Name: Lipsync Precision API: Video Dubbing by HeyGen
Brand: magicapi
SKU: api-magicapi-high-accuracy-lip-sync-api-heygen-lipsync-precision
Availability: InStock
Author: API Market

Shashank Agarwal

# 🗣️ High-Accuracy Lipsync API (HeyGen Lipsync Precision)

## Overview
HeyGen Lipsync Precision replaces or dubs the audio on a video. You send a source video and a replacement audio file, and the model re-animates the lip movements in the video to match the new audio using HeyGen's avatar inference. Optional switches strip background music from the source video, enhance speech in the output and let the output length adjust to the new audio.

Only `video` and `audio` are required. Each request returns the URL of one video.

## Features
- **Lipsync to new audio:** `video` is the source video to lipsync and `audio` is the replacement audio file. Both are passed as URLs.
- **Dynamic duration:** `enable_dynamic_duration` (default `true`) allows the output duration to adjust to match the new audio length.
- **Background music removal:** set `disable_music_track` to `true` to strip background music from the source video (default `false`).
- **Speech enhancement:** set `enable_speech_enhancement` to `true` to enhance speech quality in the output (default `false`).

## Use Cases
- **Dubbing and localization:** match a speaker's lips to a translated voice track.
- **Dialogue fixes:** replace a line of dialogue after the shoot without reshooting.
- **AI avatars and presenters:** make a recorded or generated presenter speak a new script.
- **Personalized video messages:** reuse one recording with different audio for each recipient.

## Visual Examples
This is a real request sent through api.market and the file it returned.

Inputs used: `video` and `audio` as shown below. All other fields were left at their defaults (`enable_dynamic_duration` true, `disable_music_track` false, `enable_speech_enhancement` false).

**Input video (`video`):** [Watch the input video](https://blog.api.market/wp-content/uploads/2026/10/lipsync-input-talk-api-market.mp4)

**Input audio (`audio`):** [Listen to the input audio](https://blog.api.market/wp-content/uploads/2026/10/realtime-tts-1.5-max-output-api-market.mp3)

**Output video:** [Watch the example video](https://blog.api.market/wp-content/uploads/2026/10/lipsync-precision-output-api-market.mp4)

About the inputs: in our testing the model needed the source video to have its own audio track and the video and audio to be the same length. For this example we used a talking video, with its own audio track, trimmed to the length of the speech audio (about 5.4 seconds). The returned video was 5.459 seconds long.

## Pricing
- **Pay As You Go (PAYG) pricing:** you only pay for what you use.
- **Price:** $0.084 per API unit.
- **1 API unit** = 1 second of output video, rounded up to the next whole second. There are no variants or tiers: every second costs the same.
- **Worked example:** a 5 second output video is 5 units = $0.42. The example above returned 5.459 seconds of video, which rounds up to 6 units = $0.504.
- **Failed or cancelled predictions** are not billed.
- **GET requests** to check prediction status (GET /api/v1/magicapi/high-accuracy-lip-sync-api-heygen-lipsync-precision/predictions/{id}) are free and don't count toward API unit usage.
- **No monthly subscription fee.**

## API Documentation

### Base URL
`https://prod.api.market/api/v1/magicapi/high-accuracy-lip-sync-api-heygen-lipsync-precision`

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

### Asynchronous Processing
**IMPORTANT:** This API is asynchronous.
1. POST `/predictions` with the model `version` and your `input`.
2. The API returns **201 Created** with a prediction `id` and a `status` of `starting` or `processing`. 201 means the request was accepted; it is not an error.
3. Poll GET `/predictions/{id}` until `status` is `succeeded`, `failed` or `canceled`.
4. When `status` is `succeeded`, `output` holds the URL of the lipsynced video.
5. When `status` is `failed`, the `error` field explains why.

The example request above took about 1.5 minutes to finish, so allow a generous timeout when polling.

