When I record a jack stream at 192kHz rate the recording speed is doubled. That is when I play it back it plays at double speed. In addition, I have a clock display on the system and it shows that the recording time calculated by the -V switch is 1/2 the rate it should be. (e.g. 10 seconds wall clock is 5 seconds jack_capture -V clock)
If I use the jack_connect and connect the ports to other services the signal is correctly interpreted.
Experimentation reveals that the system is actually producing 96kHz.
Environment:
- OS: Raspian
- Uname -a: Linux cuimhne-bd4bc2f8 5.4.79-v7+ #1373 SMP Mon Nov 23 13:22:33 GMT 2020 armv7l GNU/Linux
- Platform: Pi 3 A+
- Soundcard: pisound
- Jack start command: /usr/bin/jackd -t 2000 -R -P 95 -d alsa -d hw:pisound -r 192000 -p 1024 -n 2 -X seq -s (NOT using the systemctl mechanism)
- Jack_capture command: jack_capture -V
I executed a timing of the capture and a snd-file info dump of the result. The wall clock agrees with the timing in that the 5 second recording took 10 seconds.
$ time jack_capture --disable-console -d 5 /recordings/5sec.wav
>>> Warning. Could not set higher priority for a SCHED_OTHER process using setpriority().
>>>
>>> Recording to "/recordings/5sec.wav". The recording is going
>>> to last 5.000000 seconds Press <Ctrl-C> to stop before that.
>>> Please wait while writing all data to disk. (shouldn't take long)
Finished.
real 0m10.332s
user 0m0.269s
sys 0m0.185s
$ sndfile-info /tmp/5sec.wav
The results are:
sndfile-info /recordings/5sec.wav
========================================
File : /recordings/5sec.wav
Length : 7680088
RIFF : 7680080
WAVE
fmt : 16
Format : 0x3 => WAVE_FORMAT_IEEE_FLOAT
Channels : 2
Sample Rate : 192000
Block Align : 8
Bit Width : 32
Bytes/sec : 1536000
fact : 4
frames : 960000
PEAK : 24
version : 1
time stamp : 1610274863
Ch Position Value
0 0 0
1 0 0
data : 7680000
End
----------------------------------------
Sample Rate : 192000
Frames : 960000
Channels : 2
Format : 0x00010006
Sections : 1
Seekable : TRUE
Duration : 00:00:05.000
Signal Max : 0 (-inf dB)
Jack component versions
jack_capture --version
0.9.73
jackd --version
jackdmp version 1.9.12 tmpdir /dev/shm protocol 8
This information was originally provided in a jack_capture ticket: https://github.com/kmatheussen/jack_capture/issues/43
The result there was that Jack was reporting 192Khz but jack_capture was only receiving 96Khz from ALAS driver, so that ticket was closed an another opened with Jack (https://github.com/jackaudio/jack2/issues/702). However there is a belief that the issue is in the ALSA driver.
The output from PiSound sounds proper.
The path through the system is
guitar ----> pisound in ---> Jack ---> pisound out ---> amplifier
|
v
jack_capture ---> disk
Hey, I couldn’t reproduce the jack_capture -d 5 taking 10 seconds, I had MODEP running, Jack set up with these settings:
/usr/bin/jackd -t 2000 -R -P 95 -d alsa -d hw:pisound -r 192000 -p 512 -n 3 -X seq -s -S
If you’d like to see what are the parameters currently enabled on Pisound, you can do so by printing this file (docs):
/proc/asound/card1/pcm0c/sub0/hw_params
You may have to edit the digits according to the aplay -l output.
$ cat /proc/asound/card1/pcm0c/sub0/hw_params
closed
same result for status and sw_params.
Please note that I am running -p 1024 -n 2
If you specify the paramaters as I listed above, and simply do the capture to send the input to the output on the pisound and then run jack_capture. The output of the jack_capture should show the problem.
Was jack turned off when you ran ‘cat’? Try running it while it is on, or maybe even when jack_capture is running.
Here’s what I tried now:
Jack is running like this: /usr/bin/jackd -t 2000 -R -P 95 -d alsa -d hw:pisound -r 192000 -p 1024 -n 2 -X seq -s -S
patch@patchbox:~ $ cat /proc/asound/card1/pcm0p/sub0/hw_params
access: MMAP_INTERLEAVED
format: S16_LE
subformat: STD
channels: 2
rate: 192000 (192000/1)
period_size: 1024
buffer_size: 2048
patch@patchbox:~ $ cat /proc/asound/card1/pcm0c/sub0/hw_params
access: MMAP_INTERLEAVED
format: S16_LE
subformat: STD
channels: 2
rate: 192000 (192000/1)
period_size: 1024
buffer_size: 2048
patch@patchbox:~ $ jack_connect system:playback_1 system:capture_1
patch@patchbox:~ $ jack_connect system:playback_2 system:capture_2
patch@patchbox:~ $ jack_lsp -A
system:capture_1
alsa_pcm:hw:pisound:out1
system:capture_2
alsa_pcm:hw:pisound:out2
system:playback_1
alsa_pcm:hw:pisound:in1
system:playback_2
alsa_pcm:hw:pisound:in2
system:midi_capture_1
alsa_pcm:Midi-Through/midi_playback_1
Midi-Through:midi/playback_1
system:midi_playback_1
alsa_pcm:Midi-Through/midi_capture_1
Midi-Through:midi/capture_1
system:midi_capture_2
alsa_pcm:pisound/midi_playback_1
pisound:midi/playback_1
system:midi_playback_2
alsa_pcm:pisound/midi_capture_1
pisound:midi/capture_1
system:midi_capture_3
alsa_pcm:MPK-mini/midi_playback_1
MPK-mini:midi/playback_1
system:midi_playback_3
alsa_pcm:MPK-mini/midi_capture_1
MPK-mini:midi/capture_1
system:midi_capture_4
alsa_pcm:pisound-ctl/midi_playback_1
pisound-ctl:midi/playback_1
system:midi_playback_4
alsa_pcm:pisound-ctl/midi_capture_1
pisound-ctl:midi/capture_1
patch@patchbox:~ $ time jack_capture --disable-console -d 5
>>> Warning. Could not set higher priority for a SCHED_OTHER process using setpriority().
>>> Recording to "jack_capture_02.wav". The recording is going
>>> to last 5.000000 seconds Press <Ctrl-C> to stop before that.
>>> Please wait while writing all data to disk. (shouldn't take long)
Finished.
real 0m5.380s
user 0m0.001s
sys 0m0.414s
patch@patchbox:~ $ sndfile-info jack_capture_02.wav
========================================
File : jack_capture_02.wav
Length : 7680088
RIFF : 7680080
WAVE
fmt : 16
Format : 0x3 => WAVE_FORMAT_IEEE_FLOAT
Channels : 2
Sample Rate : 192000
Block Align : 8
Bit Width : 32
Bytes/sec : 1536000
fact : 4
frames : 960000
PEAK : 24
version : 1
time stamp : 1610377219
Ch Position Value
0 630978 0.00671407
1 212809 0.00729392
data : 7680000
End
----------------------------------------
Sample Rate : 192000
Frames : 960000
Channels : 2
Format : 0x00010006
Sections : 1
Seekable : TRUE
Duration : 00:00:05.000
Signal Max : 0.00729392 (-42.74 dB)
I don’t know what changed but I am unable to get the off speed recording anymore. If it should arise again I will attempt your request above. In the mean time I suppose this can be closed, or at least put on the back burner.
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