From 96819abcf2275a40984ab442cece106e51c86f3e Mon Sep 17 00:00:00 2001
From: ValueOn AG <p.motsch@valueon.ch>
Date: Sat, 7 Mar 2026 02:12:20 +0100
Subject: [PATCH] fix: Audio-Chunk Overlap - 1s Pre-Roll nach gesendeten Chunks
 behalten, STT Wortanfang nicht abschneiden

Made-with: Cursor
---
 src/bot/audioCaptureProcedure.ts | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/bot/audioCaptureProcedure.ts b/src/bot/audioCaptureProcedure.ts
index 293978d..3e9a670 100644
--- a/src/bot/audioCaptureProcedure.ts
+++ b/src/bot/audioCaptureProcedure.ts
@@ -23,7 +23,7 @@ class AudioCaptureProcessor extends AudioWorkletProcessor {
     this.targetRate = opts.targetRate || 16000;
     this.maxSamplesPerChunk = this.nativeRate * 8;
     this.minRmsThreshold = 0.0003;
-    this.preRollSamples = Math.ceil(this.nativeRate * 0.5);
+    this.preRollSamples = Math.ceil(this.nativeRate * 1.0);
     this.minFlushSamples = Math.ceil(this.nativeRate * 0.5);
     this.silenceFlushCallbacks = 6;
     this.ratio = this.nativeRate / this.targetRate;
@@ -99,8 +99,10 @@ class AudioCaptureProcessor extends AudioWorkletProcessor {
         return true;
       }
 
-      this.chunkBuffer = [];
-      this.samplesCollected = 0;
+      const keep = Math.min(this.preRollSamples, merged.length);
+      const preRoll = merged.slice(merged.length - keep);
+      this.chunkBuffer = [preRoll];
+      this.samplesCollected = keep;
     }
     return true;
   }
@@ -274,7 +276,7 @@ export class AudioCaptureProcedure {
             const useScriptProcessor = () => {
               const minRmsThreshold = 0.0003;
               const maxSamplesPerChunk = nativeRate * 8;
-              const preRollSamples = Math.ceil(nativeRate * 0.5);
+              const preRollSamples = Math.ceil(nativeRate * 1.0);
               const minFlushSamples = Math.ceil(nativeRate * 0.5);
               const silenceFlushCallbacks = 6;
               const ratio = nativeRate / targetRate;
@@ -348,8 +350,10 @@ export class AudioCaptureProcedure {
                     samplesCollected = keep;
                     return;
                   }
-                  chunkBuffer = [];
-                  samplesCollected = 0;
+                  const keep = Math.min(preRollSamples, merged.length);
+                  const preRoll = merged.slice(merged.length - keep);
+                  chunkBuffer = [preRoll];
+                  samplesCollected = keep;
                 }
               };