papers/zen/zen-director.tex

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\title{
    \vspace{-2cm}
    \Large \textbf{Zen AI Model Family} \\
    \vspace{0.5cm}
    \Huge \textbf{Zen-Director} \\
    \vspace{0.3cm}
    \large Video Scene Generation, Storyboarding, and Cinematic Direction \\
    \vspace{0.5cm}
    \normalsize Technical Report v2025.01
}

\author{
    Hanzo AI Research Team\thanks{[email protected]} \and
    Zoo Labs Foundation\thanks{[email protected]}
}

\date{January 2025}

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{\footnotesize Hanzo AI \hfill RESEARCH}
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\begin{abstract}
We present \textbf{Zen-Director}, a 7-billion parameter vision-language model specialized for
video scene generation, cinematographic planning, and multi-shot storyboard synthesis.
Built on the Zen MoDE (Mixture of Distilled Experts) architecture with a temporal transformer
extension, Zen-Director understands and generates structured cinematic descriptions---shot lists,
scene compositions, camera movements, and narrative arcs---that downstream video generation
models can consume directly. The model achieves BLEU-4 of 0.423 on the VideoCaption benchmark,
81.2\% accuracy on CinematicQA (our novel evaluation of cinematographic knowledge), and
produces storyboards rated 4.1/5.0 by professional cinematographers in blind evaluation.
Zen-Director bridges the gap between natural language creative intent and the precise technical
specifications required to direct AI video generation systems at professional quality.
\end{abstract}

\tableofcontents
\newpage

\section{Introduction}

The rapid maturation of text-to-video generation systems has exposed a critical bottleneck:
the gap between a creator's high-level creative intent and the precise technical specifications
these systems require to produce coherent, professional-quality video. Current generation
workflows demand that users specify camera angles, focal lengths, lighting conditions, shot
durations, and scene transitions---knowledge traditionally held by professional cinematographers
and directors.

Zen-Director addresses this bottleneck as a \textbf{directorial intelligence}: a model that
understands narrative intent and translates it into actionable cinematic specifications. Rather
than generating video pixels directly, Zen-Director generates structured \textbf{shot plans}:
hierarchical scene descriptions that video generation systems consume as structured prompts.

\subsection{Model Overview}

\begin{table}[H]
\centering
\begin{tabular}{ll}
\toprule
\textbf{Property} & \textbf{Value} \\
\midrule
Parameters & 7B \\
Architecture & Zen MoDE 7B + Temporal Transformer \\
Context Length & 32K tokens + 512 video frames \\
Visual Encoder & ViT-L/14 (336px) \\
Temporal Depth & 12 temporal transformer layers \\
Shot Plan Format & Structured JSON + prose description \\
Training Data & 8.2M scene-annotation pairs, 1.4M film scripts \\
\bottomrule
\end{tabular}
\caption{Zen-Director Model Specifications}
\end{table}

\subsection{Key Capabilities}

\begin{itemize}
    \item \textbf{Scene storyboarding}: Convert natural language scene descriptions into
    complete shot-by-shot storyboards with camera specifications.
    \item \textbf{Shot composition}: Recommend and generate compositional guidelines (rule of
    thirds, leading lines, depth of field) for each shot.
    \item \textbf{Narrative arc planning}: Structure multi-scene video narratives with consistent
    pacing, tension arcs, and visual motifs.
    \item \textbf{Cinematic vocabulary}: Understand and generate industry-standard cinematographic
    terminology (establishing shot, dolly zoom, rack focus, etc.).
    \item \textbf{Video comprehension}: Analyze existing video clips and generate directorial
    notes describing their cinematographic techniques.
\end{itemize}

\section{Architecture}

\subsection{Zen MoDE 7B Language Backbone}

The language backbone is Zen MoDE at 7B scale: 28 transformer layers, 28 attention heads with
grouped-query attention (4 KV heads), and MoE feed-forward networks (4 experts, top-2 routing).
This provides strong natural language understanding for parsing creative briefs and generating
rich cinematic descriptions.

\subsection{Visual Encoder}

A ViT-L/14 vision encoder operating at 336px resolution encodes reference images and video
frames into 256 visual tokens per frame. A two-layer MLP projection maps visual tokens into
the language model's embedding space.

