Monday, 17 February 2014

Minecraft - Music Visualiser

Not much to say about this...  Its a music visualiser / graphic equaliser for Minecraft!

I read a post on the raspberry pi forum, by a guy called SpaceGerbil who had created a music visualiser using an 8x8 led matrix, so I went code robbing.

After a pretty major code overhaul, including the removal of a global variable (tish tish), I had a music visualiser for Minecraft, I basically replaced the 8x8 led matrix functions with a class for creating columns of different colour wool in Minecraft.

The only problem was it ran like a dog, a fat asthmatic dog at that, with the music cutting in and out.  So I cranked up the overclocking to the max and increased the chunk size (i.e. the amount of data the program reads ahead and analyses).  This got me to the point where it worked, but the refresh rate was slow, so I moved to 2 Pi's, one running Minecraft, the other running the music analyser and visualiser program, success this was much better!  The video was actually recorded on the PC version of Minecraft using a Bukkit server with the Raspberry Juice plugin with the analyser and visualiser program running on a Pi.

The music visualisation is created by using an FFT algorithm and I am hopeful that I'll be able to change it to use the new interface created which uses the GPU to calculate the FFT's, but the lack of a python interface held me back.  Ill keep on looking though.

Download and run
You can download the code direct from github, so run minecraft, open/create a world and follow the instructions:

sudo apt-get install git-core
cd ~
git clone
cd minecraft-music


#!/usr/bin/env python

# 8 band Audio equaliser from wav file
# Original code from Space Gerbil

# Heavily Modded to be a minecraft equaliser
import alsaaudio as aa
from struct import unpack
import numpy as np
import wave
import threading
import sys
import minecraft
import block
import time
import copy

class MCEqualiser():
    def __init__(self):
        #open connection to minecraft = minecraft.Minecraft.create()
        pos =
        #store variables
        self.x = pos.x + 5
        self.y = pos.y
        self.z = pos.z
        #clear area
        self.drawnMatrix = np.array([0,0,0,0,0,0,0,0])

    def drawEqualiser(self, newMatrix):
        x,y,z = self.x,self.y,self.z
        #loop through the columns
        for column in range(0,8):
            # only update columns which have changed
            if self.drawnMatrix[column] != newMatrix[column]:
                # do I need to add or take away block?
                #  add blocks
                if self.drawnMatrix[column] < newMatrix[column]:
                #  remove blocks
                if self.drawnMatrix[column] > newMatrix[column]:
        self.drawnMatrix = newMatrix.copy()

# Initialise matrix
matrix    = np.array([0,0,0,0,0,0,0,0])
power     = []
weighting = [2,2,8,8,16,32,64,64] # Change these according to taste

# Set up audio
wavfile ="/home/pi/minecraft-music/hot.wav","r")
sample_rate = wavfile.getframerate()
no_channels = wavfile.getnchannels()
chunk       = 4096 
#chunk       = 8192
#chunk       = 16384 #use this value if running it all on one Pi
output = aa.PCM(aa.PCM_PLAYBACK, aa.PCM_NORMAL)

# Return power array index corresponding to a particular frequency
def piff(val):
    return int(2*chunk*val/sample_rate)
def calculate_levels(data, chunk,sample_rate,matrix):
#    global matrix
    # Convert raw data (ASCII string) to numpy array
    data = unpack("%dh"%(len(data)/2),data)
    data = np.array(data, dtype='h')
    # Apply FFT - real data
    # Remove last element in array to make it the same size as chunk
    # Find average 'amplitude' for specific frequency ranges in Hz
    power = np.abs(fourier)   
    matrix[0]= int(np.mean(power[piff(0)    :piff(156):1]))
    matrix[1]= int(np.mean(power[piff(156)  :piff(313):1]))
    matrix[2]= int(np.mean(power[piff(313)  :piff(625):1]))
    matrix[3]= int(np.mean(power[piff(625)  :piff(1250):1]))
    matrix[4]= int(np.mean(power[piff(1250) :piff(2500):1]))
    matrix[5]= int(np.mean(power[piff(2500) :piff(5000):1]))
    matrix[6]= int(np.mean(power[piff(5000) :piff(10000):1]))
    matrix[7]= int(np.mean(power[piff(10000):piff(20000):1]))
    # Tidy up column values for the LED matrix
    # Set floor at 0 and ceiling at 8 for LED matrix
    return matrix

#Create Minecraft Equaliser object
mcequaliser = MCEqualiser()

    # Process audio file   
    print "Processing....."
    data = wavfile.readframes(chunk)
    while data!='':
        matrix=calculate_levels(data, chunk,sample_rate,matrix)
        data = wavfile.readframes(chunk)

except KeyboardInterrupt:
    print "User Cancelled (Ctrl C)"

    print "Unexpected error - ", sys.exc_info()[0], sys.exc_info()[1]


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