7 Jun
2011
7 Jun
'11
11:25 p.m.
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/…
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