From 09ed0e1f302b050e3fd76906018235802254a1f1 Mon Sep 17 00:00:00 2001
From: Alexey Khit <alexey.khit@gmail.com>
Date: Wed, 28 Jul 2021 16:50:21 +0300
Subject: [PATCH] Adds support SDP Plan B fallback

---
 format/webrtcv3/adapter.go | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/format/webrtcv3/adapter.go b/format/webrtcv3/adapter.go
index 1c66a45..06269db 100644
--- a/format/webrtcv3/adapter.go
+++ b/format/webrtcv3/adapter.go
@@ -93,7 +93,9 @@ func (element *Muxer) WriteHeader(streams []av.CodecData, sdp64 string) (string,
 		Type: webrtc.SDPTypeOffer,
 		SDP:  string(sdpB),
 	}
-	peerConnection, err := element.NewPeerConnection(webrtc.Configuration{})
+	peerConnection, err := element.NewPeerConnection(webrtc.Configuration{
+		SDPSemantics: webrtc.SDPSemanticsUnifiedPlanWithFallback,
+	})
 	if err != nil {
 		return "", err
 	}