A Full-Bandwidth Audio Codec With Low Complexity And Very Low Delay

TL;DR

This paper introduces a low-delay, low-complexity full-bandwidth audio codec based on MDCT with short frames, outperforming existing codecs at 96 kbit/s with only 4 ms delay.

Contribution

It presents a novel low-delay audio codec using short-frame MDCT and gain-shape quantization, achieving high performance with minimal complexity.

Findings

Outperforms ULD codec at 96 kbit/s with 4 ms delay

Total complexity is only 17 WMOPS for real-time 48 kHz operation

Maintains spectral envelope with gain-shape quantization

Abstract

We propose an audio codec that addresses the low-delay requirements of some applications such as network music performance. The codec is based on the modified discrete cosine transform (MDCT) with very short frames and uses gain-shape quantization to preserve the spectral envelope. The short frame sizes required for low delay typically hinder the performance of transform codecs. However, at 96 kbit/s and with only 4 ms algorithmic delay, the proposed codec out-performs the ULD codec operating at the same rate. The total complexity of the codec is small, at only 17 WMOPS for real-time operation at 48 kHz.