AudioTimeStamp availability at the AU kernel level
AudioTimeStamp availability at the AU kernel level
- Subject: AudioTimeStamp availability at the AU kernel level
- From: sergey detkin <email@hidden>
- Date: Mon, 15 Jan 2007 22:23:48 -0500
thanks Stefan, thanks Everyone
that definitely helped, however it seems that i have more to worry
about now.
in my plugin, i use the kernel approach so now i call those callbacks
from the kernel's Process() to figure out current playback position
in musical time,
but it always seems a bit off and i'm worrying about how accurate the
info that i'm getting back is.
as far as i understand, when the kernel's Process() is called the
host is Not Guaranteed
to have it's Current playback position Exactly at the First Sample of
the buffer being processed,
so the information returned by the host doesn't give me to-the-sample
accurate playback position
relative to the current musical time.
is this correct?
there is an AudioTimeStamp passed all the way down to
AUEffectBase::Render()
which might be useful for the type of AU that i'm trying to put
together,
but it is not passed even to AUEffectBase::ProcessBufferLists()
making the kernels unaware of the real playback state.
that is, if i'm not missing anything...
so my problem then is that kernels are always slightly out of synch
with the host,
when they try to apply processing at the beat boundary. (again, there
might be something else i've missed)
can anyone point me in the right direction 'cause i'm obviously doing
something
that was done a hundred times previously by people smarter than me?
is there a way for a kernel to lay hands on the AudioTimeStamp passed
to the *::Render() from above?
thanks for looking into this,
sergey
On Jan 9, 2007, at 8:51 AM, Stefan Gretscher wrote:
Hi Sergey,
Am 06.01.2007 um 06:47 schrieb sergey detkin:
what makes an AU aware of the tempo?
how to sync it with beats [and bars]?
Look at the host callbacks:
file:///Developer/Examples/CoreAudio/Documentation/AudioUnits/
Topics/au_properties.html#HostCallback_GetBeatAndTempo
file:///Developer/Examples/CoreAudio/Documentation/AudioUnits/
Topics/au_properties.html#HostCallback_GetMusicalTimeLocation
At render time your AU can call these callbacks to query the
information you need.
Best,
Stefan
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| References: | |
| | >Metronome (From: sergey detkin <email@hidden>) |
| | >Re: Metronome (From: Stefan Gretscher <email@hidden>) |