[Jack-Devel] Recorded from OSS /dev/dsp sound is too high pitched on FreeBSD

Yuri yuri at rawbw.com
Mon Jan 9 18:26:12 CET 2017

On 01/09/2017 02:38, Hans Petter Selasky wrote:
> FYI:
> The "speed" integer is updated to the actual rate when the 
> SNDCTL_DSP_SPEED IOCTL returns. I think this behaviour is the 
> expected. Jackd should use this returned rate. An alternative would be 
> to use FreeBSD's virtual_oss to wrap the DSP device.
> --HPS 

Yes, so Jack should use the adjusted value as an actual value. It should 
also decide what does it do when the adjusted values for input and 
output are different. It should probably fail and have the way to work 
around, to disable SNDCTL_DSP_COOKEDMODE. It should provide and suggest 
the option to prevent the COOKEDMODE.

On 01/09/2017 08:16, Chris Caudle wrote:
> I looked back at your first email and you never showed the entire output
> from jackd as it starts.  The console messages printed should display the
> determined paramaters.  On ALSA systems there is a message showing what

arguments: -r -doss -r44100 -p1024 -n3 -w16 --capture /dev/dsp6 
--playback /dev/dsp2
 > jackd 0.124.1
 > 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 ..
 > oss_driver: /dev/dsp6 : 0x10/2/32000 (4096)
 > oss_driver: /dev/dsp2 : 0x10/2/48000 (4096)
 > oss_driver: indevbuf 4096 B, outdevbuf 4096 B
 > oss_driver: not using barrier mode, (single thread)

> sample rate is used if it is not the same as the sample rate requested.
> Maybe OSS does not return that information.  That would be a limitation of
> OSS or maybe an error in the jackd OSS driver, not a generic jackd
> problem.  I have never heard of anyone using the OSS driver, how many
> users of that are there?

FreeBSD uses OSS. When people try using Jack the often fail. So I am 
trying to figure out what is wrong.

On 01/09/2017 08:26, Dan MacDonald wrote:
> I'm very interested in Yuri's results as I'd like to use JACK under 
> FreeBSD. Supposedly (theoretically) both Ardour 5 and MusE 3 git 
> should be able to run under FreeBSD these days.
> Anyone using JACK under BSD is dependent upon JACK's OSS driver but 
> last time I tried JACK under a FBSD 11 pre-release it failed to start 
> at all. I haven't tried it since 11-RELEASE.

With the rc script 
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=215889 it is easy to 
start. The other possible problems are the speed adjustment this thread 
is about, and the realtime priority the other thread is about (-r avoids 


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