Re: [ecasound] Bug Report: Ecasound goes silent

On Tue, Apr 03, 2012 at 10:10:11AM -1000, Joel Roth wrote:
> On Tue, Apr 03, 2012 at 02:20:08PM -0400, S. Massy wrote:
> > On Thu, Mar 15, 2012 at 09:42:49PM +0200, Kai Vehmanen wrote:
> > > Hi,
> > >
> > > >Symptoms:
> > > >No more sound is heard, but the engine still seems to be running (clock
> > > >is moving, engine-status is "running", seems to obey transport
> > > >commands).
> > >
> > > thanks for the excellent bugreport! I managed to reproduce this with
> > > your test session, and am looking for the root cause. Upon initial
> > > look, this would seem to be an issue with the JACK callbacks. I also
> > > got one crash while ecasound called jack_port_get_latency_range().
> > > That is suspicous as the semantics of that call have changes a bit
> > > (since the related ecasound code was written).
> > Two more interesting facts:
> > - When the bug is triggered, the clock stops updating in real-time and
> > instead seems to be refreshed every 4 or 5 seconds, jumping by that
> > about that amount.
>
> Seeking can cause problems with JACK because repositioning
> in multiple files can take more time than a running JACK
> transport allows to its clients.
>
> Nama deals with this by stopping the transport (if running),
> issuing a seek command, allowing a short time for Ecasound
> to update file positions, then restarting the transport.
>
> Except that you found several cases where Nama was using
> Ecasound setpos rather than wrapping it with this
> special logic.
>
> Will be interested to see if your problems are reduced by
> these fixes to Nama.
That definitely contributes to making nama more stable by a significant
margin, but remember that the bug isn't merely triggered by seeking but
also by mute/solo, especially as the number of tracks/busses grows. It
could be ecasound needs to have the ability to skip a jack period if it
can't meet the deadline, or perhaps a mechanism to throttle the rate of
iam/eci commands it can process within a given timeframe.

Cheers,
S.M.

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Received on Fri Apr 6 08:15:01 2012