[LAD] timing the processing of queues between engine and ui threads?

Iain Duncan iainduncanlists at gmail.com
Sun Nov 6 19:31:55 UTC 2011

>>> The only difference non-jack would make is you need some function to
>>> tell you roughly what audio time it is you can call from another thread.
>> Does one use the system clock for that?
> I think frame time (a frame of samples) is meant here  ? That time is
> delivered in the jackd process callback.
>> Is it accurate enough?
> Depends on the system clock used, I presume.
> For best accuracy, you have to configure your kernel to support HPET
> (high precision event) timers
> and make ALSA use it as default.

the clock used for the system clock is less important than using a DLL
> to "link" the audio clock and the system clock. this enables you to
> answer the question "if its time T on clock1, what time is it on
> clock2?"
> fons wrote the canonical paper on this for a Linux Audio conference a
> few years ago, and JACK contains a DLL for this purpose
> (jack_get_microseconds() will return a prediction of the current time
> according to the audio clock, based on the system clock and the DLL.

thanks, it's sounding increasing like I should be using jack for the time

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