[LAU] Default Jack metering (XFCE QJackCTL)

Tim termtech at rogers.com
Wed Oct 3 21:41:11 CEST 2018

On 10/03/2018 01:26 PM, Len Ovens wrote:
> Auto connect is not a part of jackd or it's specification. It is done by 
> each application that chooses to do so. Some of them may choose to allow 
> you to auto connect to another set of ports besides system_1/2 (I don't 
> know of any off hand). However, the main problem with trying to have 
> applications auto connect to anything other than system_1/2 is that 
> anything else may not exist when jackd is started. So while things like 
> Ardour will reconnect to whatever it was connected to the last time it 
> was run, if what it was connected to last time is not yet started, that 
> connection will not happen. A workaround that is still maybe not 
> finished yet, is to run your jack application inside of Carla as a 
> plugin. But jackd itself does not come with such infrastructure.

Hi, just a side note. I'm not sure how other apps handle this
  situation, but in MusE I have programmed it to remember
  those connections.
They are preserved so that the next time they re-appear,
  the song finds them. You NEVER lose them unless you
  specifically tell MusE to purge them.

This was crucial for Jack midi USB devices for example.
If you unplug and re-plug a USB midi device, its ports get
  new 'canonical' system names (system_3, _4 etc).
This makes it impossible to use those names to remember them.
So instead I take the first or second 'alias' port names,
  which do NOT change, so it ALWAYS finds the connections,
  even after re-plugging.

That is why port aliases are SO VERY important and should
  never be removed from Jack.

At the time, I found this behaviour lacking in any
  session manager, it also appeared to me impossible for
  a session manger to even accomplish this - to know
  which port was supposed to be which port the app wanted.
Thus the feature is tightly integrated in MusE,
  and so very dependent on those port alias names.
Maybe things have changed with session managers over
  the last several years ?

I am planning to extend that behaviour for missing
  audio plugins and so on.
Credo: Nothing ever 'lost' unless the user says so.


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