A novel scheme for perceptual coding of audio for robust and real-time communication is designed and analyzed. As an alternative to PCM, DPCM, and more general noise-shaping converters, we propose to use psychoacoustically optimized noise-shaping quantizers based on the moving-horizon principle. In moving-horizon quantization, a few samples look-ahead is allowed at the encoder, which makes it possible to better shape the quantization noise and thereby reduce the resulting distortion over what

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... possible with conventional noise-shaping techniques. It is rst shown that signicant gains over linear PCM can be obtained without introducing a delay and without requiring post-processing at the decoder, i.e., the encoded samples can be stored as e.g., 16-bit linear PCM on CD-ROMs, and played out on standards-compliant CD players. We then show that multiple-description coding can be combined with moving-horizon quantization in order to combat possible erasures on the wireless link without introducing additional delays. Index Terms Low delay source coding, multiple-description coding, moving horizon quantization, perceptual audio coding Jan Østergaard is with the