From b09639b71d2fba1f553a4341d74200ade37056cc Mon Sep 17 00:00:00 2001
From: Emiliana <38952746+emilianavt@users.noreply.github.com>
Date: Fri, 22 May 2020 18:51:34 +0200
Subject: [PATCH] Lip sync should now be able to handle stereo audio where one
 track is silent, but Unity's microphone input is forced to mono audio
 anyways. It still improves things with canned audio.

---
 Examples/OpenSeeVRMDriver.cs | 28 ++++++++++++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/Examples/OpenSeeVRMDriver.cs b/Examples/OpenSeeVRMDriver.cs
index 0745462..1484227 100644
--- a/Examples/OpenSeeVRMDriver.cs
+++ b/Examples/OpenSeeVRMDriver.cs
@@ -806,8 +806,32 @@ public class OpenSeeVRMDriver : MonoBehaviour {
             return;
         
         audioVolume = 0f;
-        foreach (float v in buffer)
-            audioVolume += Mathf.Abs(v);
+        float leftVolume = 0f;
+        float rightVolume = 0f;
+        bool channel = false;
+        foreach (float v in buffer) {
+            float sample = Mathf.Abs(v);
+            audioVolume += sample;
+            if (channels > 1) {
+                if (channel)
+                    rightVolume += sample;
+                channel = !channel;
+            }
+        }
+        if (channels > 1) {
+            leftVolume = audioVolume - rightVolume;
+            if (rightVolume < leftVolume / 3f) {
+                audioVolume = 2f * leftVolume;
+                for (int i = 0; i + 1 < buffer.Length; i += 2) {
+                    buffer[i + 1] = buffer[i];
+                }
+            } else if (leftVolume < rightVolume / 3f) {
+                audioVolume = 2f * rightVolume;
+                for (int i = 0; i + 1 < buffer.Length; i += 2) {
+                    buffer[i] = buffer[i + 1];
+                }
+            }
+        }
         audioVolume /= buffer.Length;
 
         int totalLen = partialPos + buffer.Length;