1 Aug
2010
1 Aug
'10
12:23 a.m.
Hello:
I am very much new to Linux and Linux audio. I am trying to measure audio
IO latency for my system.
Jdelay seems to be the right tool but when I run it on the terminal, I am
getting message "Signal below threshold..." which probably might be because
Jack is trying to capture audio and ends up getting the low noise floor
because I do not have meaningful signal source connected. But then I tried
to patch the this App to the qJACKctl app but the settings console is
not straight forward to interpret. as it involved many parameters.
I guess there are # of frames per period that may eventually be used
to calculate the target latency but *is there a step-by step document
description for Jdelay and any other JACK tools and also using JACK audio
server in an effective manner*? Also, qJACKctl console does not offer
options for very low sampling rates like 8 KHz. With ALSA, this should be
possible but may be this particular tool does not support it. Can anyone
help here?
Thanks,
-F
1 Aug
1 Aug
12:33 a.m.
Hi Arvind!
I'm not really sure about a JACK guide in general. I seem to remember, that
there are. take a look at these sites of collections:
http://linux-sound.org
and
http://apps.linuxaudio.org
There you should find some good docs for that.
As to working with lower samplerates. ALSA can do it, because it has a
built-in resampling mechanism (type plug or plughw). JACK doesn't have that.
It would really be in its interest I thik. but there are some apps, that use
JACK and have built-in resampling themselves. Tools, that use libsamplerate
(libsrc). I know the big player have such things (mplayer and others).
Besides that, if youneed some questions answered about JACK and other user
stuff, you will find help on the Linux-Audio-Users' mailinglist. there should
be a lot inthe archives and the list is quite active and there are very
helpful and nice people over there too.
Kindly yours
Julien
--------
Music was my first love and it will be my last (John Miles)
======== FIND MY WEB-PROJECT AT: ========
http://ltsb.sourceforge.net
the Linux TextBased Studio guide
======= AND MY PERSONAL PAGES AT: =======
http://www.juliencoder.de
1:01 a.m.
On 07/31/2010 11:23 PM, Arvind Venkatasubramanian wrote:
Hello:
I am very much new to Linux and Linux audio. I am trying to measure
audio IO latency for my system.
Jdelay seems to be the right tool but when I run it on the terminal, I
am getting message "Signal below threshold..." which probably might be
because Jack is trying to capture audio and ends up getting the low
noise floor because I do not have meaningful signal source connected.
But then I tried to patch the this App to the qJACKctl app but the
settings console is not straight forward to interpret. as it involved
many parameters.
I guess there are # of frames per period that may eventually be used
to calculate the target latency but *is there a step-by step document
description for Jdelay and any other JACK tools and also using JACK
audio server in an effective manner*? Also, qJACKctl console does not
offer options for very low sampling rates like 8 KHz. With ALSA, this
should be possible but may be this particular tool does not support it.
Can anyone help here?
re. qjackctl settings you can actually write whatever sample-rate you
want. you're not limited to the options given in the drop-down list.
however, that doesn't mean that the soundcard will stick to it, ever :)
cheers
--
rncbc aka Rui Nuno Capela
rncbc(a)rncbc.org
8:37 p.m.
Thanks to Julien and Rui Capela. Being a musician and engineer, this seems
to be a great place to land in and learn new stuff in this world
of Linux audio. Currently, I am still not able to find document that I need
to solve 2 existing problems:
*Question on using JDelay:*
I have only one web source that has some details about using this tool:
http://www.kokkinizita.net/linuxaudio/ and this reads: "It uses a phase
measurements on a set of tones to measure the delay from the output to the
input".
How do I use these phase measurements and how do I pass in these tones? Are
they special tones? What kind of oscillator do I need to use to generate
these special tones? How do I pass in an audio tick or click? How do I do
other settings?
