Audio Beat Detection System

Help and Feedback Scripting Support
#1

I would like to know if there is a way to find an audios BPM or a beat detection system, I’ve seen some games do it, I looked on the Wiki and only found this code which uses playback loudness, but it creates a weird looking bar and I need something which can find the BPM or detect a beat in a song

while true do
 local amplitude = math.clamp(sound.PlaybackLoudness / maxLoudness, 0, 1)
 bar.Size = UDim2.new(amplitude, 0, 1, 0)
 wait(0.05)
end

Any help is appreciated! Thank you!

– Kris

5 Likes
#2

I don’t know of any games that do this, and getting beats from just volume can be very inaccurate. But volume is the only variable Roblox gives us to work with sounds real-time.

I came up with this. The maxLoudness seems to vary per song to get a perfect number, and songs with quiet or loud filler segments obviously mess it up. It managed to tell me 117 bpm for a 120 bpm song.

local sound = script.Parent
local beats = 0
local maxLoudness = 410
sound:Play()
game:GetService("RunService").RenderStepped:Connect(function()
    local loudness = sound.PlaybackLoudness
    if loudness > maxLoudness then
        beats = beats+1
    end
end)

local function getAverageBpm()
    local minutesElapsed = sound.TimePosition/60
    return beats/minutesElapsed
end
while wait(1) do
    print(getAverageBpm())
end
4 Likes
#3

Thank you! I’ll try this out and see if it works, also, for maxLoudness, would that have to change accordingly to the song or can a script figure it out? Thanks :smiley:

– Kris

#4

A script could figure that out, but only if it plays the song entirely once before starting to measure beats. If a human doesn’t do it it won’t ever be perfect because a script can’t really know how loud a beat is supposed to be.

1 Like
#5

Oh ok, I think I can find a way to do this.