Adaptive Prediction With Transform Domain Quantization For Low-rate Audio Coding

The technique of Adaptive Predictive Coding with Transform domain Quantization (APCTQ) has been studled for high quality coding of audio signals, at rates in the range 1.5 2.5 bit/sample. This technique is a combination of time domain predictive methods with transform domain quantization methods. Near transparent quality performance has been obtained at 5 kHz and 7.5 kHz bandwidths at rates of 24 kbit/s and 32 kbit/s respectively. In general, the APC-TQ technique is applicable over a wide range of signal bandwidths from 5 kHz to 20 kHz, for efficient transmission of high quality audio signals for applications such as direct audio broadcasing.