How to create an audio fade in effect with UWP AudioGraph?

Question

I have an app that plays audio files. When the user starts audio playback, I want the audio to fade in from effectively 0 volume to 1 over a duration of 300ms or something like that.

I've been playing with the AudioGraph sample from GitHub and I learned that there's a Limiter effect that can control the loudness of an audio. How can I use this to change the loudness of an audio file over a duration of 300ms?

Or is there another way I can implement a fade effect?

Answer 1

How can I use this to change the loudness of an audio file over a duration of 300ms?

You can use a timer to control the loudness when starting audio playback. This is a test I conducted in the official sample(Scenario5_InboxEffects.xaml.cs), and the effect is very good. The code is as follows.

 //Scenario5_InboxEffects.xaml.cs

 private void TogglePlay()
 {
     if (graphButton.Content.Equals("Start Graph"))
     {
         graph.Start();
         graphButton.Content = "Stop Graph";
         audioPipe.Fill = new SolidColorBrush(Colors.Blue);
         //just for a test
         FadeEffect(300, 1, 1500);
     }
     ....
 }

private async void FadeEffect(int delay, uint startLoudness, uint endLoudness)
{
     
       for (int i = 1; i <= delay; i++)
       {
           var chip = (endLoudness - startLoudness) / (delay * 1.0) * i;
           limiterEffectDefinition.Loudness = (uint)(startLoudness + chip);
           limiterEffectDefinition.Release = 10;
           fileInputNode.EnableEffectsByDefinition(limiterEffectDefinition);
           await Task.Delay(1);
       }
}

Or is there another way I can implement a fade effect?

Sorry, there is currently no related API in Windows Runtime AudioGraph.