# Merge Video & Audio

> Add voiceover, music or sound effects to a video. Set each track's volume and start time, and keep, lower or mute the video's own sound.

Source: https://nodaro.ai/docs/nodes/video/merge-video-audio

The **Merge Video & Audio** node combines a video with one or more audio tracks into one video file. Each track has its own volume and start time, and the video's own sound can stay under the new tracks or be muted. Use it to add a voiceover, background music or sound effects to a video.

- Found in: Video › Sound for Video
- Output: video
- API type: `merge-video-audio`

## When to use it
- Add an AI voiceover to a video.
- Lay background music under a clip.
- Combine speech from [Text to Speech](https://nodaro.ai/docs/nodes/audio/text-to-speech) with generated clips.
- Add sound effects to a silent generated video.

## Quick start
### Add the node

Press Tab on the canvas and choose **Video › Sound for Video › Merge Video & Audio**.

### Connect the video and the audio

Wire the video and every audio track into the **Media** input. The first connected video is the base of the result.

### Set the tracks

Open the settings panel. Under **Video Source**, keep or mute the **Original Audio**. Under **Audio Tracks**, set the **Vol** and the **Start** of each track.

### Run it

Click **Run** on the node. The video with its new sound appears on the node.

Workflow: A voiceover and a quieter music track are merged onto a generated product clip.

- Generate Video → Merge Video & Audio (media)
- Text to Speech → Merge Video & Audio (media)
- Generate Music → Merge Video & Audio (media)

## Inputs
| Input | Accepts | What it does |
| --- | --- | --- |
| **Media** | Video and audio nodes, such as Generate Video, Text to Speech, Generate Music and Upload Audio | The first connected video is the base. Every audio node becomes an audio track. A further video adds its sound as a track, marked as audio extracted from video. |

The output, **Video**, is the video with the merged sound.

## Settings
### Video Source

The first connected video. Its own sound is the **Original Audio**:

| Setting | What it does |
| --- | --- |
| **Original Audio** | **Keep**, the default, keeps the video's own sound under the new tracks. Click the badge to switch to **Muted**. |
| **Vol** | The loudness of the original sound, from 0% to 200%. The default is 30%. |
| **Role** | Tags the original sound as **Background** (the default), **Narration** or **Effect**. |

### Audio Tracks

Every connected audio source is a track. The tracks are listed in the order of their start times, and the play button next to a track previews it.

| Setting | What it does |
| --- | --- |
| **Role** | Tags the track as **Dialogue**, **Narration**, **Background** or **Effect**. The default follows the source: speech from Text to Speech is **Dialogue**, music from Generate Music is **Background**, and a sound from Text to Audio is **Effect**. |
| **Vol** | The loudness of the track, from 0% to 200%. The default is 100%. |
| **Start** | The point of the video, in seconds, where the track begins. The default is 0. |

Audio that runs past the end of the video stops with the video. Audio that ends before the video leaves silence after it.

## Troubleshooting
**The run is refused before it starts.** Every input must carry real media. If a connection feeds the node something that is not a media file, for example a text output wired into the **Media** input, the run is refused before any credits are reserved. The message names the node and quotes the value it received.

## Tips
- **Merge last.** Put this node after all the video processing, such as trims, joins and speed changes.
- **Replace the sound completely.** Mute the **Original Audio**. You can also strip the sound first with [Remove Audio](https://nodaro.ai/docs/nodes/video/remove-audio), but it is not required.
- **Keep the music under the voice.** Lower the **Vol** of a music track, for example to 40%, so the voiceover stays clear.
- **Mix complex soundtracks first.** To blend many tracks before you merge them, use [Mix Audio](https://nodaro.ai/docs/nodes/audio/mix-audio).
- **Reuse a processed soundtrack.** Pull a video's sound out with [Extract Audio](https://nodaro.ai/docs/nodes/video/extract-audio), process it, then merge it back here.

## Frequently asked questions

### How do I replace the video's sound instead of mixing it?

In the settings panel, click the Keep badge next to Original Audio so that it shows Muted. The output then carries only your audio tracks.

### Can I add several audio tracks at once?

Yes. Connect every audio node to the Media input. Each one becomes a track with its own volume and start time.

### What happens when the audio is longer than the video?

The audio stops at the end of the video. Audio that is shorter than the video leaves silence after it ends.

### How do I make the music start later?

Set the track's Start value, in seconds. The track begins at that point of the video.

### How loud is the video's own sound after the merge?

By default the original sound is kept at 30% volume under the new tracks. Change its Vol value, from 0% to 200%, or mute it.