record sounds in mono

HISTORY.md

@@ -8,6 +8,7 @@
 
 ### 2020-01-28
 * new dev version
+* gui: record sounds in mono
 
 ## 5.4.4:
 * **Notable Fixes**

src/gui.js

@@ -9805,8 +9805,14 @@ SoundRecorderDialogMorph.prototype.buildContents = function () {
     this.body.fixLayout();
 
     if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
-        navigator.mediaDevices.getUserMedia({ audio: true })
-            .then(function (stream) {
+        navigator.mediaDevices.getUserMedia(
+            {
+                audio: {
+                    channelCount: 1 // force mono, currently only works on FF
+                }
+                
+            }
+        ).then(function (stream) {
             myself.mediaRecorder = new MediaRecorder(stream);
             myself.mediaRecorder.ondataavailable = function (event) {
                 audioChunks.push(event.data);