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