diff --git a/app.js b/app.js
index e39c1dc..9e5f3f9 100644
--- a/app.js
+++ b/app.js
@@ -97,7 +97,7 @@ const mediaCodecs = [
     // clockRate: 48000,
     // channels: 2,
     clockRate: 48000,
-		mimeType: "audio/opus",
+		mimeType: "audio/webm;codecs=opus", // https://developer.mozilla.org/en-US/docs/Web/Media/Formats/WebRTC_codecs#supported_audio_codecs
 		parameters: {
 			minptime: 10,
 			useinbandfec: 1
@@ -109,7 +109,7 @@ const mediaCodecs = [
   },
   {
     kind: 'video',
-    mimeType: 'video/VP8',
+    mimeType: 'video/VP8', // https://developer.mozilla.org/en-US/docs/Web/Media/Formats/WebRTC_codecs#supported_video_codecs
     clockRate: 90000,
     parameters: {
       'x-google-start-bitrate': 1000,