diff --git a/client.go b/client.go
index 9583638c..84ca17e5 100644
--- a/client.go
+++ b/client.go
@@ -1382,7 +1382,7 @@ func (c *Client) doSetup(
 
 func (c *Client) isChannelPairInUse(channel int) bool {
 	for _, cm := range c.medias {
-		if cm.tcpChannel == channel || cm.tcpChannel == (channel+1) {
+		if (cm.tcpChannel+1) == channel || cm.tcpChannel == channel || cm.tcpChannel == (channel+1) {
 			return true
 		}
 	}
diff --git a/server_session.go b/server_session.go
index 03192f60..07901846 100644
--- a/server_session.go
+++ b/server_session.go
@@ -1115,7 +1115,7 @@ func (ss *ServerSession) handleRequestInner(sc *ServerConn, req *base.Request) (
 
 func (ss *ServerSession) isChannelPairInUse(channel int) bool {
 	for _, sm := range ss.setuppedMedias {
-		if sm.tcpChannel == channel || sm.tcpChannel == (channel+1) {
+		if (sm.tcpChannel+1) == channel || sm.tcpChannel == channel || sm.tcpChannel == (channel+1) {
 			return true
 		}
 	}