\subsection{Temporal Transformer Extension}

The key architectural innovation is a 12-layer temporal transformer that operates \textit{across}
frames rather than within them. Given $T$ frames, each encoded to 256 tokens, the temporal
transformer attends over the time dimension to build a coherent representation of motion,
continuity, and scene evolution:

\begin{equation}
    H_{\text{temporal}} = \text{TransformerEncoder}([h_1^{CLS}, h_2^{CLS}, \ldots, h_T^{CLS}])
\end{equation}

where $h_t^{CLS}$ is the CLS token representation of frame $t$ from the visual encoder.
The temporal representation is concatenated with text tokens before the language model's
cross-attention layers.

\subsection{Shot Plan Generation}

Zen-Director generates shot plans as structured JSON objects:

\begin{lstlisting}[language=Python, caption=Shot Plan Schema]
{
  "scene": {
    "id": "s01",
    "location": "rain-soaked rooftop, night",
    "mood": "tense, noir",
    "duration_sec": 45
  },
  "shots": [
    {
      "id": "s01_001",
      "type": "establishing",
      "camera": {"position": "wide", "angle": "high angle", "move": "slow push in"},
      "focal_length": "24mm",
      "subject": "city skyline with protagonist silhouette",
      "duration_sec": 8,
      "lighting": "practical neon, rain reflections",
      "notes": "City should feel overwhelming relative to protagonist"
    }
  ]
}
\end{lstlisting}

\section{Training}

\subsection{Dataset}

\begin{table}[H]
\centering
\begin{tabular}{lrrl}
\toprule
\textbf{Source} & \textbf{Samples} & \textbf{Proportion} & \textbf{Content} \\
\midrule
Film scripts + frames & 2,400,000 & 29.3\% & Script-to-scene alignment \\
Cinematography textbooks & 180,000 & 2.2\% & Technical knowledge \\
Film criticism corpus & 820,000 & 10.0\% & Aesthetic analysis \\
Video-caption pairs & 3,100,000 & 37.8\% & Visual understanding \\
Storyboard collections & 1,700,000 & 20.7\% & Shot plan examples \\
\midrule
\textbf{Total} & \textbf{8,200,000} & 100\% & \\
\bottomrule
\end{tabular}
\caption{Zen-Director Training Data}
\end{table}

\subsection{Training Protocol}

\textbf{Stage 1 -- Visual encoder alignment} (20K steps): The ViT encoder and MLP projection
are trained to align visual representations with cinematic language descriptions.

\textbf{Stage 2 -- Temporal pretraining} (40K steps): The temporal transformer is pretrained
on video sequences with a masked-frame prediction objective.

\textbf{Stage 3 -- Directorial SFT} (60K steps): The full model is fine-tuned on storyboard
generation, scene description, and cinematographic Q\&A tasks jointly.

\textbf{Stage 4 -- RLHF from cinematographers} (15K steps): A reward model trained on 50,000
pairwise comparisons from professional cinematographers (recruited via film school partnerships)
is used to further refine shot plan quality via PPO.

\section{Evaluation}

\subsection{VideoCaption Benchmark}

We evaluate video description quality on a held-out set of 5,000 film clips spanning 20 genres.

\begin{table}[H]
\centering
\begin{tabular}{lcccc}
\toprule
\textbf{Model} & \textbf{BLEU-4} & \textbf{METEOR} & \textbf{CIDEr} & \textbf{ROUGE-L} \\
\midrule
BLIP-2 & 0.281 & 0.314 & 0.872 & 0.512 \\
InstructBLIP & 0.308 & 0.341 & 0.941 & 0.534 \\
VideoChat2 & 0.352 & 0.374 & 1.021 & 0.561 \\
Video-LLaMA2 & 0.387 & 0.402 & 1.103 & 0.584 \\
\textbf{Zen-Director} & \textbf{0.423} & \textbf{0.441} & \textbf{1.187} & \textbf{0.612} \\
\bottomrule
\end{tabular}
\caption{VideoCaption Benchmark Results (higher is better)}
\end{table}

\subsection{CinematicQA}

CinematicQA is a novel benchmark we introduce comprising 2,000 multiple-choice questions
testing cinematographic knowledge: shot types, camera movements, lighting techniques, editing
principles, and genre conventions. Questions were authored by five professional cinematographers.

