Pygame Mixer: Play Sound Effects and Music

pygame.mixer plays two kinds of audio:

• Sounds (pygame.mixer.Sound): short effects loaded into memory, such as a jump or a coin. Many can play at once.
• Music (pygame.mixer.music): one long track streamed from its file, usually looping in the background.

Press Play, click the game, and press Space, the arrow keys or the mouse button to hear the effects. The music starts with the game.

import pygame

pygame.init()
screen = pygame.display.set_mode((480, 300))
clock = pygame.time.Clock()
font = pygame.font.Font(None, 30)

jump = pygame.mixer.Sound("assets/sounds/jump.ogg")
coin = pygame.mixer.Sound("assets/sounds/coin.ogg")
click = pygame.mixer.Sound("assets/sounds/click.ogg")
coin.set_volume(0.6)

pygame.mixer.music.load("assets/music/theme.ogg")
pygame.mixer.music.set_volume(0.4)
pygame.mixer.music.play(-1)

last = "Space, arrows or click"
running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.KEYDOWN:
            if event.key == pygame.K_SPACE:
                jump.play()
                last = "jump"
            elif event.key in (pygame.K_LEFT, pygame.K_RIGHT, pygame.K_UP, pygame.K_DOWN):
                coin.play()
                last = "coin"
        elif event.type == pygame.MOUSEBUTTONDOWN:
            click.play()
            last = "click"

    screen.fill((34, 30, 58))
    screen.blit(font.render(f"Last sound: {last}", True, "white"), (20, 130))
    pygame.display.flip()
    clock.tick(60)

pygame.mixer.music.stop()
pygame.quit()

The sounds and music are from the free pack in the assets folder (Kenney, CC0). On your computer, use your own files and paths.

Sound effects

laser = pygame.mixer.Sound("laser.ogg")   # load once, before the loop
laser.play()                              # each time you need it

Load each file once. Calling pygame.mixer.Sound("laser.ogg") inside the loop reads the file from disk on every shot.

Background music

pygame.mixer.music.load("theme.ogg")
pygame.mixer.music.play(-1)        # -1 repeats forever
pygame.mixer.music.set_volume(0.4)

To change tracks, for example from the menu theme to the level theme, call load() and play() again.

Formats

OGG is the safest single choice. A wrong path raises FileNotFoundError: No file 'jump.ogg' found in working directory ..., the same message as for images; a file pygame cannot decode raises a pygame.error.

Channels

Each playing sound uses a channel; pygame has 8 by default. When all are busy a new sound may not play. pygame.mixer.set_num_channels(16) allows more, and pygame.mixer.Channel(0).play(sound) reserves a channel for something that must always be heard, such as the player's voice.