RE: IOAudioEngine::clipOutputSamples cannot be called
RE: IOAudioEngine::clipOutputSamples cannot be called
- Subject: RE: IOAudioEngine::clipOutputSamples cannot be called
- From: "David Tan" <email@hidden>
- Date: Thu, 4 Dec 2008 09:48:32 +0800
Hi Jeff,
Thanks for your continuous help :-)
You're right, I didn't call takeTimeStamp(). It's might be the key point of
my issue. I'll try to setup it. But unfortunately I don't have much
experience about it, so maybe I'll bother you more posts. Thanks in advance!
Best Regards,
David Tan,
Software Engineer,
Dextrys Co., Ltd.
-----Original Message-----
From: coreaudio-api-bounces+david.tan=email@hidden
[mailto:coreaudio-api-bounces+david.tan=email@hidden] On
Behalf Of Jeff Moore
Sent: Wednesday, December 03, 2008 4:48 AM
To: CoreAudio-API Mailing List
Subject: Re: IOAudioEngine::clipOutputSamples cannot be called
The HAL won't actually start doing any IO with your device until it
sees the first time stamp from the driver. This could lead to a
situation where performAudioStart() has been called but there are no
subsequent calls to the kernel trap (and hence to your
clipOutputSamples() method).
Is it possible that you've set your driver up such that it isn't
dropping a time stamp in this case?
On Dec 2, 2008, at 1:58 AM, David Tan wrote:
> Hi All,
>
> Actually I'm developing a FireWire audio driver.
> As my understanding, the clipOutputSamples() should be called after
> the performAudioStart() be called no matter if the DCL program is
> running or not.
> Is that correct?
>
> BTW, I use iTunes to play music and the progress cannot step
> forwards. I think that clipOutputSamples() cannot be called explains
> it. Is that correct?
>
> Best Regards,
> David Tan,
> Software Engineer,
> Dextrys Co., Ltd.
> From: coreaudio-api-bounces+david.tan=email@hidden
[mailto:coreaudio-api-bounces+david.tan=email@hidden
> ] On Behalf Of David Tan
> Sent: Tuesday, December 02, 2008 4:38 PM
> To: CoreAudio-API Mailing List
> Subject: IOAudioEngine::clipOutputSamples cannot be called
>
> Hi Apple,
>
> I have asked this question two weeks before and Jeff kindly gave me
> some confirmation that the overridden of it is feasible.
> But unfortunately I'm still blocked at this issue.
>
> Now my question is: is it possibly caused by incorrect setup of
> output IOAudioStream?
> Although I can see my device on Sound Preference Pane and HALLab
> device window, I'm suspicious of something incorrect in it.
> BTW, my audio engine creates one input stream and one output stream
> respectively.
>
> Thanks a lot!
>
> Best Regards,
> David Tan,
> Software Engineer,
> Dextrys Co., Ltd.
>
--
Jeff Moore
Core Audio
Apple
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