This trips people up because it inverts the usual order. In a normal edit you assemble footage and the length falls out of it. In a beat-matched edit the music is the spine, so its length *is* the video's length before you have chosen a single clip.
What each platform allows
| Platform | Maximum | Where attention actually holds |
|---|---|---|
| Instagram Reels | Up to 3 minutes | 15–30 seconds |
| TikTok | Up to 10 minutes | 15–34 seconds |
| YouTube Shorts | Up to 3 minutes | 15–30 seconds |
| Facebook Reels | Up to 90 seconds | 15–30 seconds |
Crop the song, not the edit
The instinct is to build the whole thing and trim the end. That breaks a beat-matched edit twice: the last cut no longer lands on a beat, and the music stops mid-phrase, which the ear notices even when the eye does not.
Crop the track first, to a window that starts and ends on a musical phrase — usually a multiple of four or eight beats. Then build to it. The edit ends when the music resolves, which is the thing that makes a short video feel finished rather than cut off.
Picking the window
- Find the strongest eight-bar section of the track — usually the drop or the first chorus.
- Set the start on the first beat of that section, not a moment before it.
- Take 16 or 32 bars, whichever lands nearer 20 seconds.
- Check the end sits on a downbeat. If it does not, move it, not the start.
Easy Reels caps a track at 60 seconds — measured on the window you use, not the file. A four-minute song is perfectly usable: crop it to the 20 seconds you want and the rest is irrelevant to the render.
The one case for going long
Tutorials and walkthroughs earn their length, because the viewer arrived for the information rather than the rhythm. Even then, cut to the beat — it holds attention through the parts where nothing is being demonstrated.