Handle stereo audio correctly

src/hooks/useTranscriber.ts

@@ -147,8 +147,25 @@ export function useTranscriber(): Transcriber {
             if (audioData) {
                 setTranscript(undefined);
                 setIsBusy(true);
+
+                let audio;
+                if (audioData.numberOfChannels === 2) {
+                    const SCALING_FACTOR = Math.sqrt(2);
+
+                    let left = audioData.getChannelData(0);
+                    let right = audioData.getChannelData(1);
+
+                    audio = new Float32Array(left.length);
+                    for (let i = 0; i < audioData.length; ++i) {
+                        audio[i] = SCALING_FACTOR * (left[i] + right[i]) / 2;
+                    }
+                } else {
+                    // If the audio is not stereo, we can just use the first channel:
+                    audio = audioData.getChannelData(0);
+                }
+
                 webWorker.postMessage({
-                    audio: audioData.getChannelData(0),
+                    audio,
                     model,
                     multilingual,
                     quantized,