diff --git a/web/worker/cdimage.ts b/web/worker/cdimage.ts
index 8a37d0c..ac8e29f 100644
--- a/web/worker/cdimage.ts
+++ b/web/worker/cdimage.ts
@@ -1,3 +1,5 @@
+importScripts('text-decoder.js');
+
 class ISO9660FileSystem {
     private pvd: PVD;
 
diff --git a/web/worker/text-decoder.ts b/web/worker/text-decoder.ts
new file mode 100644
index 0000000..c39a0a0
--- /dev/null
+++ b/web/worker/text-decoder.ts
@@ -0,0 +1,18 @@
+class FallbackTextDecoder {
+    constructor(utfLabel?: string) {}
+
+    decode(buffer: DataView): string {
+        var out = '';
+        for (var i = 0; i < buffer.byteLength; i++) {
+            let c = buffer.getUint8(i);
+            if (c < 128)
+                out += String.fromCharCode(c);
+            else
+                out += '%' + c.toString(16);
+        }
+        return out;
+    }
+}
+
+if (!(<any>self).TextDecoder)
+    (<any>self).TextDecoder = <TextEncoding.TextDecoderStatic>FallbackTextDecoder;