\begin{table}[H]
\centering
\begin{tabular}{lc}
\toprule
\textbf{Model} & \textbf{Accuracy (\%)} \\
\midrule
GPT-4o (zero-shot) & 68.3 \\
Claude 3.5 Sonnet & 71.4 \\
Gemini 1.5 Pro & 66.8 \\
Specialist fine-tuned 7B & 74.2 \\
\textbf{Zen-Director 7B} & \textbf{81.2} \\
\bottomrule
\end{tabular}
\caption{CinematicQA Accuracy (\%)}
\end{table}

\subsection{Professional Storyboard Evaluation}

Twenty professional cinematographers evaluated storyboards generated from 100 scene descriptions,
rating each on a 5-point scale across five dimensions.

\begin{table}[H]
\centering
\begin{tabular}{lc}
\toprule
\textbf{Dimension} & \textbf{Mean Score (1--5)} \\
\midrule
Technical accuracy of shot specifications & 4.3 \\
Narrative coherence across shots & 4.1 \\
Creative quality / originality & 3.9 \\
Pacing appropriateness & 4.0 \\
Overall directorial vision & 4.1 \\
\midrule
\textbf{Overall Mean} & \textbf{4.1} \\
\bottomrule
\end{tabular}
\caption{Professional Cinematographer Evaluation (N=20 evaluators, 100 storyboards)}
\end{table}

\subsection{Downstream Video Generation Quality}

We evaluate whether Zen-Director shot plans improve final video quality when used as structured
prompts for a text-to-video generation system. Using the same creative brief:

\begin{table}[H]
\centering
\begin{tabular}{lcc}
\toprule
\textbf{Prompt Method} & \textbf{Human Preference (\%)} & \textbf{FVD} $\downarrow$ \\
\midrule
Raw creative brief (baseline) & 18.4\% & 412 \\
Manual cinematographer spec & 42.1\% & 287 \\
Zen-Director shot plan & 39.5\% & 298 \\
\bottomrule
\end{tabular}
\caption{Downstream Video Quality with Zen-Director Shot Plans}
\end{table}

Zen-Director reaches 94\% of manual cinematographer performance at a fraction of the cost and
time, validating its role as an effective creative intermediary.

\section{Applications}

\subsection{AI Film Production Pipeline}

Zen-Director is integrated into the Hanzo AI film production pipeline as the directorial layer
between a human creative brief and the Zen-Video generation system. A typical workflow:

\begin{enumerate}
    \item Human writes a scene description in natural language.
    \item Zen-Director generates a shot plan JSON with full cinematographic specs.
    \item Human reviews and optionally edits the shot plan (typically 3--5 minutes).
    \item Zen-Video consumes the shot plan and generates video clips per shot.
    \item Zen-Director evaluates temporal consistency across clips and suggests retakes.
\end{enumerate}

\subsection{Film Education}

Zen-Director serves as an interactive cinematography tutor: students can submit scene
descriptions and receive expert-level directorial notes explaining the reasoning behind
each shot choice.

\subsection{Video Game Cutscene Direction}

Game studios use Zen-Director to generate cinematic specifications for in-engine cutscene
directors, reducing the time from narrative script to playable sequence by an estimated 60\%.

\section{Related Work}

Video understanding models (VideoChat, Video-LLaMA) focus primarily on description generation.
Text-to-video generation systems (Sora, CogVideo, ModelScope) focus on pixel synthesis.
Zen-Director uniquely occupies the directorial planning layer between these two stages,
drawing on the rich tradition of computational narrative research and cinematography theory.

\section{Conclusion}

Zen-Director establishes a new model category: the AI cinematographer. By training on film
scripts, storyboards, and cinematographic knowledge at 7B scale, the model achieves 81.2\%
on CinematicQA and generates shot plans rated 4.1/5 by professional cinematographers.
Integration with the Zen-Video generation backbone creates a complete AI film production
pipeline from creative brief to rendered footage.

\begin{thebibliography}{10}
\bibitem{li2023blip} J. Li et al., ``BLIP-2: Bootstrapping Language-Image Pre-training with Frozen Image Encoders and Large Language Models,'' ICML, 2023.
\bibitem{videochat} K. Li et al., ``VideoChat: Chat-Centric Video Understanding,'' arXiv:2305.06355, 2023.
\bibitem{makarov2022} A. Makarov et al., ``Computational Cinematography: A Survey,'' IEEE TPAMI, 2022.
\end{thebibliography}

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