public java.lang.String getAudioTopic() {
      java.lang.Object ref = audioTopic_;
      if (!(ref instanceof java.lang.String)) {
        com.google.protobuf.ByteString bs = (com.google.protobuf.ByteString) ref;
        java.lang.String s = bs.toStringUtf8();
        audioTopic_ = s;
        return s;
      } else {
        return (java.lang.String) ref;
      }
    }
<pre>
Description of the content. Eg. "Recordings of federal supreme court
hearings from 2012".
</pre>

<code>string audio_topic = 10;</code>

@return The audioTopic.
java-speech/proto-google-cloud-speech-v1/src/main/java/com/google/cloud/speech/v1/RecognitionMetadata.java