Method and apparatus for coding audio signals based on perceptual model
Patent 5285498 Issued on February 8, 1994. Estimated Expiration Date: March 2, 2012. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
Coding of high quality stereophonic audio signals is accomplished in a perceptual filterbank coder which exploits the interchannel redundancies and psychoacoustic. Using perceptual principles, switching between a normal and short window of input samples improve output signal quality for certain input signals, particularly those having a rapid attack. Switching is also accomplished between coding of left and right channels and so- called sum and difference channels in response to particular signal conditions. A number of new perceptually based techniques, including improved threshold determinations, result in high quality.
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