[LAD] alsa seq client ids??

Clemens Ladisch cladisch at fastmail.net
Thu Sep 13 12:07:50 UTC 2007

Jens M Andreasen wrote:
> > $ aplaymidi -l
> >  Port    Client name                      Port name
> >  14:0    Midi Through                     Midi Through Port-0
> >  14:1    Midi Through                     Midi Through Port-1
> Ome thing I have many times wondered, what is the semantics of those
> Midi Through ports? In hardware those would be replications of Midi
> Input to some other hardware device, and on output you would never see
> them ... Is it supposed to be some kind of Midi Merge or what is it?

The semantics if a Midi Through port is simple: anything received by the
port is also sent from the port.

If you make several connections from other ports to a through port, the
data is indeed merged.

If you make several connections from a through port to other ports, the
received data is copied to all ports.

These ports aren't used that much in practice because any ALSA sequencer
port that allows connections allows any number of them.


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