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<h1>audiorx.cpp</h1><div class="fragment"><pre class="fragment"><span class="comment">// audiorx. </span>
<span class="comment">// A simple and amusing program for testing basic features of ccRTP.</span>
<span class="comment">// Copyright (C) 2001,2002 Federico Montesino <fedemp@altern.org></span>
<span class="comment">// </span>
<span class="comment">// This program is free software; you can redistribute it and/or modify</span>
<span class="comment">// it under the terms of the GNU General Public License as published by</span>
<span class="comment">// the Free Software Foundation; either version 2 of the License, or</span>
<span class="comment">// (at your option) any later version.</span>
<span class="comment">// </span>
<span class="comment">// This program is distributed in the hope that it will be useful,</span>
<span class="comment">// but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
<span class="comment">// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the</span>
<span class="comment">// GNU General Public License for more details.</span>
<span class="comment">// </span>
<span class="comment">// You should have received a copy of the GNU General Public License</span>
<span class="comment">// along with this program; if not, write to the Free Software</span>
<span class="comment">// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA</span>
<span class="comment">// A very simple mu-law encoded audio player.</span>
<span class="comment">// This is an introductory example file that illustrates basic usage</span>
<span class="comment">// of ccRTP. You will also see a bit on how to use CommonC++ threads and</span>
<span class="comment">// TimerPort.</span>
<span class="comment">// I am a player of \mu-law encoded RTP audio packets. I </span>
<span class="comment">// do not accept any arguments.</span>
<span class="preprocessor">#include <cstdio></span>
<span class="preprocessor">#include <cstdlib></span>
<span class="comment">// Some consts common to audiorx and audiotx</span>
<span class="preprocessor">#include <audio.h></span>
<span class="comment">// In order to use ccRTP, the RTP stack of CommonC++, you only need to</span>
<span class="comment">// include ...</span>
<span class="preprocessor">#include <<a class="code" href="rtp_8h.html" title="Generic and audio/video profile specific RTP interface of ccRTP.">ccrtp/rtp.h</a>></span>
<span class="preprocessor">#ifdef CCXX_NAMESPACES</span>
<span class="preprocessor"></span><span class="keyword">using namespace </span>ost;
<span class="keyword">using namespace </span>std;
<span class="preprocessor">#endif</span>
<span class="preprocessor"></span>
<span class="keyword">class </span>ccRTP_AudioReceiver: <span class="keyword">public</span> Thread, <span class="keyword">public</span> TimerPort
{
<span class="keyword">private</span>:
<span class="comment">// This is the file we will write to (/dev/audio)</span>
<span class="keywordtype">int</span> audiooutput;
<span class="comment">// The aforementioned file will be transmitted through this socket</span>
<a name="_a0"></a><a class="code" href="class_single_thread_r_t_p_session.html" title="This template class adds the threading aspect to the RTPSessionBase template in one...">RTPSession</a> *socket;
<span class="keyword">public</span>:
<span class="comment">// Constructor</span>
ccRTP_AudioReceiver(){
audiooutput=open(<span class="stringliteral">"/dev/audio"</span>,O_WRONLY<span class="comment">/*|O_NDELAY*/</span>);
<span class="keywordflow">if</span>( audiooutput > 0 ){
cout << <span class="stringliteral">"Audio device is ready to play."</span> << endl;
}<span class="keywordflow">else</span>{
cout << <span class="stringliteral">"I could not open /dev/audio "</span> << endl;
exit();
}
socket=NULL;
}
<span class="comment">// Destructor. </span>
~ccRTP_AudioReceiver(){
terminate();
<span class="keyword">delete</span> socket;
::close(audiooutput);
}
<span class="comment">// This method does almost everything.</span>
<span class="keywordtype">void</span> run(<span class="keywordtype">void</span>){
<span class="comment">// redefined from Thread.</span>
<span class="comment">// Before using ccRTP you should learn something about other</span>
<span class="comment">// CommonC++ classes. We need InetHostAddress...</span>
<span class="comment">// Construct loopback address</span>
InetHostAddress local_ip;
local_ip = <span class="stringliteral">"127.0.0.1"</span>;
<span class="comment">// Is that correct?</span>
<span class="keywordflow">if</span>( ! local_ip ){
<span class="comment">// this is equivalent to `! local_ip.isInetAddress()'</span>
cerr << <span class="stringliteral">": IP address is not correct!"</span> << endl;
exit();
}
cout << local_ip.getHostname() <<
<span class="stringliteral">" is going to listen to perself through "</span> <<
local_ip << <span class="stringliteral">"..."</span> << endl;
