Re: Input callback only getting called every couple of seconds.
Re: Input callback only getting called every couple of seconds.
- Subject: Re: Input callback only getting called every couple of seconds.
- From: Jeff Moore <email@hidden>
- Date: Fri, 8 Dec 2006 14:33:40 -0800
As far as I can tell, my iSight only supports a sample rate of 48K.
So, I'd expect that you'd get a kAudioDeviceUnsupportedFormatError
error trying to set the sample rate to 8K. Did you get an error? If
not, you should file a bug. The proper work around would be to ask the
device for it's list of supported sample rates and pick one from the
list.
In fact, you might want to do that anyway in the name of being
compatible with lots of input devices rather than just assuming the
rate you want is supported. Very few devices are going to support a
sample rate of 8K these days.
On Dec 8, 2006, at 2:10 PM, Bill Cunning wrote:
I have run into something interesting, and I don't have a clue where
to
start looking for the problem.
I am capturing voice from mic, and after some initial flailing about
(coming from windows) I got it all working with a usb headset/mic.
Yesterday I hooked up an isight camera/mic combination, and ran into
this problem.
As I set up the audio unit, everything works without error except the
call to set default sample rate
--AudioDeviceSetProperty(id,
0,0,1,kAudioDevicePropertyNominalSampleRate,
size,&rate) where rate = 8000. I expected this and will downsample the
captured audio to get it to the desired sample rate. Continued setup
of
the device all appears to work fine (err always = 0 on the various
calls) and the mic does appear to capture data, the problem is that
the
input callback is only getting called about every 1.8 seconds, but the
buffers only contain about 16 ms of data. If I switch back to the
headset mic id and restart, the callback is called as expected.
I expect I am missing something obvious here, but I can't see it :)
--
Jeff Moore
Core Audio
Apple
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