[alsa-devel] problems howto send simple 'noteon' event with pyalsa...

[ki.ber.kom.uni.st]

e,
i was happy user of PySeq [1] and it was easy to send directly
'noteon' event.. more or less in python interactoin session:
import pyseq

seq = pyseq.PySeq()
seq.createOutPort()
event = snd_seq_event()
event.setSource(0)
event.setSubscribers()
event.setNoteOn(ch, note, velocity)
event.sendAsIs(seq)

it seems that pyalsa will go along alsa development so i tried pyalsa.. but....

i tried this:

from pyalsa import alsaseq

seq = alsaseq.Sequencer()
seq.create_simple_port("myPort", alsaseq.SEQ_PORT_TYPE_APPLICATION,
alsaseq.SEQ_PORT_CAP_SUBS_READ | alsaseq.SEQ_PORT_CAP_READ |
alsaseq.SEQ_PORT_CAP_WRITE | alsaseq.SEQ_PORT_CAP_SUBS_WRITE)

event = alsaseq.SeqEvent(alsaseq.SEQ_EVENT_NOTE)
event.set_data({'note.note' : 0x40, 'note.velocity' : 127,
'note.duration' : 1, 'note.off_velocity' : 0})
event.dest = (20, 0)
seq.output_event(event)
seq.drain_output()

after drain it says:
"SequencerError: Failed to drain output: Invalid argument"
i can connect and disconnect ports around and (20,0) is functional
port where i send events with no problems from PySeq...

any ideas? do i have to use queues to be able to send 'noteon'.. for
my purposes it seems to me that that's overkill....

thanx..

[1] http://www.sci.ccny.cuny.edu/~brinkman/software/pyseq/