private void ensureFaceAnnotationsIsMutable() {
      if (!((bitField0_ & 0x00000010) != 0)) {
        faceAnnotations_ =
            new java.util.ArrayList<com.google.cloud.videointelligence.v1beta2.FaceAnnotation>(
                faceAnnotations_);
        bitField0_ |= 0x00000010;
      }
    }
<pre>
Label annotations on frame level.
There is exactly one element for each unique label.
</pre>

<code>
repeated .google.cloud.videointelligence.v1beta2.LabelAnnotation frame_label_annotations = 4;
</code>
java-video-intelligence/proto-google-cloud-video-intelligence-v1beta2/src/main/java/com/google/cloud/videointelligence/v1beta2/VideoAnnotationResults.java