On Mon, Aug 2, 2010 at 4:23 AM, <fons@kokkinizita.net> wrote:

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

====================================================================

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

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...

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

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