### Endpoints

#### Create a Prediction
`POST /predictions`

```bash
curl -X POST "https://prod.api.market/api/v1/magicapi/high-accuracy-lip-sync-api-heygen-lipsync-precision/predictions" \
  -H "Content-Type: application/json" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY" \
  -d '{
    "version": "03d0f07dd626f1ef31febe77bcd36109359811887a9e358803747a9da2707d28",
    "input": {
      "video": "https://blog.api.market/wp-content/uploads/2026/10/lipsync-input-talk-api-market.mp4",
      "audio": "https://blog.api.market/wp-content/uploads/2026/10/realtime-tts-1.5-max-output-api-market.mp3"
    }
  }'
```

Response (201 Created):
```json
{
  "id": "ufawqhfynnddngldkgtslldrkq",
  "version": "03d0f07dd626f1ef31febe77bcd36109359811887a9e358803747a9da2707d28",
  "status": "starting",
  "created_at": "2026-10-13T11:08:05.862Z"
}
```

#### Check Prediction Status
`GET /predictions/{id}`

```bash
curl -X GET "https://prod.api.market/api/v1/magicapi/high-accuracy-lip-sync-api-heygen-lipsync-precision/predictions/ufawqhfynnddngldkgtslldrkq" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY"
```

Response (200 OK) once the prediction has finished:
```json
{
  "id": "ufawqhfynnddngldkgtslldrkq",
  "status": "succeeded",
  "input": {
    "video": "https://blog.api.market/wp-content/uploads/2026/10/lipsync-input-talk-api-market.mp4",
    "audio": "https://blog.api.market/wp-content/uploads/2026/10/realtime-tts-1.5-max-output-api-market.mp3"
  },
  "output": "https://blog.api.market/wp-content/uploads/2026/10/lipsync-precision-output-api-market.mp4",
  "error": null,
  "created_at": "2026-10-13T11:08:05.862Z",
  "started_at": "2026-10-13T11:08:06.862Z",
  "completed_at": "2026-10-13T11:09:45.362Z"
}
```

### Input Parameters
| Parameter | Type | Required | Default | Description |
|---|---|---|---|---|
| `video` | string (URL) | Yes | none | Source video file to lip-sync. |
| `audio` | string (URL) | Yes | none | Replacement audio file. The video's lip movements will be re-animated to match this audio using high-accuracy avatar inference. |
| `enable_dynamic_duration` | boolean | No | `true` | Allow the output duration to adjust to match the new audio length. |
| `disable_music_track` | boolean | No | `false` | Strip background music from the source video. |
| `enable_speech_enhancement` | boolean | No | `false` | Enhance speech quality in the output. |

### Output
`output` is a single URL (string) pointing to the lipsynced MP4 video.

## Status Codes
- **200 OK:** prediction status returned.
- **201 Created:** prediction accepted. Poll GET `/predictions/{id}` for the result.
- **400 Bad Request:** invalid or missing input fields.
- **401 Unauthorized:** missing or invalid API key.
- **404 Not Found:** unknown prediction ID.
- **429 Too Many Requests:** too many requests in a short time. Wait and retry.
- **500 Internal Server Error:** server-side error. Retry after a short wait.

## 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
- **Request errors (4xx):** check the response body, fix the input fields and send the request again.
- **Failed predictions:** when GET returns `status: "failed"`, read the `error` field. If it fails, check that the source video has its own audio track and that the video and audio are the same length. Failed predictions are not billed.
- **Rate limits (429) and server errors (5xx):** retry with exponential backoff.

