Wavefunction sound sampling synthesis
AssigneeATI International SRL
InventorAvery L. Wang
Life of this patent
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Abstract
A signal representation method and apparatus for digital audio provides high quality low cost resampling by transferring the difficult interpolative computations into front-end (off-line) preprocessing, thereby reducing the load on the tone generating synthesis processor. This allows nearly perfect arbitrary-ratio resampling of stored waveforms at a fraction of the cost of prior art resampling. It also allows elimination of the prior art polyphase coefficient table since the waveform reconstruction information is fully contained within the polynomials. This is especially advantageous for execution on general purpose multi-tasking media processors.
Claims37
A method for producing a sound, comprising the acts of:
- defining a sequence of time points;
- associating a polynomial with each time point;
- calculating a sample value for each time point by evaluating the associated polynomial;
- and
- providing the calculated sample values in the sequence to generate the sound.
A method of producing a sound, comprising the acts of:
- providing an input waveform;
- segmenting the input waveform at segmentation points into a plurality of segments;
- fitting a polynomial to each segment;
- and
- storing coefficients of the polynomial for later reproduction of the input waveform.
An apparatus for encoding an input waveform, comprising:
- a time segment segmenter which receives the input waveform and defines a time segment length;
- a waveform segmenter coupled to the time segment segmenter and which segments the input waveform at segmentation points defined by the time segment length;
- a polynomial fitter coupled to the waveform segmenter and which fits a polynomial having a plurality of coefficients to each waveform segment;
- and
- a storage element coupled to the polynomial fitter, and which stores the coefficients of the polynomials.
An apparatus for playing back a sound, comprising:
- a note selector;
- a time segment generator coupled to the note selector;
- a segment selector coupled to the time segment selector;
- a storage element holding coefficients and coupled to the note selector and segment selector, thereby to output the coefficients representing a note selected by the note selector;
- a polynomial evaluator coupled to the storage element;
- and
- a digital to analog converter coupled to the polynomial evaluator.
Dependencies are inferred from the claim text.