UniTok: A Unified Tokenizer for Visual Generation and Understanding

Fuente: arXiv
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Main Authors: Ma, Chuofan, Jiang, Yi, Wu, Junfeng, Yang, Jihan, Yu, Xin, Yuan, Zehuan, Peng, Bingyue, Qi, Xiaojuan
Format: Preprint
Published: 2025
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author Ma, Chuofan
Jiang, Yi
Wu, Junfeng
Yang, Jihan
Yu, Xin
Yuan, Zehuan
Peng, Bingyue
Qi, Xiaojuan
author_facet Ma, Chuofan
Jiang, Yi
Wu, Junfeng
Yang, Jihan
Yu, Xin
Yuan, Zehuan
Peng, Bingyue
Qi, Xiaojuan
contents Visual generative and understanding models typically rely on distinct tokenizers to process images, presenting a key challenge for unifying them within a single framework. Recent studies attempt to address this by connecting the training of VQVAE (for autoregressive generation) and CLIP (for understanding) to build a unified tokenizer. However, directly combining these training objectives has been observed to cause severe loss conflicts. In this paper, we show that reconstruction and semantic supervision do not inherently conflict. Instead, the underlying bottleneck stems from limited representational capacity of discrete token space. Building on these insights, we introduce UniTok, a unified tokenizer featuring a novel multi-codebook quantization mechanism that effectively scales up the vocabulary size and bottleneck dimension. In terms of final performance, UniTok sets a new record of 0.38 rFID and 78.6% zero-shot accuracy on ImageNet. Besides, UniTok can be seamlessly integrated into MLLMs to unlock native visual generation capability, without compromising the understanding performance. Additionally, we show that UniTok favors cfg-free generation, reducing gFID from 14.6 to 2.5 on ImageNet 256$\times$256 benchmark. GitHub: https://github.com/FoundationVision/UniTok.
format Preprint
id arxiv_https___arxiv_org_abs_2502_20321
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle UniTok: A Unified Tokenizer for Visual Generation and Understanding
Ma, Chuofan
Jiang, Yi
Wu, Junfeng
Yang, Jihan
Yu, Xin
Yuan, Zehuan
Peng, Bingyue
Qi, Xiaojuan
Computer Vision and Pattern Recognition
Artificial Intelligence
Visual generative and understanding models typically rely on distinct tokenizers to process images, presenting a key challenge for unifying them within a single framework. Recent studies attempt to address this by connecting the training of VQVAE (for autoregressive generation) and CLIP (for understanding) to build a unified tokenizer. However, directly combining these training objectives has been observed to cause severe loss conflicts. In this paper, we show that reconstruction and semantic supervision do not inherently conflict. Instead, the underlying bottleneck stems from limited representational capacity of discrete token space. Building on these insights, we introduce UniTok, a unified tokenizer featuring a novel multi-codebook quantization mechanism that effectively scales up the vocabulary size and bottleneck dimension. In terms of final performance, UniTok sets a new record of 0.38 rFID and 78.6% zero-shot accuracy on ImageNet. Besides, UniTok can be seamlessly integrated into MLLMs to unlock native visual generation capability, without compromising the understanding performance. Additionally, we show that UniTok favors cfg-free generation, reducing gFID from 14.6 to 2.5 on ImageNet 256$\times$256 benchmark. GitHub: https://github.com/FoundationVision/UniTok.
title UniTok: A Unified Tokenizer for Visual Generation and Understanding
topic Computer Vision and Pattern Recognition
Artificial Intelligence
url https://arxiv.org/abs/2502.20321