music problems when using pygame + multiprocessing

Question

I'm tring to run a script that would play music via a process. the code below is a stripped down version of my code but it's good enough to replicate the problem. If I call the normal() procedure I hear music so I know the procedure is correct and everything is connected properly, however, if I call normal() using multiprocessing there is no sound... It runs normal() but still no audio...

Any suggestions? thanks!

#!/usr/bin/python
# 
# Import required Python libraries
import pygame, time
import multiprocessing as mp
localtime = time.asctime( time.localtime(time.time()) )
pygame.init()
cs = 0 

def normal( cs ):
# main loop
    try:
        if cs == 1: 
              while cs == 1:
                 print " Starting normal function"   
                 pygame.mixer.music.load('/home/user/scripts/music.mp3')
                 pygame.mixer.music.play()
                 time.sleep(20)
                 pygame.mixer.music.stop()              
              #return;

    except KeyboardInterrupt:
        print "Quit" 

try:

  print " Starting music"   
  # play here 
  cs = 1
  p2 = mp.Process(target=normal, args=(cs,))
  p2.start()
  p2.terminate()
 #normal( cs )           

except KeyboardInterrupt:
  print "  Quit" 
# End script

what is the sample rate of your file? – Shapi Oct 27 '15 at 17:50 — Shapi, Oct 27 '15 at 17:50

score 1 · Answer 1 · answered Apr 14 '21 at 20:23

Following code worked for me:
setting multiprocessing start method to spawn.

import pygame, time
import multiprocessing as mp
localtime = time.asctime( time.localtime(time.time()) )
pygame.init()
cs = 0 

def normal( cs ):
# main loop
    try:
        if cs == 1: 
              while cs == 1:
                 print(" Starting normal function")
                 pygame.mixer.music.load('/home/sumit/qt/audio.wav')
                 pygame.mixer.music.play()
                 time.sleep(20)
                 pygame.mixer.music.stop()              
              #return;

    except KeyboardInterrupt:
        print("Quit") 
if __name__ == '__main__': 
    try:
        mp.set_start_method('spawn')
        print(" Starting music")   
        # play here 
        cs = 1
        p2 = mp.Process(target=normal, args=(cs,))
        p2.start()
        p2.join()
        p2.terminate()
        #normal( cs )           

    except KeyboardInterrupt:
        print("Quit") 
    # End script

score 0 · Answer 2 · edited May 23 '17 at 10:28

0

Try this:

pygame.mixer.music.load('/home/user/scripts/music.mp3')
pygame.mixer.music.play(-1,0) # add this args
sleep(20) #remove this line
mixer.music.stop() #remove this line

Adding pygame.mixer.music.play(-1,0) means that the music will play in loop until you quit the game e.g.

Try to remove sleep(20) and mixer.music.stop().

Also check if you are playing a 44.1kHz MP3, the default 22050 frequency works, but a 48kHz mp3 plays in less than half speed - 48000 or 24000 works then.

Or try this approach depending on sample rate:

pygame.mixer.init(frequency=22050, size=-16, channels=2, buffer=4096)
sound = pygame.mixer.Sound('/home/user/scripts/music.mp3').play()

Or try this.

edited May 23 '17 at 10:28

Community

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answered Oct 27 '15 at 18:01

Shapi

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Thanks for trying but it still didn't solve the problem. The function "normal" seems to be working fine if I call it directly, it seems that only when I call it via the multiprocessing there is no audio.. I do see the output of "Starting normal function" when calling it via p2.start() – badatz Oct 27 '15 at 18:13
@badatz what happens if you `print "here"` after the `pygame.mixer.music.play(-1,0)`? – Shapi Oct 27 '15 at 18:14

music problems when using pygame + multiprocessing

2 Answers2

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