How To Add Music To A Video?
Music plays under your whole video, in the editor’s previews and in the MP4 you download or schedule.
Steps
Add a track
In the left menu, click Audio, then its Music tab. Click Add music, then pick a track from the music library or your uploads, or upload an MP3.

You need to be signed in to add music.
Adjust it
Once a track is added, you can set:
- Start at: where in the track the video’s music begins.
- Volume: how loud it plays.
- Fade out: how long it takes to fade at the end of the video.
A track shorter than the video starts again from the top.
Cut slides on the beat
Click Cut slides on the beat to make every slide change on a beat of the music. PostNitro finds the track’s tempo, then moves each slide’s change to the nearest beat. A slide is never cut before its animations finish: it waits for the next beat instead. Each slide keeps the length the beat gave it, so click it again after you change the track, where it starts, or the slides.
Tracks without a steady beat, such as ambient music, can’t be cut to one.
Change or remove it
Click Change track to pick another one, or Remove music to take it off.
Ask Nitro AI
On paid plans, ask Nitro AI in the AI chat to add music, change the track, take it off, make it quieter or louder, start it later in the track, fade it out, or cut the slides on the beat. Asked for music without a track named, it picks your newest and says which.
Nitro AI uses your workspace’s own tracks only: it can’t search the music library or upload one. Add a track in Audio first, and it can use it from then on.
Tip: If you pick a track on the Media page first, Audio offers to use it in your video.