Hi! I nearly finished alsaseq driver for jackmidi, but have a problem. Alsaseq reorders events in fast sequences, so note-on/note-off pairs got mixed. The algorithm of sending is simple: snd_seq_ev_schedule_real(&alsa_event, output_que, 1, &timestamp); frame_time = jack_frame_time(self->jack); frame_offset = event.time - frame_time; offset = ((long long)frame_offset) * 1000000000 / rate; timestamp.tv_sec = (long) (offset / 1000000000); timestamp.tv_nsec = (long) (offset % 1000000000); snd_seq_event_output(self->seq, &alsa_event); Here are the traces of what is going on: jackmidi_alsaseq reads events from external midi interface and send them to another midi interface. Log shows what is being sent to alsaseq and when. Output format is: [event] at [event.time] ([frame_time] + [frame_offset]) (+[offset]ns) c0ff@ace ~/src/jack/alsamidi $ ./jackmidi_alsaseq port created: in (20:0) MIDI 1 port created: out (20:0) MIDI 1 port created: in (24:0) USB Trigger Finger MIDI 1 port created: out (24:0) USB Trigger Finger MIDI 1 port_event: ADD 130:0 port created: out (130:0) aseqdump 90 4e 7f at 86646526 (86622198 + 24328) (+506833333ns) 80 4e 40 at 86649830 (86622200 + 27630) (+575625000ns) 90 4e 7f at 86654006 (86622201 + 31805) (+662604166ns) 80 4e 40 at 86656795 (86638582 + 18213) (+379437500ns) 90 4e 7f at 86660562 (86638584 + 21978) (+457875000ns) 80 4e 40 at 86663502 (86638584 + 24918) (+519125000ns) 90 4e 7f at 86666819 (86638585 + 28234) (+588208333ns) 80 4e 40 at 86669453 (86638585 + 30868) (+643083333ns) 90 4e 7f at 86673078 (86654965 + 18113) (+377354166ns) 80 4e 40 at 86676430 (86654966 + 21464) (+447166666ns) 90 4e 6f at 86678638 (86654967 + 23671) (+493145833ns) 80 4e 40 at 86680654 (86654968 + 25686) (+535125000ns) We can see that all events go strictly in order (their frame_time is monotonically increasing). Frame offsets are so big, because it runs under jackd -d dummy -p 16384. At the same time, aseqdump is hooked to jackmidi_alsaseq output port: c0ff@ace ~ $ aseqdump Waiting for data at port 130:0. Press Ctrl+C to end. Source_ Event_________________ Ch _Data__ 0:1 Port subscribed 128:5 -> 130:0 0:1 Port subscribed 128:2 -> 130:0 128:2 Note on 0 78 127 128:2 Note off 0 78 64 128:2 Note off 0 78 64 128:2 Note on 0 78 127 128:2 Note on 0 78 127 128:2 Note on 0 78 127 128:2 Note off 0 78 64 128:2 Note on 0 78 127 128:2 Note off 0 78 64 128:2 Note off 0 78 64 128:2 Note on 0 78 111 128:2 Note off 0 78 64 We see, Note on/Note off events are mixed. Your suggestions, please. Regards, Dmitry. P.S. Not wanting to start a flame war, but it is exactly the case, why it's better for jackmidi driver to use as lower-level interface as possible - less problems, more control. P.P.S. alsa-devels, if you reply, please CC me, i'm not subscribed.