How to Use JSON to Get the Best Results from Gemini VO3 Video Output – With Example

Using JSON to create a VO3 Flash2.5 Gemini videos is by far the best way

If you’ve been experimenting with Google’s Gemini VO3 video generation model, you’ll know that the quality of your results depends heavily on the quality of your prompt. While you can simply describe what you want in plain text, using JSON for your VO3 prompts gives you more control, repeatability, and consistency – especially when you want precise character appearances, camera work, and scene details.

https://youtu.be/L4TUOlVg_M0

In this post, I’ll explain how Gemini VO3 works, why JSON is the better approach for professional results, and then walk you through a real working JSON prompt example so you can adapt it for your own projects.

You can download my JSON template pack here.

How Gemini VO3 Works

Gemini VO3 is designed to generate realistic talking-head or cinematic clips based on a structured prompt. You tell it:

• Who the character is (appearance, style, demeanour)
• How the camera behaves (angle, lens type, motion)
• The scene’s setting, lighting, and mood
• The audio and dialogue to match lip movement

If you provide just a short sentence, VO3 will fill in the gaps – but that often leads to inconsistent outputs. Using structured JSON lets you give VO3 a precise, machine-readable set of instructions so you get the same style every time.

Why JSON is Better for VO3 Video Prompts

1. Precision – You can set exact parameters like frame rate, lens focal length, lighting type, and even colour palette.
2. Repeatability – If you want the same character across multiple videos, you can just reuse their JSON profile.
3. Control over style – Define mood, wardrobe, props, and even specific actions.
4. Complex scenes – Include multiple clips, each with different camera angles or environments.
5. Team collaboration – Developers, designers, and marketers can all edit the same JSON without losing details in translation.

By working in JSON, you remove ambiguity and give VO3 exactly what it needs.

Step-by-Step Guide: Understanding the Example JSON

Below is an example JSON prompt I used to create a realistic UK car dealer testimonial video.

1. Character Profile

"character_name": "Paul Turner",
"character_profile": {
"age": 42,
"height": "5'10\" / 178 cm",
"build": "average build with a bit of a solid frame",
"skin_tone": "light with slight weathering from outdoor work",
"hair": "short dark brown, slightly tousled",
"eyes": "grey-blue eyes",
"demeanour": "approachable, straight-talking, no-nonsense"
}

This defines Paul Turner’s physical appearance and personality – keeping him believable as a UK car dealer.

2. Global Style

"global_style": {
"camera": "handheld, slightly looser framing for a casual feel",
"color_grade": "true-to-life outdoor tones – soft blues, muted greys",
"lighting": "natural daylight, slightly overcast",
"outfit": "rolled-up light blue shirt sleeves, dark gilet, black jeans, sturdy brown boots",
"max_clip_duration_sec": 8,
"aspect_ratio": "16:9"
}

This applies to the whole video – the handheld camera and overcast light make it look natural, as if filmed on a real forecourt.

3. Clips Section

"clips": [
{
"id": "S1_ForecourtPitch",
"shot": {
"composition": "Medium shot, 35 mm lens",
"camera_motion": "gentle pull-in",
"frame_rate": "24 fps"
},
"scene": {
"location": "UK used car forecourt",
"time_of_day": "midday",
"environment": "outdoors, cars lined up with price stickers"
},
"dialogue": {
"line": "Marketcheck data allows me to buy cars that sell faster for more margin so I highly recommend you try it."
}
}
]

This part controls the action and dialogue. VO3 will lip-sync the line in a UK English accent and animate the character naturally.

4. Visual & Audio Details

Inside each clip, you can set:

• Props – In this case, a car key and clipboard.
• Colour palette – Ensures consistency in skin tone and environment colours.
• Audio emotion and flow – Direct, confident, conversational.

Key Takeaways for Writing Your Own VO3 JSON Prompts

• Always start with a clear character_profile for consistency.
• Use global_style to lock in camera, lighting, and colour so multiple videos match.
• Break your video into clips for more complex storytelling.
• Include audio defaults if you want consistent tone and style.
• Keep it realistic if you want your audience to trust the character.

By structuring your Gemini VO3 prompts in JSON like this, you’ll produce videos that are more consistent, more professional, and more aligned with your brand.

You can download my JSON template pack with placeholders for characters, styles, and clip variations so visitors to your site can copy and customise them instantly.