[LAU] MIDI over wifi on Linux, revisited

karl at aspodata.se karl at aspodata.se
Mon Jan 4 20:19:51 UTC 2016


Jonathan Brickman:
...
> Which, strangely enough, brings me right back to primordial methods.  
> After all, even audio and video streaming over a gigabit wired LAN 
> depends on caching if it's going to be hifi and truly flawless, TCP/UDP 
> was never designed to keep packets in original order.

UDP is what you are talking about.

https://en.wikipedia.org/wiki/Transmission_Control_Protocol

  TCP provides reliable, ordered, and error-checked delivery
  of a stream of octets between applications running on hosts
  communicating over an IP network. 

so TCP solves the in order reliable thing, but might give you jitter
and latency.

> I really do wonder.  What about this for Linux-to-Linux MIDI:
> 
> - Processes on each end of the link connect to their respective MIDI 
> port devices via simple binary opens
> - The processes set up two TCP connections over the LAN, two separate 
> TCP ports, one for each direction of data flow
> - The processes set up two Zmodem connections, small block sizes, one 
> connection each direction, one per TCP port
> 
> Anyone know why this should not be maximally reliable and low-latency 
> too?  We don't have to worry about any of the details of the data being 
> transmitted; Zmodem handles what history needs there are; either the 
> wifi rig is good enough or not.

Two processes, one at each end, just pushing a midi byte stream over a 
TCP connection (socketpair) "should work", but you might need some kind
of session control. Everything you put in on one should get out on the
other side, barring something that makes the socketpair to go down.

Regards,
/Karl Hammar

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