Add splitter/merger node to play channel specified by parameter

mdabbagh88 · Apr 1, 2016 · c7e96c3 · c7e96c3
1 parent fd6efe6
commit c7e96c3
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Showing 2 changed files with 30 additions and 2 deletions.
diff --git a/src/wavesurfer.js b/src/wavesurfer.js
@@ -301,6 +301,7 @@ var WaveSurfer = {
         this.params.channel = channel;
         this.drawer.clearWave();
         this.drawBuffer();
+        this.backend.setChannel(channel);
     },
 
     /**

diff --git a/src/webaudio.js b/src/webaudio.js
@@ -57,7 +57,7 @@ WaveSurfer.WebAudio = {
             });
             this.filters = null;
             // Reconnect direct path
-            this.analyser.connect(this.gainNode);
+            this.analyser.connect(this.splitter);
         }
     },
 
@@ -91,7 +91,7 @@ WaveSurfer.WebAudio = {
             filters.reduce(function (prev, curr) {
                 prev.connect(curr);
                 return curr;
-            }, this.analyser).connect(this.gainNode);
+            }, this.analyser).connect(this.splitter);
         }
 
     },
@@ -128,6 +128,30 @@ WaveSurfer.WebAudio = {
         this.scriptNode.onaudioprocess = null;
     },
 
+    createChannelNodes: function () {
+        var channels = this.buffer.numberOfChannels;
+
+        this.splitter = this.ac.createChannelSplitter(channels);
+        this.merger = this.ac.createChannelMerger(channels);
+
+        this.setChannel(this.params.channel);
+
+        this.analyser.disconnect();
+        this.analyser.connect(this.splitter);
+
+        this.merger.connect(this.gainNode);
+    },
+
+    setChannel: function (channel) {
+        var channels = this.buffer.numberOfChannels;
+
+        this.splitter.disconnect();
+
+        for (var c = 0; c < channels; c++) {
+            this.splitter.connect(this.merger, channel === -1 ? c : channel, c);
+        }
+    },
+
     createAnalyserNode: function () {
         this.analyser = this.ac.createAnalyser();
         this.analyser.connect(this.gainNode);
@@ -248,6 +272,8 @@ WaveSurfer.WebAudio = {
         this.disconnectSource();
         this.gainNode.disconnect();
         this.scriptNode.disconnect();
+        this.merger.disconnect();
+        this.splitter.disconnect();
         this.analyser.disconnect();
     },
 
@@ -256,6 +282,7 @@ WaveSurfer.WebAudio = {
         this.lastPlay = this.ac.currentTime;
         this.buffer = buffer;
         this.createSource();
+        this.createChannelNodes();
     },
 
     createSource: function () {