From 61f7ad05e918cb50f962d03c955e53afc0ed0ad0 Mon Sep 17 00:00:00 2001
From: leo <260626284+cameledev@users.noreply.github.com>
Date: Wed, 10 Jun 2026 17:59:09 +0200
Subject: [PATCH] =?UTF-8?q?=F0=9F=90=9B(frontend)=20fix=20noise=20reductio?=
 =?UTF-8?q?n=20left-channel-only=20audio?=
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Fix bug with RNNoise noise reduction which interprets mono input
as left channel with some browsers.
---
 CHANGELOG.md                                          |  4 ++++
 .../rooms/livekit/processors/RnnNoiseProcessor.ts     | 11 ++++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 87491848..4cd090d7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,10 @@ and this project adheres to
 
 - ♻️(addon) improve Outlook add-on: i18n support, feedback link, smarter link
 
+### Fixed
+
+- 🐛(frontend) fix noise reduction left-channel-only audio
+
 ## [1.19.0] - 2026-06-04
 
 ### Added
diff --git a/src/frontend/src/features/rooms/livekit/processors/RnnNoiseProcessor.ts b/src/frontend/src/features/rooms/livekit/processors/RnnNoiseProcessor.ts
index 69a71009..d8324bdb 100644
--- a/src/frontend/src/features/rooms/livekit/processors/RnnNoiseProcessor.ts
+++ b/src/frontend/src/features/rooms/livekit/processors/RnnNoiseProcessor.ts
@@ -43,7 +43,16 @@ export class RnnNoiseProcessor implements AudioProcessorInterface {
 
     this.noiseSuppressionNode = new AudioWorkletNode(
       audioContext,
-      NoiseSuppressorWorklet_Name
+      NoiseSuppressorWorklet_Name,
+      {
+        // RNNoise is a mono algorithm. Its worklet only denoises and writes
+        // channel 0. Force any (possibly stereo) input to down-mix to a single
+        // channel and emit a single channel, so we don't produce a stereo frame
+        // whose right channel is left silent.
+        channelCount: 1,
+        channelCountMode: 'explicit',
+        outputChannelCount: [1],
+      }
     )
 
     this.destinationNode = audioContext.createMediaStreamDestination()