Re: [Jack-Devel] jack_get_sample_rate - JackAudio

13 Dec 2016

(Added jack-devel mailing list again)

Yes, I would think that jack_get_sample_rate is the only way to know the
sample rate.

If qjackctl shows different information it must be a bug in qjackctl.
However, I noticed that your jack version is 7 years old. If qjackctl
displayed
the wrong information in 2009, it's probably been fixed now.

On Tue, Dec 13, 2016 at 11:00 AM, ROBERT WOLF <
robert.wolf(a)hercsmusicsystems.com.au&gt; wrote:

...
  In this case I would understand as follows:
 1. Starting JACK server with 22050 Hz sampling rate is more-or-less a
 recommendation only.
 2. The way to know the sampling rate for sure is to call
 *jack_get_sample_rate*.
 3. I can testify that the actual sampling rate is the same as reported by
 *jack_get_sampling_rate*, because if it was not then my program would
 sound differently.

 If my understanding is correct then I consider the case closed!

 Cheers,

 Robert

 On 13/12/16 20:13, Kjetil Matheussen wrote:

 (putting back jack-devel again)

 It just says that it configures for 22050Hz, it doesn't say whether it
 succeeded.
 So things seems to work as it should.

 On Tue, Dec 13, 2016 at 10:38 AM, ROBERT WOLF <robert.wolf@
 hercsmusicsystems.com.au> wrote:

  Two programs show this information:

 1. QJackCtl.
 2. When I run my own program *AND* jack server is not running, *THEN*
 for some reason the jack server gets started (apparently using the command
 stored in .jackdrc file) and I see the following printout:

 jackd 0.122.0
 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 = 22050
 creating alsa driver ... hw:PCH,0|hw:PCH,0|1024|2|22050
 |0|0|nomon|swmeter|-|32bit
 ALSA lib conf.c:4578:(parse_args) Unknown parameter 1
 ALSA lib conf.c:4711:(snd_config_expand) Parse arguments error: No such
 file or directory
 ALSA lib control.c:953:(snd_ctl_open_noupdate) Invalid CTL hw:PCH,0
 control open "hw:PCH,0" (No such file or directory)
 configuring for 22050Hz, period = 1024 frames (46.4 ms), buffer = 2
 periods
 ALSA: final selected sample format for capture: 32bit integer
 little-endian
 ALSA: use 2 periods for capture
 ALSA: final selected sample format for playback: 32bit integer
 little-endian
 ALSA: use 2 periods for playback

 *HOWEVER!!!! **jack_get_sample_rate(...);* still reports *44100*.

 How intriguing?!

 On 13/12/16 19:53, Kjetil Matheussen wrote:

 Which program shows this window?

 (added jack-devel mailing list back to the conversation)

 On Tue, Dec 13, 2016 at 8:35 AM, ROBERT WOLF <
 robert.wolf(a)hercsmusicsystems.com.au&gt; wrote:

  There is a window with messages and it says
this:

 configuring for 22050Hz, period = 1024 frames (46.4 ms), buffer = 2
 periods

 On 13/12/16 11:09, Kjetil Matheussen wrote:

 On Mon, Dec 12, 2016 at 7:33 AM, ROBERT WOLF <
 robert.wolf(a)hercsmusicsystems.com.au&gt; wrote:

  Dear All,

 According to the documentation *jack_get_sample_rate* reports the
 sample rate as was used by *jackd*.
 This does not happen in my case.
 I start *jackd* using different sampling rates (i.e. 22050, ect.).
 JACK reports that it does indeed uses the selected sampling rate.

 But *jack_get_sample_rate* always returns 44100.

 Why?

  How did Jack report that it used the selected sampling rate?
 I.e. where did you read that?