Send WS response on MJPEG or MP4 stream starts

cmd/mjpeg/mjpeg.go

@@ -121,6 +121,8 @@ func handlerWS(tr *api.Transport, _ *api.Message) error {
 		return err
 	}
 
+	tr.Write(&api.Message{Type: "mjpeg"})
+
 	tr.OnClose(func() {
 		stream.RemoveConsumer(cons)
 	})

cmd/mp4/ws.go

@@ -86,6 +86,8 @@ func handlerWSMP4(tr *api.Transport, msg *api.Message) error {
 		return err
 	}
 
+	tr.Write(&api.Message{Type: "mp4", Value: cons.MimeType})
+
 	tr.OnClose(func() {
 		stream.RemoveConsumer(cons)
 	})