---
title: "Add background music"
method: POST
path: "/v1/studio/music"
tags: ["Audio"]
---

# Add background music

`POST /v1/studio/music`

## Request

- Base URL: `https://apihub.co.il`
- URL: `https://apihub.co.il/v1/studio/music`
- Auth: HTTP bearer

Mix a music track under the video: volume, loop, fades, and automatic ducking under speech.

**Billing:** Per second of output (≤720p / 1080p tiers; audio and images cheaper) + transcription seconds when captions or silence removal transcribe automatically + the voice clean-up per second of output when asked for (`audio.denoise` / `enhance`, off by default) and only when it found noise to reduce or enhanced the voice (`auto` on a clean recording is free) + effect seconds for a heavy engine effect in `effects` (its seconds on screen × its measured weight — GET /v1/effects). Failed renders are not charged. · **Rate limit:** 30/min · **Asynchronous**

## Headers

- `Idempotency-Key` string
- `X-Tag` string
- `x-wait-ms` integer

## Request body

- object
  - `duck` boolean: Lower the music automatically while someone speaks
  - `loop` boolean
  - `output` object
    - `fit` 'crop' | 'blur' | 'pad': When the aspect ratio changes: crop the edges, blurred copy behind, or solid bars
    - `fps` number
    - `format` 'mp4' | 'webm' | 'mov' | 'gif' | 'mp3' | 'wav' | 'm4a' | 'jpg' | 'png'
    - `quality` 'draft' | 'standard' | 'high': high (default) = best picture; draft renders fastest for previews
    - `background` string: Bar colour for fit=pad
    - `resolution` '480' | '720' | '1080' | 'source': Short side in pixels (1080 = Full HD). `source` keeps the input size, max 1080
    - `aspect_ratio` 'original' | '9:16' | '16:9' | '1:1' | '4:5' | '4:3': 9:16 for Reels/TikTok/Shorts, 1:1 or 4:5 for feed, 16:9 for YouTube
  - `volume` number
  - `duck_db` number: With `duck`: how far the music dips under speech, dB — −6 (default) = half as loud under the voice, −3 a gentle dip, −18 a deep one. A fixed depth whatever the speaker's level; attack 40 ms, release 700 ms
  - `start_ms` number: Start the music this far into the video
  - `music_url` string, uri, required
  - `normalize` boolean: Bring the track to a standard loudness first, so `volume` means the same for every file (a quiet file is not lost under the speech)
  - `video_url` string, uri, required: Public URL of the source video (mp4, mov, webm, mkv…) — or the `url` of a previous render
  - `fade_in_ms` number
  - `fade_out_ms` number
  - `original_volume` number

## Response `200`

Completed (or 202 while processing)

- object
  - `id` string: Execution id — stable across internal retries; use it with GET /v1/executions/{id}
  - `status` 'pending' | 'processing' | 'completed' | 'partial' | 'failed' | 'cancelled' | 'timeout'
  - `operation` string
  - `tag` string, nullable: Your X-Tag, if sent
  - `created_at` string, date-time
  - `completed_at` string, date-time, nullable
  - `output` object: Operation result (see each operation). While a Studio render is processing: `stage` (queued · transcribing · downloading · preparing · cleaning_voice · mixing_audio · rendering · finishing), `phase` (the engine's: download · prepare · voice · audio · encode · qa · upload, or null), `progress` (a percent, 0–100) and `progress_fraction` (0–1), `eta_seconds` (seconds left, never below 0) and `estimate_seconds`
  - `error` string, nullable
  - `usage` object
    - `credits_charged` number, nullable
    - `credits_reserved` number
    - `estimated_credits` number
    - `cost_source` 'provider_reported' | 'calculated' | 'estimated' | 'null', nullable
    - `provider_usage` object, nullable: Normalised consumption, e.g. { VIDEO_SECOND: 22.4 }
  - `balance` object
    - `available` number
    - `reserved` number

## Other responses

- `202`: Processing — poll GET /v1/executions/{id}
- `400`: Invalid input
- `402`: Insufficient credits / project budget
- `404`: Resource not found (or not yours)
- `429`: Rate limited
- `503`: Service temporarily paused

---

[API](https://skmtc.dev/apihub/apis/apihub-one-api-for-chat-image-video-ai.md) · [All operations](https://skmtc.dev/apihub/apis/apihub-one-api-for-chat-image-video-ai/llms.txt) · [OpenAPI document](https://skmtc.dev/apihub/apis/apihub-one-api-for-chat-image-video-ai/revisions/a8caa42835ce?raw)