private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.video.livestream.v1.AudioStream,
            com.google.cloud.video.livestream.v1.AudioStream.Builder,
            com.google.cloud.video.livestream.v1.AudioStreamOrBuilder>
        getAudioStreamFieldBuilder() {
      if (audioStreamBuilder_ == null) {
        if (!(elementaryStreamCase_ == 2)) {
          elementaryStream_ = com.google.cloud.video.livestream.v1.AudioStream.getDefaultInstance();
        }
        audioStreamBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.video.livestream.v1.AudioStream,
                com.google.cloud.video.livestream.v1.AudioStream.Builder,
                com.google.cloud.video.livestream.v1.AudioStreamOrBuilder>(
                (com.google.cloud.video.livestream.v1.AudioStream) elementaryStream_,
                getParentForChildren(),
                isClean());
        elementaryStream_ = null;
      }
      elementaryStreamCase_ = 2;
      onChanged();
      return audioStreamBuilder_;
    }
<pre>
Encoding of an audio stream.
</pre>

<code>.google.cloud.video.livestream.v1.AudioStream audio_stream = 2;</code>
java-video-live-stream/proto-google-cloud-live-stream-v1/src/main/java/com/google/cloud/video/livestream/v1/ElementaryStream.java