| 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. |
