Where is patch time derived from? It doesn't seem to be synced with
CFAbsoluteTimeGetCurrent().
To demonstrate this, create a system time patch(which uses
CFAbsoluteTimeGetCurrent()) and a patch time patch(which uses QC's
atTime: parameter I'm guessing), and plug them both into a math patch
that subtracts (giving the difference between system clock and patch
time). Then plug the math guy into an Image With String patch, and
finally to a billboard to see it go.
If patch time was synchronized with CFAbsoluteTimeGetCurrent(), the
delta would stay within a reasonable margin (depending on system load
and other external factors which I understand). However, the actual
results on my machine show that the delta decreases at a slow rate
(disregarding the ntpd time update things, as logged in system.log).
In other words, the two time sources are drifting. The ntpd updates
seem to take effect immediately, and cause a sharp transition in the
delta, so I'm guessing the ntpd delta isn't smoothed out over time to
cause this drift.
It's a really slow process, on the order of 0.001 seconds closer every
10 seconds (0,001 seconds for the European readers :), so it takes a
bit of time to notice it.
So, to keep an external timer that doesn't drift relative to the
composition's clock, which time source should I use? (obviously not
CFAbsoluteTimeGetCurrent())
--
[ christopher wright ]
[EMAIL PROTECTED]
http://softpixel.com/~cwright/
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