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Re: Some more questions about sample rate notifications

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Re: Some more questions about sample rate notifications

Subject: Re: Some more questions about sample rate notifications
From: Stéphane Letz <email@hidden>
Date: Tue, 15 Jan 2008 16:39:23 +0100

O >Either you have to fail outright and put up an alert to tell the user what happened or you need to implement some kind of fail-over to another device. This is exactly what an application >should be doing anyway. It's part of the app's job description to re-evaluate the state of a device when said state changes dynamically and handle the changes in a sensible way, whatever >they may be.

>It would seem that the root cause of your problem are that your app fails to account for the rather radical state changes that can come about when using aggregate devices. I think if you >address this, not only will your app work better under these circumstances but I imagine that it will be much more robust to changes in hardware state in general. Which is a good thing.

OK.

Before implementing a more complex fail-over mecanism I'm just trying to do a simple "warn the user if something bad happened on the driver". Basically my application is now also listening to "kAudioDevicePropertyDeviceIsRunning" property, so that having kAudioDevicePropertyDeviceIsRunning OFF would be notified to the user.

The bad thing is that that are some strange sequence of kAudioDevicePropertyDeviceIsRunning notfication occur in some situations, for example:

- start our program

- start Ableton Live: it seems Live restores it's saved SR event if the saved SR equal the current SR for the device...

- our program gets kAudioDevicePropertyDeviceIsRunning OFF then kAudioDevicePropertyDeviceIsRunning ON after some millisec..

So relying on kAudioDevicePropertyDeviceIsRunning seems not be reliable. I could probably check for the kAudioDevicePropertyDeviceIsRunning OFF state to stay a bit of time, but this start again to be complex.

Is the any other property to be listened to that could say in a more reliable way that the device is no running anymore? (or any other "sensible" strategy??)

Thanks

Stephane Letz

PS: *all* applications I'm testing (Like GarageBand, Traktor DJ studio3, Reason, Abteton Live [that even crash...]) are not able to deal correctly with "aggregate device get messed up" event (((-: _______________________________________________ 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 Follow-Ups: Re: Some more questions about sample rate notifications From: Jeff Moore <email@hidden> Prev by Date: Re: advice re: GUI notification Next by Date: Re: Some more questions about sample rate notifications Previous by thread: Re: Some more questions about sample rate notifications Next by thread: Re: Some more questions about sample rate notifications Index(es): Date Thread