Veo 3.1 Model Reference

Overview

Veo 3.1 is Google's latest video generation model, designed for filmmakers, storytellers, and developers. It produces realistic, cinematic 4-8 second video clips (extendable via API) with synchronized native audio, including dialogue, sound effects, ambient noise, and music. The model supports both text-to-video and image-to-video workflows, with advanced controls for reference images, scene extensions, first/last frame interpolation, and object insertion/removal.

Key Capabilities

• Resolutions: 720p (default), 1080p, and 4K (preview; 8-second duration only for higher resolutions)
• Aspect Ratios: 16:9 (landscape) and 9:16 (portrait)
• Durations: 4, 6, or 8 seconds (8 seconds required for reference images, high resolution, or extensions)
• Frame Rate: 24 FPS
• Inputs: Text prompts (up to 1,024 tokens), up to 3 reference images for character/style consistency, or prior Veo-generated videos for extension
• Outputs: MP4 video with embedded native audio
• Creative Controls: Reference images (portrait/landscape), scene extension, first/last frame transitions, object add/remove, camera movements (dolly, pan, zoom), and cinematic styling
• Audio: Native generation fully synced to visuals—supports dialogue (in quotes), SFX, ambient sound, and music

Strengths

• Exceptional realism in physics, lighting, shadows, and natural motion
• Superior prompt adherence and cinematic understanding (camera language, composition, styles)
• Rich native audio that enhances storytelling without post-production
• Strong character and style consistency via reference images
• Flexible creative tools for professional workflows (extensions, transitions, object editing)
• Available across Google AI Studio, Gemini API, Vertex AI, and consumer tools like Gemini app

Limitations

• Short base clip length (4-8 seconds; extensions possible but limited to Veo-generated source videos)
• Generation latency varies (seconds to minutes depending on load and resolution)
• Strict safety filters block harmful or policy-violating content (including certain person generation in some regions)
• All outputs include visible watermark + SynthID digital watermark for AI detection
• Videos stored temporarily (2 days in API); must be downloaded promptly
• No guaranteed determinism even with seed; audio dialogue consistency can vary for longer speech
• Higher resolutions and extensions have stricter constraints (e.g., 720p only for some extensions)

How to Write Effective Prompts

Veo 3.1 excels with highly descriptive, cinematic prompts. Structure your prompt like a film direction:

1. Subject + Action: Start with the main scene and motion (e.g., "A wise old owl soaring through moonlit clouds")
2. Camera & Composition: Specify shots and movement ("follow shot", "slow dolly zoom", "shallow depth of field")
3. Style & Mood: Add artistic direction ("cinematic, photorealistic", "in the style of Studio Ghibli")
4. Audio: Describe sound explicitly ("wings flapping loudly", "mellow hip-hop beat with faint city murmurs", or dialogue: "What manner of magic is this?" the owl hooted)
5. Reference Images: Upload 1-3 images for characters/objects/styles to lock consistency

Example Prompt: "A medium shot of a seasoned grey-bearded man in sunglasses and a paisley shirt standing on a bustling city street at dusk. Camera slowly pushes in as he smiles. Faint city murmurs and distant chatter, accompanied by a mellow soulful hip-hop beat. 'The city always got a story,' the older man murmurs thoughtfully. Cinematic lighting, realistic physics."

Negative Prompt Example (supported): "blurry, distorted faces, text, logos, watermarks, low quality, artifacts"

Use the API parameters for fine control: aspect_ratio, resolution, durationSeconds, and reference images.