3. AI Voiceover

Generate a narrated voiceover for your video using AI.

Generate a narrated voiceover for your video using AI. This is useful for explainer videos, product demos, documentary-style narration, storytelling, and any situation where spoken audio enhances context.

How It Works

The AI Voiceover tile takes a written script (or auto-generated script, depending on mode), synthesizes a natural-sounding voice, and aligns it with your video. You choose the voice style and script mode, and Mosaic handles the timing and audio mixing.

Input and Settings

Voice

Select from a range of AI voices with different genders, tones, and delivery styles.
You can preview the selected voice before committing.

Use cases:

• Professional narration (corporate, training, onboarding)
• Energetic narration for social content
• Calm educational explanations

Script Mode

Choose how the narration script is created.

Modes include:

• Custom Script: You provide the exact text
• (Other modes may include auto-generated, depending on provider)

If using Custom Script, the script field becomes required.

Use cases:

• Precise storytelling
• Product walkthroughs
• Brand-compliant messaging
• Reading long-form copy without re-recording

Custom Script

Enter the exact text you want spoken in the voiceover.

Best practices:

• Keep sentences short for clarity
• Use punctuation for natural pauses
• Mention on-screen references ("as you can see here…")

Time Script to Video Moments (Optional)

When enabled, Mosaic attempts to align portions of the script with visual beats in the video.

Benefits:

• More dynamic pacing
• Better alignment with scene changes
• Reduces manual timing work

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API Info

Node Params & API Details

• Node ID: 9570c960-b32b-4e4d-8871-5775d886f7cb

Node params

Param	Type	Required	Default	Notes
voice_provider	"elevenlabs"	No	"elevenlabs"	Other providers are currently rejected by runtime.
voice_id	string	No	"UgBBYS2sOqTuMpoF3BR0"	ElevenLabs voice ID (curated or custom).
script_mode	"custom_script" | "prompt"	Yes	"custom_script"	Controls which text source is used.
custom_script	string	Conditional	""	Required when script_mode="custom_script".
prompt	string	Conditional	""	Required when script_mode="prompt".
time_script_to_video	boolean	No	false	Attempts beat/scene-aware timing.

Parameter groups

• Voice selection: voice_provider, voice_id
• Script source mode: script_mode, custom_script, prompt
• Timing behavior: time_script_to_video

Scenario requirements

• script_mode="custom_script" -> non-empty custom_script required.
• script_mode="prompt" -> non-empty prompt required.

Runtime notes

• UI filtering keeps only the active text field for the selected mode.
• If voice_provider is omitted, runtime hard-defaults to ElevenLabs.

Example

{
  "voice_provider": "elevenlabs",
  "voice_id": "UgBBYS2sOqTuMpoF3BR0",
  "script_mode": "custom_script",
  "custom_script": "Today we're launching a faster way to review and publish your videos.",
  "time_script_to_video": true
}