How to Add Music to Video: Pick, Trim, Fade and Duck
To add music to a video, you put the track on its own audio layer and trim it to the part you want. Then you set a fade in and out, and lower it whenever someone speaks. In Cut Express you do all of that by asking Claude: “Add this track under the whole video, fade in over a second, drop it under my voice, fade out on the last shot.” You get the rendered MP4 back in your chat. The home page shows real renders with the exact prompts that made them.
The steps are simple. The parts that make music sound right, or wrong, are where it starts, how loud it sits, and how it ends.
Why does background music often sound off?
You’ve heard it: a video where the track starts mid-phrase, drowns the voice, then stops dead when the video ends. Nothing is wrong with the song. The edit around it is unfinished. A viewer can’t name the problem, but it reads as amateur, and on a talking video they stop following what you say.
How do I add music to a video, step by step?
- Pick the track for the job. Upbeat for a fast recap, calm for a tutorial, tension for a reveal. A photo slideshow with a Ken Burns effect wants something slower. Match the energy of the footage, not your favourite song.
- Choose the part. Most tracks have an intro that’s too slow for a short video. Start at the part that matches your opening.
- Set the level. Music under a voice sits well below it. Music alone, like in a travel montage, can be louder.
- Fade in and out. A short fade in (under a second) and a longer fade out (one to three seconds) hide the edges.
- Duck under speech. Lower the music while someone talks, then let it come back up. Our ducking guide covers levels and ramps.
- Loop if it’s short. If the track ends before the video, loop it rather than leaving silence.
How do I add music with Claude?
Connect Cut Express to Claude, upload your clips and your track in the panel (or from Claude Code), then describe what you want:
Use the track I uploaded as background music. Start it at 0:12 of the song, under the whole video. Fade in over 0.5 s, fade out over 2 s at the end. Duck it to 25% whenever I’m talking.
Claude writes one audio track with the part of the song, its volume, fades and ducking. With a voice-over track (one you upload or one Claude makes), ducking is automatic: the music drops whenever the voice plays. When the speech is in the clip itself, Claude reads the transcript and dips the music around your lines with a volume curve. Cut Express has no automatic beat sync. Stock tracks come with their tempo, though, so Claude can space the cuts to it when you ask.
You can stack up to 40 audio tracks: your clips’ own sound, a voice-over, music, and sound effects on the cuts.
What if I don’t have a track?
Cut Express can search a stock music library from the chat. Claude searches by genre and mood and sees each track’s length and tempo before picking:
| What you say | What Claude searches |
|---|---|
| “Something upbeat for a travel recap” | Genre Pop or Electronic, mood Upbeat or Happy |
| “Calm music for a tutorial” | Genre Lofi or Ambient, mood Peaceful or Laid Back |
| “Big, dramatic build for a launch” | Genre Cinematic, mood Epic or Dramatic |
| “Moody night city vibe” | Genre Synthwave, mood Dark or Groovy |
Searching is free. Adding a track counts toward your stock files for the month: 50 on Pro, 150 on Ultra, no credits.
For where sound effects go on top of the music, see sound effects for YouTube videos. For the rest of the edit, see video editing tips.
Which music settings fit which video?
| Video | Music level | Ducking | Ending |
|---|---|---|---|
| Talking head, tutorial | Low, well under the voice | Yes, strong | Fade out over 2 s |
| Vlog with some speech | Medium | Yes, light | Fade on the last shot |
| Montage, travel recap, no speech | Full | No | End on a beat or fade |
| Faceless video with voice-over | Low | Yes | Fade out over 2 s |
| Ad with voice-over | Low under the voice, up between lines | Yes | Up on the logo, then fade |
Can I use any song I like?
Only if you have the right to. Platforms like YouTube, Instagram and TikTok check uploads for copyrighted music, and a match can mute your video, block it in some countries, or send its ad revenue to the rights holder. Use music you’ve licensed, music from the platform’s own library, or stock music, and read its terms for how you plan to use the video.
FAQ
Can Claude match cuts to the beat?
There is no automatic beat sync. With a stock track, Claude knows the tempo and can space cuts to it. With your own track, tell it the tempo or the moments to cut on.
Can I keep the original sound of my clips under the music?
Yes. Each clip has its own volume. Keep it, lower it or mute it.
Can I lower the music for just one part?
Yes. Ask “drop the music between 0:10 and 0:14” and Claude adds a volume dip there.
Does adding music cost credits?
No. Credits are for generated voices, sound effects and transcripts. A voice-over to go with your music costs credits; see AI voiceover for video.
Try it on your own footage
Upload your clips and a track, or ask Claude to find one.
14 days free, then $19/month. Cancel before day 14 and you pay nothing.