Popiai-skill/content-creation/video-prompting/references/models/official-hilo/prompting.md

Official Hilo Video Generation - Prompting Guide

Model Overview

Attribute	Value
Tool Name	official_videos_generation
Available Models	Official-Hilo-2.3-Fast, Official-Hilo-2.3, Official-Hilo-02
Duration	6s or 10s
Resolution	768P, 1080P
Input Modes	I2V (first frame, recommended), I2V + last frame, pure T2V
Special Features	Background sound effects, automatic prompt optimization, lip sync (via official_generate_video_based_on_image_and_audio)

Core Principles

1. Always Use I2V Mode

Always prioritize using a first frame image (first_frame_images) to drive generation. Pure text-to-video quality is far inferior to image-to-video.

Workflow: Generate a high-quality first frame with an image model → Then generate video with Hilo.

2. Prompt Structure

Hilo prompts should read like a natural language shot description, not a keyword dump:

[Shot type and movement], [Subject and their action], [Environment details], [Lighting and atmosphere], [Style modifiers]

3. Automatic Prompt Optimization

enable_prompt_optimize is enabled by default — Hilo will automatically expand and optimize your prompt. If you've already written a very precise prompt, you can disable this feature for more precise control.

Best Practices

Camera Language

Explicitly specify shot types and camera movements:

Shot Type	English Expression
Close-up	Close-up shot, extreme close-up
Medium shot	Medium shot, waist-up shot
Wide shot	Wide shot, establishing shot
Long shot	Long shot, aerial view
Tracking	Tracking shot, following shot
Push/Pull	Dolly in / dolly out, zoom in / zoom out
Pan	Pan left / pan right
Crane	Crane shot, tilt up / tilt down
Orbit	Orbit shot, 360-degree rotation
Handheld	Handheld camera, shaky cam
Static	Static shot, locked-off camera

Action Description

• Use progressive tense for continuous actions: A woman is walking through...
• Use action sequences for changes: She turns her head slowly, then breaks into a smile
• Control action intensity: Only 1-2 actions within 6s, 2-3 actions within 10s
• Avoid overly intense full-body movements (e.g., running, dancing) — they tend to cause distortion

I2V + Last Frame (Official-Hilo-02 exclusive)

last_frame_images is only supported by Hilo-02. Ideal for:

• Scene transitions (day → night)
• Expression changes (calm → smile)
• Object transformations (bud → bloom)

Background Sound

Setting enable_background_sound: true automatically generates ambient sound effects matching the visuals (wind, water flow, city noise, etc.). Suitable for natural scenes that don't need music.

Common Pitfalls

1. Don't use negative statements: The model cannot understand "no people" — describe what you want instead
2. Don't overload adjectives: 3-5 style words are enough; too many will conflict
3. Don't cram too many actions into 6s: One clear action beats three vague ones
4. Don't skip the first frame: Pure T2V quality is unreliable — always provide a first frame
5. Text content: The model cannot reliably generate on-screen text

Example Prompts

Character Close-up (6s, I2V)

Close-up shot, a young woman with long black hair slowly turns her head toward the camera, her expression shifts from contemplative to a gentle smile. Soft golden hour light illuminates her face from the side. Shallow depth of field, cinematic color grading, film grain.

Aerial Landscape (10s, I2V)

Aerial drone shot slowly ascending over a misty mountain valley at dawn. Layers of fog drift between the peaks as the first rays of sunlight paint the ridges gold. The camera gradually tilts down to reveal a winding river below. Epic cinematic scale, 4K quality, nature documentary style.

Scene Transition (6s, I2V + last frame, Hilo-02)

Smooth transition, the scene gradually shifts from warm afternoon light to cool blue twilight. Cherry blossom petals drift through the air as the lighting changes. The woman's silhouette remains centered in frame. Dreamy, ethereal atmosphere, soft focus background.

Dynamic Action (10s, I2V)

Medium tracking shot, a street musician plays acoustic guitar on a rain-soaked city sidewalk at night. Neon reflections shimmer in puddles around his feet. Pedestrians with umbrellas pass in the background as bokeh lights create a dreamy atmosphere. Camera slowly orbits around the musician. Moody, cinematic, urban night photography style.