On Tue, 2011-06-07 at 22:50 +0200, Robin Gareus wrote: > BTW. IIRC you should not use the -X... options for JACK-midi but rather > use a2j instead. AFAIK there were/are [timing?] issues with the built-in > JACK midi backends. (see Jeremy's workshop slides on how to launch a2j > using qjackctl's "Execute Script" option.) > > HTH, > robin Yesno! Perhaps it's better to avoid -Xseq, but I'm using JACK2 from svn with -Xalsarawmidi + a2jmidi_bridge to get a jitter free hw MIDI output of Qtractor's ALSA MIDI. I don't believe latency tests, but I believe what I hear and what I see for the waveforms. No jitter! Before Jack2 from svn I experienced 1 - 3 ms jitter for hw MIDI (ALSA), depending to the used MIDI interface, I can't make music even with 1ms jitter, I'm able to hear this, see the following from jack devel list: On Sat, 2011-06-04 at 03:54 +0200, Ralf Mardorf wrote: Similar good results as before :) > > Cheers! > > Ralf > > Current Debian testing 64-bit > Two TerraTec EWX24/96 PCI > One RME HDSPe AIO PCI express > > # svn up /usr/src/jackmp > At revision 4447. > # chgrp audio /dev/hpet > # chmod g+rw /dev/hpet > # modprobe snd-hrtimer > > $ uname -a > Linux debian 2.6.33.9-rt31 #1 SMP PREEMPT RT Thu Jun 2 12:42:46 CEST > 2011 x86_64 GNU/Linux > > $ jackd --sync -Xalsarawmidi -dalsa -r48000 -p256 > 'system:midi_capture_1', alias='system:1-1 HDSPM MIDI 1 1 in' > 'system:midi_capture_2', alias='system:1-2 HDSPM MIDI 2 1 in' > 'system:midi_capture_3', alias='system:2-1 TerraTec EWX24/96 MIDI 1 in' > 'system:midi_capture_4', alias='system:3-1 TerraTec EWX24/96 MIDI 1 in' > system:midi_playback_1', alias='system:1-1 HDSPM MIDI 1 1 out' > system:midi_playback_2', alias='system:1-2 HDSPM MIDI 2 1 out' > system:midi_playback_3', alias='system:2-1 TerraTec EWX24/96 MIDI 1 out' > system:midi_playback_4', alias='system:3-1 TerraTec EWX24/96 MIDI 1 out' > > CPU frequency scaling performance > > $ jack_midi_latency_test -m 3 -s 8192 -t 5 "system:1-1 HDSPM MIDI 1 1 > out" "system:1-1 HDSPM MIDI 1 1 in" > Waiting for connections ... > Waiting for test completion ... > > Reported out-port latency: 5.33-5.33 ms (256-256 frames) > Reported in-port latency: 5.33-5.33 ms (256-256 frames) > Average latency: 12.23 ms (559.04 frames) > Lowest latency: 12.21 ms (558 frames) > Highest latency: 12.30 ms (562 frames) > Peak MIDI jitter: 0.09 ms (4 frames) > Average MIDI jitter: 0.01 ms (0.18 frames) > > Jitter Plot: > 0.0 - 0.1 ms: 8192 > > Latency Plot: > 12.2 - 12.3 ms: 8192 > > Messages sent: 8192 > Messages received: 8192 > $ jack_midi_latency_test -m 3 -s 8192 -t 5 "system:2-1 TerraTec EWX24/96 > MIDI 1 out" "system:2-1 TerraTec EWX24/96 MIDI 1 in" > Waiting for connections ... > Waiting for test completion ... > > Reported out-port latency: 5.33-5.33 ms (256-256 frames) > Reported in-port latency: 5.33-5.33 ms (256-256 frames) > Average latency: 12.23 ms (558.97 frames) > Lowest latency: 12.21 ms (558 frames) > Highest latency: 12.29 ms (562 frames) > Peak MIDI jitter: 0.09 ms (4 frames) > Average MIDI jitter: 0.00 ms (0.05 frames) > > Jitter Plot: > 0.0 - 0.1 ms: 8192 > > Latency Plot: > 12.2 - 12.3 ms: 8192 > > Messages sent: 8192 > Messages received: 8192 > > Old install, Edubuntu Maverick 32-bit on the same machine, just two > TerraTec EWX24/96 PCI, no PCI express > Test output copied from > http://lists.jackaudio.org/private.cgi/jack-devel-jackaudio.org/2011-April/007423.html > > revision 4290 > Linux edubuntu 2.6.33.7.2-rt30 #1 SMP PREEMPT RT Sun Jan 30 21:00:46 CET > 2011 i686 GNU/Linux > > $ jackd --sync -Xalsarawmidi -dalsa -r48000 -p256 > > $ jack_midi_latency_test -m 3 -s 8192 -t 5 "system:TerraTec EWX24/96 > MIDI out" "system:TerraTec EWX24/96 MIDI in" > Reported out-port latency: 5.33-5.33 ms (256-256 frames) > Reported in-port latency: 5.33-5.33 ms (256-256 frames) > Average latency: 11.06 ms (530.95 frames) > Lowest latency: 11.04 ms (530 frames) > Highest latency: 11.10 ms (533 frames) > Peak MIDI jitter: 0.06 ms (3 frames) > Average MIDI jitter: 0.00 ms (0.02 frames) > > Jitter Plot: > 0.0 - 0.1 ms: 8192 > > Latency Plot: > 11.0 - 11.1 ms: 8189 > 11.1 - 11.2 ms: 3 > > Messages sent: 8192 > Messages received: 8192 _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
