private void RegisterStreamCallback()
{
_streamCallback = (IntPtr handle, uint bytes, IntPtr _) =>
{
BufferAvailable?.Invoke(this, new AudioPlaybackBufferAvailableEventArgs((int)bytes));
};
AudioOutput.SetStreamChangedCallback(_handle, _streamCallback, IntPtr.Zero)
.ThrowIfFailed("Failed to set stream changed callback.");
}
private void RegisterStreamCallback()
{
_streamCallback = (IntPtr handle, uint bytes, IntPtr _) =>
{
BufferAvailable?.Invoke(this, new AudioPlaybackBufferAvailableEventArgs((int)bytes));
};
AudioIOUtil.ThrowIfError(
AudioOutput.SetStreamChangedCallback(_handle, _streamCallback, IntPtr.Zero),
$"Failed to create {nameof(AudioPlayback)}");
}
internal static extern int SetStreamChangedCallback(IntPtr handle, AudioStreamCallback callback, IntPtr user_data);
internal static extern RecorderErrorCode SetAudioStreamCallback(RecorderHandle handle,
AudioStreamCallback callback, IntPtr userData);
internal static extern AudioIOError SetStreamCallback(IntPtr handle, AudioStreamCallback callback, IntPtr user_data);
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
// Set our view from the "main" layout resource
SetContentView(Resource.Layout.Main);
// Get our button from the layout resource,
// and attach an event to it
Button button = FindViewById <Button> (Resource.Id.myButton);
double seconds_offset = 0.0;
int sample_rate = 48000;
double seconds_per_frame = 1.0 / (double)sample_rate;
double pitch = 440.0;
double radians_per_second = pitch * 2.0 * Math.PI;
double volume_rate = 4.0;
button.Click += delegate {
using (var builder = new AudioStreamBuilder()) {
builder.SharingMode = Natives.OboeSharingMode.Exclusive;
builder.Usage = Natives.OboeUsage.Media;
builder.PerformanceMode = Natives.OboePerformanceMode.LowLatency;
builder.AudioApi = Natives.OboeAudioApi.AAudio;
foreach (var pi in builder.GetType().GetProperties())
{
if (pi.GetMethod != null)
{
Console.Error.WriteLine($"Builder: {pi}: {pi.GetValue (builder)}");
}
}
var callbacks = new AudioStreamCallback();
AudioStream stream = null;
callbacks.AudioReady += (obj, audioData, numFrames) => {
Console.Error.WriteLine($"AUDIO READY: {obj} {numFrames}");
int channels = stream.ChannelCount;
// generate sine wave.
for (int frame = 0; frame < numFrames; frame++)
{
double sample = Math.Sin((seconds_offset + frame * seconds_per_frame) * radians_per_second) * volume_rate;
for (int ch = 0; ch < channels; ch++)
{
unsafe { *((float *)audioData + frame * channels + ch) = (float)sample; }
}
}
return(Natives.OboeDataCallbackResult.Continue);
};
builder.Callbacks = callbacks;
stream = builder.OpenStream();
foreach (var pi in stream.GetType().GetProperties())
{
if (pi.GetMethod != null)
{
Console.Error.WriteLine($"Stream: {pi}: {pi.GetValue (stream)}");
}
}
stream.Start();
Task.Delay(3000).Wait();
stream.Stop();
}
};
}