> ## Documentation Index
> Fetch the complete documentation index at: https://www.tella.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Add background music to your video
> Add background music to a Tella video from the built-in library or upload your own track. Background music is mixed under your existing audio and fades in and out — it does not replace your voiceover. How to upload audio, why uploaded music fades in and out, can I add a separate voiceover track.
You can add background music to your Tella video from Tella’s built-in music library, or upload your own track. You can also preview tracks, adjust the volume, and remove or replace music at any time.
Audio you upload here is **background music** — it's mixed in *underneath* the audio that's already in your video (your voiceover, screen audio, and so on) and plays quietly behind it. It is **not** a voiceover or main audio track, and it does not replace your existing audio.
Tella doesn't support importing a standalone voiceover or narration track, or recording a voiceover over an existing clip. To narrate a recording, record your mic at the same time as your screen, or re-record the clip. See [Can I combine two separate recordings into one video?](/docs/help/faq/combine-separate-recordings).
Background music applies to the **whole video**, not to a single clip — there's one background track for the video, and it plays across every clip.
### Open the audio tab
1. Open your video in the Tella editor.
2. Select the **audio** tab.
### Browse and preview Tella’s background music
1. In the audio tab, browse the background music that is available.
2. Select a track to preview it.
3. Click **Play** to hear how it sounds.
4. Use the seek control to skip around and preview different parts of the track.
5. Browse the full set until you find a track you like.
### Add a track to your video
1. When you find a track you like, select **add**.
2. The full track is added across the full duration of your video.
### Adjust the music volume
1. Use the volume control in the audio tab to make the music louder or quieter.
### Remove or replace the track
1. To remove the current track, select the remove option in the audio tab.
2. Add a different built-in track, or upload your own to replace it.
### Upload your own background music
1. In the audio tab, select **upload**.
2. Choose an audio file from your computer.
This is useful if you have branded music, something you created yourself, or a custom track.
### Why does my uploaded audio fade in/out?
Background music is meant to sit gently behind your voice, so Tella shapes it automatically:
* **It fades in at the start and fades out at the end** of your video, so the music eases in and out instead of cutting abruptly. This is expected behavior for background music — it's not a glitch with your file.
* **It's mixed under your existing audio** at the music volume you set, so your voiceover and screen audio stay in front.
If you uploaded a track expecting it to play at full volume as the main audio, that's why it sounds quiet and fades — the Audio tab is for background music, not for a primary voiceover track.
### How Tella handles track length
* If your background track is longer than your video, Tella fades it out at the end of the video.
* If your background track is shorter than your video, Tella loops it so you have music for the full duration.
### Preview your video with music
1. Click **Play** to preview the video with your background music.
2. If needed, adjust the volume until it sounds right.
### Set background music via the API or MCP
Background music can also be set and removed programmatically. Use `PUT /v1/videos/{id}/background-music` and `DELETE /v1/videos/{id}/background-music` in the [Public API](/docs/introduction), or the `set_background_music` and `remove_background_music` tools in the [MCP server](/docs/mcp-server#background-music).