COMPANDING APPARATUS AND METHOD TO REDUCE QUANTIZATION NOISE USING ADVANCED SPECTRAL EXTENSION

摘要

Embodiments are directed to a companding method and system for reducing coding noise in an audio codec. A compression process reduces an original dynamic range of an initial audio signal through a compression process that divides the initial audio signal into a plurality of segments using a defined window shape, calculates a wideband gain in the frequency domain using a non-energy based average of frequency domain samples of the initial audio signal, and applies individual gain values to amplify segments of relatively low intensity and attenuate segments of relatively high intensity. The compressed audio signal is then expanded back to substantially the original dynamic range that applies inverse gain values to amplify segments of relatively high intensity and attenuating segments of relatively low intensity. A QMF filterbank is used to analyze the initial audio signal to obtain a frequency domain representation.

主权项

1. A method of expanding an audio signal comprising:
receiving an audio signal; and expanding the audio signal to an expanded dynamic range through an expansion process comprising: dividing the received audio signal into a plurality of time-segments using a defined window shape, calculating a wideband gain for each time-segment in the frequency domain using a non-energy based average of a frequency domain representation of the audio signal, and applying individual gain values to each time-segment to obtain the expanded dynamic range audio signal, wherein the application of the individual gain values amplifies segments of relatively high intensity and attenuates segments of relatively low intensity.