Add BGM / Audio Mix Tool

Add background music to a video. Adjust source vs BGM volume, fade in/out, and looping.

Local processing — no upload

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Video file

MP4 / MOV / WebM

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BGM audio

MP3 / WAV / AAC / M4A / OGG

Original audio volume 100%

BGM volume 50%

BGM fade-in (sec)

BGM fade-out (sec)

BGM looping

Output length

If the source video has no audio, set "Original audio volume" to 0% and turn on BGM looping to overlay BGM on a silent clip.

Processing… 0%

Download mixed video

Popular uses

Add background musicMix with narrationTune fades

Next tools

Volume Normalizer Audio Extractor Mute Video Tool

What this tool does

Mix the original track and BGM with independent volumes
Auto-loop BGM that is shorter than the video
Fade-in / fade-out in seconds
Trim output to video length or to BGM length
Accepts MP3 / WAV / M4A / AAC / Ogg

How to use

1
Pick a video and BGM
Drop the video and the audio track separately.
2
Set the mix balance
100% original / 25–50% BGM is a good starting point for narrated content.
3
Configure fades and loop
Fade-in 1–2s, fade-out 2–3s. Toggle loop on for short BGMs.
4
Run the mix
Download once the preview shows up.

What each setting means

Original volume

Volume of the source audio. 0% mutes the original entirely.

BGM volume

Volume of the added track. 25–50% keeps speech audible.

Fade in / out

Duration of the audio fade in seconds.

Loop BGM

Repeats short tracks until the video ends.

Output length

Trim to video length or to BGM length.

Recommended settings

Vlog / explainer with narration

Original 100% / BGM 25% · fade 2s · loop on

Keeps narration intelligible and avoids gaps in long clips.

Music-only edit (no original audio)

Original 0% / BGM 80% · fade 2s

Strips environmental noise and lets the music carry the clip.

TikTok / Shorts SFX punch-in

Original 70% / BGM 100% · fade 0s

Snap effects benefit from no fade.

Common pitfalls

Symptom: BGM ends before the video

Cause: BGM is shorter than the video and loop is off.

Fix: Enable the “Loop BGM” toggle.

Symptom: Distortion / clipping

Cause: Combined levels exceed 0 dBFS.

Fix: Drop BGM to ≤50% or run output through the Volume Normalizer.

Symptom: Fade does not apply

Cause: Fade duration is longer than the BGM itself.

Fix: Keep fade ≤ BGM length.

Equivalent FFmpeg commands

Reference commands you can run on the desktop FFmpeg CLI.

Mix BGM with the original audio

ffmpeg -i video.mp4 -i bgm.mp3 -filter_complex "[0:a]volume=1[a0];[1:a]volume=0.3,afade=t=in:st=0:d=2,afade=t=out:st=58:d=2[a1];[a0][a1]amix=inputs=2:duration=first[a]" -map 0:v -map "[a]" -c:v copy out.mp4

volume=0.3 → 30% BGM, with 2s fades.

Loop a short BGM under a longer video

ffmpeg -i video.mp4 -stream_loop -1 -i bgm.mp3 -filter_complex "[0:a]volume=1[a0];[1:a]volume=0.3[a1];[a0][a1]amix=inputs=2:duration=first[a]" -map 0:v -map "[a]" -c:v copy -shortest out.mp4

-stream_loop -1 loops indefinitely; -shortest stops at the video.

Browser support & limits

Recommended max: video 500 MB / BGM 100 MB
Audio formats: MP3 / WAV / M4A / AAC / Ogg
Video codec: H.264 (mp4) only

Privacy

This tool runs ffmpeg.wasm directly in your browser. Files never leave your device — everything runs locally. Read the privacy policy →

Frequently asked questions

Where can I find royalty-free BGM?

YouTube Audio Library, Free Music Archive, Pixabay Music, and Bensound are popular options. Always verify commercial-use rights on the source page.

How do I mute the original audio?

Set Original Volume to 0%. Only the BGM remains.

Can I sequence multiple BGM tracks?

This tool mixes one BGM per pass. Concatenate audio tracks externally first if you need a sequence.

Audible click at loop boundaries

Looping BGMs that aren’t mastered for seamless looping will pop. Pick a loop-ready file or set a 0.5s fade-out at the loop point.

Mono BGM?

Yes — mono and stereo are auto-converted to stereo.

Output format?

MP4 (H.264 video copied + AAC audio re-mixed). Original video is not re-encoded.