Showcase 2 – QT Simple VoIP Program

This software is a DEMO, intended to demonstrates MY SKILLS in this subjects:

[table id=2 /]


Showcase2 is a simple VoIP program completely developed using QT libraries, and C++, intended to be used inside your private network (does not implements any NAT traversal algorithm). Download this demo and prepare yourself with microphone and earphones.



  1. download & install VS 2015 redist using this link (or search from google).
  2. download software using this link
  3. unpack contents in a empty folder
  4. Double click and run simple_voip_program.exe
  5. You must see first about dialog, just click OK and continue next screen.

Ubuntu 16.04:

  1. download software using this link
  2. unpack contentes in a empty folder
  3. Double click and run deploy/simple_voip_linux_qt
  4. You must see first about dialog, just click OK and continue next screen.

Then you see VoIP program screen:

Just follow steps in order is showed.

NOTE: maybe you guess, but this program needs a partner or peer program running in other pc machine, both connected to the same private network (same router for example).

NOTE: i suggest you download and run Wireshark software, in order to sniff UDP packets traveling through UDP ports 20000 (control channel) & 20001 (voice channel).

Code Snippet

qint64 AudioInput::readData(char *data, qint64 maxlen)
    qint64 total = 0;
    QByteArray datagram;
    QHostAddress src_addr;
    int s, count;

    count = 0;
        while(total < maxlen && audioUdpSocket->hasPendingDatagrams())
            if(audioUdpSocket->readDatagram(, datagram.size(), &src_addr) <= 0) continue;
            QByteArray decompress = qUncompress(datagram);
            s = decompress.size() - sizeof(int);
            if(s + total > maxlen) s = maxlen - total;
            if(s <= 0) return total;
            memcpy(data + total, + sizeof(int), s);
            total += s;
    } while(total == 0 && count++ < 5);
    return total;


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