diff --git a/.gitignore b/.gitignore
index 08e8372..bb92dfd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,4 @@ Playback-win32.zip
 Playback.app
 Playback.app.zip
 .DS_Store
+.idea
diff --git a/playlist.js b/playlist.js
index 5e666b9..41e4f11 100644
--- a/playlist.js
+++ b/playlist.js
@@ -10,6 +10,8 @@ var concat = require('concat-stream')
 
 var noop = function () {}
 
+var allowedExts = ['mpg', 'mkv', 'mp4', 'mp3', 'vtt', 'srt']
+
 module.exports = function () {
   var that = new events.EventEmitter()
 
@@ -141,6 +143,9 @@ module.exports = function () {
 
       file.length = st.size
       file.name = path.basename(link)
+      file.extension = file.name.split(".").pop().toLowerCase()
+      if (allowedExts.indexOf(file.extension) === -1) return cb("File format not supported")
+
       file.createReadStream = function (opts) {
         return fs.createReadStream(link, opts)
       }