Creating videos with consistent characters across multiple scenes has always been one of the biggest challenges for content creators, animators, and AI video enthusiasts. Imagine spending hours generating the perfect character in one scene, only to have them look completely different in the next frame. Frustrating, right?

Thanks to recent advancements in AI video generation technology, we now have powerful tools called "system prompts" combined with "slot tokens" that solve this exact problem. These techniques allow you to maintain character consistency, control lighting conditions, manage costumes, and even direct camera movements across your entire video project. Learn more about Google's Veo 3 AI video technology from DeepMind.

What Are System Prompts for Video Generation?

Think of system prompts as the master instructions you give to an AI video generator before it starts creating your content. Unlike regular prompts that describe individual scenes, system prompts set up rules and guidelines that apply to your entire video project.

System prompts act like a director's notes that tell the AI: "Remember this character's appearance throughout the whole video" or "Keep the lighting consistent in all indoor scenes." This approach ensures that the AI doesn't "forget" important details as it moves from scene to scene.

Understanding Slot Tokens: The Secret to Consistency

Slot tokens are like labeled containers where you store specific information that needs to stay consistent throughout your video. Instead of repeating the same descriptions over and over, you define something once in a slot token and reference it whenever needed.

The Three Main Types of Slot Tokens

Modern video generation systems typically use three primary categories of slot tokens:

1. Character Slots: Store detailed information about your characters including facial features, body type, hairstyle, age, ethnicity, and any distinguishing characteristics
2. Costume & Environment Slots: Define clothing, accessories, props, and environmental settings that should remain consistent
3. Technical Slots: Control lighting conditions, camera angles, movement styles, and cinematography preferences

How to Use Slot Tokens for Character Consistency

Let's break down how you can practically implement slot tokens to maintain perfect character consistency across your multi-scene video project:

Step 1: Define Your Character in Detail

When creating a slot token for a character, be extremely specific. Instead of saying "a young woman," describe every important detail:

• Approximate age and age indicators
• Face shape, eye color, nose shape, and lip characteristics
• Hair color, length, texture, and style
• Skin tone and any distinctive marks
• Body build and height relative to other characters
• Typical expressions or mannerisms

Step 2: Create Costume and Wardrobe Tokens

Characters often need to wear the same outfit across multiple scenes, or change into specific costumes for different parts of your story. Costume tokens allow you to define these wardrobe elements once and apply them consistently:

For example, you might create a token called "detective_outfit" that includes: "navy blue trench coat, white button-down shirt, black tie, dark gray slacks, and worn leather shoes." Whenever you need this character in their detective outfit, you simply reference this token instead of retyping everything.

Step 3: Set Up Lighting and Atmosphere Tokens

Lighting dramatically affects how characters appear on screen. By using lighting slot tokens, you ensure that the mood and visibility remain consistent within scene groups:

• Golden Hour Token: Warm, soft lighting from low sun angle
• Office Fluorescent Token: Cool, even overhead lighting
• Dramatic Noir Token: High contrast with deep shadows
• Natural Daylight Token: Bright, neutral outdoor lighting

Managing Camera Movements with Slot Tokens

Camera movement consistency is just as important as character consistency for creating professional-looking videos. Slot tokens for camera work help you maintain a coherent visual style throughout your project.

Common Camera Movement Tokens

Here are some popular camera movement patterns you can define as tokens:

• Steady Documentary Style: Minimal movement, tripod-mounted feel
• Handheld Dynamic: Slight natural shake, following action closely
• Cinematic Dolly: Smooth lateral or forward/backward movement
• Dramatic Push-In: Slow zoom toward subject for emphasis
• Orbiting Shot: Camera circles around the subject

By defining these camera behaviors in your system prompt, you can ensure that action scenes all share the same energetic camera style, while dialogue scenes maintain their calmer approach.

Practical Workflow: Putting It All Together

Now that you understand the individual components, let's walk through a practical workflow for creating a multi-scene video with consistent characters:

1. Initial Setup: Write your system prompt defining both characters using detailed slot tokens
2. Environment Tokens: Create separate tokens for each location (coffee_shop_setting, park_setting, office_setting)
3. Lighting Coordination: Assign appropriate lighting tokens to each location
4. Camera Planning: Choose camera movement styles that match each scene's emotional tone
5. Scene Generation: Generate each scene while referencing the appropriate slot tokens
6. Review and Adjust: Check consistency and refine tokens if needed

Common Challenges and How to Overcome Them

Problem: Character Features Still Change Between Scenes

If your character's appearance isn't staying consistent, the issue usually lies in insufficient detail in your character token. Go back and add more specific descriptors, particularly for the most noticeable features like face shape, distinctive hairstyle, and eye characteristics.

Problem: Lighting Looks Different Despite Using Same Token

Environmental factors in your scene description might be overriding your lighting token. Make sure your scene prompts don't include conflicting lighting descriptions. If you've set a "golden hour" lighting token, avoid mentioning "midday sun" in individual scene prompts.

Problem: Token System Feels Too Complex

Start simple. You don't need to create tokens for everything immediately. Begin with just character consistency, then gradually add costume, lighting, and camera tokens as you become more comfortable with the system.

Best Practices for Maximum Consistency

After working with system prompts and slot tokens across numerous projects, here are the techniques that deliver the best results:

• Be Specific But Not Restrictive: Provide clear details without over-constraining the AI's creative interpretation
• Test Your Tokens: Generate a few test scenes before committing to a full project to ensure your tokens work as expected
• Maintain Token Naming Consistency: Use clear, descriptive names for your tokens that you'll remember later (character_john_detective not char1)
• Document Your Tokens: Keep a separate document listing all your tokens and their descriptions for easy reference
• Update Gradually: If you need to modify a character's appearance mid-project, make changes gradually rather than drastically rewriting the entire token

Advanced Techniques: Conditional Tokens

As you become more experienced, you can create conditional tokens that change based on scene requirements. For example, your character might have a "daytime_appearance" token and an "evening_appearance" token, with subtle differences in makeup, lighting response, or wardrobe details.

This approach gives you flexibility while maintaining the core character identity that makes them recognizable across all scenes.

The Future of Character Consistency in AI Video

The technology behind system prompts and slot tokens continues to evolve rapidly. We're seeing improvements in several key areas:

• Better facial feature recognition and maintenance across longer videos
• More intuitive token systems that require less manual description
• Enhanced ability to maintain consistency even with dramatic lighting or angle changes
• Integration with reference images for even more precise character control

As these systems improve, creating professional-quality multi-scene videos with perfect character consistency will become even more accessible to individual creators and small teams.

Conclusion: Mastering Consistency for Professional Results

System prompts combined with slot tokens represent a fundamental shift in how we create AI-generated videos. By understanding and properly implementing these tools, you can achieve the kind of character and environmental consistency that was previously only possible with traditional animation or live-action filming.

The key is to start with strong foundational tokens for your main characters and essential settings, then gradually expand your system as you learn what works best for your creative style. With practice, the process becomes second nature, and you'll find yourself producing multi-scene videos with seamless consistency that rivals professionally produced content.

Whether you're creating educational content, short films, marketing videos, or entertainment projects, mastering these techniques will dramatically improve the quality and professionalism of your work. The investment in learning this system pays off exponentially as your video projects grow in complexity and scope. For additional insights on character development, explore Pixar's character storytelling course on Khan Academy.