private com.google.protobuf.SingleFieldBuilderV3<
            com.google.protobuf.Duration,
            com.google.protobuf.Duration.Builder,
            com.google.protobuf.DurationOrBuilder>
        getStartTimeOffsetFieldBuilder() {
      if (startTimeOffsetBuilder_ == null) {
        startTimeOffsetBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.protobuf.Duration,
                com.google.protobuf.Duration.Builder,
                com.google.protobuf.DurationOrBuilder>(
                getStartTimeOffset(), getParentForChildren(), isClean());
        startTimeOffset_ = null;
      }
      return startTimeOffsetBuilder_;
    }
<pre>
Time-offset, relative to the beginning of the video,
corresponding to the start of the segment (inclusive).
</pre>

<code>.google.protobuf.Duration start_time_offset = 1;</code>
java-video-intelligence/proto-google-cloud-video-intelligence-v1p1beta1/src/main/java/com/google/cloud/videointelligence/v1p1beta1/VideoSegment.java