Patents Represented by Attorney, Agent or Law Firm Helene Plotka Workman
  • Patent number: 5581480
    Abstract: Briefly, a method and apparatus for mixing a plurality of channels of digital audio samples using a non-linear clipping function which has a variable scaling factor is disclosed. The non-linear curving function is capable of being graphically represented by a curve which is sloped at the edges before reaching the maximum values. In a first embodiment, the non-linear clipping function is applied to the samples and values are calculated in real-time. Preferably, inputs to the non-linear clipping function are modified depending upon any significant trends, e.g. increasing or decreasing, in the sums of samples over time. In a second embodiment, to reduce processor overhead, prior to real time application of the non-linear clipping function, the calculations are performed and a lookup table is generated. This lookup table is then used during real time to apply the clipping function to the input data so that the non-linear function is not recalculated whenever multiple channels are mixed.
    Type: Grant
    Filed: May 10, 1994
    Date of Patent: December 3, 1996
    Assignee: Apple Computer, Inc.
    Inventors: Kipley J. Olson, James D. Reekes, Samuel C. Dicker