No audio output using raspberry pi and pygame.midi

Question

I have a Raspberry Pi 2 and a set of speakers connected to the 3.5mm headphone jack. I've got most audio coming out of my speakers by running amixer set name='PCM Playback Route' 1. pygame.mixer works absolutely wonderfully without doing anything special. However, when I try to run my pygame.midi code I hear nothing.

I don't think it's a problem with my code personally. If I run python -m pygame.examples.midi --output, I see the graphical piano, no errors are thrown, but I hear no audio out.

I'm running Ubuntu Mate on my pi, but this thread makes it seem like that's not the issue.

• Luke Taylor: My code just reads input from my MIDI keyboard, and tries to play the output, I will post it on github if it is useful for resolving my issue

Answer 1

I solved it by running sudo apt-get install timidity and then changing my outport port from 0 to 3.

Answer 2

I had a similar problem with pygame. However, I found that my issue was completely unrelated. This may be the case for you as well.

The problem is likely not a product of an issue with the pygame.midi, so much as it lies with the fact that your raspberry pi may be configured to forward its audio output to the HDMI cable connection.

I found that a fix can be arranged with two simple commands:

Typing the following commands tells us what our audio output is configured to:

amixer cget name='PCM Playback Route'

My output was this: (your's should be similar)

numid=3,iface=MIXER,name='PCM Playback Route'
 ; type=INTEGER,access=rw------,values=1,min=0,max=2,step=0
 : values=0

If the last line (value) is 0, the audio output is configured to the HDMI. Changing this value to 1 can easily allow the sound output to go through the 3.5mm audio jack!

Do this using this command:

amixer cget name='PCM Playback Route' 1

And that is all that there should be to it!

• Sylvain: it should be 'cset' instead of 'cget' in the last block of code :)

Answer 3

Probable cause of the problem can be in the output port mismatch.

Type aconnect -i to display a list of the readable input ports. These are the ports which provide incoming MIDI data.

$ sudo aconnect -i

response should have something like:

client 0: 'System' [type=kernel]
 etc....
client 20: 'USB MIDI Interface' [type-kernel, card=1]
 0 'USB MIDI Interface MIDI 1'

Type aconnect -o to display a list of the writable output ports. These are the ports which send outgoing MIDI data. Again; response should have something like:

 client 20: 'USB MIDI Interface' [type-kernel, card=1]
 0 'USB MIDI Interface MIDI 1'

Finally, type aconnect 14:0 20:0 to establish a bridge between the RaspberryPi port [14] in my case and the MIDI OUT port [20] {my case}.

$ sudo aconnect 14:0 20:0

Type aconnect -x to remove all connections when finished. Individual connections can be removed using the -d option. If you ever need usage information about aconnect, just type aconnect -h or man aconnect.

Good Luck!

• Ingo: The OP solved the problem by running sudo apt-get install timidity and then changing the outport port from 0 to 3. Just read his old answer.