AudioTools[Scale] - scales audio data by the specified ratio or to the specified size
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Calling Sequence
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Scale(audArray, scale, options)
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Parameters
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audArray
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Array or Matrix containing the audio data to scale
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scale
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scale factor or desired length of scaled audio
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options
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options modifying the scaling operation
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Description
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The Scale command rescales audio data, producing a new audio object with the specified size.
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The audArray parameter specifies the audio to scale, and must be a dense, rectangular, one or two dimensional Array, Vector, or Matrix with datatype=float[8].
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The scale parameter specifies either the desired scaling ratio, or the desired length, in samples, of the scaled audio data. The former is expressed as a numeric value. The latter is expressed as an integer range giving the desired resulting array indices.
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By default, scaling is done using B-spline interpolation. This produces excellent results reasonably fast. When reducing audio data using scale factors smaller than 1/2.5, the scaling is done in steps to avoid unnecessary information loss. For example, scaling by 1/4 is accomplished by scaling twice by 1/2. The nature of the algorithm makes this stepwise scaling unnecessary when enlarging audio data.
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If the method=nearest option is specified, scaling is done using the nearest-neighbor algorithm. This produces poorer results, but the algorithm is very fast. This method is often suitable for producing low-quality rescalings of audio data.
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Specifying method=bspline is equivalent to the default behavior.
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NOTE: Scaling does not change the sampling rate of the data, which means that it does change the pitch. For example, scaling down by a factor of 0.5 will double the pitch (increase it by one octave). To resample audio data without affecting the pitch, use the AudioTools[Resample] command.
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Examples
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Download Help Document
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