2. AI B-Roll

Automatically generate or source relevant B-roll that matches what's being said in your video.

Automatically generate or source relevant B-roll that matches what's being said in your video, helping you increase visual variety, storytelling quality, and audience retention.

AI B-roll is especially useful for talking-head videos, interviews, podcasts, explainers, and educational content that benefit from visual support.

How It Works

The AI B-Roll tile analyzes your video's speech, plans relevant visual cutaways, generates short video clips, and overlays them at appropriate timestamps.

You can control:

• B-roll density
• Video generation model
• Aspect ratio
• Whether generated clips include audio
• Maximum number of generated clips
• Visual style and content focus

Input & Settings

Coverage Level

Defines how much B-roll gets added per minute.

Options include (may vary by build):

• Minimal
• Moderate ← Balanced default
• High
• Maximal

Use Minimal for subtle enhancement and Maximal for heavy coverage.

Video Model

Select which AI model to generate B-roll with.

Supported API values:

• seedance-2
• veo-3.1
• veo-3.1-fast
• veo-3.1-lite

Different models produce different visual styles (cinematic, realistic, stylized, etc.).

Aspect Ratio

Controls the shape of generated B-roll.

Options:

• Auto (recommended) → Matches your input video or target platform
• 16:9 for YouTube/desktop
• 9:16 for TikTok/Reels/Shorts Choose based on your final output format.

Generate Audio (Optional)

Toggle to include audio in the generated B-roll.

Notes:

• Not all models support audio
• Useful for cinematic segments
• Not required for overlay-style B-roll

Max Video Generations

Sets the max number of B-roll scenes to create.

The backend caps this at 20 generated clips for deterministic runtime.

Style & Content Prompt (Optional)

Use this to define:

• Visual style
• Subject matter
• Tone / vibe

Examples:

• "Cinematic city skyline shots, wide angle, slow motion"
• "Stock footage of office work and laptops, clean and modern"
• "Playful animated visuals matching educational content"
• "Nature and planet shots, documentary style"

Leave blank to let Mosaic choose based on content.

Usage Recommendations

Use AI B-roll to:

• Break up long talking segments
• Add visual context to explanations
• Support storytelling
• Improve audience retention

AI B-roll works great when combined with:

• Clips (extract highlights first)
• Reframe (convert to 9:16 for TikTok)
• Captions (add subtitles)
• AI Music (background audio)

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API Info

Node Params & API Details

• Node ID: 2160392b-ebe8-4f3d-b81e-fd11bdbbeb77

Node params

Param	Type	Required	Default	Notes
coverage_level	"low" | "moderate" | "high" | "max"	No	"moderate"	Amount/frequency of generated B-roll.
prompt	string	No	""	Optional visual/style guidance.
video_model	"seedance-2" | "veo-3.1" | "veo-3.1-fast" | "veo-3.1-lite"	No	"seedance-2"	Model choice for generated B-roll clips.
asset_types	("video")[]	No	["video"]	Fixed to video generation in current implementation.
aspect_ratio	"auto" | "16:9" | "9:16"	No	"auto"	Generated clip framing mode.
generate_audio	boolean	No	false	Include audio in generated clips when supported by the selected model.
max_video_generations	number	No	20 effective	UI/metadata may allow higher values; backend hard cap is 20.

Parameter groups

• Coverage strategy: coverage_level, max_video_generations
• Generation model: video_model, asset_types, aspect_ratio, generate_audio
• Creative guidance: prompt

Scenario requirements

• Keep max_video_generations within 1..20 for deterministic behavior.
• Some model/aspect combinations are rejected by backend validators.

Runtime notes

• coverage_level controls target placement density and minimum gaps.
• max_video_generations is capped at 20.

Example

{
  "coverage_level": "moderate",
  "video_model": "seedance-2",
  "aspect_ratio": "9:16",
  "generate_audio": false,
  "max_video_generations": 10,
  "prompt": "Add short cinematic cutaways that reinforce key points."
}