Re: [LAU] MIDI over wifi on Linux, revisited

From: Chris Caudle <chris@email-addr-hidden>
Date: Thu Jan 07 2016 - 02:12:04 EET

On Mon, January 4, 2016 6:49 pm, Jonathan E. Brickman wrote:
> The motivation for me is simple. I have worn out too many USB ports to
> be happy about it!!!

You're jumping through hoops to get WiFi to work because you want a
connector saver?

Wait, I thought this was about MIDI. Is it MIDI, or USB? Or MIDI data
which is being generated by a USB connected device?

Anyway, connector saver is what we called an adapter to be used in
situations where a connector was going to be mated much more than designed
for.
For example, say you are worried about wearing out the USB connector on
your laptop. You make a cable that connects to the laptop, with a USB A
female on the other end (extension cable, in other words). Make a way to
keep the cable attached permanently to the laptop (tricky since the
connector sticks out). Say for example the connector can tolerate 500
mating cycles, so previously you would wear out the laptop connector after
500 times of connecting and disconnecting your device. Now with the
extension mounted, the end of the extension wears out after 500 times, so
you get a new one, that is 2 mating cycles for the computer. After 500
more times of connecting and removing your device the cable wears out
again, so you change it, 3 cycles on the laptop. This way you can get
500*500=250 000 mating cycles before you wear out the connector on the
laptop.
Of course for a portable system it isn't quite so simple, since the
connector sticks out, so you can't really carry around something like a
permanently attached extension cable without risking breaking the
connector by bumping into something. The technique is more useful for
something fixed, say you have a computer on work bench in a repair shop
that you use to test out devices, so you are inserting and removing a lot
more than usual.

I don't remember if you said what was at each end of the wireless
connection. Will that be a computer running Linux at both ends, or only
at one end?

I didn't hear anyone mention it before, but the rtp-MIDI specification
says you can run over TCP, which should take care of most packet loss
issues, although the variable latency of WiFi would still make it not
recommended for real time use.
https://tools.ietf.org/html/rfc4695
The scenic tools mentioned earlier implement rtp-MIDI, but I don't have
any idea whether it supports all the options to allow you to pick that you
want TCP rather than UDP transport of the RTP packets.

-- 
Chris Caudle
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Received on Thu Jan 7 04:15:02 2016

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