Scaling the Codebook Size of VQGAN to 100,000 with a Utilization Rate of 99%

TL;DR

This paper introduces VQGAN-LC, a novel image quantization model that significantly enlarges the codebook size to 100,000 with over 99% utilization, improving performance across multiple image tasks.

Contribution

The paper presents a new approach to scale the VQGAN codebook to 100,000 entries with high utilization, using a pre-trained encoder and a projector for alignment, surpassing previous limitations.

Findings

Achieved a codebook size of 100,000 with over 99% utilization.

Demonstrated improved performance in image reconstruction and generation tasks.

Outperformed previous VQGAN variants in various image-related benchmarks.

Abstract

In the realm of image quantization exemplified by VQGAN, the process encodes images into discrete tokens drawn from a codebook with a predefined size. Recent advancements, particularly with LLAMA 3, reveal that enlarging the codebook significantly enhances model performance. However, VQGAN and its derivatives, such as VQGAN-FC (Factorized Codes) and VQGAN-EMA, continue to grapple with challenges related to expanding the codebook size and enhancing codebook utilization. For instance, VQGAN-FC is restricted to learning a codebook with a maximum size of 16,384, maintaining a typically low utilization rate of less than 12% on ImageNet. In this work, we propose a novel image quantization model named VQGAN-LC (Large Codebook), which extends the codebook size to 100,000, achieving an utilization rate exceeding 99%. Unlike previous methods that optimize each codebook entry, our approach begins with a codebook initialized with 100,000 features extracted by a pre-trained vision encoder. Optimization then focuses on training a projector that aligns the entire codebook with the feature distributions of the encoder in VQGAN-LC. We demonstrate the superior performance of our model over its counterparts across a variety of tasks, including image reconstruction, image classification, auto-regressive image generation using GPT, and image creation with diffusion- and flow-based generative models. Code and models are available at https://github.com/zh460045050/VQGAN-LC.