Re: [pygame] Confusing values from mixer.Channel.get_sound()

[Greg Ewing]

On 26/12/20 3:38 am, Pavils Jurjans wrote:
I first play a sound (get the channel object in return), and let it play 
until the end. channel.get_sound() returns None, as it should. Then I 
play this sound a second time (storing the returned channel object in 
another variable). While the sound is still playing, if I query the 
first channel.get_sound(), I get the reference to the sound object.


Because you started playing the second sound after the first one
finished, it re-used the same channel.

I added a couple of lines to print out the repr of the sound
object returned by each play() call. This is what I got:

Play the sound on channel1
channel1 = 
After 1 second: channel1 -  True
After 7 seconds: channel1 -  False
Play the sound on channel2
channel2 = 
After 1 seconds: channel1 -  True , channel2 -  True
After 4 seconds: channel1 -  True , channel2 -  True
After 7 seconds: channel1 -  False , channel2 -  False

You can see that channel1 and channel2 are actually the same
channel object.

I don't think there's anything you can do about that; you'll
have to re-think your method of detecting whether a sound is
still playing.

Note that you can use Channel.set_endevent() to arrange for an
event to be posted when a sound finishes playing.

--
Greg

[pygame] Confusing values from mixer.Channel.get_sound()

[Pavils Jurjans]

I am getting strange behavior when reading channel.get_sound() value from a
supposedly silent channel.

I first play a sound (get the channel object in return), and let it play
until the end. channel.get_sound() returns None, as it should. Then I play
this sound a second time (storing the returned channel object in another
variable). While the sound is still playing, if I query the first
channel.get_sound(), I get the reference to the sound object.

Is this a bug or it's by design? This behavior messes up my application
logic, because I store the returned channel objects to query later if the
sound is still playing on them.

I tested the problem on both Pygame 1.9.6 and 2.0.0.

Here's my test code:

import pygame
from time import sleep

mixer = pygame.mixer
mixer.pre_init(44100, -16, 1, 8192)
mixer.init()
mixer.set_num_channels(10)
pygame.init()

dog = mixer.Sound('dog.ogg')
dog = mixer.Sound('apps/sounds/media/animal: dog.ogg')

# Test #1: use channel.get_sound() to see what sound the channel is
playing. It should return None, when no sound is playing. This test passes.
def channel_test_1():
channel1 = dog.play()
sleep(1)
print('After 1 second:', channel1.get_sound() == dog)
sleep(6)
print('After 7 seconds:', channel1.get_sound() == dog)

# Test #2: play sound on one channel. Let it play to the end. The
channel1.get_sound() returns None. Then play the sound on channel2. The
channel1.get_sound() should still return None, however once the sound
starts playing on channel2, the channel1.get_sound() is no more None. This
test fails.
def channel_test_2():
print('Play the sound on channel1')
channel1 = dog.play()
sleep(1)
print('After 1 second: channel1 - ', channel1.get_sound() == dog)
sleep(6)
print('After 7 seconds: channel1 - ', channel1.get_sound() == dog)
print('Play the sound on channel2')
channel2 = dog.play()
sleep(1)
print('After 1 seconds: channel1 - ', channel1.get_sound() == dog, ',
channel2 - ', channel2.get_sound() == dog)
sleep(3)
print('After 4 seconds: channel1 - ', channel1.get_sound() == dog, ',
channel2 - ', channel2.get_sound() == dog)
sleep(3)
print('After 7 seconds: channel1 - ', channel1.get_sound() == dog, ',
channel2 - ', channel2.get_sound() == dog)

channel_test_2()

Here are my results for the channel_test_2():

>>> channel_test_2()
Play the sound on channel1
After 1 second: channel1 -  True
After 7 seconds: channel1 -  False
Play the sound on channel2
After 1 seconds: channel1 -  True , channel2 -  True
After 4 seconds: channel1 -  True , channel2 -  True
After 7 seconds: channel1 -  False , channel2 -  False


The dog.ogg sound is 5.5 seconds long. For the sake of complete
representation, I attach the audio file of this good boy to this post.


dog.ogg
Description: audio/ogg