> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://help.ammlabs.io/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# Audio requirements

Upload each track as a **WAV or FLAC** file of up to **500 MB**. MP3 and other formats aren't accepted. Upload the final master: what you upload is what the stores receive.

## File requirements

| Requirement | Detail |
|---|---|
| Format | WAV or FLAC |
| Maximum size | 500 MB per file |
| One file per track | Each file you upload becomes one track. |

## Upload your audio

1. Open your release in the builder and go to the **Tracks** section.
2. Upload or drop your files. Each file becomes a track, and its file name becomes the track title. Check and correct the titles afterwards.
3. Drag tracks to put them in order.

To swap a track's audio before you submit, open the track and click **Replace audio** under **Audio master**. Click the play button on a track to listen and check you uploaded the right version.

![An open track showing the Version field, the Replace audio button, the Explicit switch and the Previously released switch](https://ammdistro.com/helpdesk/distro-builder-track-details.webp =1200xauto)

## Upload errors

| Message | What to do |
|---|---|
| "Only WAV and FLAC files are accepted" | Export the track as WAV or FLAC. Renaming an MP3 to .wav doesn't work. |
| "File size exceeds 500MB limit" | Export the track again. Very long tracks may need FLAC, which is smaller than WAV. |

If an upload stops partway, check your connection and upload the file again.

## Things to check before you submit

* **The right version.** Listen to each track in the builder. A clean and an explicit version of the same song are separate recordings.
* **Explicit content.** Set each track to **Clean** or **Explicit** to match the lyrics.
* **No silence or extra material** you don't want in stores, such as count-ins or long gaps at the end.

||| Once your release is in stores, you can't change its audio. Check every track before you submit.

## Common questions

### Can I upload an MP3?

No. Only WAV and FLAC files are accepted.

### Do you check bit depth or sample rate?

The builder doesn't reject files based on bit depth or sample rate. Upload the master your mastering engineer delivered.

### A track I already released elsewhere: do I upload it again?

Yes. Upload the audio, then mark the track **Previously released** and enter its existing ISRC so the streams stay linked. See **Previously released music, ISRCs and UPCs**.

**Related:** [Create a release, step by step](https://help.ammlabs.io/en/article/01-create-a-release-step-by-step-z1607w/) · [Titles, versions and featured artists](https://help.ammlabs.io/en/article/04-titles-versions-and-featured-artists-13arciz/) · [Previously released music, ISRCs and UPCs](https://help.ammlabs.io/en/article/09-previously-released-music-isrcs-and-upcs-1rgpzwl/) · [Check and submit your release](https://help.ammlabs.io/en/article/11-check-and-submit-your-release-1gcucgm/)