High quality low complexity scalable wavelet audio coding

This paper presents an audio coder for real-time multimedia applications. To achieve high quality at low bit rate, the audio coder uses a wavelet packet decomposition to transform the audio data into the wavelet domain, and a psychoacoustic model is used to minimize quantization noise. The wavelet packet decomposition tree structures were chosen in a way to closely mimic the critical bands in a psychoacoustic model. Instead of determining the masking thresholds in the Fourier domain, the wavelet coefficients are used to drive the psychoacoustic model directly. Most of the standard industrial sampling frequencies are supported by this coder. An efficient bit rate control scheme was designed such that the audio coder operates at virtually any desired bit rate level. The audio coder achieves near perceptually lossless quality at or below 80 kb/s for most audio sources. Real-time encoding/decoding is possible by using only a fraction of a Pentium or faster CPU.