| 摘要 |
The invention relates to a system for the perceptual coding of signals, which is intended for the scalable compression/decompression of musical audio. According to the invention, samples of a signal are obtained over time and a representation of the signal in the spectral range is obtained by means of a mathematical transformation. A psychacoustic model is used to establish the amount of hearing-insensitive quantification noise in each sample. Favour is given to a pre-determined subassembly of quantification values which are easy to compress, such that said values are more probable than the remaining values. The binary words resulting from the quantification can be coded directly using any suitable binary compression method or can be divided into bit-planes which are compressed separately. The inventive system also employs frequency-predictive coding techniques, making use of the correlation that exists between corresponding coefficients in frequencies that are similar over time and the use of a multi-resolution analysis which is adapted to the most important frequencies present in the signal.
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