private com.google.protobuf.RepeatedFieldBuilderV3<
            com.google.cloud.videointelligence.v1beta2.NormalizedBoundingBox,
            com.google.cloud.videointelligence.v1beta2.NormalizedBoundingBox.Builder,
            com.google.cloud.videointelligence.v1beta2.NormalizedBoundingBoxOrBuilder>
        getNormalizedBoundingBoxesFieldBuilder() {
      if (normalizedBoundingBoxesBuilder_ == null) {
        normalizedBoundingBoxesBuilder_ =
            new com.google.protobuf.RepeatedFieldBuilderV3<
                com.google.cloud.videointelligence.v1beta2.NormalizedBoundingBox,
                com.google.cloud.videointelligence.v1beta2.NormalizedBoundingBox.Builder,
                com.google.cloud.videointelligence.v1beta2.NormalizedBoundingBoxOrBuilder>(
                normalizedBoundingBoxes_,
                ((bitField0_ & 0x00000001) != 0),
                getParentForChildren(),
                isClean());
        normalizedBoundingBoxes_ = null;
      }
      return normalizedBoundingBoxesBuilder_;
    }
<pre>
Normalized Bounding boxes in a frame.
There can be more than one boxes if the same face is detected in multiple
locations within the current frame.
</pre>

<code>
repeated .google.cloud.videointelligence.v1beta2.NormalizedBoundingBox normalized_bounding_boxes = 1;
</code>
java-video-intelligence/proto-google-cloud-video-intelligence-v1beta2/src/main/java/com/google/cloud/videointelligence/v1beta2/FaceFrame.java