[Experiment] Alpha Channel Support

modules/rtp_rtcp/source/rtp_payload_registry.cc

Index: modules/rtp_rtcp/source/rtp_payload_registry.cc
diff --git a/modules/rtp_rtcp/source/rtp_payload_registry.cc b/modules/rtp_rtcp/source/rtp_payload_registry.cc
index 6619f5c28e9c3dd02b8b417e96bd4570a9f4441b..3a9734f3a925d6f5722892dabb8a4ef9f2268e5c 100644
--- a/modules/rtp_rtcp/source/rtp_payload_registry.cc
+++ b/modules/rtp_rtcp/source/rtp_payload_registry.cc
@@ -68,6 +68,8 @@ RtpVideoCodecTypes ConvertToRtpVideoCodecType(VideoCodecType type) {
     case kVideoCodecRED:
     case kVideoCodecULPFEC:
       return kRtpVideoNone;
+    case kVideoCodecStereo:
+      return kRtpVideoStereo;
     default:
       return kRtpVideoGeneric;
   }