Re: [Jack-Devel] Place for bug reporting

On Tue, Jun 03, 2014 at 05:28:35PM +0400, TimKa wrote:

> jackd_netsource -H <master_IP> I get a lot of "nextrun amount 21ms"
> and less 106 or 61ms on master console. Unfortunately I can not find
> any information on Web by this issue so trying to find right way by
> mail list. //

It just means "something is wrong", where "something" could mean
anything from system tuning to hardware design (who knows if your SoC
has some crappy design that prevents timely memory access for NIC
and audio simultaneously?)

> I did not get any feedback again, so after these three unsuccessful
> steps I decided to write my own network clients, because it's much
> more clear to understand and debug. So I wrote very simpe send/recv
> client with jitter buffer on receiving side but after some time of
> proper working it's became broken and I start got xruns and

Clock drift. I assume you used jackd clients on both sides. Since they
advance independently, one side will over- or underflow sooner than
later.

You either need to slave one clock to the sender (this boils down to
writing another network backend; you could also stick with netjack) or
resample on the receiving side to the local clock (IIRC that's what
jacktrip does)


> So right now I do not have working solution based on jackd and
> thinking about writing my own alsaclient( with similar functionality.

You're discovering the fundamentals of network audio, most prominently
clock synchronisation. It really boils down to this.

Doing all this on a limited embedded system doesn't exactly help, that
is why you didn't get any feedback: only few have done this before, and
those who were successful are most likely selling this stuff by now.


Worse, there is no active netjack dev at the moment, so you're literally
on your own. There are a couple of patches, but apparently, nobody
cares. Feel free to familiarize yourself with the subject and become the
netjack dev, maybe together with Leonardo.

When I say netjack, I mean both incarnations (netjack1, netjack2).


Posting logs of underruns won't get you nowhere, this doesn't even
qualify as a bug report. A segfault without a stacktrace neither.



Cheers

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