diff --git a/src/parsing/saio.js b/src/parsing/saio.js
index 23293376..1e200b44 100644
--- a/src/parsing/saio.js
+++ b/src/parsing/saio.js
@@ -1,6 +1,6 @@
 BoxParser.createFullBoxCtor("saio", function(stream) {
 	if (this.flags & 0x1) {
-		this.aux_info_type = stream.readUint32();
+		this.aux_info_type = stream.readString(4);
 		this.aux_info_type_parameter = stream.readUint32();
 	}
 	var count = stream.readUint32();
diff --git a/src/parsing/saiz.js b/src/parsing/saiz.js
index 06a6cb50..90fc2740 100644
--- a/src/parsing/saiz.js
+++ b/src/parsing/saiz.js
@@ -1,6 +1,6 @@
 BoxParser.createFullBoxCtor("saiz", function(stream) {
 	if (this.flags & 0x1) {
-		this.aux_info_type = stream.readUint32();
+		this.aux_info_type = stream.readString(4);
 		this.aux_info_type_parameter = stream.readUint32();
 	}
 	this.default_sample_info_size = stream.readUint8();