Re: [Jack-Devel] Dispersing MIDI messages: one to multiple

Thank you all.

So the princple "should work". That's all I wanted to know. As far as I
could see, there were no problems with writing messages - according to
output.

API documentation does not provide any examples (only demo code does), so I
was - experimenting more or less. Thus so many commented lines. I apologize.

It's time to check jack's log, also. I've spotted messages like "Yoshimi
client didn't finish..." in console.

Cheers,
Marjan

2015-01-29 15:19 GMT+01:00 Robin Gareus <[hidden]>:

> Hi Marjan,
>
> On 01/29/2015 11:08 AM, Marjan Mrak wrote:
>
> [..]
>
> > Or is there a better way to "disperse" one MIDI message to several
> > channels?
>
> There are existing projects, e.g. midish, mididings, qmidiroute,..
> but your hardcoded approach is fine if it addresses your issue.
>
> [..]
>
> > It works, but if I am using it, totaly at random sound output
> > "hangs" for like 10th of second.
>
> As Harry noted, if verb == 1, the printf() debug info could be the
> cause (blocking wait for the printed text to reach the terminal).
> Other than that there's no obvious reason, but it's a bit hard to read
> the code with all the commented out lines all and unscoped variables
> over the place.
>
> A few comments below inline:
>
> > static int process(jack_nframes_t nframes, void *arg) { int res =
> > 0; int i; int j;
> >
> > //unsigned char* buffer; unsigned char jbuffer[3];
> >
> > void* port_buf = jack_port_get_buffer(output_port, nframes);
> >
> > //get events void* in_port_buf = jack_port_get_buffer(input_port,
> > nframes); jack_nframes_t n =
> > jack_midi_get_event_count(in_port_buf);
> >
> > jack_midi_clear_buffer(port_buf);
> >
> > if(n==0) return 0;
> >
> > jack_midi_event_t jev;
> >
> >
> > if(verb == 1) printf("%i: Data arrived!\n", cnt);
> >
> > for(i = 0;i<n;i++){
> >
> > res = jack_midi_event_get(&jev,in_port_buf,i); if(res == 0){
> > if(verb == 1){ printf("Got event, %i bytes!\n",(int) jev.size);
> > for(j=0;j<jev.size;j++) printf("%i: %i\n",j,jev.buffer[j]); } }
> > else{ if(verb == 1) printf("ERROR getting event!\n"); return 0; }
> >
> >
> > //transmit data cnt++; //buffer = jack_midi_event_reserve(port_buf,
> > i, 3);
> >
>
> check the event size
>
>    if (jev.size != 3) {
>        continue;
>    }
>
> If there are one or two byte messages (eg active-sensing or
> midi-clock) at the input, all sorts of undefined behaviour could happen.
>
> Yet, in the code below this should be a non-issue, it always check the
> status byte first.
>
> >
> > //controll to MIDI channel 1! if(jev.buffer[0] == 176 &&
> > jev.buffer[1] == 97){ if(verb == 1) printf("MUTE CONTROL CH1
> > sent\n"); //first button: set mute register on channel 1
> > //buffer[0] = 176; //buffer[1] = 7; //buffer[2] = jev.buffer[2];
> > jbuffer[0] = 176;
>
> I'd like to suggest to use hex values for the status byte, 0xb0
> instead of 176 to improve readability.
>
> > jbuffer[1] = 7; jbuffer[2] = jev.buffer[2]; res =
> > jack_midi_event_write(port_buf, jev.time, jbuffer, 3); }
> >
> > else if(jev.buffer[0] == 176 && jev.buffer[1] == 96){ if(verb ==
> > 1) printf("MUTE CONTROL to CH2 sent\n"); //second button: set mute
> > register on channel 2 //buffer[0] = 177; //buffer[1] = 7;
> > //buffer[2] = jev.buffer[2]; jbuffer[0] = 177; jbuffer[1] = 7;
> > jbuffer[2] = jev.buffer[2]; res = jack_midi_event_write(port_buf,
> > jev.time, jbuffer, 3); }
> >
> > else if(jev.buffer[0] == 176 && jev.buffer[1] == 66){ if(verb ==
> > 1) printf("MUTE CONTROL CH3 sent\n"); //third button: set mute
> > register on channel 3 //buffer[0] = 176; //buffer[1] = 7;
> > //buffer[2] = jev.buffer[2]; jbuffer[0] = 178; jbuffer[1] = 7;
> > jbuffer[2] = jev.buffer[2]; res = jack_midi_event_write(port_buf,
> > jev.time, jbuffer, 3); }
> >
