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I was getting this error when I tried to run my pygame.midi code:

ALSA lib conf.c:3558:(snd_config_hooks_call) Cannot open shared library libasound_module_conf_pulse.so (/usr/lib/alsa-lib/libasound_module_conf_pulse.so: libasound_module_conf_pulse.so: cannot open shared object file: No such file or directory)
ALSA lib seq.c:935:(snd_seq_open_noupdate) Unknown SEQ default

I found out that the path Python was searching for did not exist. For some reason, libasound_module_conf_pulse.so is located in /usr/lib/x86_64-linux-gnu/alsa-lib, so I created alsa-lib directory in /usr/lib/ and copied the contents of usr/lib/x86_64-linux-gnu/alsa-lib in it.

That fixed the first error. Now, I am encountering another error, which I think is related to the really shady fix I applied above (why I included both of them in the same question). When running pygame.init() I get this error:

ALSA lib pcm_dmix.c:1089:(snd_pcm_dmix_open) unable to open slave

I have searched the web and found only one question related but sadly left unanswered. What I understand is that using methods from pygame.midi works but using methods from pygame such as init throws the error.

So, this code works fine:

import pygame.midi
import pygame

def print_devices():
    for n in range(pygame.midi.get_count()):
        print (n,pygame.midi.get_device_info(n))

def number_to_note(number):
    notes = ['c', 'c#', 'd', 'd#', 'e', 'f', 'f#', 'g', 'g#', 'a', 'a#', 'b']
    return notes[number%12]

def readInput(input_device):
    clock = pygame.time.Clock()
    while True:
        if input_device.poll():
            event = input_device.read(1)[0]
            data = event[0]
            timestamp = event[1]
            note_number = data[1]
            velocity = data[2]
            if (velocity!=0):
                print (number_to_note(note_number), velocity)



if __name__ == '__main__':
    pygame.midi.init()
    my_input = pygame.midi.Input(3)
    readInput(my_input)
    my_output = pygame.midi.Output(2)
    my_output.note_on(90,120)
    my_output.note_off(90, 120)

but adding pygame.init() throws the slave error.

I am using Ubuntu 20.04 and Python 3.8 in PyCharm.

Edit: Running the above code directly in Python from the terminal does not give the slave error on pygame.init() but will sometimes give a (snd_pcm_recover) underrun occurred error.

Sederfo
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  • The "Unknown SEQ default" message means that ALSA and/or PulseAudio is not installed correctly, or that the ALSA configuration files have been modified in an inappropriate way. – CL. Nov 02 '20 at 18:59

1 Answers1

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I had the same issue using PyGame in Blender, the "hack" above, copying the files to /usr/lib/alsa-lib got rid of the error for me and made sounds and PyGame work properly. I only had this issue on Ubuntu, not my Mac. I didn't ever get the "slave" error.

FTR, I am using PyGame to input live MIDI commands from either a keyboard or controller to animate in Blender.

Alan Odom
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