[Jack-Devel] jack-trauma for audio over IP

Hello,

my name is Daniele and I'm quite new to this ML, even if I played
around with JACK for some time now.

I'd like to share with who's interested a small JACK client I
wrote with my friend and colleague Andrea Lusuardi and called JACK
Trauma, in order to hear more opinions and possibly improve it.

It's all here: https://bitbucket.org/torelizer/jack-trauma
or also https://github.com/torelizer/jack_trauma

Despite the name (that's a long story) it's a simple tool to relay JACK
channels over IP, in a way similar to Jacktrip but with some different
design choices.

We based the transmission on UDPLite, and we made it focused on low
latency, and wanting to provide the possibility for the user to send
every channel to a specific IP address, allowing for one-to-many
configurations. This feature is not currently there in the code you see
(even if it's achieavable with small modifications) because we only
added it in the Python module we derived from this, that hasn't already
been published because it's still quite "dirty" but will come soon.
Multicast addresses can be used as well anyway, and it does the same
job better in most normal cases.

The way it works is simply one channel -> one buffer -> one packet, and
that's it, of course it requires JACK to be running with the same
period size on the sender and the receiver(s).
It's mainly focused on having good performances on a small LAN, with
traffic conditions not "extreme" and with average values of packet loss
and delay.
The approach with packet loss is brutal, which means there is none,
it's still good for listening but maybe not so great for recording.

So far it has been successfully tested sending up to 64 channels, with
JACK using a period size down to 64 (on a dedicated gigabit LAN and
using I7's).
Running multiple instances when sending a lot of channels is also
possible and generally better. Generally speaking, given how it
works an increase in a number of channels makes it more sensible to
network delays, and this is actually measurable with tests on localhost
playing with tc.

We also tested it on wireless LAN, where obviously the story is quite
different, but if using no more than two channels in a one-to-one
link, with JACK having a period size of 512, it's fairly usable in
low traffic conditions.

We haven't done a very precise latency measurement yet but basic
listening tests are very promising (on Ethernet of course).

So, that's it, we'll be working on improving it and we are thinking
about a GUI and possibly a LV2 plugin version when we'll have time.

If anybody is interested, any feedback is welcome so we can make it
better!

-- 
Daniele Torelli
----------------------
www.danieletorelli.net

1392913042.13419_0.ltw:2,RSa <9b9ab9bc05224cf2829bab202a2529a4 at danieletorelli dot net>