Re: [Jack-Devel] jackd1/jackd2: FFADO port name divergence

On Thu, Jan 26, 2012 at 11:28:01AM +0100, Adrian Knoth wrote:
 
> I hence agree with Nedko that the jack core can be lean. Maybe unlimited
> aliases or pretty names would be nice, but some really don't want
> system:capture_56 in the session file. They then say good bye to
> "canonical port names".

There is another approach which I'm moving to. It amounts to using
Jack only for what in a HW world would be the 'fixed wiring' of
your studio, the big bundles of cables that go under the floor. 

* You need either real persistent ports, or a connection manager that
  emulates them. That is, it remembers a set of apps, their ports
  and connections, and remakes the connections as soon as both ends
  are available. Qjackctl's patchbay does this in a way.

* All apps have a fixed set of input/outputs which does not depend
  on any per session or project configuration. For example : a DAW
  application is configured to have 200 inputs and 100 outputs which
  are just named input-1..200 and output-1..100. Inputs 1..20 are
  connected to soundcard capture channels. They may end up as mic
  inputs in the studio, line inputs for external instruments, etc.
  Another group goes to a software effects rack. Some may go to
  a sofware patchbay application. Others are fixed connections to
  soft synths etc. etc. Similar for outputs. All this is set up
  once and never changes unless it's necessary.

* All apps have a configuration that knows where it ports are connected
  and that provides logical names for them. This again is fixed - this
  configuration belongs to the application in a particular studio and
  not to a session or project. 

* The DAW (and all other apps where it matters) have an internal routing
  system allowing to use any Jack port for any internal function. This
  routing system presents Jack ports using the configured logical names.
  For example, you can select the input of channel strip #15 as Studio
  Mic input #6. These internal connections are stored in session or
  project files.
 
The net effect is that once things are set up, you can basically forget
about Jack. It provides the connections in the same dumb way as the fixed
wiring of a hardware based studio would. This changes only when you add
'new epuipment'. All the intelligence is in the apps (which is different
from having it in a separate session manager).

When a project is moved to another studio the actual connections (wiring)
there may be completely different. But if the DAW and other apps) there
have been configured properly and equivalent ports are available then the
right internal routing will be set up automatically. This remains completely
internal to the application(s).  

All this is similar to how e.g. a big digital mixer is wired an set up. 
It may have e.g 32 analog ins/outs, 4 ADAT ins/outs, maybe one or two
MADI interfaces. All this is wired up once and the mixer is configured
to know what is connected where. 

And yes, it amounts to having an 'additional layer of indirection', and
then fixing the roles of each layer.

Ciao,

--  
FA

Vor uns liegt ein weites Tal, die Sonne scheint - ein Glitzerstrahl.

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