> > else if(jev.buffer[0] == 176 && jev.buffer[1] == 67){ if(verb ==
> > 1) printf("MUTE CONTROL to CH4 sent\n"); //fourth button: set mute
> > register on channel 4 //buffer[0] = 177; //buffer[1] = 7;
> > //buffer[2] = jev.buffer[2]; jbuffer[0] = 179; jbuffer[1] = 7;
> > jbuffer[2] = jev.buffer[2]; res = jack_midi_event_write(port_buf,
> > jev.time, jbuffer, 3); }
> >
> > else if(jev.buffer[0] == 176 && jev.buffer[1] == 64){ if(verb ==
> > 1) printf("MUTE CONTROL to CH5 sent\n"); //fifth button: set mute
> > register on channel 5 //buffer[0] = 177; //buffer[1] = 7;
> > //buffer[2] = jev.buffer[2]; jbuffer[0] = 180; jbuffer[1] = 7;
> > jbuffer[2] = jev.buffer[2]; res = jack_midi_event_write(port_buf,
> > jev.time, jbuffer, 3); }
> >
> > else if(jev.buffer[0] == 176 && jev.buffer[1] == 65){ if(verb ==
> > 1) printf("MUTE CONTROL to CH6 sent\n"); //sixth button: set mute
> > register on channel 6 //buffer[0] = 177; //buffer[1] = 7;
> > //buffer[2] = jev.buffer[2]; jbuffer[0] = 181; jbuffer[1] = 7;
> > jbuffer[2] = jev.buffer[2]; res = jack_midi_event_write(port_buf,
> > jev.time, jbuffer, 3); }
> >
> > else if(jev.buffer[0] == 176 && jev.buffer[1] == 7){ if(verb == 1)
> > printf("MUTE CONTROL to CH7 sent\n"); //seventh button: set mute
> > register on channel 7 //buffer[0] = 177; //buffer[1] = 7;
> > //buffer[2] = jev.buffer[2]; jbuffer[0] = 182; jbuffer[1] = 7;
> > jbuffer[2] = jev.buffer[2]; res = jack_midi_event_write(port_buf,
> > jev.time, jbuffer, 3); }
> >
> > else if(jev.buffer[0] == 176 && jev.buffer[1] == 10){ if(verb ==
> > 1) printf("MUTE CONTROL to CH8 sent\n"); //eighth button: set mute
> > register on channel 8 //buffer[0] = 177; //buffer[1] = 7;
> > //buffer[2] = jev.buffer[2]; jbuffer[0] = 183; jbuffer[1] = 7;
> > jbuffer[2] = jev.buffer[2]; res = jack_midi_event_write(port_buf,
> > jev.time, jbuffer, 3); }
> >
> >
> >
> >
> > else if((jev.buffer[0]& 0xF0) == 128 || (jev.buffer[0]& 0xF0) ==
> > 144){ //note key, pass through if(verb == 1) printf("SOUND
> > PASSED-THROUGH\n"); //notes; let them pass //buffer[0] =
> > jev.buffer[0]; //buffer[1] = jev.buffer[1]; //buffer[2] =
> > jev.buffer[2]; jbuffer[0] = jev.buffer[0];  //CH1 jbuffer[1] =
> > jev.buffer[1]; jbuffer[2] = jev.buffer[2]; res =
> > jack_midi_event_write(port_buf, jev.time , jbuffer, 3); jbuffer[0]
> > = jev.buffer[0] + 1; //CH2
>
> These can produce invalid messages. e.g some channel 15 data will
> alter the status byte. (Note on -> Aftertouch)
>
> uint8_t channel = jev.buffer[0] & 0x0f;
> uint8_t status = jev.buffer[0] & 0xf0;
> channel = (channel + 1) & 0x0f;
> jbuffer[0] = status | channel;
>
>
> > jbuffer[1] = jev.buffer[1]; jbuffer[2] = jev.buffer[2]; res =
> > jack_midi_event_write(port_buf, jev.time , jbuffer, 3); jbuffer[0]
> > = jev.buffer[0] + 2; //CH3 jbuffer[1] = jev.buffer[1]; jbuffer[2] =
> > jev.buffer[2];
>
> ^^ no need to re-assign, jbuffer[1], jbuffer[2]
>
> > res = jack_midi_event_write(port_buf, jev.time , jbuffer, 3);
> > jbuffer[0] = jev.buffer[0] + 3; //CH4 jbuffer[1] = jev.buffer[1];
> > jbuffer[2] = jev.buffer[2];
>
> ditto.
>
> > res = jack_midi_event_write(port_buf, jev.time , jbuffer, 3); }
> >
> > //res = jack_midi_event_write(port_buf, i, jev.buffer, 3); //res =
> > jack_midi_event_write(port_buf, jev.time, jbuffer, 3);
> >
>
> Just stop if you can't write more events or a write failed.
>
>     if (!res) {
>         break;
>     }
>
> but that's just some minor optimization. It won't hurt much to keep
> calling jack_midi_event_write() again. it will just be a no-op. It's
> very unlikely to happen anyway.
>
> >
> > }
> >
> > return 0;
> >
> > }
>
> It should work in principle, maybe there's a flaw elsewhere in the
> setup code.
>
> Cheers!
> robin
>

1422598028.17738_0.ltw:2, <CADOWEz8NN1Q7_aED3y35--tf5a0nEK6CSCKVJxEnUzCE+quA-Q at mail dot gmail dot com>