Sound
Add music, effects and voice to a scene video: tracks on the timeline in seconds, fades, loops, ducking, credits, limits, and how the preview and the render mix them.
A scene video can have sound. It lives in the spec as a list of tracks on the video's own timeline.
A track#
| Field | Meaning |
|---|---|
kind | music, sfx or voice |
source | A sound you uploaded (storage:<id>) or an https address |
start, duration, offset | Seconds on the timeline, and where in the file to start |
volume | From 0 to 1 |
fadeIn, fadeOut | Seconds |
loop | Repeat to fill the duration |
duck | The level music dips to under voice and effects |
credit | Who made it, shown for your own records |
A video can have at most 24 tracks.
Preview and render#
The preview plays the same mix as the picture. Browsers keep a page silent until it has been touched, so click or tap first. The browser render mixes all tracks to one stereo bus and writes one AAC track into the MP4. A video with no tracks has no audio track.
Where sound comes from#
- Your own: upload a file in the app, or use an https address.
- A licensed library: Video can search a library of licensed music and effects when the deployment has one connected. On a deployment without one, the search says so and you use your own sound.