提出新方法解决生成模型训练不稳与代码本坍缩问题
VP-VAE: Rethinking Vector Quantization via Adaptive Vector Perturbation
- 用可微扰动替代传统量化器,解耦表示学习与离散化
- 实验显示重建质量提升且令牌使用更均衡
- 适合关注稳定训练与高效离散表示的研究者
向量量化变分自编码器(VQ-VAE)是现代生成建模的基础,但常因表示学习与离散代码本优化的耦合导致训练不稳定和“代码本坍缩”。本文提出VP-VAE(向量扰动变分自编码器),通过消除训练中对显式代码本的需求,实现两者的解耦。核心洞察是:从神经网络视角看,量化本质是在潜在空间注入结构化扰动。因此,VP-VAE 使用基于Metropolis-Hastings采样的分布一致、尺度自适应的潜在扰动,取代不可微的量化器,实现无需代码本的稳定训练,并增强对推理时量化误差的鲁棒性。在潜在变量近似均匀的假设下,推导出轻量级变体FSP(有限标量扰动),为FSQ类固定量化器提供统一理论解释与实际改进。在图像与音频基准上的大量实验表明,VP-VAE与FSP提升了重建保真度,实现了更均衡的令牌使用,同时避免了耦合代码本训练的固有不稳定性。
原文摘要 · Abstract (English)
Vector Quantized Variational Autoencoders (VQ-VAEs) are fundamental to modern generative modeling, yet they often suffer from training instability and "codebook collapse" due to the inherent coupling of representation learning and discrete codebook optimization. In this paper, we propose VP-VAE (Vector Perturbation VAE), a novel paradigm that decouples representation learning from discretization by eliminating the need for an explicit codebook during training. Our key insight is that, from the neural network's viewpoint, performing quantization primarily manifests as injecting a structured perturbation in latent space. Accordingly, VP-VAE replaces the non-differentiable quantizer with distribution-consistent and scale-adaptive latent perturbations generated via Metropolis--Hastings sampling. This design enables stable training without a codebook while making the model robust to inference-time quantization error. Moreover, under the assumption of approximately uniform latent variables, we derive FSP (Finite Scalar Perturbation), a lightweight variant of VP-VAE that provides a unified theoretical explanation and a practical improvement for FSQ-style fixed quantizers. Extensive experiments on image and audio benchmarks demonstrate that VP-VAE and FSP improve reconstruction fidelity and achieve substantially more balanced token usage, while avoiding the instability inherent to coupled codebook training.
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