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ravelox / pimidi

Raspberry Pi RTP MIDI
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How do I change the MIDI Channel? #74

Closed alpho-gav closed 4 years ago

alpho-gav commented 4 years ago

How can I use 4 different midi channels? I haven't been able to figure out which argument is for the channel, and how to use a number in the field.

Thanks

ravelox commented 4 years ago

MIDI messages are documented at https://www.midi.org/specifications/item/table-1-summary-of-midi-message

For NoteOn and NoteOff events, for example, the first byte of the message would be:

1000nnnn

or

1001nnnn

where nnnn is the channel from 0000 (0) to 1111 (15)

alpho-gav commented 4 years ago

Ok. Where would that go in the command? bytes = struct.pack("BBBB", 0x90, 0x30, int(midi_channel_note), 127)

I just want to be able to output any midi note between 1-83 on channels 1-4

ravelox commented 4 years ago

You need something like:

channel=4 command=0x90 note=56 velocity=127

bytes = struct.pack("BBB", command + channel, note, velocity)

alpho-gav commented 4 years ago

It looks like if my channel is always outputting 144 and coming over as "0" on my midi software

alpho-gav commented 4 years ago

From my midi logger on the windows computer: Midi-In message - Device - 0 - Channel 0 - Command - NoteOn(9) - Data1 - 2 Data2 - 127

ravelox commented 4 years ago

Can you paste the script you're using?

alpho-gav commented 4 years ago

Here's a snippet/example from my 5,000+ lines.

midi_note = "10_30" midi_index = midinote.find("") midi_channel = int(midi_note[midi_index - 1]) midi_channel_note = int(midi_note[midi_index + 1]) s = configureMIDI() channel = int(midi_channel) command = 0x90 note = midi_channel_note velocity = 127 print("BBB" + str(command + channel) + " " + str(note) + " " + str(velocity)) bytes = struct.pack("BBB", command + channel, note, velocity) s.send( bytes ) s.close()

ravelox commented 4 years ago

What does your print command show you for that MIDI command? Because channel is represented as 0-15, you need to set the channel to be n-1 where n is the channel that you want ( for channel 4, it should be channel=3 ).

alpho-gav commented 4 years ago

You got me to look deeper into how I did the indexing. This was this fix: midi_channel = int(midi_note[:midi_index]) - 1

Thank you!! PiMidi has been working awesome.

ravelox commented 4 years ago

Glad it was an easy fix :)