# Ffmpeg Api | Merge Audio Video

FFmpeg Audio-Video Merge API combines video files with external audio sources or audio extracted from other videos. It ensures precise synchronization, preserves original quality, and delivers smooth, high-quality playback. Ideal for post-production, dubbing, voiceovers, and automated media processing workflows.

## API Information

- **Model Slug:** ffmpeg-api-merge-audio-video
- **Branded URL:** https://www.eachlabs.ai/ffmpeg-api/ffmpeg/ffmpeg-api-merge-audio-video
- **Provider:** Ffmpeg Api
- **Category:** Video to Video
- **Output Type:** video
- **Status:** active
- **Base Cost:** $0.0002 per second
- **Estimated Processing Time:** 5 seconds
- **Interactive Demo:** https://www.eachlabs.ai/ai-models/ffmpeg-api-merge-audio-video

## Pricing

- **Charge Type:** dynamic
- **Estimate:** $0.0002 per second
- **Pricing Details:** default: $0.0002

## Input Schema

| Parameter | Type | Required | Default | Constraints | Description |
|-----------|------|----------|---------|-------------|-------------|
| video_url | string | Yes | - | - | URL of the video file. |
| audio_url | string | Yes | - | - | URL of the audio file to merge with the video. |
| start_offset | number | No | 0 | - | Audio start offset in seconds. Default: 0. |

## Example Request

```bash
curl -X POST https://api.eachlabs.ai/v1/prediction/ \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "ffmpeg-api-merge-audio-video",
  "input": {
    "audio_url": "https://cdn-us.eachlabs.ai/defaults/c39a22b986b7308c375d47a59e4f95b02c7066bf659a3de052b66df973556b5a.mp3",
    "video_url": "https://cdn-us.eachlabs.ai/defaults/335f17d7539a67a20e592276be8ba348d9a7767036f8a3ae46215abf1c4e5fdf.mp4"
  }
}'
```

## Output Schema

Response returned by `GET /v1/prediction/{id}` when the job completes:

```json
{
  "status": "success",
  "predictionID": "string",
  "output": "string (URL of generated video)",
  "metrics": {
    "predict_time": "number (seconds)"
  }
}
```

## Polling

```bash
curl https://api.eachlabs.ai/v1/prediction/{PREDICTION_ID} \
  -H "Authorization: Bearer YOUR_API_KEY"
```

| Status | Meaning |
|--------|---------|
| `processing` | Still running — poll again |
| `success` | Done — read `output` |
| `error` | Failed — read `message` / `details` |

## Webhook (alternative to polling)

Pass `"webhook_url": "https://your.host/path"` in the create request. Eachlabs POSTs this payload when the job ends:

```json
{
  "exec_id": "prediction-uuid",
  "status": "succeeded",
  "output": "https://...",
  "error": ""
}
```

`status` is `"succeeded"` or `"failed"`. `exec_id` equals the `predictionID` from create. Return 2xx within 30 seconds.

## Errors

Error body: `{ "status": "error", "message": "...", "details": "..." }`

| Code | Meaning |
|------|---------|
| `400` | Invalid input |
| `401` | Missing / invalid `Authorization` bearer token |
| `404` | Unknown model or prediction id |
| `429` | Rate limit — 100 creates / min, 10 concurrent per key |
| `5xx` | Retry with backoff |

## Overview

**ffmpeg-api-merge-audio-video — Video-to-Video AI Model**

Developed by Ffmpeg Api as part of the ffmpeg family, **ffmpeg-api-merge-audio-video** is a powerful video-to-video AI model that seamlessly combines video files with external audio sources or audio extracted from other videos, ensuring precise synchronization for professional-grade media processing. This API excels in post-production workflows by preserving original video quality while delivering smooth, high-fidelity playback without re-encoding where possible. Ideal for developers seeking an **ffmpeg-api-merge-audio-video API** to automate dubbing, voiceovers, and media merging, it handles multi-input tasks efficiently via simple HTTP requests.

Unlike generic video editors, **ffmpeg-api-merge-audio-video** leverages FFmpeg's native capabilities for stream-specific copying, such as -c:v copy for video and -c:a aac for audio, minimizing processing time and quality loss in automated pipelines.

## Usage Notes

- API Base URL: `https://api.eachlabs.ai/v1`
- Authentication: send `Authorization: Bearer YOUR_API_KEY`. Generate a key from the Eachlabs dashboard at https://www.eachlabs.ai/dashboard/api-keys.
- File-typed parameters (`*_url`, `image_url`, `video_url`, `audio_url`, etc.) accept publicly-reachable HTTPS URLs only. Upload your asset first (GCS / S3 / your CDN) and pass the resulting URL. Data-URIs and localhost URLs are rejected.
- For structured parameters (arrays / objects) send real JSON values, not stringified payloads.
- Monetary values are reported in USD; per-token / per-megapixel rates may be billed in micro-cents internally.
- Prefer `webhook_url` over polling for long-running predictions — see the Webhook Callback section.