[alsa-devel] Development Question
M. Gagnon
fire_void at hotmail.com
Wed Mar 21 02:02:10 CET 2007
> > >What is the output of the program?
> >
> > pending events size: 28
> > pending events size: 56
> > pending events size: 84
> > ...
> > BEFORE DRAIN: pending events size: 476
> > AFTER DRAIN: pending events size: 0
>
>Looks OK. In theory, all events should be sent somewhere.
>
>Please run aseqdump and send the events to its port. What does it
>output?
>
% aseqdump
Waiting for data at port 128:0. Press Ctrl+C to end.
Source_ Event_________________ Ch _Data__
0:1 Port subscribed 129:0 -> 128:0
129:0 Note on 2 60 127
0:1 Port unsubscribed 129:0 -> 128:0
Seems like only one event gets sent - just like what i hear.
>Run "cat /proc/asound/seq/queues" and
>"cat /proc/asound/seq/timer".
>
% cat /proc/asound/seq/queues
queue 0: [Queue-0]
owned by client : 128
lock status : Locked
queued time events : 0
queued tick events : 0
timer state : Running
timer PPQ : 96
current tempo : 500000
current BPM : 120
current time : 1.536000000 s
current tick : 294
queue 1: [Queue-1]
owned by client : 129
lock status : Locked
queued time events : 0
queued tick events : 0
timer state : Running
timer PPQ : 48
current tempo : 1000000
current BPM : 60
current time : 1.488000000 s
current tick : 71
% cat /proc/asound/seq/timer
Timer for queue 0 : system timer
Period time : 0.004000000
Skew : 65536 / 65536
Timer for queue 1 : system timer
Period time : 0.004000000
Skew : 65536 / 65536
thanks for your help
just as reminder (so the output can be interpreted) this is my latest code
/*
all:
g++ midi_receiver.cpp -o AlsaNoteTest -lasound
*/
#include <stdio.h>
#include <alsa/asoundlib.h>
#include "midi_receiver.h"
#include <vector>
#include <iostream>
#include <unistd.h>
#include <pthread.h>
pthread_t thread1;
char *message1 = "Thread 1";
int iret1;
void *play_func( void *ptr )
{
AlsaNotePlayer::play();
}
int main()
{
AlsaNotePlayer::findDevices();
AlsaNotePlayer::openDevice(128, 0);
AlsaNotePlayer::setTempo(60, 48);
int time=0;
int duration = 50;
AlsaNotePlayer::noteOn_seq(1, 60, 127, time);
time += duration;
AlsaNotePlayer::noteOff_seq(1, 60, 0, time);
AlsaNotePlayer::noteOn_seq(1, 62, 127, time);
time += duration;
AlsaNotePlayer::noteOff_seq(1, 62, 0, time);
AlsaNotePlayer::noteOn_seq(1, 60, 127, time);
time += duration;
AlsaNotePlayer::noteOff_seq(1, 60, 0, time);
AlsaNotePlayer::noteOn_seq(1, 59, 127, time);
time += duration;
AlsaNotePlayer::noteOff_seq(1, 59, 0, time);
// ----------
AlsaNotePlayer::noteOn_seq(1, 63, 127, time);
time += duration;
AlsaNotePlayer::noteOff_seq(1, 63, 0, time);
AlsaNotePlayer::noteOn_seq(1, 65, 127, time);
time += duration;
AlsaNotePlayer::noteOff_seq(1, 65, 0, time);
AlsaNotePlayer::noteOn_seq(1, 63, 127, time);
time += duration;
AlsaNotePlayer::noteOff_seq(1, 63, 0, time);
AlsaNotePlayer::noteOn_seq(1, 61, 127, time);
time += duration;
AlsaNotePlayer::noteOff_seq(1, 61, 0, time);
iret1 = pthread_create( &thread1, NULL, play_func, (void*) message1);
pthread_join( thread1, NULL);
while(1)
{
usleep(10000);
}
}
namespace AlsaNotePlayer
{
class MidiDevice
{
public:
int client, port;
char* name;
MidiDevice(int client_arg, int port_arg, const char* name_arg)
{
client = client_arg;
port = port_arg;
name = (char*)name_arg;
}
};
std::vector<MidiDevice> devices;
struct MidiContext
{
snd_seq_t* sequencer;
int queue;
snd_seq_addr_t address;
int port;
snd_seq_port_subscribe_t *subs;
};
struct MidiContext MidiContext;
snd_seq_addr_t address;
void findDevices()
{
snd_seq_client_info_t* clientInfo;
if (snd_seq_open(&MidiContext.sequencer, "default", SND_SEQ_OPEN_OUTPUT, 0)
< 0)
{
return;
}
snd_seq_client_info_alloca(&clientInfo);
snd_seq_client_info_set_client(clientInfo, -1);
// iterate through clients
while (snd_seq_query_next_client(MidiContext.sequencer, clientInfo) >= 0)
{
snd_seq_port_info_t* pinfo;
snd_seq_port_info_alloca(&pinfo);
snd_seq_port_info_set_client(pinfo,
snd_seq_client_info_get_client(clientInfo));
snd_seq_port_info_set_port(pinfo, -1);
// and now through ports
while (snd_seq_query_next_port(MidiContext.sequencer, pinfo) >= 0)
{
unsigned int capability = snd_seq_port_info_get_capability(pinfo);
