Model Definition

What is HappyHorse-1.0?

HappyHorse-1.0 is a state-of-the-art open-source AI video generation model with 15 billion parameters. It is a unified Transformer that jointly generates video and synchronized audio from text or image prompts, delivering cinematic 1080p quality with multilingual lip-sync. The model features a 40-layer self-attention architecture with 4 modality-specific layers on each end and 32 shared layers, processing text, video, and audio via self-attention only — no cross-attention required. This design replaces multi-stream complexity with a single unified pipeline. HappyHorse-1.0 natively supports six languages — Chinese, English, Japanese, Korean, German, and French — with expressive facial performance, natural speech coordination, realistic body motion, and accurate lip-sync. It generates synchronized dialogue, ambient sound, and Foley alongside video frames, eliminating the need for post-production dubbing. The model achieves generation in only 8 denoising steps without classifier-free guidance, maintaining output quality at record speeds. HappyHorse-1.0 currently leads the Artificial Analysis Text to Video Arena with an Elo score of 1333.