v=0
o=- 0 0 IN IP4 127.0.0.1
s=No Name
c=IN IP4 127.0.0.1
t=0 0
a=tool:libavformat 58.29.100
m=audio 1234 RTP/AVP 97
b=AS:800
a=rtpmap:97 PCMU/32000/2