SwitchCodec: A High-Fidelity Nerual Audio Codec With Sparse Quantization

We present a universal high-fidelity neural audio compression algorithm that can compress speech, music, and general audio below 3 kbps bandwidth. Although current state-of-the-art audio codecs excel in audio compression, their effectiveness significantly declines when embedding space is sharply reduced, which corresponds to higher compression. To address this problem, we propose Residual Experts Vector Quantization (REVQ), which significantly expands the available embedding space and improves the performance while hardly sacrificing the bandwidth. Furthermore, we introduce a strategy to ensure that the vast embedding space can be fully utilized. Additionally, we propose a STFT-based discriminator to guide the generator in producing indistinguishable spectrograms. We demonstrate that the proposed approach outperforms baseline methods through detailed ablations.