> Hi all,
> There was a thread about creating a custom AU to play a simple sine wave:
>
http://lists.apple.com/archives/coreaudio-api/2008/nov/msg00292.html
> I did the same thing and use the DefaultOutputUnit example from Apple sample
> to construct sine tone in callback:
> static OSStatus renderInput(void *inRefCon, AudioUnitRenderActionFlags
> *ioActionFlags,
> const AudioTimeStamp *inTimeStamp, UInt32 inBusNumber, UInt32
> inNumberFrames, AudioBufferList *ioData)
> {
> double frequency = 440.0;
> double j = 0.0;
> double cycleLength = kGraphSampleRate / frequency;
> SInt16 *toneBuffer = (SInt16 *)ioData->mBuffers[0].mData
> for (UInt32 frame; frame<512; ++frame)
> {
> Float32 nextFloat = sin(j/cycleLength * (M_PI*2.0)) ;
> toneBuffer[frame] = 32768.0*nextFloat;
> j += 1.0;
> if (j>cycleLength) {
> j = j - cycleLength;
> }
> }
> return noErr;
> }
> It works in iphone simulator, but :
> - the sound that comes out is "buzz saw" noise instead of a pure sine tone.
> - on a device, the sound only comes out of headphone, not through the
> speaker.
> Does any of you have similar issues?
>
>