Subject: Re: [linux-audio-dev] muse and /dev/rtc
From: Fons Adriaensen (fons.adriaensen_AT_skynet.be)
Date: Tue Nov 23 2004 - 02:41:47 EET
On Mon, Nov 22, 2004 at 07:00:59PM -0500, Paul Davis wrote:
> how far ahead can you queue without getting into trouble when the user
> does realtime edits?
>
> think about this for long enough, and i think you will come to same
> conclusion: deliver events in a process-callback-style fashion, more
> or less "just in time".
Yes, but it's the same with audio: once you have sent your samples to e.g.
ALSA, there's no way back, and it is the hardware that does the final timing
of the samples.
So the key to correct use is in the phrase 'just in time' - it would
probably be a bad idea to queue more than a few tens of milliseconds ahead.
But even using the sequencer in this way would avoid requiring a process
swap for each and every timed event. An efficient way to use it would be
to enqueue the events for the next period inside the JACK process callback,
if the app has audio as well.
-- FA
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