Re: Observing CurrentPlayTime in AUScheduledSoundPlayer
Re: Observing CurrentPlayTime in AUScheduledSoundPlayer
- Subject: Re: Observing CurrentPlayTime in AUScheduledSoundPlayer
- From: William Stewart <email@hidden>
- Date: Thu, 31 May 2007 14:52:13 -0700
But that's a fine approach. The reason that you don't get a
notification for this is that it changes every sample, so at 44.1KHz
it changes 44,100 times a second.
We take a similar approach as you do for drawing meters; set up some
kind of time slice (30X a second) that you want to refresh the
display, and then away you go. It also helps to optimise the amount
of screen space you redraw when you are doing these.
Bill
On 31/05/2007, at 12:50 PM, Stephen F. Booth wrote:
Hello all,
I'm using an AUScheduledSoundPlayer to feed an AUGraph, and I would
like to have an UI indication of playback position. Is there a way
to observe changes in kAudioUnitProperty_CurrentPlayTime without
polling? I've tried using AUEvents, but my callback is never
called even when I know the property is changing (because audio is
playing). Here is how I register for the event:
AudioUnitEvent propertyEvent;
propertyEvent.mEventType = kAudioUnitEvent_PropertyChange;
propertyEvent.mArgument.mProperty.mAudioUnit = _generatorUnit;
propertyEvent.mArgument.mProperty.mPropertyID =
kAudioUnitProperty_CurrentPlayTime;
propertyEvent.mArgument.mProperty.mScope = kAudioUnitScope_Global;
propertyEvent.mArgument.mProperty.mElement = 0;
err = AUEventListenerAddEventType(_listener, NULL, &propertyEvent);
I was under the impression (after some googling and reading the
list archives) that anytime an AudioUnit property changes, a
notification should be generated, so I'm stumped. I also tried
using AudioUnitPropertyListeners directly, but couldn't get that to
work either.
Currently I'm using an NSTimer that fires every so often to query
the property and causes an UI update- which works- but I don't like
it.
Stephen _______________________________________________
Do not post admin requests to the list. They will be ignored.
Coreaudio-api mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden
--
mailto:email@hidden
tel: +1 408 974 4056
________________________________________________________________________
__
"Much human ingenuity has gone into finding the ultimate Before.
The current state of knowledge can be summarized thus:
In the beginning, there was nothing, which exploded" - Terry Pratchett
________________________________________________________________________
__
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Coreaudio-api mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden