase configuration for a frame of the image data, and provide a phase control signal to the phase light modulator, the phase control signal configured to cause the phase light modulator to generate the projection light in accordance with the phase configuration for the frame.

Abstract: In a method to improve backwards compatibility when decoding high-dynamic range images coded in a wide color gamut (WCG) space which may not be compatible with legacy color spaces, hue and/or saturation values of images in an image database are computed for both a legacy color space (say, YCbCr-gamma) and a preferred WCG color space (say, IPT-PQ). Based on a cost function, a reshaped color space is computed so that the distance between the hue values in the legacy color space and rotated hue values in the preferred color space is minimized. HDR images are coded in the reshaped color space. Legacy devices can still decode standard dynamic range images assuming they are coded in the legacy color space, while updated devices can use color reshaping information to decode HDR images in the preferred color space at full dynamic range.

Abstract: A method of generating a substitution frame for a lost audio frame of an audio signal is presented. The method may comprise determining an audio filter based on samples of a valid audio frame preceding the lost audio frame. The method may comprise generating the substitution frame based on the audio filter and the samples of the valid audio frame preceding the lost audio frame. The method may be advantageously applied to a low frequency effects (LFE) channel of a multi-channel audio signal.

Abstract: Several embodiments of scalable image processing systems and methods are disclosed herein whereby color management processing of source image data to be displayed on a target display is changed according to varying levels of metadata.

Abstract: Described are methods of processing an audio signal for packet loss concealment. The audio signal comprises a sequence of frames, each frame containing representations of a plurality of audio channels and reconstruction parameters for upmixing the plurality of audio channels to a predetermined channel format. One method includes: receiving the audio signal; and generating a reconstructed audio signal in the predefined channel format based on the received audio signal. Generating the reconstructed audio signal comprises: determining whether at least one frame of the audio signal has been lost; and if a number of consecutively lost frames exceeds a first threshold, fading the reconstructed audio signal to a predefined spatial configuration. Also described is a method of encoding an audio signal. Yet further described are apparatus for carrying out the methods, as well as corresponding programs and computer-readable storage media.

Abstract: Several embodiments of scalable image processing systems and methods are disclosed herein whereby color management processing of source image data to be displayed on a target display is changed according to varying levels of metadata.

Abstract: A method for encoding an image having been cut up into partitions. The method includes: predicting data of a current partition based on an already encoded and then decoded reference partition, generating a predicted partition; determining residual data by comparing data relating to the current partition with the predicted partition, the residual data associated with various digital data items. Prior producing a signal containing the encoded information, performing the following steps; determining, from the predetermined residual data, a subset containing residual data capable of being modified; calculating the value of a function representative of the residual data; comparing the calculated value with a value of at least one of the digital data items; based on the comparison, modification or non-modification of at least one of the residual data items of the subset; and, in the event of a modification, entropy encoding the at least one modified residual data item.

Abstract: Image data is received for rendering an image on an image display to a viewer (402). The image data specifies a pixel value of the image for a pixel of the image display to render. The pixel value for the pixel includes multiple component pixel values corresponding to multiple color components of a color space. A color gamut locational value of the pixel value is computed based on two or more component pixel values in the multiple component pixel values of the pixel value specified for the pixel (404). The color gamut locational value is used to determine whether bandwidth broadening is to be applied to image rendering light produced by the pixel of the image display to render the pixel value (406). The image rendering light is directed to the viewer.

Abstract: Several embodiments of scalable image processing systems and methods are disclosed herein whereby color management processing of source image data to be displayed on a target display is changed according to varying levels of metadata.

Abstract: The present disclosure relates to a method and an audio processing system (1) for generating a pair of binaural audio signals (LB, RB). The method comprises obtaining (S1a) a pair of input audio signals (L, R) of an audio presentation, performing upmixing (S2) of the input audio signals (L, R) to generate three decorrelated audio signals (LD, RD, CD), each decorrelated audio signal having a direction of incidence (41, 42, 43) on a listening position. The method further comprises, for each decorrelated audio signal, determining a pair of interaural difference values based on the direction of incidence of the decorrelated audio signals (LD, RD, CD), a head-related transfer model and head rotation information. The method further comprises generating (S4) a binaural audio signal pair (LB, RB) based on the three decorrelated audio signals (LD, RD, CD) and the interaural difference values.

Abstract: Methods, apparatus, programs, and storage media for enhancing speech signals based on a neural network are provided. The method includes receiving a speech signal and a corresponding reference speech signal. A first set of band features is extracted from the speech signal and a second set of band features is extracted from the reference speech signal, wherein each feature in the first set of band features corresponds to a frequency band of the speech signal and each feature in the second set of band features corresponds to a frequency band of the reference speech signal. A first mask is determined by inputting the third set of band features into a speech enhancement neural subnetwork. The low frequency mask part and the increased number of entries are combined into a second mask. A fourth set of band features is determined based on the second mask and the speech signal.

Abstract: A projection system and calibration method therefor relate to a light source configured to emit a light in response to an image data, an illumination optical system configured to steer the light, the illumination optical system including a first lens group and a second lens group, a digital micromirror device (DMD) including a plurality of micromirrors respectively configured to reflect the steered light to a predetermined location as on-state light or to reflect the steered light as off-state light to a light dump; determining a deviation between an actual angle of orientation and an expected angle of orientation of a respective micromirror of the plurality of micromirrors; calculating a first amount of lateral adjustment corresponding to the first lens group and a second amount of lateral adjustment corresponding to the second lens group, and actuating the first and second lens groups according to the corresponding first and second amount.

Abstract: A method is disclosed for playing a live stream in a media player that includes a playback buffer for buffering received video packets according to a target buffer size. The method comprises measuring time fluctuations in arrival of the received video packets in the playback buffer, and adjusting the target buffer size based on the measured time fluctuations.

Abstract: The present invention relates to coding of audio signals, and in particular to high frequency reconstruction methods including a frequency domain harmonic transposer. A system and method for generating a high frequency component of a signal from a low frequency component of the signal is described.