fix value check
fix value check

guoweis/webrtc,mauricionr/samples,fippo/webrtc,taylor-b/samples,webrtc/samples,taylor-b/samples,guoweis/webrtc,webrtc/samples,mauricionr/samples,samdutton/webrtc,mauricionr/samples,samdutton/webrtc,fippo/webrtc,guoweis/webrtc