freeswitch/conf/autoload_configs/local_stream.conf.xml

<configuration name="local_stream.conf" description="stream files from local dir">
  <directory name="moh/8000" path="$${base_dir}/sounds/music/8000">
    <param name="rate" value="8000"/>
    <param name="shuffle" value="true"/>
    <param name="channels" value="1"/>
    <param name="interval" value="20"/>
    <param name="timer_name" value="soft"/>
  </directory>

  <directory name="moh/16000" path="$${base_dir}/sounds/music/16000">
    <param name="rate" value="16000"/>
    <param name="shuffle" value="true"/>
    <param name="channels" value="1"/>
    <param name="interval" value="20"/>
    <param name="timer_name" value="soft"/>
  </directory>
</configuration>