PHP不能发RTSP请求吗

Question

function SendRequest()
    {  
  //  $sRequest=$this->MakeRequestString();
$sRequest="DESCRIBE rtsp：//192.168.2.160:8557/PSIA/Streaming/channels/2?videoCodecType=H.264 RTSP/1.0\r\nCSeq=1\r\napplication/sdp\r\nUser-Agent:VLC media playe\r\n\r\n";
      
    if (!($sockRtsp = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)))
  {  
            die('socket_create() failed!');  
          }       if (!($resSockRtsp = socket_connect($sockRtsp,'192.168.2.160',8557)))
  {  
            die('socket_connect() failed!');  
          }       if(!socket_write($sockRtsp, $sRequest, strlen($sRequest)))
{
die('socket_write() failed!');
}
    $this->sResponse = '';  
    while ($sRead = socket_read($sockRtsp, 4096))
  {  
            $this->sResponse.= $sRead;  
// echo "$sRead";
          }  

    socket_close($sockRtsp);  
        }