Question

I have an application using JACK MIDI under Linux. It works perfectly on 32 bit machines, but on my new one, which is 64 bits, I get event loss all the time.

I checked:

• Values coming from jack_ringbuffer_read, they are OK (valid 2-3 bytes MIDI messages);
• midi_out_port and client, they are OK (non-null) and appearing on my JACK port list;

Here’s part of the code:

#define MidiMessageSize 3

jack_client_t* client;
jack_port_t* midi_out_port;

char current_message[MidiMessageSize];

jack_ringbuffer_t* midi_rb;

int process (jack_nframes_t nframes, void *arg)
{
  void* output_buffer = jack_port_get_buffer(midi_out_port, nframes);

  jack_midi_clear_buffer(output_buffer);

  int read_space = jack_ringbuffer_read_space(midi_rb);

  if (read_space == 0) return 0;

  int i;

  for (i = 0; i < read_space; i += MidiMessageSize)
  {
    jack_ringbuffer_read(midi_rb, current_message, MidiMessageSize);
    jack_midi_event_write(output_buffer, i/MidiMessageSize,
               (jack_midi_data_t*)current_message, MidiMessageSize);
    if (jack_midi_get_lost_event_count(midi_out_port)) {
      printf("Lost\n"); // I get here always
    }
  }  

  jack_ringbuffer_reset(midi_rb);

  return 0;
}

What may be wrong?

Thanks,

Answer 1

Strangely JACK (last version) is sending all midi events right, but jack_midi_get_lost_event_count is always returning me 1. Just ignored it and now my code is working.
Still this don’t happen in 32 bit, but anyway now it’s working.