This article answers a practical question: runway video has a soundtrack switch, so if I set it to "auto," what music does the system give me — and could it land me in a copyright mess?
The short answer first: the platform provides no music library. Auto soundtrack will only ever use audio you uploaded to Assets yourself. It will not go looking for a track somewhere else and drop it into your clip.
How auto soundtrack picks a track
- Upload audio you're licensed to use to 📦 Other assets in Assets.
- Tag the audio with a style. Tags matching a runway style name are matched first.
- Set the soundtrack to "auto" when you submit the runway video.
- At render time the system looks at which style that particular clip drew, and prefers audio of yours whose tag matches. If nothing matches, it picks another track from the audio you've uploaded.
The music is looped to cover the clip and then trimmed to its length. It's laid directly over the finished video rather than mixed as a second track against the original audio.
Drama Ads works differently: you pick a track manually from Assets, and the system verifies the asset is audio belonging to your account before it goes through. Here too, nothing external is chosen for you.
What happens when you have no audio
If there isn't a single audio file in your library, the clip goes out silent: the job completes as normal, no error, no retry, and no extra credits. If the mixing step itself fails, it falls back to a silent clip the same way — already-rendered footage is never thrown away.
If you don't want background music at all, set the soundtrack to "no soundtrack" and the system skips the step entirely.
Why we don't ship a music library
Music licensing is messier than it looks. The same track is typically licensed differently for personal versus commercial use, differently by region, and differently again depending on whether derivative works and redistribution are allowed — and there are two separate rights, the recording and the composition. If the platform casually handed you a track that "looks free," the risk wouldn't disappear; it would just move onto you. It's your store's assets and your ad accounts that get throttled, muted or taken down, not our servers.
When the license chain is in your own hands, it's at least traceable and defensible. That's why we'd rather ask you to upload one extra file than run a library.
Worth checking before you license a track
- Whether the license covers commercial use, not just personal creator use.
- Whether it covers the regions and platforms you're publishing to, and for how long.
- Marketplace and short-video platforms' built-in commercial music libraries are usually only covered while the content stays on that platform. If you plan to export the clip and use it elsewhere, check those terms yourself.
- Keep the receipt or the license document with the file so you can produce it later.
Rights to a real person's likeness are a separate rule — see Why the likeness confirmation is mandatory. The broader commercial-use boundary is in Can I use the output commercially?.