$ jack_delay -h --help does not show me the help menu
*Question on using QJACKctl:*
I was able to create some basic setting, load and read latency that gets
printed on the terminal. But what do the parameters on the setting tab of
console pop up mean? No soft mode, monitor, priority, time out etc and the
options tab. How do I use these options and tine tune them in order to set
the minimum feasible latency for the application that I intend to develop?
Above all, if the drop down menu options does not allow me to choose lower
sampling rates, what command do I use on the CLI to do the setting. Or Do I
need to edit QJACKctl's .conf file to set lower sampling rates manually.
My Intel sound card supports sampling rates of 8kHz and 16 kHz. I confirmed
this by looking into Audacity device ID setting. I know that I am asking
some basic stuff but my problem is that I do not find the right
documentation for solving my problems.
Your reply in this regard will be greatly appreciated.
Kind regards,
-F
Arvind V
On Sat, Jul 31, 2010 at 7:01 PM, Rui Nuno Capela <rncbc(a)rncbc.org> wrote:
On 07/31/2010 11:23 PM, Arvind Venkatasubramanian
wrote:
Hello:
I am very much new to Linux and Linux audio. I am trying to measure
audio IO latency for my system.
Jdelay seems to be the right tool but when I run it on the terminal, I
am getting message "Signal below threshold..." which probably might be
because Jack is trying to capture audio and ends up getting the low
noise floor because I do not have meaningful signal source connected.
But then I tried to patch the this App to the qJACKctl app but the
settings console is not straight forward to interpret. as it involved
many parameters.
I guess there are # of frames per period that may eventually be used
to calculate the target latency but *is there a step-by step document
description for Jdelay and any other JACK tools and also using JACK
audio server in an effective manner*? Also, qJACKctl console does not
offer options for very low sampling rates like 8 KHz. With ALSA, this
should be possible but may be this particular tool does not support it.
Can anyone help here?
re. qjackctl settings you can actually write whatever sample-rate you
want. you're not limited to the options given in the drop-down list.
however, that doesn't mean that the soundcard will stick to it, ever :)
cheers
--
rncbc aka Rui Nuno Capela
rncbc(a)rncbc.org
_______________________________________________
Linux-audio-dev mailing list
Linux-audio-dev(a)lists.linuxaudio.org
http://lists.linuxaudio.org/listinfo/linux-audio-dev
8:53 p.m.
On 08/01/2010 07:37 PM, Arvind Venkatasubramanian wrote:
*Question on using QJACKctl:*
I was able to create some basic setting, load and read latency that gets
printed on the terminal. But what do the parameters on the setting tab
of console pop up mean? No soft mode, monitor, priority, time out etc
and the options tab. How do I use these options and tine tune them in
order to set the minimum feasible latency for the application that I
intend to develop? Above all, if the drop down menu options does not
allow me to choose lower sampling rates, what command do I use on the
CLI to do the setting. Or Do I need to edit QJACKctl's .conf file to
set lower sampling rates manually.
all options on the qjackctl setup settings dialog are mapped in a
one-to-one basis to jackd command line options. they are just presented
in a bland gui dialog for convenience.
cheers
--
rncbc aka Rui Nuno Capela
rncbc(a)rncbc.org
2 Aug
2 Aug
4:47 a.m.
On Sun, Aug 1, 2010 at 2:53 PM, Rui Nuno Capela <rncbc(a)rncbc.org> wrote:
On 08/01/2010 07:37 PM, Arvind Venkatasubramanian
wrote:
*To measure sound card latency by patching JDelay in qJackctl:*
*Irrespective* of changing different parameters combinations, I get the
following printed out in the terminal:
Signal below threshold...
Signal below threshold...
Signal below threshold...
2072.829 frames 43.184 ms Inv
2072.866 frames 43.185 ms Inv
2072.846 frames 43.184 ms Inv
2072.838 frames 43.184 ms Inv
2072.855 frames 43.184 ms Inv
2072.840 frames 43.184 ms Inv
2072.842 frames 43.184 ms Inv
2072.853 frames 43.184 ms Inv
2072.835 frames 43.184 ms Inv
2072.848 frames 43.184 ms Inv
The program does not seem to recognize the changes I made in the GUI
parameters settings.
