PROMPT GUIDE

How to Add BGM and Sound Effects to AI Videos

An AI video becomes much more engaging with sound. At the same time, many people get stuck on sound rights or volume balance. This guide covers two ways to add BGM and sound effects to AI videos, how to choose sounds you are allowed to use, and volume guidelines that keep it easy to listen to.

Last updated: 2026-10-22 approx. 3 min read

日本語版

The short answer

There are two ways to add BGM and sound effects to an AI video: use a video generator that also makes audio, or layer sound in a video editor after making the video. Either way, check the usage terms of each sound (commercial use, credit) and keep the BGM quieter than voices and effects.

How do you add sound to an AI video?

Either use an AI that also makes audio, or layer sound later in an editor.

Some video generators can make ambient sound or dialogue together with the picture. Many services, however, make only the picture, so you add BGM and sound effects afterwards in a video editor. Whether a service can make sound, and what kinds, varies by service and version, so check the official documentation.

Method	Strengths	Watch out for
A video generator that also makes audio	Picture and sound timing match easily	You may not be able to choose sound quality or content in detail
Layer sound later in an editor	You can choose any sound and adjust volume	You must check the usage terms yourself
Make BGM with a music AI	Easy to match the video length and mood	Check that service terms of use

Anime girl reading by a rainy window, a scene that suits rain sound effects — 雨音が合う場面

Anime girl walking along a sunny seaside road, a scene for wave and wind sounds — 雨音が合う場面

Illustration usage rules

How do you add BGM and sound effects afterwards, step by step?

Finish the picture first, then layer BGM, then sound effects, then balance the volume.

Steps to add BGM and sound effects to an AI video

Finish joining the video cuts and decide the final length
Choose BGM that fits the mood and check its usage terms (commercial use, credit)
Fit the BGM to the video length and fade it in at the start and out at the end
Place sound effects that match the motion, such as footsteps, wind or a door, on the frames where that motion happens
Listen on both phone speakers and earphones and adjust the volume balance

How do you choose sounds you are allowed to use?

Choose material with clear terms for commercial use and credit, and use it as the terms say.

You cannot use commercial songs or sound from TV or anime in your video without permission. Free material also often comes with conditions such as "no commercial use" or "credit required", so read the terms on the download page before using it. Some social platforms offer songs you can use inside their apps. Music made with a music AI also has conditions that differ by service terms.

What volume balance is easy to listen to?

The basic rule is to keep the BGM one step quieter than dialogue and sound effects.

Problem	Cause	Fix
The BGM is too loud	The BGM is as loud as everything else	Lower the BGM a step, and further during dialogue
Sound effects sound off-timing	The sound is not lined up with the motion frame	Move it to the frame where the foot touches the ground, for example
It cuts off abruptly at the end	The BGM ending was not handled	Fade it out over the last one or two seconds
It is inaudible on phones	The track is mostly low frequencies	Check on phone speakers too and choose another sound
The sound distorts	Too many layered sounds made it too loud	Lower the overall volume and reduce overlapping sounds

Rinka's tips

Some people watch short videos on mute, so also show important information in captions
Using sound effects only for things visible on screen, such as footsteps, wind or birds, sounds natural
For loop videos, choose BGM whose length fits the loop so the sound does not break at the seam

After adding sound, listen from start to finish and check for spots where the volume jumps or the sound does not match the picture. Listening again after a break can reveal mismatches you missed.

For making vertical short videos: How to Make Vertical Short Videos (9:16) with AI →

For making loop videos: How to Make an AI Video Loop (Tips to Hide the Seam) →

For how to write video generation prompts: How to Write AI Video Prompts (Motion, Camera and Time) →

Copy-and-paste: example requests for an AI that makes audio

Examples of describing ambient sound in the text, for services that make audio together with the picture.

An anime girl reads a book by a window on a rainy afternoon. Soft rain sounds against the glass, a page turning, quiet room ambience, no music.

An anime girl walks along a seaside road on a sunny day. Gentle waves, a light breeze, distant seagulls, footsteps on the pavement.

FAQ

Frequently Asked Questions

How do I add BGM to an AI video?

Use a video generator that also makes audio, or layer BGM onto the finished video in an editor. Layering it afterwards lets you choose the track and volume freely.

Can I use my favorite song in an AI video?

You cannot use commercial songs without permission. Choose free material with stated usage terms, songs provided by the social platform, or music whose terms of use allow it.

How loud should the BGM be?

The basic rule is one step quieter than dialogue and sound effects. Check on both phone speakers and earphones.

I do not know where to place sound effects.

Place them on the frames where a visible motion happens, such as a foot touching the ground or a door closing. The trick is not to add too many sounds that are not on screen.