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title = soundMeter heading = Making a Sound Meter in Python subheading = A basic usage of audio handling libraries for creating a fun sound-meter! category = Tutorials tags = Python, Audio author = Krish Mehta date = August 4, 2016 //(DO NOT REMOVE THESE LINES) //(WRITE YOUR BLOG BELOW FROM LINE 12)

Those who have seen the 3 blocks of audience in PCSA compete during the STAB Orientation for the loudest cheer, know what this Sound Meter is.

Target

To analyse any incoming sound(be it mic or laptop microphone) and find its maximum volume. Actually, using other detailed operations you can estimate the frequency etc. Basically, once we read the audio input stream we can use the desired computations on it.

Plan of action

This is roughly what we need to do:

  1. Read the input from the laptop microphone or the mic(in our case, that requires setting it to default recording device)
  2. Find the maximum value of the sound channels over a chunk of inputs.
  3. Display it!

Libraries used:

pyaudio for audio stream input. audioop for max value analysis. pygame for display.

import time, audioop
import pygame
import pyaudio
import wave

#Initialisation for PyAudio
CHUNK = 1024
FORMAT = pyaudio.paInt16
CHANNELS = 2
RATE = 44100
RECORD_SECONDS = 5
#Object
p = pyaudio.PyAudio()
stream = p.open(format=FORMAT, channels=CHANNELS, rate=RATE, input=True, frames_per_buffer=CHUNK)

#PyGame initialisations and basic objects
pygame.init()
screensize = (900, 600)
screen=pygame.display.set_mode(screensize)
pygame.display.set_caption("Shout harder.. :D")

#Defining colors
WHITE=(255,255,255)
RED=(255,128,128)
YELLOW=(255,255,128)
BLUE=(0,0,255)

#Loop till close button clicked
done=False
clock=pygame.time.Clock()

#variables
score=[]
width=0.8

margin = 20
samples_per_section = screensize[0]/3 - 2*margin

sound_tracks = [[0]*samples_per_section]*3
max_value = [0]*3

current_section = 0
while not done:

	#Limits CPU usage to max 10 times per second
	#Not required here because already the for loop takes averages over some time
	#clock.tick(10)

	total=0
	#Now we read data from device for around one second
	for i in range(0,2):
            #l,data = inp.read()
			data=stream.read(CHUNK)
			#oreo_sound.append(data)
			if True:
				reading=audioop.max(data, 2)
				total=total+reading
			time.sleep(.0001)

	#any scaling factor
	total=total/100

	sound_tracks[current_section] = sound_tracks[current_section][1:] + [total]
	max_value[current_section] = max(max_value[current_section], total)

	screen.fill(WHITE)

    # draw highlighted section
	pygame.draw.rect(screen,YELLOW,(screensize[0]/3*current_section, 0,screensize[0]/3, screensize[1]))

	for i in range(3):
		sectionx = i*screensize[0]/3 + margin
            #add meet wala last year ka feature
		pygame.draw.rect(screen,RED,(sectionx, screensize[1] - max_value[i],screensize[0]/3 - 2*margin, max_value[i]))

		for j in range(0,screensize[0]/3 - 2*margin):
			x = j + sectionx
			y = screensize[1] - sound_tracks[i][j]
			pygame.draw.rect(screen,BLUE,(x, y, 1, sound_tracks[i][j]))

	#frame flip must happen after all drawing commands
	pygame.display.flip()

	#Set close button event
	for event in pygame.event.get():
            if event.type==pygame.QUIT:
                done=True
            if event.type==pygame.MOUSEBUTTONUP :
                if event.button == 3:
                    # right button pressed, clear all arrays
                    sound_tracks = [[0]*samples_per_section]*3
                    max_value = [0]*3
                    current_section = 0
                else:
                    pos = pygame.mouse.get_pos()
                    current_section = (pos[0] * 3) / screensize[0]
                    print pos, current_section
	
#clearing the resources
pygame.quit()
stream.stop_stream()
stream.close()
p.terminate()
pygame.quit()

Have fun!

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