## Implementation Guide

### JavaScript
```javascript
const apiKey = "YOUR_API_MARKET_KEY";
const baseUrl = "https://prod.api.market/api/v1/magicapi/high-accuracy-lip-sync-api-heygen-lipsync-precision";

async function createPrediction(input) {
  const response = await fetch(`${baseUrl}/predictions`, {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "x-api-market-key": apiKey
    },
    body: JSON.stringify({ version: "03d0f07dd626f1ef31febe77bcd36109359811887a9e358803747a9da2707d28", input })
  });
  if (response.status !== 201 && response.status !== 200) {
    throw new Error(`API error: ${response.status} ${await response.text()}`);
  }
  return response.json();
}

async function waitForPrediction(id, timeoutMs = 1200000, intervalMs = 5000) {
  const start = Date.now();
  while (Date.now() - start < timeoutMs) {
    const response = await fetch(`${baseUrl}/predictions/${id}`, {
      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 new Promise((resolve) => setTimeout(resolve, intervalMs));
  }
  throw new Error("Timed out waiting for the prediction");
}

const prediction = await createPrediction({
  "video": "https://blog.api.market/wp-content/uploads/2026/10/lipsync-input-talk-api-market.mp4",
  "audio": "https://blog.api.market/wp-content/uploads/2026/10/realtime-tts-1.5-max-output-api-market.mp3"
});
const output = await waitForPrediction(prediction.id);
console.log(output);
```

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

API_KEY = "YOUR_API_MARKET_KEY"
BASE_URL = "https://prod.api.market/api/v1/magicapi/high-accuracy-lip-sync-api-heygen-lipsync-precision"

def create_prediction(input_data):
    response = requests.post(
        f"{BASE_URL}/predictions",
        headers={"Content-Type": "application/json", "x-api-market-key": API_KEY},
        json={"version": "03d0f07dd626f1ef31febe77bcd36109359811887a9e358803747a9da2707d28", "input": input_data},
    )
    if response.status_code not in (200, 201):
        raise Exception(f"API error: {response.status_code} {response.text}")
    return response.json()

def wait_for_prediction(prediction_id, timeout=1200, interval=5):
    start = time.time()
    while time.time() - start < timeout:
        response = requests.get(
            f"{BASE_URL}/predictions/{prediction_id}",
            headers={"x-api-market-key": API_KEY},
        )
        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(interval)
    raise Exception("Timed out waiting for the prediction")

prediction = create_prediction({
  "video": "https://blog.api.market/wp-content/uploads/2026/10/lipsync-input-talk-api-market.mp4",
  "audio": "https://blog.api.market/wp-content/uploads/2026/10/realtime-tts-1.5-max-output-api-market.mp3"
})
print(wait_for_prediction(prediction["id"]))
```

### cURL
```bash
# Step 1: create the prediction (returns 201 Created with an id)
curl -X POST "https://prod.api.market/api/v1/magicapi/high-accuracy-lip-sync-api-heygen-lipsync-precision/predictions" \
  -H "Content-Type: application/json" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY" \
  -d '{
    "version": "03d0f07dd626f1ef31febe77bcd36109359811887a9e358803747a9da2707d28",
    "input": {
      "video": "https://blog.api.market/wp-content/uploads/2026/10/lipsync-input-talk-api-market.mp4",
      "audio": "https://blog.api.market/wp-content/uploads/2026/10/realtime-tts-1.5-max-output-api-market.mp3"
    }
  }'

# Step 2: poll with the returned id until status is succeeded, failed or canceled
curl -X GET "https://prod.api.market/api/v1/magicapi/high-accuracy-lip-sync-api-heygen-lipsync-precision/predictions/ufawqhfynnddngldkgtslldrkq" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY"
```

## FAQ
**Q: What kind of video and audio should I send?**  
A: A source video of a person speaking and the replacement audio, both as URLs. In our testing the model needed the source video to have its own audio track and the video and audio to be the same length, so trim the video to the length of the new audio before sending it.

**Q: What does `enable_dynamic_duration` do?**  
A: It allows the output duration to adjust to match the new audio length. It is on (`true`) by default. You are billed for the seconds of video the model returns.

**Q: Can I remove background music from the source video?**  
A: Yes. Set `disable_music_track` to `true` to strip background music from the source video.

**Q: What does `enable_speech_enhancement` do?**  
A: It enhances speech quality in the output. It is off (`false`) by default.

**Q: Is POST returning 201 an error?**  
A: No. 201 Created means the prediction was accepted. Use the returned `id` to poll GET `/predictions/{id}` until `status` is `succeeded`, `failed` or `canceled`.

## 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.


Replace or dub the audio on a video with HeyGen Lipsync Precision. Send a video and an audio file, get back a lipsynced video. $0.084 per second of output.