arXiv AI

Taming the Entropy Cliff: Variable Codebook Size Quantization for Autoregressive Visual Generation

arXiv Computer Vision
Sep 23

StableVQ: Practical Guidelines for Stable Vector-Quantized Tokenizer Training

StableVQ introduces practical guidelines to improve training stability for vector‑quantized tokenizers used in image generation models. It addresses instability caused by the entanglement of encoder–decoder and codebook training by proposing three techniques: Dynamic STE for the encoder, Region VQ Loss for the codebook, and a Decoupled Schedule for independent learning rates. Experiments on ImageNet show consistent gains in stability, codebook utilization, and reconstruction quality across various settings.

By Bao Tang, Jiahao Guo, Haoxiang Cao, Wenyu Liu, Changqian Yu, Kun Gai, Xinggang Wang
arXiv Computation and Language
Sep 18

D-Quant: Driftable Entropy Coding for KV Cache Quantization

The paper introduces D-Quant, a KV cache quantization framework that addresses the memory bottleneck of large language models by using a drift mechanism to convert entropy-coded representations into fixed-size bitstreams. This approach leverages the non-uniform distribution of KV cache values—after rotation and normalization, they approximate a normal distribution—allowing entropy coding to assign shorter codewords to frequent symbols while maintaining regular memory layouts suitable for parallel attention kernels. D-Quant thus aims to reduce memory footprint and bandwidth usage without sacrificing performance.

By Yi Su, Hong Liu, Guanghua Yu, Jianchen Zhu
arXiv Computer Vision
Oct 23

Bound-Conditioned Latent Inference for Progressive Image Compression

Bound-Conditioned Latent Inference (BLI) redefines progressive trit-plane coding as sequential latent inference under shrinking interval constraints, using decoded trits to set lower and upper bounds for each latent element. BLI jointly refines Gaussian parameters and latent estimates with hyperprior information, enabling tighter constraints and flexible refinement schedules. Experiments on Kodak, CLIC, and JPEG-AI demonstrate state‑of‑the‑art rate‑distortion performance, reducing BD‑rate by 17.78% over DPICT and 7.96% over CTC while using far fewer parameters and lower latency.

By Jaeseok Jang, Seungmin Jeon, Kwang Pyo Choi, Chang-Su Kim
arXiv Machine Learning
Oct 23

Extreme Compression of Per-Layer Embeddings via Cross-Layer Latent Vector Quantization

The paper introduces OPTIC, a method for extreme compression of per-layer embeddings (PLE) in Transformer models. OPTIC stores a single quantized code per token and decodes it at each layer with a layer‑specific affine decoder, achieving up to 100× compression while retaining 97.8% of performance on seven benchmarks. At higher compression rates (594× and 1,002×), OPTIC still preserves 90.5% and 84.1% of performance, and it reduces GPU memory usage by 29.7% with minimal speed loss.

By Jiacheng Liu, Yaxin Luo, Xiaohan Zhao, Peng Sun, Xinyi Shang, Jiacheng Cui, Yonina C. Eldar, Zhiqiang Shen
arXiv Machine Learning
Sep 14

Breaking the Token Ceiling: Distilling Smaller, Stronger Byte Models

The paper investigates whether small models distilled from larger ones behave similarly when using byte versus token tokenization. It introduces two methods—Marginalize‑It (approximate) and End‑Of‑Token (exact)—to convert token logits to byte logits, and conducts a large‑scale study on decoder‑only dense transformers ranging from 1 billion to 1 trillion bytes of data. Results show that while token‑based models excel early, byte‑based models eventually surpass them with more compute, achieving higher performance ceilings, greater data efficiency, and lower logit storage costs.

By Kalyani Marathe, Artidoro Pagnoni, Tomasz Limisiewicz, Margaret Li, Mike Lewis, Luke Zettlemoyer, Srinivasan Iyer