Name: Video to Sound Effects API: Mirelo Video-to-SFX v1
Brand: magicapi
SKU: api-magicapi-video-to-soundtrack-generator-mirelo-video-to-sfx-v1
Availability: InStock
Author: API Market

Shashank Agarwal

# 🔊 Video Sound Effects Generator API (Mirelo Video-to-SFX v1)

## Overview
Mirelo Video-to-SFX v1 generates sound effects for a video. Its developer describes it as generating synced sounds for any video and returning the video with its new sound track.

Send a video URL as `video_path`. The model generates `num_samples` sound variations for `duration` seconds of the video and returns one MP4 per variation, each with the generated sound added. An optional `text_prompt` guides the kind of sound.

## Features
- **Sound for silent video**: send a video URL as `video_path` and get the same video back with a generated sound track.
- **Several variations per request**: `num_samples` (1 to 4, default 2) sets how many variations you get. Each one is a separate MP4 file in `output`.
- **Length and start point**: `duration` (1 to 10 seconds, default 10) sets how many seconds of sound to generate, and `start_offset` (0 to 300 seconds, default 0) sets where in the video generation starts.
- **Text guidance**: an optional `text_prompt` steers the kind of sounds generated.
- **Quality and creativity controls**: `steps` (1 to 30, default 25) and `creativity_coef` (1 to 10, default 4.5).
- **Repeatable results**: set `seed` to an integer to reproduce a result.

## Use Cases
1. **Silent AI-generated clips**: add sound effects to video clips that were generated without audio.
2. **Social and short-form video**: add matching sound to short clips before publishing.
3. **Prototyping sound design**: generate several variations of a scene's sound and pick the one that fits.
4. **Stock and B-roll footage**: add ambient sound to footage that has none.

## Visual Examples
### Example Input
Video: [Watch the example input video](https://blog.api.market/wp-content/uploads/2026/10/hailuo-2.3-fast-output-api-market.mp4) (a short silent clip)

Settings: `duration` 6, `num_samples` 2. No `text_prompt`; all other fields were left at their defaults.

### Example Output
The request returned two variations of the same clip, each with its own generated sound track:

- [Watch the example output (sample 1)](https://blog.api.market/wp-content/uploads/2026/10/video-to-sfx-v1-output-1-api-market.mp4)
- [Watch the example output (sample 2)](https://blog.api.market/wp-content/uploads/2026/10/video-to-sfx-v1-output-2-api-market.mp4)

## Input Parameters
| Field | Type | Required | Default | Allowed values | Description |
| --- | --- | --- | --- | --- | --- |
| `video_path` | string (URL) | Yes |  |  | URL of the video to add sound effects to. Videos longer than 10 seconds are trimmed to 10 seconds |
| `text_prompt` | string | No | `""` |  | Optional text that guides the sound effect generation, for example the sounds you expect to hear |
| `seed` | integer | No | none |  | Random seed for reproducibility. Leave it empty or use -1 for a random seed, or set any integer for repeatable results |
| `num_samples` | integer | No | `2` | 1 to 4 | Number of sound effect variations to generate. Each sample is returned as a separate video file |
| `duration` | integer | No | `10` | 1 to 10 | Duration of the generated sound effects in seconds |
| `steps` | integer | No | `25` | 1 to 30 | Number of processing steps for the generation model. Higher values may improve quality but take longer |
| `creativity_coef` | number | No | `4.5` | 1 to 10 | Controls how creative the generated sound is. Higher values are more creative |
| `start_offset` | number | No | `0` | 0 to 300 | Point in the video, in seconds, from which to generate audio. 0 starts at the beginning |

## Pricing
- **Pay As You Go (PAYG) pricing**: you only pay for what you use.
- **Price**: $0.0088 per API unit.
- **1 API unit = $0.0088. Each request uses a number of units set by its options**: units = `duration` (seconds, 1 to 10) x `num_samples` (1 to 4).
- `text_prompt`, `steps`, `creativity_coef`, `start_offset` and `seed` do not change the unit count.

| `duration` | `num_samples` | API units | Price per request |
| --- | --- | --- | --- |
| 5 s | 2 | 10 | $0.09 |
| 6 s | 2 | 12 | $0.11 (example request) |
| 10 s | 1 | 10 | $0.09 |
| 10 s | 2 | 20 | $0.18 (defaults) |
| 10 s | 4 | 40 | $0.35 |

