diff --git a/src/ogg.js b/src/ogg.js
index ea757ce..0eae164 100644
--- a/src/ogg.js
+++ b/src/ogg.js
@@ -4,38 +4,42 @@ var AV = require('av');
 try {
   var OggDemuxer = require('ogg.js');
 } catch (e) {};
-if (!OggDemuxer) return;
-
-OggDemuxer.plugins.push({
-  magic: "\177FLAC",
-  
-  init: function() {
-    this.list = new AV.BufferList();
-    this.stream = new AV.Stream(this.list);
-  },
-  
-  readHeaders: function(packet) {
-    var stream = this.stream;
-    this.list.append(new AV.Buffer(packet));
-    
-    stream.advance(5); // magic
-    if (stream.readUInt8() != 1)
-      throw new Error('Unsupported FLAC version');
-      
-    stream.advance(3);
-    if (stream.peekString(0, 4) != 'fLaC')
-      throw new Error('Not flac');
-      
-    this.flac = AV.Demuxer.find(stream.peekSingleBuffer(0, stream.remainingBytes()));
-    if (!this.flac)
-      throw new Error('Flac demuxer not found');
-    
-    this.flac.prototype.readChunk.call(this);
-    return true;
-  },
-  
-  readPacket: function(packet) {
-    this.list.append(new AV.Buffer(packet));
-    this.flac.prototype.readChunk.call(this);
-  }
-});
+
+// return calling outside a function will be not proper.
+// if (!OggDemuxer) return;
+
+if (OggDemuxer) {
+  OggDemuxer.plugins.push({
+    magic: "\177FLAC",
+
+    init: function() {
+      this.list = new AV.BufferList();
+      this.stream = new AV.Stream(this.list);
+    },
+
+    readHeaders: function(packet) {
+      var stream = this.stream;
+      this.list.append(new AV.Buffer(packet));
+
+      stream.advance(5); // magic
+      if (stream.readUInt8() != 1)
+        throw new Error('Unsupported FLAC version');
+
+      stream.advance(3);
+      if (stream.peekString(0, 4) != 'fLaC')
+        throw new Error('Not flac');
+
+      this.flac = AV.Demuxer.find(stream.peekSingleBuffer(0, stream.remainingBytes()));
+      if (!this.flac)
+        throw new Error('Flac demuxer not found');
+
+      this.flac.prototype.readChunk.call(this);
+      return true;
+    },
+
+    readPacket: function(packet) {
+      this.list.append(new AV.Buffer(packet));
+      this.flac.prototype.readChunk.call(this);
+    }
+  });
+}