17 Jun
2005
17 Jun
'05
8:51 p.m.
Hi
I need a program that will allow me to send predefined program changes
to alsa clients. I imagine something like a chain of programs, grouped
together in songs, grouped together in sets, grouped together in bands.
Anyways, is there such a program outthere? I'd prefer text-based, and
shortcut driven...
If not, could anyone point me in the right direction of some
documentation on how to write such a program, esp how to register as an
alsa-client and exactly what should be send out how for it to be program
change. I'd like to write in python, if possible...
Thanks in advance.
--
peace, love & harmony
Atte
http://www.atte.dk
18 Jun
18 Jun
9:41 a.m.
Atte,
If not, could anyone point me in the right direction
of some
documentation on how to write such a program, esp how to register as an
alsa-client and exactly what should be send out how for it to be program
change. I'd like to write in python, if possible...
I've created Python
bindings for a good chunk of the ALSA sequencer.
You can find the code at
http://www.math.tu-berlin.de/~brinkman/software/midikinesis/
The module pyseq.py contains the sequencer bindings, and applications
like midikinesis.py, midigen.py, and playtune.py should give you an
idea as to how to work with pyseq.py.
As for your specific question of how to send pgm change messages,
here's how I would do this with pyseq.py.
First version: Send event right away, without scheduling via queues.
---------------------------------------------------------------------
from pyseq import *
s=PySeq()
p=s.createOutPort()
raw_input("hook up ports, press return")
e=snd_seq_event()
e.setPgmChange(0, 8) # channel, value
s.sendEvent(e, p) # send event directly
---------------------------------------------------------------------
Second version: Schedule event for a specific time, via queues:
---------------------------------------------------------------------
from pyseq import *
import time
s=PySeq()
p=s.createOutPort()
raw_input("hook up ports, press return")
q=Queue(s)
q.setTempo(120, 192) # 100 beats per minute, 192 ticks per beat
q.start()
e=snd_seq_event()
e.setPgmChange(0, 8) # channel, value
q.postEvent(e, p, 1920) # send via queue after 1920 ticks, i.e., 5 secs
time.sleep(5.5) # wait for event to occur
---------------------------------------------------------------------
Please let me know if you have any questions.
Best,
Peter
10:01 a.m.
Atte André Jensen wrote:
I need a program that will allow me to send predefined
program changes
to alsa clients.
You could load snd-virmidi, connect its port(s) to the destination
port(s), and then call something like
amidi -p hw:X,Y -S "c1 23"
If not, could anyone point me in the right direction
of some
documentation on how to write such a program, esp how to register as an
alsa-client and exactly what should be send out how for it to be program
change.
In C, this would be something like this:
snd_seq_t *seq;
snd_seq_event_t ev;
snd_seq_open(&seq, "default", SND_SEQ_OPEN_DUPLEX, 0);
snd_seq_set_client_name(seq, "my funky program changer");
snd_seq_create_simple_port(seq, "source port",
SND_SEQ_PORT_CAP_READ,
SND_SEQ_PORT_TYPE_MIDI_GENERIC |
SND_SEQ_PORT_TYPE_APPLICATION);
snd_seq_ev_clear(&ev);
snd_seq_ev_set_dest(&ev, dest_client, dest_port);
snd_seq_ev_set_direct(&ev);
snd_seq_ev_set_pgmchange(&ev, channel, program);
snd_seq_event_output_direct(seq, &ev);
HTH
Clemens
2:05 p.m.
Clemens,
In C, this would be something like this:
snd_seq_t *seq;
snd_seq_event_t ev;
snd_seq_open(&seq, "default", SND_SEQ_OPEN_DUPLEX, 0);
snd_seq_set_client_name(seq, "my funky program changer");
snd_seq_create_simple_port(seq, "source port",
SND_SEQ_PORT_CAP_READ,
SND_SEQ_PORT_TYPE_MIDI_GENERIC |
SND_SEQ_PORT_TYPE_APPLICATION);
snd_seq_ev_clear(&ev);
snd_seq_ev_set_dest(&ev, dest_client, dest_port);
snd_seq_ev_set_direct(&ev);
snd_seq_ev_set_pgmchange(&ev, channel, program);
snd_seq_event_output_direct(seq, &ev);
I've taken your code snippet and replaced the line
snd_seq_ev_set_dest(...)
by
snd_seq_ev_set_broadcast(...)
expecting to see this event broadcast to any ports
that'll listen, but I'm not seeing any reception on
any input port. Isn't this the way to broadcast
events? Any pointers would be appreciated.
Best,
Peter
PS: Here's the modified code:
#include <alsa/asoundlib.h>
int main(int argc, char **argv) {
snd_seq_t *seq;
snd_seq_event_t ev;
snd_seq_open(&seq, "default", SND_SEQ_OPEN_DUPLEX, 0);
snd_seq_set_client_name(seq, "my funky program changer");
snd_seq_create_simple_port(seq, "source port",
SND_SEQ_PORT_CAP_READ,
SND_SEQ_PORT_TYPE_MIDI_GENERIC |
SND_SEQ_PORT_TYPE_APPLICATION);
snd_seq_ev_clear(&ev);
//snd_seq_ev_set_dest(&ev, 80, 0);
snd_seq_ev_set_broadcast(&ev);
snd_seq_ev_set_direct(&ev);
snd_seq_ev_set_pgmchange(&ev, 1, 9);
snd_seq_event_output_direct(seq, &ev);
return 0;
}
22 Jun
22 Jun
6:03 a.m.
Peter Brinkmann wrote:
I've taken your code snippet and replaced the
line
snd_seq_ev_set_dest(...)
by
snd_seq_ev_set_broadcast(...)
expecting to see this event broadcast to any ports
that'll listen, but I'm not seeing any reception on
any input port.
This is a bug in the documentation. It should state that broadcasting
isn't implemented. (There is some code in the kernel driver, but it
has been disabled.)
To send to all ports subscribed to your port, use
snd_seq_ev_set_subs().
HTH
Clemens
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4 comments
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participants (3)
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Atte André Jensen -
Clemens Ladisch -
Peter Brinkmann