摘要:
An apparatus for looping or data-compressing sampled waveform data digitized from musical sound signals (or the like) to produce sound source data, recording the sound source data on a storage medium, and reading out the sound source data from the storage medium for reproduction. To eliminate amplitude discontinuities at repetition points during looping, two connection samples of repetitive waveform portions having values closest to each other are selected from actual samples and interpolated samples. An interpolation filter performs multiple oversampling to produce the interpolated samples. The interpolation filter includes a filter for each degree of oversampling, and all the filters have the same amplitude characteristics. By asserting pulse code modulated data at the beginning portion of a looping domain, adverse compression effects can be avoided without the necessity of providing compression parameters. When reading out sound source data from the storage medium, a data start address and a looping start address are loaded, in that order, into an address generator. A discriminating flag indicating the presence or absence of the looping domain and a discriminating flag indicating the end of the sound source data can be included in the sound source data to facilitate control of looping or end of reproduction.
摘要:
The present invention relates to a method and an apparatus for processing a signal, which are used to effectively reproduce an audio signal, and more particularly, to a method for generating a filter for an audio signal, which are used for implementing a filtering for input audio signals with a low computational complexity and a parameterization apparatus therefor.To this end, provided are a method for generating a filter of an audio signal, including: receiving at least one proto-type filter coefficient for filtering each subband signal of an input audio signal; converting the proto-type filter coefficient into a plurality of subband filter coefficients; truncating each of the subband filter coefficients based on filter order information obtained by at least partially using characteristic information extracted from the corresponding subband filter coefficients, the length of at least one truncated subband filter coefficients being different from the length of truncated subband filter coefficients of another subband; and generating FFT filter coefficients by fast Fourier transforming (FFT) the truncated subband filter coefficients by a predetermined block size in the corresponding subband and a parameterization unit using the same.
摘要:
The specification relates to the processing of a digital input signal. The digital input signal is convolved with a first time slice of an impulse response with a first direct convolution filter. In parallel, the digital input signal is divided into multiple frequency bands, and each of the multiple frequency bands of the digital input signal are convolved with a second time slice of the impulse response using an equal number of direct convolution filters. The outputs of the equal number of direct convolution filters are recombined and a delay compensation is applied to the recombined outputs. An output of the direct convolution filter is summed with the delayed and recombined outputs to form a zero-to-near-zero latency convolution output.
摘要:
The present invention provides a method of generating, on a data processing system, a multi-channel audio convolution reverb, said method comprising providing a plurality of impulse responses corresponding to a desired room to be simulated; receiving, in input, multi-channel audio sample data; performing, for each respective audio channel, same channel convolution operation on said respective audio channel with a corresponding impulse response; for each audio channel other than said respective audio channel, performing cross-channel convolution operation respectively with a corresponding cross-channel impulse response; performing combination of the results of the respective convolution operations; and outputting the combination (or summation) result as said output audio channel; wherein, in said performing said cross-channel convolution operation, wherein at least one convolution operation is performed corresponding to a shorter length of impulse response than at least one other convolution operation, preferably, said cross-channel convolution operation being performed only for an initial part of said cross-channel impulse response, said initial part being defined by a definition parameter.
摘要:
Methods and apparatus for simulating the sound of an acoustic percussion instrument. A first stored waveform signal representative of the impulse response of an acoustic percussion instrument is convolved with a waveform produced by a sensor circuit attached to a physical playing surface. Undesirable response characteristics of the playing surface and sensor circuit may be filtered out by deconvolving sensor output, or the stored waveform representing the acoustic instrument, with the impulse response of the combination of the playing surface and the sensor circuit.
摘要:
The present invention provides a method of generating, on a data processing system, a multi-channel audio convolution reverb, said method comprising providing a plurality of impulse responses corresponding to a desired room to be simulated; receiving, in input, multi-channel audio sample data; performing, for each respective audio channel, same channel convolution operation on said respective audio channel with a corresponding impulse response; for each audio channel other than said respective audio channel, performing cross-channel convolution operation respectively with a corresponding cross-channel impulse response; performing combination of the results of the respective convolution operations; and outputting the combination (or summation) result as said output audio channel; wherein, in said performing said cross-channel convolution operation, wherein at least one convolution operation is performed corresponding to a shorter length of impulse response than at least one other convolution operation, preferably, said cross-channel convolution operation being performed only for an initial part of said cross-channel impulse response, said initial part being defined by a definition parameter.
摘要:
An apparatus estimates an impulse response for use in reproduction of a sound in a desired acoustic space. In the apparatus, a first acquisition section acquires space information indicating a spatial shape of the acoustic space and an acoustic reflectivity of a boundary surface enclosing the acoustic space. A second acquisition section acquires point information indicating positions of a sound generation point and a sound reception point set in the acoustic space. An estimation section estimates a set of acoustic ray paths of the sound traveling from the sound generation point to the sound reception point based on the acquired space information and the point information. A third acquisition section acquires directivity information indicating an acoustic directivity of the sound generation point and the sound reception point. A weighting section estimates an acoustic intensity of each acoustic ray path, and weights each acoustic intensity by the acquired directivity information. A determination section determines the impulse response based on directions of the respective acoustic ray paths toward the sound reception point and the weighed acoustic intensities of the respective acoustic ray paths.
摘要:
A method and apparatus are provided for changing the pitch of a tabulated waveform in wavetable based synthesizers. Harmonics that normally would be aliased before a transposition process are removed by a discrete time low pass filter at the same time that the tabulated waveform is reconstruction and resampling.
摘要:
A method for resampling includes convolving a given set of samples with the impulse response function of a low-pass filter. In this method, values of the impulse response required for the convolution calculation are computed at the time of resampling from a segmented polynomial approximating the impulse response. In one embodiment, the method is applied to provide musical tones of various pitches from a stored waveform.
摘要:
A keyboard operated electronic musical instrument is disclosed which has a number of tone generators each of which is assigned to an actuated keyswitch. The generated musical waveshapes are transformed to produce tones having a time variant spectra by processing the waveshapes with a time variant masking function.