pygame audio playback speed

Question

quick question.

I'm running pygame under linux just to play some audio files. I've got some .wav files and I'm having problems playing them back at the right speed.

import pygame.mixer, sys, time

#plays too fast
pygame.mixer.init(44100)
pygame.mixer.music.load(sys.argv[1])
pygame.mixer.music.play()
time.sleep(5)
pygame.mixer.quit()

#plays too slow
pygame.mixer.init(22100)
pygame.mixer.music.load(sys.argv[1])
pygame.mixer.music.play()
time.sleep(5)
pygame.mixer.quit()

I've ggogle code searched some stuff but everybody seems to be fine calling the init function with its default parameters. Can others try running this script and seeing if they get the same behavior or not? Does anybody know how to speed it up? Or adjust the speed for each file?

Thanks.

Answer 1

I figured it out... There is a wave module http://docs.python.org/library/wave.html and it can read the sample rate for wav files.

Answer 2

To improve Chris H answer. Here is a example of how to use the wave library.

import wave
import pygame

file_path = '/path/to/sound.wav'
file_wav = wave.open(file_path)
frequency = file_wav.getframerate()
pygame.mixer.init(frequency=frequency)
pygame.mixer.music.load(file_path)
pygame.mixer.music.play()

Remember that if you want to change frequency or any other parameter used in pygame.mixer.init you must call pygame.mixer.quit first. Pygame documentation

Answer 3

Open your audio file in a free audio tool like Audacity. It will tell you the sampling rate of your media. It will also allow you to convert to a different sampling rate so all your sounds can be the same.

Answer 4

I had some mp3 audio tracks playing back slowed down. I updated the mixer frequency to be based on the mp3 sample rate using mutagen like so:

import pygame, mutagen.mp3

song_file = "your_music.mp3"

mp3 = mutagen.mp3.MP3(song_file)
pygame.mixer.init(frequency=mp3.info.sample_rate)

pygame.mixer.music.load(song_file)
pygame.mixer.music.play()

And it fixed the problem.