Enable async mode

Change-Id: Iabb6667850a181333a1c2bd7eeb95ddd592da42c
diff --git a/docker/Dockerfile b/docker/Dockerfile
index 882c5d0..7cfcbfa 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -25,4 +25,4 @@
      pip3 install -r requirements.txt
 
 ENTRYPOINT ["./bin/person_detection.sh"]
-CMD ["-i gstreamer"]
+CMD ["-i gstreamer -pt 0.75"]