This is a possible roadmap to improve the current Jack
support in Csound. It would allow a gradual change without
(AFAIK) breaking anything on the way.


First phase
-----------

* Add two more variables to the global Csound 'object'
  struct:

   - ninputs
   - noutputs     

  as well as the required data structures to store any
  number of Jack ports (a Jack port is represented by
  a single pointer, the number is fixed after startup,
  and there could also be 'reasonable' absolute limits).   

* Allow the user to set these values when using Jack,
  and create this number of input and output ports
  with default names.

* Ensure that 'nchannels' can not be set higher than
  min (ninputs, noutputs), and initialise the existing
  audio ports array from the first nchannels jack ports.
  This ensures that current opcodes will continue to work
  also with Jack.

* Implement new audio I/O opcodes using ninputs and
  noutputs, and allowing I/O to any subset of inputs
  or outputs, or at least to each single one separately.
  In the first phase these opcodes would be available
  only when using Jack.

* (optional) Provide opcodes to change the default
  names of Csound's Jack ports.

* (optional) Provide opcodes to connect/disconnect
  Csound's Jack ports to/from external applications.

* (optional, orthogonal to all the rest) Remove the
  buffering between Jack and Csound's internals, 
  and require nsmps * k = period, for integer k.
  Modify 'unsafe' opcodes (diskin, diskout etc.)
  to make them RT-safe (this means adding read-ahead,
  write-behind in a separate thread).


Second phase, as time permits
-----------------------------

* Modify the existing audio I/O opcodes to use ninputs
  and noutputs and the corresponding data structures,
  making them independent of the old ones.

* Modify the other audio interfaces to use ninputs and
  noutputs.

* Make assignment to nchannels set both ninputs and
  noutputs, but encourage users to use the latter two
  directly. Mark nchannels as 'deprecated'.


Allow some time to pass.


Third phase
-----------

* Remove nchannels and everything related, as nothing
  should depend on it anymore.


Ciao,

-- 
FA

O tu, che porte, correndo si ?
E guerra e morte !

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