有 GstPadProbeReturn 已被我的 main 调用的信息

Question

当我的源正在抓取流时，回调函数被调用，我有 wxMessageBox("Got buffer"); 显示文本 Got Buffer。但是在这一点上，我不知道如何在我的主代码中获得信息，即我的流实际上正在抓取一些东西，所以我可以显示它（我想确保我的管道在请求显示之前正在抓取一些东西）。例如，更改我的工具栏图标，指示用户管道实际上正在抓取某些东西并且他可以显示它。你可以在下面找到我的代码：

#include "MainWindow.h"


wxBEGIN_EVENT_TABLE(MainWindow, wxFrame)
    EVT_TOOL(10001, LoadVideo)
wxEND_EVENT_TABLE()

MainWindow::MainWindow(const wxString& title) : wxFrame(NULL, wxID_ANY, title, wxPoint(30, 30), wxSize(1224, 1024))
{
    wxInitAllImageHandlers();
    wxBitmap load(wxT("bitmap.png"), wxBITMAP_TYPE_PNG);

    wxPanel* bg = new wxPanel(this, wxID_ANY);
    bg->SetBackgroundColour(wxColor(230, 230, 230));

    m_renderWindow = new wxWindow(bg, wxID_ANY);
    m_renderWindow->SetBackgroundColour(*wxBLACK);

    // Layout the UI.
    wxBoxSizer* szr1 = new wxBoxSizer(wxVERTICAL);
    wxBoxSizer* szr2 = new wxBoxSizer(wxHORIZONTAL);

    szr1->Add(m_renderWindow, wxSizerFlags(1).Expand().Border(wxBOTTOM));
    szr1->Add(szr2, wxSizerFlags(0));

    bg->SetSizer(szr1);
    toolbar->AddTool(10001, _T("ContinuousShot"), load);
    toolbar->Realize();
    Layout();

    // Set up the event handlers.
#ifdef __WXGTK__
    m_renderWindow->Bind(wxEVT_CREATE, &MainWindow::OnRendererWinCreated, this);
#endif
    // Initialize GStreamer.
    m_xid = 0;
    m_pipeline = NULL;
    gst_init(NULL, NULL);
}

        
GstPadProbeReturn buffer_out_cb(GstPad* pad, GstPadProbeInfo* info, gpointer user_data)
    {
    
        GstElement* pipe = (GstElement*)user_data;
    
        //toolbar->SetToolNormalBitmap(10001, wxBitmap(wxT(icon-open-device.png), wxBITMAP_TYPE_PNG));

        wxMessageBox("Got buffer");
        gst_element_set_state(pipe, GST_STATE_PAUSED);
    
        
        //remove the probe if you don't need it anymore, otherwise return GST_PAD_PROBE_OK
        return GST_PAD_PROBE_REMOVE;
    }

void MainWindow::LoadVideo(wxWindowCreateEvent&)
    {
        GstPad* pad;
        GError* error = NULL;
        //GstElement* pipeline;
        GstElement* source;
    
        GstCaps* caps = gst_caps_new_simple("application/x-rtp",
            "media", G_TYPE_STRING, "video",
            "payload", G_TYPE_INT, 96,
            "encoding-name", G_TYPE_STRING, "H264",
            NULL);
    
        m_pipeline = gst_parse_launch("udpsrc name=source !rtpjitterbuffer !rtph264depay !h264parse !avdec_h264 !autovideoconvert !d3dvideosink name=mysink sync=false ", &error);
        if (!m_pipeline) {
            g_print("Parse error: %s\n", error->message);
            exit(1);
        }
    
        source = gst_bin_get_by_name(GST_BIN(m_pipeline), "source");
        g_object_set(G_OBJECT(source), "caps", caps, NULL);
        g_object_set(G_OBJECT(source), "port", m_port, NULL);
    
        pad = gst_element_get_static_pad(source, "src");
        gst_pad_add_probe(pad, GST_PAD_PROBE_TYPE_BUFFER, (GstPadProbeCallback)buffer_out_cb, m_pipeline, NULL);
        gst_object_unref(pad);
    
    #ifdef __WXGTK__
        GstElement* sink = gst_bin_get_by_name((GstBin*)m_pipeline, "mysink");
        gst_video_overlay_set_window_handle(GST_VIDEO_OVERLAY(sink), m_xid);
    #elif defined __WXMSW__
        GstElement* sink = gst_bin_get_by_name((GstBin*)m_pipeline, "mysink");
        WXWidget hwnd = m_renderWindow->GetHandle();
        gst_video_overlay_set_window_handle(GST_VIDEO_OVERLAY(sink),
            reinterpret_cast<guintptr>(hwnd));
    #endif
    
        gst_element_set_state(m_pipeline, GST_STATE_PLAYING);
    
    }

Answer 1

解决方案：

在回调函数中传递一个指针 (gpointer user_data)，例如一个 int，如果回调没有被调用则为 0，如果被调用则为 1

有 GstPadProbeReturn 已被我的 main 调用的信息

Have the information that GstPadProbeReturn have been called by my main

wxwidgets

gstreamer-1.0