Hello,
On Thu, Mar 13, 2008 at 9:34 AM, Jaroslav Kysela <perex@xxxxxxxx> wrote:
> On Thu, 13 Mar 2008, ki.ber.kom.uni.st wrote:
> > 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....
You can send NOTEON events without a queue, but you cannot send NOTE
events without a queue. (subtle difference: note_ON_)
The following code will work; 14:0 is "midi-through" in my system... I
run aseqdump -p 14:0 on another window:
seq = alsaseq.Sequencer()
event = alsaseq.SeqEvent(alsaseq.SEQ_EVENT_NOTEON)
event.set_data({'note.note' : 0x40, 'note.velocity' : 64})
event.dest = (14, 0)
seq.output_event(event)
seq.drain_output()
> > 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)
AFAIK, You don't need a port if you are sending events directly.
Now, if you subscribe and connect ports, you don't need to assign them
into the event, because a new event is created with
snd_seq_ev_set_subs called..
You can check this and other stuff with the following code:
-ini-------------
def _find_attributes(typelist):
l = []
for t in typelist:
d = t.__dict__.items()
for k, v in d:
v = "%s" % v
if v.startswith("<attribute"):
l.append(k)
l.sort()
return l
def dump_event(port, name = 'seqevent'):
print "Dumping Event ---------->"
print "%s" % port
l = _find_attributes([alsaseq.SeqEvent])
for k in l:
print "%-30.30s %s" % (name + "." + k, port.__getattribute__(k))
return
seq = alsaseq.Sequencer()
event = alsaseq.SeqEvent(alsaseq.SEQ_EVENT_NOTEON)
event.set_data({'note.note' : 0x40, 'note.velocity' : 64})
dump_event(event)
seq.output_event(event)
seq.drain_output()
-------------end--
> > event = alsaseq.SeqEvent(alsaseq.SEQ_EVENT_NOTE)
> > event.set_data({'note.note' : 0x40, 'note.velocity' : 127,
> > 'note.duration' : 1, 'note.off_velocity' : 0})
note.duration and note.off_velocity make sense only for
SEQ_EVENT_NOTE, but you need a queue... so, use SEQ_EVENT_NOTEON and
SEQ_EVENT_NOTEOFF instead....
I'm planning to move event.set_data() to attributes, like
event.note_note, event.note_velocity ... Tell me what you think!
> > event.dest = (20, 0)
> > seq.output_event(event)
> > seq.drain_output()
> >
> > after drain it says:
> > "SequencerError: Failed to drain output: Invalid argument"
Well, that's what asoundlib says... weird, don't you think?
Alsa hackers: This is a good proof that alsa-lib message errors
really, really sucks... Is there any chance to change this? I mean, if
I volunteer to improve this could be accepted? Any hints for doing
this?
[...]
> > 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....
Remember: python is far away of real-time so if you get weirds timings
you may reconsider using a queue anyway!
HTH,
--
Aldrin Martoq
http://aldrinvideopodcast.podshow.com/
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