How I did it:
1. I connected my sound card out to sound card in.
2. Then patched my JackDelay In to system caputre 1.
3. I patched playback 1 to JackDelay out.
Regards,
Arvind V
*Question on using QJACKctl:*
I was able to create some basic setting, load and read latency that gets
printed on the terminal. But what do the parameters on the setting tab
of console pop up mean? No soft mode, monitor, priority, time out etc
and the options tab. How do I use these options and tine tune them in
order to set the minimum feasible latency for the application that I
intend to develop? Above all, if the drop down menu options does not
allow me to choose lower sampling rates, what command do I use on the
CLI to do the setting. Or Do I need to edit QJACKctl's .conf file to
set lower sampling rates manually.
all options on the qjackctl setup settings dialog are mapped in a
one-to-one basis to jackd command line options. they are just presented
in a bland gui dialog for convenience.
cheers
--
rncbc aka Rui Nuno Capela
4:55 a.m.
On Sun, Aug 1, 2010 at 10:46 PM, Arvind Venkatasubramanian
<mdu.arvind(a)gmail.com> wrote:
2072.829 frames 43.184 ms Inv
you have used a setting that produces 2048 frames of "software
latency", and your soundcard signal path (A/D etc) adds an additional
24 frames of latency for the output->input pathway (likely 12 frames
on the output path and 12 on the input, though this can't really be
measured precisely).
The program does not seem to recognize the changes I
made in the GUI
parameters settings.
qjackctl does not have any effect on the settings unless you *also*
stop & start JACK. this will stop jdelay too.
5:06 a.m.
On Sun, Aug 1, 2010 at 10:55 PM, Paul Davis <paul(a)linuxaudiosystems.com>wrote;wrote:
On Sun, Aug 1, 2010 at 10:46 PM, Arvind
Venkatasubramanian
<mdu.arvind(a)gmail.com> wrote:
Thanks for reply. This is exactly the problem that I want to solve. My
system latency cannot exceed 10 ms. Therefore, I need to fine tune the
settings to a point where I can get this done without any Xrun interrupts.
2048 frames of Jdelay latency + sound card delay contributes to greater
delay, which I do not desire. Should I then change my sound card? Does it
make a big difference? I am using HDA Intel ALC880 Analog sound card.
Everytime I changed the qJACKctl parameter settings, I "DID" stop Jackd,
quited Jack, quited Jdelay and restarted again. Therefore, I am not sure if
I am committing any fault.
I am looking forward to hearing.
Thx,
-F
Arvind V
2072.829 frames 43.184 ms Inv
you have used a setting that produces 2048 frames of "software
latency", and your soundcard signal path (A/D etc) adds an additional
24 frames of latency for the output->input pathway (likely 12 frames
on the output path and 12 on the input, though this can't really be
measured precisely).
The program does not seem to recognize the
changes I made in the GUI
parameters settings.
qjackctl does not have any effect on the settings unless you *also*
stop & start JACK. this will stop jdelay too.
10:23 a.m.
On Sun, Aug 01, 2010 at 11:06:36PM -0400, Arvind Venkatasubramanian wrote:
Everytime I changed the qJACKctl parameter settings, I
"DID" stop Jackd,
quited Jack,
What do you mean by 'quited Jack' ? Are you running jackd in a terminal ?
Then Qjackctl's settings will not affect it. Just use the Start/Stop
buttons in Qjackctl.
Also check your sound card mixer. Make sure you don't loop back the input
to output there. And use Jaaa to check the input signal - it could be
clipping. You should see 7 frequencies, the strongest at FS/16, and the
six others at lower level and frequency (or just compare the the output
of Jdelay).
10 ms latency at 8 khz will be difficult, just a good antialising
filter will produce something like that. No problem at 48 kHz.
Ciao,
--
FA
There are three of them, and Alleline.
11:15 p.m.
