diff --git a/dev/player.html b/dev/player.html
index 9c2e4a3..bc930c2 100644
--- a/dev/player.html
+++ b/dev/player.html
@@ -43,10 +43,10 @@ console.log(await input.getMimeType())
 let videoTrack = await input.getPrimaryVideoTrack(); 
 let audioTrack = await input.getPrimaryAudioTrack(); 
 
-if (!(await videoTrack.canDecode())) {
+if (!(await videoTrack?.canDecode())) {
 	videoTrack = null;
 }
-if (!(await audioTrack.canDecode())) {
+if (!(await audioTrack?.canDecode())) {
 	audioTrack = null;	
 }
 
diff --git a/todo.txt b/todo.txt
index fc2f829..2ed9e18 100644
--- a/todo.txt
+++ b/todo.txt
@@ -2,4 +2,5 @@
 - Throw if edit list detected
 - Add the new audio codecs to muxers
 - Mov muxer!!! Only mov can hold PCM audio, MP4 cannot
-- Metadata methods for computing average fps and bitrate
\ No newline at end of file
+- Metadata methods for computing average fps and bitrate
+- A stream source?? Or like a callback-driven source
\ No newline at end of file