🤖 AI Summary
Existing text-to-video models struggle to jointly control multiple subjects, event timing, shot transitions, and camera motion. This work proposes a unified video diffusion model that, for the first time, represents heterogeneous cinematic elements—subjects, events, camera movements, and shots—as entity-centric conditional primitives operating over specific time intervals, while leveraging reference images to enhance visual consistency. The method introduces a parameter-free coordinated Rotary Position Embedding (RoPE) scheme that integrates interval-sampled temporal RoPE with 2D entity–time cross-attention RoPE, effectively addressing attention routing across both time and entities. Evaluated on two newly introduced benchmarks, the model significantly outperforms six specialized single-aspect baselines, achieving state-of-the-art performance in dense caption following, shot transition timing accuracy, and user preference studies.
📝 Abstract
Cinematic video depicts multiple subjects acting or interacting at specific moments, captured with deliberate camera movement, and stitched together by shot transitions. Together, these elements demand a level of fine-grained control beyond current text-to-video models. Existing work addresses each axis in isolation: multi-subject personalization, temporal control, multi-shot synthesis, or camera control; no prior framework jointly integrates all four. We present CineOrchestra, a unified video diffusion model that controls subjects, events, cameras, and shot transitions simultaneously. Our key insight is that these heterogeneous cinematic elements share a fundamental structure: each is an entity acting over a specific temporal interval, which can therefore all be expressed through one shared structure of entity-centric conditioning primitives, augmented with reference images for visual entities. This formulation reduces the architectural challenge to a single positional encoding problem, which we solve with two parameter-free coordinated rotary embeddings: (a) an interval-sampled temporal RoPE that yields consistent attention behavior across events of dramatically varying duration, and (b) a 2D entity-temporal cross-attention RoPE that disambiguates per-entity conditions and routes each to its corresponding spatiotemporal region. On two new benchmarks, CineOrchestra outperforms six per-axis specialists on dense caption following and shot-transition timing, with consistent gains in a pairwise user study and component ablations.