- **Example request**: `duration` 6 and `num_samples` 2 used 12 API units, so it cost $0.11 (12 x $0.0088 = $0.1056).
- If you omit `duration` and `num_samples`, the defaults (10 seconds, 2 samples) apply and the request uses 20 units. Set `duration` to the length you need to avoid paying for unused seconds.
- **Failed or cancelled predictions are not billed.**
- **GET requests to check prediction status** are free and don't count toward API unit usage.
- **No monthly subscription fee.**

## API Documentation

### Base URL
All API requests go to: `https://prod.api.market/api/v1/magicapi/video-to-soundtrack-generator-mirelo-video-to-sfx-v1`

### Authentication
Send your api.market API key in the `x-api-market-key` header:
```
x-api-market-key: YOUR_API_MARKET_KEY
```

### Asynchronous Processing
**IMPORTANT**: This API is asynchronous. The flow is:
1. Send a POST request to `/predictions`. A successful request returns **201 Created** with a prediction `id` and a `status` of `starting` or `processing`.
2. Poll GET `/predictions/{id}` with that ID.
3. Keep polling while `status` is `starting` or `processing`.
4. Stop when `status` is `succeeded` (read `output`), `failed` or `canceled` (read `error`).

Requests usually finish in under a minute. A polling interval of 2 seconds and an overall timeout of 600 seconds (10 minutes) work well.

### Endpoints

#### Create a Prediction
```bash
curl -X POST "https://prod.api.market/api/v1/magicapi/video-to-soundtrack-generator-mirelo-video-to-sfx-v1/predictions" \
  -H "Content-Type: application/json" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY" \
  -d '{
    "version": "34ea7bf892b6e989be29a9ee613d36a31d62fcbccc79b8c3f27852e0f01f2f87",
    "input": {
      "video_path": "https://blog.api.market/wp-content/uploads/2026/10/hailuo-2.3-fast-output-api-market.mp4",
      "duration": 6,
      "num_samples": 2
    }
  }'
```

Response (201 Created):
```json
{
  "id": "chpxga6npnrmr0d17ypayt77h8",
  "version": "34ea7bf892b6e989be29a9ee613d36a31d62fcbccc79b8c3f27852e0f01f2f87",
  "status": "starting",
  "created_at": "2026-10-15T13:07:34.088Z"
}
```

#### Check Prediction Status
```bash
curl -X GET "https://prod.api.market/api/v1/magicapi/video-to-soundtrack-generator-mirelo-video-to-sfx-v1/predictions/{id}" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY"
```

Response when the prediction has finished (200 OK):
```json
{
  "id": "chpxga6npnrmr0d17ypayt77h8",
  "status": "succeeded",
  "output": [
    "https://blog.api.market/wp-content/uploads/2026/10/video-to-sfx-v1-output-1-api-market.mp4",
    "https://blog.api.market/wp-content/uploads/2026/10/video-to-sfx-v1-output-2-api-market.mp4"
  ],
  "error": null,
  "created_at": "2026-10-15T13:07:34.088Z",
  "started_at": "2026-10-15T13:07:35.088Z",
  "completed_at": "2026-10-15T13:08:10.641Z"
}
```

`output` is a list of URLs, one per sample (`num_samples`). Each URL points to an MP4 of your video with one generated sound track.

### Status Codes
- **201 Created**: prediction created (POST `/predictions`). This is the normal success response.
- **200 OK**: prediction details returned (GET `/predictions/{id}`).
- **400 Bad Request**: invalid input, for example a missing `video_path`, a `duration` above 10 or a `num_samples` above 4.
- **401 Unauthorized**: missing or invalid API key.
- **404 Not Found**: no prediction with that ID.
- **429 Too Many Requests**: rate limit exceeded.
- **500 Internal Server Error** or **503 Service Unavailable**: temporary server problem; retry later.

## Rate Limits

All plans allow 10 requests per second. Requests above that return `429 Too Many Requests`; back off before retrying and honour any `Retry-After` header. Polling a prediction with GET is free but still counts toward the per-second limit, so poll every 1 to 5 seconds rather than in a tight loop.

## Error Handling
- Check the HTTP status code of every request and read the response body for the error message.
- A prediction can also end with `status` set to `failed`; the `error` field then explains why. Failed predictions are not billed.
- Retry 429, 500 and 503 responses with exponential backoff. Fix the input before retrying a 400.

