Re: [linux-audio-dev] alsa ethernet streaming?

From: Asbjørn Sæbø <asbjs@email-addr-hidden>
Date: Fri Jun 17 2005 - 10:10:56 EEST

On Thu, Jun 16, 2005 at 11:38:24AM -0600, Garett Shulman wrote:
> Hello, I would like push audio streams over ethernet and was wondering
> what avenues people have tried.

I have an interest in the same thing, but with an emphasis on low
latency. I did a little bit of looking around this fall, but did not
find much. There are of course the normal streaming solutions, like
Icecast, which seem to work well, but has to large a latency for my
purposes (distributed music playing).

What I ended up with was writing my own. (Currently with assistance
from Lee Revell.) It has not come very far, but I am able to stream
music from one computer to another. It also deals with transmission
problems (lost/duplicate/out of order/late packets) and drift
adjustment. I have plans to release it in the not to distant future.
See <URL: http://www.q2s.ntnu.no/~asbjs/ldas/ldas.html > for more
information.

Then there is jack.udp, which I discovered half a year after starting my
work. This seems like a good tool. It streams jack data between two
jackds running on different computers.

There are a couple of reasons I didn't switch to jack.udp myself. As
far as I have understood (and I may well have misunderstood), jack.udp
does not do drift adjustment, so it will have synchronisation problems
if you want to use it between two computers with un-synched soundcard
clocks driving jackd. It will work well if one of the jackds is a
"slave" jackd, though. (Somebody please correct me if I'm wrong here.)

Also, the jack format keeps samples as 32bit floats. Although I do not
care that much for bandwidth issues, I found that doing away with half
of this, using 16 bit PCM, was valuable when transmitting over the
Internet in general.

Asbjørn
Received on Fri Jun 17 12:15:06 2005

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