Re: Using AudioDeviceRead?
Re: Using AudioDeviceRead?
- Subject: Re: Using AudioDeviceRead?
- From: Jeff Moore <email@hidden>
- Date: Wed, 19 Feb 2003 12:04:15 -0800
On Wednesday, February 19, 2003, at 04:21 AM, Dirk Musfeldt wrote:
Hi Jeff,
Have you started the device you are reading from?
I double-checked the IDs used with the various AudeDeviceXXX calls and
they
matched.
But have you actually called AudioDeviceStart on the device you are
going to read from? This is absolutely required in order to engage the
device's timing services. You can pass NULL as the IOProc to just start
things up if you don't have an IOProc.
Is the address of the AudioBufferList you are passing to
AudioDeviceRead() the same as the one that you registered with
kAudioDevicePropertyRegisterBufferList?
I double-checked the addresses of the AudioBufferList and they
matched, too.
Does the device you are reading from really have inputs?
I checked that.
Is the time stamp valid and for a time far enough in the past?
Maybe that could be the error. I start with
AudioDeviceGetCurrentTime()
- AudioDeviceGetProperty (... kAudioDevicePropertySafetyOffset ...)
- totalReadBufferLength / frameSize
Does that make sense?
That should be reasonable, except if the device isn't running, you
won't be getting valid time stamps.
You should also take a look at the PlayEffect sample code to see an
example of how it's done.
--
Jeff Moore
Core Audio
Apple
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