Tvheadend

Hi guys
i want to stream udp multicast to http because i want to put it in a html5 video. it would look like this
<video width=800px height=600px controls><source src='http://192.168.1.2:9981/play/stream/channel/960b0a5146f2144c6458cf804379950b' type='video/webm'></video> the video is working very well no problem with it,
but i dont get sound ,is mute ,i nkown i'm missing something in my conguration and i dont what is't.
please help me
thanks in advance
i hope you can read me