private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.videointelligence.v1p3beta1.NormalizedBoundingBox,
            com.google.cloud.videointelligence.v1p3beta1.NormalizedBoundingBox.Builder,
            com.google.cloud.videointelligence.v1p3beta1.NormalizedBoundingBoxOrBuilder>
        getNormalizedBoundingBoxFieldBuilder() {
      if (normalizedBoundingBoxBuilder_ == null) {
        normalizedBoundingBoxBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.videointelligence.v1p3beta1.NormalizedBoundingBox,
                com.google.cloud.videointelligence.v1p3beta1.NormalizedBoundingBox.Builder,
                com.google.cloud.videointelligence.v1p3beta1.NormalizedBoundingBoxOrBuilder>(
                getNormalizedBoundingBox(), getParentForChildren(), isClean());
        normalizedBoundingBox_ = null;
      }
      return normalizedBoundingBoxBuilder_;
    }
<pre>
The normalized bounding box location of this object track for the frame.
</pre>

<code>
.google.cloud.videointelligence.v1p3beta1.NormalizedBoundingBox normalized_bounding_box = 1;
</code>
java-video-intelligence/proto-google-cloud-video-intelligence-v1p3beta1/src/main/java/com/google/cloud/videointelligence/v1p3beta1/ObjectTrackingFrame.java