On Mon, Aug 2, 2010 at 4:23 AM, <fons(a)kokkinizita.net> wrote:
On Sun, Aug 01, 2010 at 11:06:36PM -0400, Arvind
Venkatasubramanian wrote:
Using Jdelay for fs = 8 KHz, I am measuring 6.359 ms and for 16 KHz, 3.466
ms without Xrun interrupts. But I need to verify this with JAAA as per your
idea but I am having issues there.
[Arvind@laspr-01 ~]$ jackd -r -d alsa -r 16000 -n 1 -p 32 -S 16 -s -H -M
jackd 0.118.0
Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn and
others.
jackd comes with ABSOLUTELY NO WARRANTY . This is free software, and you
are welcome to redistribute it
under certain conditions; see the file COPYING for details
JACK compiled with System V SHM support.
loading driver ..
apparent rate = 16000
creating alsa driver ...
hw:0|hw:0|32|2|16000|0|0|hwmon|hwmeter|soft-mode|16bit
control device hw:0
configuring for 16000Hz, period = 32 frames (2.0 ms), buffer = 2 periods
ALSA: final selected sample format for capture: 16bit little-endian
ALSA: use 2 periods for capture
ALSA: final selected sample format for playback: 16bit little-endian
ALSA: use 2 periods for playback
jack main caught signal 15
[Arvind@laspr-01 ~]$ jack_delay
capture latency = 32
playback_latency = 32
Signal below threshold...
Signal below threshold...
Signal below threshold...
Signal below threshold...
Signal below threshold...
Signal below threshold...
Signal below threshold...
152.708 frames 3.463 ms ?? Inv
152.826 frames 3.465 ms Inv
152.824 frames 3.465 ms Inv
152.823 frames 3.465 ms Inv
152.821 frames 3.465 ms Inv
152.834 frames 3.466 ms Inv
152.821 frames 3.465 ms Inv
152.832 frames 3.466 ms Inv
After starting Jack, I am able to run Jdelay. But I am not able to run
JAAA
[Arvind@laspr-01 ~]$ jackd -r -d alsa -r 16000 -n 1 -p 32 -S 16 -s -H -M
jackd 0.118.0
Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn and
others.
jackd comes with ABSOLUTELY NO WARRANTY This is free software, and you are
welcome to redistribute it
under certain conditions; see the file COPYING for details
JACK compiled with System V SHM support.
loading driver ..
apparent rate = 16000
creating alsa driver ...
hw:0|hw:0|32|2|16000|0|0|hwmon|hwmeter|soft-mode|16bit
control device hw:0
configuring for 16000Hz, period = 32 frames (2.0 ms), buffer = 2 periods
ALSA: final selected sample format for capture: 16bit little-endian
ALSA: use 2 periods for capture
ALSA: final selected sample format for playback: 16bit little-endian
ALSA: use 2 periods for playback
[Arvind@laspr-01 ~]$ jaaa -A -d hw:Intel -r 16000
Alsa_driver: Cannot open PCM device hw:Intel for playback.
Alsa_driver: Cannot open PCM device hw:Intel for capture.
Can't connect to ALSA
[Arvind@laspr-01 ~]$ jaaa -J -d hw:Intel -r 16000
Connected to JACK with 4 inputs and 4 outputs
mlockall: Cannot allocate memory
Closing JACK...
[Arvind@laspr-01 ~]$
However for higher sampling rates, I am able to open JAAA without even
issuing jackd command to start JACK separately.
[Arvind@laspr-01 ~]$ jaaa -A -d hw:Intel
playback :
nchan : 2
rate : 48000
frsize : 1024
nfrags : 2
format : S32_LE
capture :
nchan : 2
rate : 48000
frsize : 1024
nfrags : 2
format : S32_LEsynced
Connected to ALSA with 2 inputs and 2 outputs
Can't create ALSA thread with RT priority
mlockall: Cannot allocate memory
Closing ALSA...
