title: How can i generate qcelp
body: <p>For a project needs to generate <code>rtp pcap</code> with codec <code>qcelp</code>.
  <code>ffmpeg</code> only can decode it but for send with <code>rtp ffmpeg</code> need encode with <code>qcelp</code>
  I think software simulation in telecommunication use this codec
  Do you know how can I generate <code>qcelp</code> traffic with <code>sip sdp</code>?</p>