diff --git a/src/descriptor.js b/src/descriptor.js
index a8d8b13e..db5cb0a3 100644
--- a/src/descriptor.js
+++ b/src/descriptor.js
@@ -160,6 +160,13 @@ var MPEG4DescriptorParser = function () {
 	return this;
 }
 
+var MPEG4DescriptorWriter = function (descriptor) {
+	this.writeOneDescriptor = function (stream) {
+		// TODO: implement
+	}
+}
+
 if (typeof exports !== 'undefined') {
 	exports.MPEG4DescriptorParser = MPEG4DescriptorParser;
+	exports.MPEG4DescriptorWriter = MPEG4DescriptorWriter;
 }
diff --git a/src/parsing/esds.js b/src/parsing/esds.js
index 966a7566..8987e092 100644
--- a/src/parsing/esds.js
+++ b/src/parsing/esds.js
@@ -1,5 +1,5 @@
-BoxParser.createFullBoxCtor("esds", function(stream) {
-	var esd_data = stream.readUint8Array(this.size-this.hdr_size);
+BoxParser.createFullBoxCtor("esds", function (stream) {
+	var esd_data = stream.readUint8Array(this.size - this.hdr_size);
 	if (typeof MPEG4DescriptorParser !== "undefined") {
 		var esd_parser = new MPEG4DescriptorParser();
 		this.esd = esd_parser.parseOneDescriptor(new DataStream(esd_data.buffer, 0, DataStream.BIG_ENDIAN));
diff --git a/src/writing/esds.js b/src/writing/esds.js
new file mode 100644
index 00000000..694a8b5e
--- /dev/null
+++ b/src/writing/esds.js
@@ -0,0 +1,10 @@
+BoxParser.esdsBox.prototype.write = function(stream) {
+	this.version = 0;
+	this.flags = 0;
+	this.size = this.esd.size;
+	this.writeHeader(stream);
+	if (typeof MPEG4DescriptorWriter !== "undefined") {
+		var esd_writer = new MPEG4DescriptorWriter(this.esd);
+		esd_writer.writeOneDescriptor(stream);
+	}
+}
\ No newline at end of file