private com.google.protobuf.SingleFieldBuilderV3<
            com.google.protobuf.Duration,
            com.google.protobuf.Duration.Builder,
            com.google.protobuf.DurationOrBuilder>
        getDurationFieldBuilder() {
      if (durationBuilder_ == null) {
        durationBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.protobuf.Duration,
                com.google.protobuf.Duration.Builder,
                com.google.protobuf.DurationOrBuilder>(
                getDuration(), getParentForChildren(), isClean());
        duration_ = null;
      }
      return durationBuilder_;
    }
<pre>
Duration in seconds of the ad.
</pre>

<code>.google.protobuf.Duration duration = 1;</code>
java-video-stitcher/proto-google-cloud-video-stitcher-v1/src/main/java/com/google/cloud/video/stitcher/v1/VodSessionAd.java