## Implementation Guide
### Example Code

#### JavaScript
```javascript
const apiKey = "YOUR_API_MARKET_KEY";
const baseUrl = "https://prod.api.market/api/v1/magicapi/video-to-soundtrack-generator-mirelo-video-to-sfx-v1";

async function createAndWaitForPrediction(input) {
  const response = await fetch(`${baseUrl}/predictions`, {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "x-api-market-key": apiKey
    },
    body: JSON.stringify({ version: "34ea7bf892b6e989be29a9ee613d36a31d62fcbccc79b8c3f27852e0f01f2f87", input })
  });

  if (response.status !== 201) {
    throw new Error(`API error: ${response.status} ${await response.text()}`);
  }

  const prediction = await response.json();
  return pollForResults(prediction.id);
}

const delay = (ms) => new Promise((resolve) => setTimeout(resolve, ms));

async function pollForResults(predictionId) {
  const maxTimeout = 600000;
  const pollInterval = 2000;
  const startTime = Date.now();

  while (Date.now() - startTime < maxTimeout) {
    const response = await fetch(`${baseUrl}/predictions/${predictionId}`, {
      headers: { "x-api-market-key": apiKey }
    });

    if (!response.ok) {
      throw new Error(`API error: ${response.status} ${await response.text()}`);
    }

    const prediction = await response.json();

    if (prediction.status === "succeeded") {
      return prediction.output;
    }

    if (prediction.status === "failed" || prediction.status === "canceled") {
      throw new Error(`Prediction ${prediction.status}: ${prediction.error || "Unknown error"}`);
    }

    await delay(pollInterval);
  }

  throw new Error("Prediction timed out after 10 minutes");
}

createAndWaitForPrediction({
    "video_path": "https://blog.api.market/wp-content/uploads/2026/10/hailuo-2.3-fast-output-api-market.mp4",
    "duration": 6,
    "num_samples": 2
  }).then((output) => console.log(output));
```

#### Python
```python
import time
import requests

API_KEY = "YOUR_API_MARKET_KEY"
BASE_URL = "https://prod.api.market/api/v1/magicapi/video-to-soundtrack-generator-mirelo-video-to-sfx-v1"


def create_and_wait_for_prediction(input_data):
    headers = {"Content-Type": "application/json", "x-api-market-key": API_KEY}
    response = requests.post(
        f"{BASE_URL}/predictions",
        headers=headers,
        json={"version": "34ea7bf892b6e989be29a9ee613d36a31d62fcbccc79b8c3f27852e0f01f2f87", "input": input_data},
    )

    if response.status_code != 201:
        raise Exception(f"API error: {response.status_code} {response.text}")

    return poll_for_results(response.json()["id"])


def poll_for_results(prediction_id):
    max_timeout = 600
    poll_interval = 2
    headers = {"x-api-market-key": API_KEY}
    start_time = time.time()

    while time.time() - start_time < max_timeout:
        response = requests.get(f"{BASE_URL}/predictions/{prediction_id}", headers=headers)

        if response.status_code != 200:
            raise Exception(f"API error: {response.status_code} {response.text}")

        prediction = response.json()

        if prediction["status"] == "succeeded":
            return prediction["output"]

        if prediction["status"] in ("failed", "canceled"):
            raise Exception(f"Prediction {prediction['status']}: {prediction.get('error') or 'Unknown error'}")

        time.sleep(poll_interval)

    raise Exception("Prediction timed out after 10 minutes")


print(create_and_wait_for_prediction({
    "video_path": "https://blog.api.market/wp-content/uploads/2026/10/hailuo-2.3-fast-output-api-market.mp4",
    "duration": 6,
    "num_samples": 2
}))
```

## FAQ
- **What does the output contain?**
  - `output` is a list of video URLs, one per sample. Each file is your video with a different generated sound track.
- **How long can my video be?**
  - Videos longer than 10 seconds are trimmed to 10 seconds, and `duration` is at most 10 seconds. Use `start_offset` to choose where generation starts.
- **How is a request priced?**
  - Units = `duration` x `num_samples`, at $0.0088 per unit. With the defaults (10 seconds, 2 samples) a request costs $0.18; the maximum (10 seconds, 4 samples) costs $0.35.
- **Do I need a text prompt?**
  - No. `text_prompt` is optional. Without it the sound is generated from the video alone.
- **Is the 201 response from POST an error?**
  - No. 201 Created means the prediction was accepted. Use the returned `id` to poll GET `/predictions/{id}` until `status` is `succeeded`, `failed` or `canceled`.
- **What if my prediction fails?**
  - Failed predictions are not billed. Read the `error` field, adjust the input and try again.

## Contact Us
If you have any questions or need assistance, you can reach out to us through the embedded chat on the bottom right corner of the page or send an email to hello@magicapi.com.


Video to sound effects API: Mirelo Video-to-SFX v1 generates synced sound effects for any video and returns it with the new audio track. Pay as you go.