gtkmm 和 gstreamermm 测试代码抛出运行时错误

gtkmm and gstreamermm test code throws run time error

本文关键字：运行时错误 代码 测试 gstreamermm gtkmm      更新时间：2023-10-16

我正在 Ubuntu 10.04/12.04 上测试以下代码。我收到错误

#include <gtkmm.h>
#include <gstreamermm.h>
#include <iostream>
using namespace std;
class Sound
{
    public:
        Sound();
        void start_playing(double frequency);
        bool stop_playing();
    private:
        Glib::RefPtr<Gst::Pipeline> m_pipeline;
        Glib::RefPtr<Gst::Element> m_source;
        Glib::RefPtr<Gst::Element> m_sink;
};
Sound::Sound()
{
    m_pipeline = Gst::Pipeline::create("note");
    m_source = Gst::ElementFactory::create_element("audiotestsrc",
                                                   "source");
    m_sink = Gst::ElementFactory::create_element("autoaudiosink",
                                                 "output");
    m_pipeline->add(m_source);
    m_pipeline->add(m_sink);
    m_source->link(m_sink);
}
void Sound::start_playing (double frequency)
{
    m_source->set_property("freq", frequency);
    m_pipeline->set_state(Gst::STATE_PLAYING);
    /* stop it after 200ms */
    Glib::signal_timeout().connect(sigc::mem_fun(*this, &Sound::stop_playing),
                                   200);
}
bool Sound::stop_playing()
{
    m_pipeline->set_state(Gst::STATE_NULL);
    return false;
}

class Buttons : public Gtk::Window
{
public:
  Buttons();
  virtual ~Buttons();
protected:
  //Signal handlers:
  //void on_button_clicked();
  Sound sound;
  //void on_button_clicked(double frequency, Sound& sound);
  void on_button_clicked(double frequency, Sound* sound);
  //Child widgets:
  Gtk::Button m_button;
};
Buttons::Buttons()
{
  m_button.add_pixlabel("info.xpm", "cool button");
  set_title("Pixmap'd buttons!");
  set_border_width(10);
  //m_button.signal_clicked().connect( sigc::mem_fun(*this,
  //            &Buttons::on_button_clicked) );
  //m_button.signal_clicked().connect (sigc::bind<double, Sound*>(sigc::ptr_fun(&Buttons::on_button_clicked),
  //                                                  369.23, &sound));
  //m_button.signal_clicked().connect( sigc::bind<double, Sound&>( sigc::mem_fun(*this, &Buttons::on_button_clicked), 369.23, sound) ); 

  m_button.signal_clicked().connect( sigc::bind<double, Sound*>( sigc::mem_fun(*this, &Buttons::on_button_clicked), 369.23, &sound) ); 
  add(m_button);
  show_all_children();
}
Buttons::~Buttons()
{
}
/*
void Buttons::on_button_clicked()
{
  std::cout << "The Button was clicked." << std::endl;
}
*/
/*
void
Buttons::on_button_clicked(double frequency, Sound& sound)
{
    sound.start_playing (frequency);
}
*/
void
Buttons::on_button_clicked(double frequency, Sound* sound)
{
    sound->start_playing (frequency);
}

int main(int argc, char *argv[])
{
  Gtk::Main kit(argc, argv);
  Buttons buttons;
  //Shows the window and returns when it is closed.
  Gtk::Main::run(buttons);
  return 0;
}

我使用g++ gstmm1.cc -o gstmm1 ``pkg-config --cflags --libs gstreamermm-0.10 gtkmm-2.4编译 

terminate called after throwing an instance of 'std::runtime_error'
  what():  Failed to add null element.
Aborted

知道可能出了什么问题吗？这似乎与以下帖子有关http://old.nabble.com/gstmm-add-element-to-pipeline-test-td14042055.html

这对

我有用！我缺少代码 Gst：：init（）;在主（）

#include <gtkmm.h>
#include <gstreamermm.h>
#include <glibmm/main.h>
#include <iostream>

class Sound
{
    public:
        Sound();
        void start_playing(double frequency);
        bool stop_playing();
    private:
        Glib::RefPtr<Gst::Pipeline> m_pipeline;
        Glib::RefPtr<Gst::Element> m_source;
        Glib::RefPtr<Gst::Element> m_sink;
};
Sound::Sound()
{
    m_pipeline = Gst::Pipeline::create("note");
    m_source = Gst::ElementFactory::create_element("audiotestsrc",
                                               "source");
    m_sink = Gst::ElementFactory::create_element("autoaudiosink",
                                             "output");
    m_pipeline->add(m_source);
    m_pipeline->add(m_sink);
    m_source->link(m_sink);
}
void Sound::start_playing (double frequency)
{
    m_source->set_property("freq", frequency);
    //m_pipeline->set_state(Gst::STATE_NULL);
    //m_pipeline->set_state(Gst::STATE_PAUSED);
    //m_pipeline->set_state(Gst::STATE_READY);
    m_pipeline->set_state(Gst::STATE_PLAYING);
    /* stop it after 200ms */
    Glib::signal_timeout().connect(sigc::mem_fun(*this, &Sound::stop_playing),
                               200);
}
bool Sound::stop_playing()
{
    //m_pipeline->set_state(Gst::STATE_PAUSED);
    m_pipeline->set_state(Gst::STATE_NULL);
    return false;
}
class HelloWorld : public Gtk::Window
{
public:
  HelloWorld();
  virtual ~HelloWorld();
protected:
  //Signal handlers:
  void on_button_clicked();
  //Member widgets:
  Gtk::Button m_button;
  Sound sound;
};
HelloWorld::HelloWorld()
: m_button("Hear Sound")   // creates a new button with label "Hello World".
{
  // Sets the border width of the window.
  set_border_width(10);

  // When the button receives the "clicked" signal, it will call the
  // on_button_clicked() method defined below.
  m_button.signal_clicked().connect(sigc::mem_fun(*this,
          &HelloWorld::on_button_clicked));

  // This packs the button into the Window (a container).
  add(m_button);
  // The final step is to display this newly created widget...
  m_button.show();
}
HelloWorld::~HelloWorld()
{
}
void HelloWorld::on_button_clicked()
{
  std::cout << "Hello World" << std::endl;
  sound.start_playing(400);
}

int main(int argc, char* argv[]) {
  Gst::init(); 
  Glib::RefPtr<Gtk::Application> app = Gtk::Application::create(argc, argv, "org.gtkmm.example");
  HelloWorld helloworld;
  //Shows the window and returns when it is closed.
  return app->run(helloworld);
return 0;
}
相关文章：