Re: What corresponds to kAudioDevicePropertyDeviceIsRunningSomewhere in an audio driver?
Re: What corresponds to kAudioDevicePropertyDeviceIsRunningSomewhere in an audio driver?
- Subject: Re: What corresponds to kAudioDevicePropertyDeviceIsRunningSomewhere in an audio driver?
- From: Jeff Moore <email@hidden>
- Date: Fri, 23 May 2003 16:21:54 -0700
QT is a funny beast. It needs to run the audio hardware as long as
there is an open movie with a sound track around so that it's clock can
update itself. So you would see a start, but probably not see the stop
until you close all the movies.
I would do your testing with an app like Daisy (in
/Developer/Examples/CoreAudio/HAL/Daisy), where there is a direct
connection between hitting the buttons in the UI and the calls to the
driver.
On Friday, May 23, 2003, at 03:26 PM, Sean McBride wrote:
Jeff Moore (email@hidden) wrote on Tue, 20 May 2003 12:11:13 -0700:
The value of kAudioDevicePropertyDeviceIsRunningSomewhere is
determined
by the HAL receiving the start/stop/pause/resume notifications from
the
driver.
Hi Jeff,
I've done a test with the PhantomAudioDriver playing an mp3 in QT
Player.
As expected, starting the playback calls performAudioEngineStart, and
stopping the playback calls performAudioEngineStop. But with our
driver,
we get a performAudioEngineStart but never get a
performAudioEngineStop.
Any idea why this might be? (I believe this is why
kAudioDevicePropertyDeviceIsRunningSomewhere continues to report busy
after becoming busy once.)
There is a bug in the current HAL that prevents it from sending a
notification out when this value changes, but the value itself should
still be set appropriately.
That's a pity, but no big deal... I'll just have to poll for the info.
Thanks Jeff!
--
____________________________________________________________
Sean McBride, B. Eng email@hidden
Mac Software Designer +1-514-822-6000
Matrox Electronic Systems Ltd. Montrial, Quibec, Canada
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--
Jeff Moore
Core Audio
Apple
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