if ((capability & SND_SEQ_PORT_CAP_SUBS_WRITE) == 0)
{
continue;
}
int client = (snd_seq_port_info_get_addr(pinfo))->client;
int port = (snd_seq_port_info_get_addr(pinfo))->port;
std::cout << client << ":" << port << " --> " <<
snd_seq_port_info_get_name(pinfo) << std::endl;
devices.push_back( MidiDevice(client, port,
snd_seq_port_info_get_name(pinfo)) );
}
}
if (snd_seq_set_client_name(MidiContext.sequencer, "Aria") < 0)
{
return;
}
//MidiContext.address.port =
snd_seq_create_simple_port(MidiContext.sequencer, "Aria Port 0",
SND_SEQ_PORT_CAP_SUBS_WRITE, SND_SEQ_PORT_TYPE_APPLICATION);
MidiContext.address.port =
snd_seq_create_simple_port(MidiContext.sequencer, "Aria Port 0",
SND_SEQ_PORT_CAP_WRITE |
SND_SEQ_PORT_CAP_SUBS_WRITE |
SND_SEQ_PORT_CAP_READ,
SND_SEQ_PORT_TYPE_APPLICATION);
//SND_SEQ_PORT_TYPE_MIDI_GENERIC);
MidiContext.address.client = snd_seq_client_id (MidiContext.sequencer);
MidiContext.queue = snd_seq_alloc_queue (MidiContext.sequencer);
snd_seq_set_client_pool_output (MidiContext.sequencer, 1024);
}
void setTempo(int tempo_arg, int resolution)
{
// argument is not yet considered
snd_seq_queue_tempo_t *tempo;
snd_seq_queue_tempo_alloca(&tempo);
// snd_seq_queue_tempo_set_tempo(tempo, 1000000); // 60 BPM
// snd_seq_queue_tempo_set_ppq(tempo, 48); // 48 PPQ
snd_seq_queue_tempo_set_ppq(tempo, resolution);
snd_seq_queue_tempo_set_tempo(tempo, 60*1000000/tempo_arg);
snd_seq_set_queue_tempo(MidiContext.sequencer, MidiContext.queue,
tempo);
}
void openDevice(int client, int port)
{
address.client = client;
address.port = port;
snd_seq_port_subscribe_alloca(&MidiContext.subs);
snd_seq_port_subscribe_set_sender(MidiContext.subs, &MidiContext.address);
snd_seq_port_subscribe_set_dest(MidiContext.subs, &address);
snd_seq_subscribe_port(MidiContext.sequencer, MidiContext.subs);
}
void closeDevice()
{
snd_seq_port_subscribe_alloca(&MidiContext.subs);
snd_seq_port_subscribe_set_sender(MidiContext.subs, &MidiContext.address);
snd_seq_port_subscribe_set_dest(MidiContext.subs, &address);
if (snd_seq_unsubscribe_port(MidiContext.sequencer, MidiContext.subs) < 0)
{
return;
}
//snd_seq_port_subscribe_free(MidiContext.subs);
}
//************************************************************************************//
//************************************MIDI
EVENTS*************************************//
//************************************************************************************//
void noteOn_seq(int channel, int note, int velocity, int tick)
{
snd_seq_event_t event;
snd_seq_ev_clear(&event);
event.queue = MidiContext.queue;
event.source = MidiContext.address;
snd_seq_ev_set_subs(&event);
snd_seq_ev_set_source(&event, MidiContext.port);
snd_seq_ev_set_noteon(&event, channel, note, velocity);
snd_seq_ev_schedule_tick(&event, MidiContext.queue, 0, tick );
snd_seq_event_output(MidiContext.sequencer, &event);
std::cout << "pending events size: " <<
snd_seq_event_output_pending(MidiContext.sequencer) << std::endl;
}
void noteOff_seq(int channel, int note, int velocity, int tick)
{
snd_seq_event_t event;
snd_seq_ev_clear(&event);
event.queue = MidiContext.queue;
event.source = MidiContext.address;
snd_seq_ev_set_subs(&event);
snd_seq_ev_set_noteoff(&event, channel, note, velocity);
snd_seq_ev_schedule_tick(&event, MidiContext.queue, 0 /*absolute*/,
tick );
snd_seq_event_output(MidiContext.sequencer, &event);
std::cout << "pending events size: " <<
snd_seq_event_output_pending(MidiContext.sequencer) << std::endl;
}
void play()
{
snd_seq_start_queue(MidiContext.sequencer, MidiContext.queue, 0);
std::cout << "BEFORE DRAIN: pending events size: " <<
snd_seq_event_output_pending(MidiContext.sequencer) << std::endl;
int output = snd_seq_drain_output(MidiContext.sequencer);
std::cout << "AFTER DRAIN: pending events size: " <<
snd_seq_event_output_pending(MidiContext.sequencer) << std::endl;
if(output == 0) std::cout << "all events drained" << std::endl;
if(output > 0) std::cout << output << "bytes remaining" << std::endl;
if(output < 0)
{
fprintf (stderr, "Error: (%s)\n", snd_strerror (output));
//std::cout << "error" << std::endl;
}
}
}
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