Video Model Selection and Prompt Shaping

STEP 7: Video-Model Choice Card + Single-Shot Video Clips

Video-model choice card (mandatory before any clip render)

Before any clip is rendered, show the video-model choice card. The choice is stored in the Project Brief and reused for every clip in this project unless the user later changes it.

Video model card:

• H3 (recommended default) — strong on visual packaging, motion graphics, text/UI clarity, multi-modal context understanding, and cost efficiency (about 1/3 the price of comparable flagship models at 2K, 1/2 at 768P). Native dual-channel audio. Up to 15s per clip at 2K. Best for: stylized 3D animated shorts with strong design language, text overlays, motion-graphic moments, packaging-style transitions, and dialogue-driven beats where the audio is part of the deliverable.
• Seedance 2.0 (fallback for high-stakes animation performance) — strong on cinematic camera, complex shots, elastic Pixar-style performance, and tension-driven action. Best for: chase sequences, slapstick beats, climax shots where the selling point is the animation itself rather than the packaging.
• Per-shot mixed (advanced) — let the user mark video_model: H3 or video_model: Seedance2 in the Shot Description column of individual rows. Use this when the project has both packaging-heavy and performance-heavy shots. The default for unmarked rows is H3.

Resolution choice card (after video model)

Once the video model is locked, show the resolution choice card:

• 768P (recommended for H3 first pass; cost-efficient)
• 2K (H3 default quality; higher cost, sharper final render)
• 1080p (recommended for Seedance 2.0)
• 720p (Seedance 2.0 draft; lowest cost)
• Match project / custom resolution

The user must confirm a resolution before the first clip renders. Resolution can be changed per clip later if the user wants a hero shot at higher detail.

Single-shot clip rendering

For each approved table row, call the chosen video model to generate the corresponding independent video clip. Each clip must use exactly the matching section from the text storyboards document (extracted standalone node if that section was extracted, otherwise the in-document section), character card(s), and scene card from that row.

Per-shot rules common to all video models:

• Use the text storyboards document as the authoritative per-shot reference for narrative, composition, camera movement, action staging, per-second timing, and shot number. For shots that have been extracted to a standalone node, read the extracted node instead. If a pencil image storyboard also exists, use it only for human-side pose / silhouette pre-check; do not let it override the text storyboard.
• Use character cards as the authoritative identity source.
• Use scene cards as the authoritative environment source.
• Strip all storyboard double-binding labels ([char:…], [scene:…], [shot:…], [dur:…], [hook:…]) before video render — these labels are storyboard-only reference markers and must NOT appear in the final clip. Pencil image storyboards additionally have their own shot numbers, camera icons, arrows, and notes that must be removed at render time.
• The rendered clip must contain only clean full-color Pixar-inspired 3D animation content.
• No storyboard line art, no hand-drawn sketch texture, no labels, no subtitles unless requested, no watermarks.
• Maintain the approved screen size / aspect ratio and the approved video resolution from the resolution choice card.

Model-specific prompt shaping

The text storyboards document (or the extracted standalone node for that shot) feeds both models, but the prompt prefix around the storyboard differs:

• H3 prompt prefix (default): emphasize packaging keywords, design language, motion clarity, text/UI presence when relevant, and dual-channel audio intent. H3 is strong at instruction following, so the per-second directive can be sent almost verbatim. Add: Pixar-inspired 3D cartoon rendering, C4D + Octane look, stylized Q-version proportions, warm SSS skin, designed-with-detail hair, strong character design language, clean motion, on-brand color palette.
• Seedance 2.0 prompt prefix (performance fallback): emphasize cinematic camera language, elastic squash-and-stretch, anticipation, follow-through, lighting drama, and lens choice. Add: cinematic Pixar-quality 3D animation, elastic squash-and-stretch performance, Disney-style anticipation and overshoot, dramatic key lighting, lens-specific depth of field.

When the user picked per-shot mixed, apply the prefix that matches the row’s video_model field.