# Voice + BGM Mixer — yeezhan.com
> One-time pay-per-task emergency tool to make your file ready for submission.
> No credits, no balance. One payment unlocks one task result, valid for 24 hours.

Tool domain: https://audio-mix.yeezhan.com
Skill definition: https://audio-mix.yeezhan.com/skill/SKILL.md
API documentation: https://audio-mix.yeezhan.com/api/docs

## What this tool does
Overlay background music under a voice track at 0–100% BGM volume — output stays exactly as long as the voice.

## Typical user problems
- Narration over music needs the voice on top and the BGM tucked underneath — dropping both files into an editor, balancing faders and bouncing the result is overkill. Track 1 keeps full volume, the music is mixed in at your chosen level, and the result ends when the voice ends.

## Parameters
- bgm_volume: number (range 0-1), required. BGM 音量（0–1）

## Pricing
- Watermarked preview: free, no login required
- Final clean output: $0.99 one-time per task
- Require login (email/phone OTP) to complete payment
- Result available for download 24 hours after payment

## Limitations
- Max 200 MB