Re: [LAU] jack2 vs. jack1/zita vs. jack2+zita-a2j, performance differences

From: Fons Adriaensen <fons@email-addr-hidden>
Date: Thu Apr 17 2014 - 12:54:42 EEST

On Thu, Apr 17, 2014 at 02:37:00AM -0400, Paul Davis wrote:
 
> I really don't understand the goal here. Why not just run jack -d alsa -d
> hw:SB -r 48000 -p 32 ?

One reason for using the bridges (reported in private mail by another
user) is the ability to switch soundcards without having to stop Jack.

According to that user this is really convenient in particular in
combination with suspend resume. Which brings me to the real topic.

Currently this is not possible with zita-ajbridge, and the reason
is that libzita-alsa-pcmi doesn't support suspend/resume. The next
update (being tested ATM) will. Then there is one remaining problem.

Upon resume, zita-ajbridge detects 'excessive timing errors' and
waits for 15 seconds to let the dust settle. This is essentially
the same thing that occured with older Jack versions after free-
wheeling. The reason is that the DLL is not properly reset after
a resume and is using stale information.

I had a quick look at the code, and AFAICS a resume is handled
entirely within the backend, and the event is not propagated
up to the engine. So solving this may require some non-trivial
changes.

It would actually make sense to have the DLL inside the backend
instead of in the engine. The DLL state is coupled quite closely
to that of the backend, and the required code is really minimal.

Ciao,

-- 
FA
A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user@email-addr-hidden
http://lists.linuxaudio.org/listinfo/linux-audio-user
Received on Thu Apr 17 16:15:02 2014

This archive was generated by hypermail 2.1.8 : Thu Apr 17 2014 - 16:15:02 EEST