[Arvind@laspr-01 ~]$
While JAAA is running, I am not able to start Jdelay. Once JAAA operates
alongside other Jack applications, I will be able to patch the output of
Jdelay to JAAA and see if I can see those 7 tones that you internally use in
Jdelay for latency measurements. Can you please suggest some inputs here?
Regards,
Arvind V
Everytime I changed the qJACKctl parameter
settings, I "DID" stop Jackd,
quited Jack,
What do you mean by 'quited Jack' ? Are you running jackd in a terminal ?
Then Qjackctl's settings will not affect it. Just use the Start/Stop
buttons in Qjackctl.
Also check your sound card mixer. Make sure you don't loop back the input
to output there. And use Jaaa to check the input signal - it could be
clipping. You should see 7 frequencies, the strongest at FS/16, and the
six others at lower level and frequency (or just compare the the output
of Jdelay).
10 ms latency at 8 khz will be difficult, just a good antialising
filter will produce something like that. No problem at 48 kHz.
Ciao,
--
FA
====================================================================
3 Aug
3 Aug
12:06 a.m.
On Mon, Aug 2, 2010 at 5:15 PM, Arvind Venkatasubramanian
<mdu.arvind(a)gmail.com> wrote:
[Arvind@laspr-01 ~]$ jaaa -J -d hw:Intel -r 16000
Connected to JACK with 4 inputs and 4 outputs
mlockall: Cannot allocate memory
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
That's the error in that instance.
However for higher sampling rates, I am able to open
JAAA without even
issuing jackd command to start JACK separately.
[Arvind@laspr-01 ~]$ jaaa -A -d hw:Intel
Not suprising, since you're EXPLICITLY telling jaaa to use its own
ALSA backend, and not to use JACK.
While JAAA is running, I am not able to start Jdelay.
Once JAAA operates
alongside other Jack applications, I will be able to patch the output of
JACK requires more-or-less exclusive access to the audio interface. If
jaaa is using it (via its own ALSA backend), then JACK cannot run.
You seem quite confused about the role of JACK and ALSA.
--p
12:13 a.m.
On Mon, Aug 02, 2010 at 06:06:19PM -0400, Paul Davis wrote:
On Mon, Aug 2, 2010 at 5:15 PM, Arvind
Venkatasubramanian
<mdu.arvind(a)gmail.com> wrote:
That's one. He should really fix his system to allow realtime
and memory locking.
[Arvind@laspr-01 ~]$ jaaa -J -d hw:Intel -r
16000
Connected to JACK with 4 inputs and 4 outputs
mlockall: Cannot allocate memory
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
That's the error in that instance. From the results that jdelay is printing it is clear
that
the sample rate is 44.1 kHz and not 16 kHz. To avoid such
mistakes maybe Jack should print the real SR along with all
the other info it outputs on startup. I'll make future
releases of jack_delay do that as well.
Ciao,
--
FA
There are three of them, and Alleline.
1 Aug
1 Aug
10:04 p.m.
On Sun, Aug 01, 2010 at 02:37:09PM -0400, Arvind Venkatasubramanian wrote:
*Question on using JDelay:*
I have only one web source that has some details about using this tool:
http://www.kokkinizita.net/linuxaudio/ and this reads: "It uses a phase
measurements on a set of tones to measure the delay from the output to the
input".
How do I use these phase measurements and how do I pass in these tones? Are
they special tones? What kind of oscillator do I need to use to generate
these special tones? How do I pass in an audio tick or click? How do I do
other settings?
You don't need osclillators or anything else.
* Start jackd.
* Start jdelay.
* Connect jdelay to a system:capture port and to a system:playback port.
* Connect the input and output of your soundcard corresponding to those
ports using a cable. Make sure the levels are compatible.
Ciao,
--
FA
There are three of them, and Alleline.
5024
days inactive
5026
days old
linux-audio-dev@lists.linuxaudio.org
12 comments
6 participants
participants (6)
-
Arvind Venkatasubramanian -
Fons Adriaensen -
fons＠kokkinizita.net
-
Julien Claassen -
Paul Davis -
Rui Nuno Capela