TRANsFoRM CODING OF HIGH OU&I'JY DI- AUD IO AT LOW BIT RATES - ALGORITHMSAND IMPLEMENT ATIOW
Karlheinz Brandenburg, Heinz Gerhäuser, D. Seitzer · 1990
Low bit rate coding schemes for coding high quality digital audio at bit rates of 64 to 128 kbitlsec. per channel are described. LC-ATC (Low-Complexity Adaptive Transform Coding) and OCF (Optimum Coding in the Frequency domain) both use transform coding to get high redundancy removal and high adaptation to the perceptual requirements. OCF uses entropy coding of the spectral values for increased coding efficiency and flexibility of the coder. Real time implementations using DSP32(C) and DSP 56000 digital signal processors are presented for both algorithms. Results using listening tests and Noise-to-Mask Ratio (NMR) are given: CD-quality can be achieved at 2 bitlsample. At 64 kbitlsec., the quality at 15 kHz bandwidth is still higher than todays FM radio.