diff --git a/src/previous-map.js b/src/previous-map.js
index 24c7a42..ffc1f79 100644
--- a/src/previous-map.js
+++ b/src/previous-map.js
@@ -36,8 +36,10 @@ export default class PreviousMap {
     }
 
     decodeInline(text) {
+        let utfd64 = 'data:application/json;charset=utf-8;base64,';
+        let utf64  = 'data:application/json;charset=utf8;base64,';
+        let b64    = 'data:application/json;base64,';
         let uri    = 'data:application/json,';
-        let base64 = 'data:application/json;base64,';
 
         if ( this.startWith(text, uri) ) {
             return decodeURIComponent( text.substr(uri.length) );
@@ -45,6 +47,12 @@ export default class PreviousMap {
         } else if ( this.startWith(text, base64) ) {
             return Base64.decode( text.substr(base64.length) );
 
+        } else if ( this.startWith(text, utf64) ) {
+            return Base64.decode( text.substr(utf64.length) );
+
+        } else if ( this.startWith(text, utfd64) ) {
+            return Base64.decode( text.substr(utfd64.length) );
+
         } else {
             let encoding = text.match(/data:application\/json;([^,]+),/)[1];
             throw new Error('Unsupported source map encoding ' + encoding);