SeMoCo: A Semantic-First Motion Codec for Motion Language Modeling

arXiv:2608.24334 · cs.CV, cs.CL, cs.GR · Submitted 2026-08-25 · Read on arXiv

cs.CV, cs.CL, cs.GR

Submitted: 2026-08-25

Updated: 2026-08-28

Code: https://github.com/OMEGA-i/SeMoCo-Tokenizer

License: http://creativecommons.org/licenses/by/4.0/

The gist: Discrete motion representations have substantially advanced autoregressive text-to-motion generation.

Terminology

Abstract

Discrete motion representations have substantially advanced autoregressive text-to-motion generation. However, most motion tokenizers are optimized for reconstruction and do not explicitly allocate capacity according to semantic role. Action-level meaning and fine-grained kinematic detail must therefore be encoded through the same reconstruction-driven hierarchy. We introduce SeMoCo, a semantic-first motion codec, together with a dual-axis motion generator for language-conditioned motion generation. Each motion token contains one semantic token and a residual sequence of kinematic tokens. The generator models semantic progression across time and autoregressively refines the residual entries. We also construct Ω-MotionVerse, a large-scale, multi-source human-motion dataset unified under the SOMA representation. Across the reported comparisons, SeMoCo achieves the best reconstruction accuracy among the compared codecs, while strong text-to-motion results demonstrate the effectiveness of its motion tokens for downstream generation.

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