16 Aug
2015
16 Aug
'15
12:27 a.m.
On Sat, 15 Aug 2015, Will Godfrey wrote:
Clock mismatch was the clue :o
I had been a bit lazy. While switching the output device I'd neglected to also
switch the input device, so jack was seeing two slightly different 48kHz
clocks. Switch both at the same time and the problem disappears.
:)
As a matter of curiosity I wonder if we can work out what the actual difference
is. Would the Xrun occur when there was a one frame difference, one period, or
1 buffer? It's running at 256 frames per period and 2 periods per buffer. The
xruns occur every 11 minutes (and a few seconds).
While the xrun would happen at a buffer read boundary, the offending IF
would only have to be 1 frame out to be late. (if my thinking is correct)
So the timing of the xrun would be the difference in clock plus the size
of a buffer (or portion there of). That is, I think it would be unlikely
the time between xruns would be exactly the same. The minimum time between
xruns is the value I would use.
Now which one is faster?
--
Len Ovens
www.ovenwerks.net