pcmreadcallback never is called during playback

Unity
1

Hello Guys,

I’m writing a Unity class to playback and capture audio data from a microphone.
Playback part works fine I can hear my voice in the headphones but I cannot access audio samples because pcmsetposcallback is never called during playback.
It is called only once inside createSound method.
I think i’m missing some setting , also tried several OR combinations for FMOD.MODE flag but with no luck.

Thanks in advance.
Walter

public class AudioInit : MonoBehaviour {

FMOD.System lowlevel = null;
FMOD.Sound snd = null;

// callbacks delegates
FMOD.SOUND_PCMREADCALLBACK pcmreadcallbackPtr = new FMOD.SOUND_PCMREADCALLBACK (pcmreadcallbackFunc);
FMOD.SOUND_PCMSETPOSCALLBACK pcmsetposcallbackPtr = new FMOD.SOUND_PCMSETPOSCALLBACK(pcmsetposcallbackFunc);
int driverId;

// Use this for initialization
void Start () {

	int channels = 1;
	int sampleRate = 8000;
	float recordTime = 1.0f;

	// get low level instance
	FMOD_StudioSystem.instance.System.getLowLevelSystem(out lowlevel);

	// fill sound info struct
	FMOD.CREATESOUNDEXINFO soundInfo = new FMOD.CREATESOUNDEXINFO ();		
	soundInfo.cbsize = System.Runtime.InteropServices.Marshal.SizeOf (typeof(FMOD.CREATESOUNDEXINFO));
	soundInfo.length  = (uint)(sampleRate * channels * sizeof(byte) * recordTime);		
	soundInfo.numchannels       = channels;
	soundInfo.defaultfrequency  = sampleRate;
	soundInfo.format            = FMOD.SOUND_FORMAT.PCM8;
	soundInfo.pcmreadcallback = pcmreadcallbackPtr;
	soundInfo.pcmsetposcallback = pcmsetposcallbackPtr;
	soundInfo.dlsname = IntPtr.Zero;

	// FMODE MODE flag
	FMOD.MODE mode = FMOD.MODE.OPENUSER | FMOD.MODE.LOOP_NORMAL;

	// create sound
	FMOD.RESULT res = lowlevel.createSound((string)null, mode, ref soundInfo, out snd);
	
	if (res != FMOD.RESULT.OK) {
		Debug.Log ("ERROR snd " + res.ToString ());
		return;
	}

	// get driver
	res = lowlevel.getDriver (out driverId);		
	if (res != FMOD.RESULT.OK) {
		Debug.Log ("ERROR getDriver " + res.ToString ());
		return;
	}

	// start record from microphone
	res = lowlevel.recordStart (driverId, snd, true);		
	if (res != FMOD.RESULT.OK) {
		Debug.Log ("ERROR recordStart " + res.ToString ());
		return;
	}

	uint pos = 0;
	uint tries = 10;
	// wait for a valid record position
	while ( !(pos > 0) && (tries--) > 0 ) {

		if ( lowlevel.getRecordPosition(driverId, out pos) == FMOD.RESULT.OK ){
			System.Threading.Thread.Sleep(100);
		} else { break; }
	}
	if ( !( pos > 0 )) {
		Debug.Log ("ERROR invalid record position");
		return;
	}

	// start playback
	FMOD.Channel chn;
	res = lowlevel.playSound (snd, new FMOD.ChannelGroup (IntPtr.Zero), false, out chn);

	if (res != FMOD.RESULT.OK) {
		Debug.Log ("ERROR recordStart " + res.ToString ());
		return;
	}


}

// not used
static FMOD.RESULT pcmsetposcallbackFunc(IntPtr soundraw, int subsound, uint position, FMOD.TIMEUNIT postype)
{
	return FMOD.RESULT.OK;
}

// only called once during lowlevel.createSound execution 
static FMOD.RESULT pcmreadcallbackFunc (IntPtr sound, IntPtr data, uint len){
	
	Debug.Log("pcmreadcallback sample size " + len.ToString());
	return FMOD.RESULT.OK;
}


// Update is called once per frame
void Update () {
}

}

2

Those callbacks aren’t what you want.

Each frame use System.getRecordPosition() to track how much audio has been recorded since the last frame, and then use Sound.@lock() to get a pointer to the data and copy it out. Be aware you’ll have to deal with the buffer wrapping around.