<span class="comment">// ____Here comes the real RTP stuff____</span>
<span class="comment">// Construct the RTP socket</span>
socket = <span class="keyword">new</span> <a name="a1"></a><a class="code" href="group__sessions.html#g24e16f350c9ae0c1e2a3f5d6a6dad9f9" title="Uses two pairs of sockets for RTP data and RTCP transmission/reception.">RTPSession</a>(local_ip,RECEIVER_BASE,0);
<span class="comment">// Set up receiver's connection</span>
socket->setSchedulingTimeout(10000);
<span class="keywordflow">if</span>( !socket->addDestination(local_ip,TRANSMITTER_BASE) )
cerr << <span class="stringliteral">"The receiver could not connect."</span>;
<span class="comment">// Let's check the queue (you should read the documentation</span>
<span class="comment">// so that you know what the queue is for).</span>
socket->startRunning();
cout << <span class="stringliteral">"The RTP queue is "</span>;
<span class="keywordflow">if</span>( socket->isActive() )
cout << <span class="stringliteral">"active."</span> << endl;
<span class="keywordflow">else</span>
cerr << <span class="stringliteral">"not active."</span> << endl;
cout << <span class="stringliteral">"Waiting for audio packets..."</span> << endl;
<span class="comment">// This will be useful for periodic execution.</span>
TimerPort::setTimer(PERIOD);
setCancel(cancelImmediate);
<span class="comment">// This is the main loop, where packets are sent and receipt.</span>
socket->setPayloadFormat(<a name="_a2"></a><a class="code" href="class_static_payload_format.html" title="Static payload format objects.">StaticPayloadFormat</a>(<a name="a3"></a><a class="code" href="group__payload.html#gg7644623ce29b8ca519d7e3f276b6ddc6095b083465fe4d6597ba586e0116022c" title="ITU-T G.711. mu-law audio 8 Khz (RFC 1890).">sptPCMU</a>));
<span class="keywordflow">for</span>( <span class="keywordtype">int</span> i=0 ; true ; i++ ){
<span class="keyword">const</span> <a name="_a4"></a><a class="code" href="class_app_data_unit.html" title="Interface (envelope) to data received over RTP packets.">AppDataUnit</a>* adu;
<span class="keywordflow">do</span>{
adu = socket-><a name="a5"></a><a class="code" href="class_app_data_unit.html#be15787e1cc84dd03b0769a5546d7a38" title="Get data as it is received in RTP packets (i.e.">getData</a>(socket->getFirstTimestamp());
<span class="keywordflow">if</span> ( NULL == adu )
Thread::sleep(5);
<span class="keywordflow">else</span> cout << <span class="stringliteral">"."</span>;
}<span class="keywordflow">while</span> ( (NULL == adu) || (adu-><a name="a6"></a><a class="code" href="class_app_data_unit.html#f41ffb3a12208e4ec9f6aa1b1180eedd">getSize</a>() <= 0) );
<span class="comment">// This is for buffering some packets at the</span>
<span class="comment">// receiver side, since playing smoothly</span>
<span class="comment">// without any reception buffer is almost</span>
<span class="comment">// impossible. Try commenting the two lines</span>
<span class="comment">// below, or stop transmission and continue</span>
<span class="comment">// later: you will probably hear noise or</span>
<span class="comment">// cracks. </span>
<span class="keywordflow">if</span> (i==0)
Thread::sleep(20);
<span class="keywordflow">if</span>(::write(audiooutput,adu-><a class="code" href="class_app_data_unit.html#be15787e1cc84dd03b0769a5546d7a38" title="Get data as it is received in RTP packets (i.e.">getData</a>(),adu-><a class="code" href="class_app_data_unit.html#f41ffb3a12208e4ec9f6aa1b1180eedd">getSize</a>()) < (ssize_t)adu-><a class="code" href="class_app_data_unit.html#f41ffb3a12208e4ec9f6aa1b1180eedd">getSize</a>())
<span class="keywordflow">break</span>;
cout << <span class="stringliteral">"."</span> << flush;
<span class="comment">// Let's wait for the next cycle</span>
Thread::sleep(TimerPort::getTimer());
TimerPort::incTimer(PERIOD);
}
} <span class="comment">// end of run</span>
};
<span class="keywordtype">int</span> main(<span class="keywordtype">int</span> argc, <span class="keywordtype">char</span> *argv[])
{
cout << <span class="stringliteral">"This is audiorx, a simple test program for ccRTP."</span> << endl;
cout << <span class="stringliteral">"I am waiting for audio packets on port "</span> << RECEIVER_BASE
<< <span class="stringliteral">"."</span> << endl;
cout << <span class="stringliteral">"Do you want to hear something? Run audiotx."</span> << endl;
cout << <span class="stringliteral">"Strike [Enter] when you are fed up. Enjoy!."</span> << endl;
<span class="comment">// Construct the main thread. </span>
ccRTP_AudioReceiver *receiver = <span class="keyword">new</span> ccRTP_AudioReceiver();
<span class="comment">// Run it.</span>
receiver->start();
cin.get();
cout << endl << <span class="stringliteral">"That's all."</span> << endl;
<span class="keyword">delete</span> receiver;
exit(0);
}
</pre></div> </div>
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