Process & capture on audio thread

Author: ladvoc

Runtime/Scripts/ApmReverseStream.cs

@@ -1,4 +1,3 @@
-using System.Threading;
 using LiveKit.Internal;
 using UnityEngine;
 
@@ -14,7 +13,6 @@ internal class ApmReverseStream
     {
         private readonly AudioBuffer _captureBuffer = new AudioBuffer();
         private readonly AudioProcessingModule _apm; // APM is thread safe
-        private Thread _thread;
         private AudioFilter _audioFilter;
 
         internal ApmReverseStream(AudioProcessingModule apm)
@@ -32,32 +30,24 @@ internal void Start()
             }
             _audioFilter = audioListener.gameObject.AddComponent<AudioFilter>();
             _audioFilter.AudioRead += OnAudioRead;
-
-            _thread = new Thread(ProcessReverseStream);
-            _thread.Start();
         }
 
         internal void Stop()
         {
-            _thread?.Abort();
             if (_audioFilter != null)
                 Object.Destroy(_audioFilter);
         }
 
-        private void ProcessReverseStream()
+        private void OnAudioRead(float[] data, int channels, int sampleRate)
         {
+            _captureBuffer.Write(data, (uint)channels, (uint)sampleRate);
             while (true)
             {
-                Thread.Sleep(Constants.TASK_DELAY);
                 using var frame = _captureBuffer.ReadDuration(AudioProcessingModule.FRAME_DURATION_MS);
-                if (frame == null) continue;
+                if (frame == null) break;
+
                 _apm.ProcessReverseStream(frame);
             }
         }
-
-        private void OnAudioRead(float[] data, int channels, int sampleRate)
-        {
-            _captureBuffer.Write(data, (uint)channels, (uint)sampleRate);
-        }
     }
 }

Runtime/Scripts/RtcAudioSource.cs

@@ -2,7 +2,6 @@
 using System.Collections;
 using LiveKit.Proto;
 using LiveKit.Internal;
-using System.Threading;
 using LiveKit.Internal.FFIClients.Requests;
 using UnityEngine;
 
@@ -43,7 +42,6 @@ public abstract class RtcAudioSource : IRtcSource
         protected AudioSourceInfo _info;
 
         // Possibly used on the AudioThread
-        private Thread _readAudioThread;
         private AudioBuffer _captureBuffer = new AudioBuffer();
         private readonly AudioProcessingModule _apm;
         private readonly ApmReverseStream _apmReverseStream;
@@ -84,42 +82,31 @@ public IEnumerator PrepareAndStart()
         public void Start()
         {
             Stop();
-            _readAudioThread = new Thread(Update);
-            _readAudioThread.Start();
             _apmReverseStream?.Start();
             AudioRead += OnAudioRead;
             Play();
         }
 
         public virtual void Stop()
         {
-            _readAudioThread?.Abort();
             _apmReverseStream?.Stop();
             AudioRead -= OnAudioRead;
         }
 
-        private void Update()
+        private void OnAudioRead(float[] data, int channels, int sampleRate)
         {
+            _captureBuffer.Write(data, (uint)channels, (uint)sampleRate);
             while (true)
             {
-                Thread.Sleep(Constants.TASK_DELAY);
                 var frame = _captureBuffer.ReadDuration(AudioProcessingModule.FRAME_DURATION_MS);
-                if (_muted || frame == null) continue;
+                if (_muted || frame == null) break;
 
-                if (_apm != null)
-                    _apm.ProcessStream(frame);
+                if (_apm != null) _apm.ProcessStream(frame);
                 Capture(frame);
             }
-        }
-
-        private void OnAudioRead(float[] data, int channels, int sampleRate)
-        {
-            _captureBuffer.Write(data, (uint)channels, (uint)sampleRate);
+            // Don't play the audio locally, to avoid echo.
             if (_sourceType == RtcAudioSourceType.AudioSourceMicrophone)
-            {
-                // Don't play the audio locally, to avoid echo.
                 Array.Clear(data, 0, data.Length);
-            }
         }
 
         private void Capture(AudioFrame frame)