Question

我正在尝试编写一个非常简单的GTK +程序，它允许我使用Gstreamer播放视频。以下是代码：

#include <gtk/gtk.h>
#include <gst/gst.h>
#include <gst/video/videooverlay.h>
#include <gdk/gdkwin32.h>

static GstElement *playbin;
static guintptr window_handle = 0;

static void report_error(GstBus *playbin_bus, GstMessage *error_message, gpointer user_data) {
    GError *error;
    gchar *debug_info;
    gst_message_parse_error(error_message, &error, &debug_info);
    g_printerr("Error received from element %s: %s\n", GST_OBJECT_NAME(error_message->src), error->message);
    g_printerr("Debugging information: %s\n", debug_info ? debug_info : "none");
    g_clear_error(&error);
    g_free(debug_info);
}

static GstBusSyncReply prepare_window_handle(GstBus *bus, GstMessage *message, GstPipeline * pipeline) {
    if (!gst_is_video_overlay_prepare_window_handle_message(message)) {
        return GST_BUS_PASS;
    }
    g_assert(window_handle != 0);
    gst_video_overlay_set_window_handle(GST_VIDEO_OVERLAY(playbin), window_handle);
    gst_message_unref(message);
    return GST_BUS_DROP;
}

static void realize_video_drawing_area(GtkWidget *video_drawing_area, gpointer user_data) {
    GdkWindow *video_window = gtk_widget_get_window(video_drawing_area);
    if (!gdk_window_ensure_native(video_window)) {
        g_error("Couldn't create native window needed for GstVideoOverlay!");
    }
    window_handle = (guintptr) GDK_WINDOW_HWND(video_window);
}

static void play(GtkButton *play_button, gpointer user_data) {
    gst_element_set_state(playbin, GST_STATE_PLAYING);
}

static void activate(GtkApplication *app, gpointer user_data) {

    GtkWidget *window = gtk_application_window_new(app);

    GtkWidget *root_pane = gtk_overlay_new();
    gtk_container_add(GTK_CONTAINER(window), root_pane);

    GtkWidget *video_drawing_area = gtk_drawing_area_new();
    gtk_container_add(GTK_CONTAINER(root_pane), video_drawing_area);
    gtk_widget_set_size_request(video_drawing_area, 800, 600);
    gtk_widget_set_double_buffered(video_drawing_area, FALSE);
    g_signal_connect(video_drawing_area, "realize", G_CALLBACK(realize_video_drawing_area), NULL);

    GtkWidget *play_button = gtk_button_new_with_label("Play");
    gtk_overlay_add_overlay(GTK_OVERLAY(root_pane), play_button);
    gtk_widget_set_halign(play_button, GTK_ALIGN_END);
    gtk_widget_set_valign(play_button, GTK_ALIGN_END);
    gtk_widget_set_margin_end(play_button, 20);
    gtk_widget_set_margin_bottom(play_button, 20);
    g_signal_connect(G_OBJECT(play_button), "clicked", G_CALLBACK(play), NULL);

    gtk_widget_show_all(window);

}

int main(int argc, char **argv) {

    gst_init(&argc, &argv);
    playbin = gst_element_factory_make("playbin", NULL);
    g_object_set(playbin, "uri", "http://techslides.com/demos/sample-videos/small.ogv", NULL);
    GstBus *playbin_bus = gst_element_get_bus(playbin);
    gst_bus_enable_sync_message_emission(playbin_bus);
    gst_bus_set_sync_handler(playbin_bus, (GstBusSyncHandler) prepare_window_handle, NULL, NULL);
    gst_bus_add_signal_watch(playbin_bus);
    g_signal_connect(playbin_bus, "message::error", G_CALLBACK(report_error), NULL);
    gst_object_unref(playbin_bus);

    GtkApplication *app = gtk_application_new("com.techn.videotest", G_APPLICATION_FLAGS_NONE);
    g_signal_connect(app, "activate", G_CALLBACK(activate), NULL);
    return g_application_run(G_APPLICATION(app), argc, argv);

}

每当我按“播放”时，音频播放开始，但我看不到视频。如果我注释掉这行

gst_bus_set_sync_handler(playbin_bus, (GstBusSyncHandler) prepare_window_handle, NULL, NULL);

视频在单独的D3D窗口中启动并播放没有问题。我在控制台中看不到相关的错误消息，除非以下计数：

(video_test.exe:5172): GStreamer-WARNING **: Failed to load plugin 'C:\msys64\mingw32\lib\gstreamer-1.0\libgstchromaprint.dll': 'C:\msys64\mingw32\lib\gstreamer-1.0\libgstchromaprint.dll': The specified module could not be found.

(video_test.exe:5172): GStreamer-WARNING **: Failed to load plugin 'C:\msys64\mingw32\lib\gstreamer-1.0\libgstfragmented.dll': 'C:\msys64\mingw32\lib\gstreamer-1.0\libgstfragmented.dll': The specified module could not be found.

(video_test.exe:5172): GStreamer-WARNING **: Failed to load plugin 'C:\msys64\mingw32\lib\gstreamer-1.0\libgstx264.dll': 'C:\msys64\mingw32\lib\gstreamer-1.0\libgstx264.dll': The specified module could not be found.

(video_test.exe:5172): GStreamer-WARNING **: Failed to load plugin 'C:\msys64\mingw32\lib\gstreamer-1.0\libgstx265.dll': 'C:\msys64\mingw32\lib\gstreamer-1.0\libgstx265.dll': The specified procedure could not be found.

(video_test.exe:5172): GLib-GObject-WARNING **: attempt to override closure->va_marshal (63c488b0) with new marshal (66925ea8)

我正在使用以下命令行编译程序：

gcc video_test.c -o video_test `pkg-config --cflags --libs gtk+-3.0 gstreamer-1.0` -lgstvideo-1.0 -Wno-deprecated-declarations

我在Windows 10机器和MinGW 32位编译器上使用MSYS2环境。我有1.0版的Gstreamer和3.0版的GTK +库。

Answer 1

我上个月在使用msys2的Windows 10上将gstreamer与gtk + 3集成时遇到了同样的问题。

Videooverlay不起作用！请改用gtks。

尝试：

#include <gtk/gtk.h>
#include <gst/gst.h>

static GstElement *playbin, *sink;

static void play(GtkButton *play_button, gpointer user_data) {
    gst_element_set_state(playbin, GST_STATE_PLAYING);
}

static void activate(GtkApplication *app, gpointer user_data) {

    GtkWidget *window = gtk_application_window_new(app);

    GtkWidget *root_pane = gtk_overlay_new();
    gtk_container_add(GTK_CONTAINER(window), root_pane);

    GtkWidget *video_drawing_area = gtk_drawing_area_new();

    g_object_get (sink, "widget", &video_drawing_area, NULL);
    gtk_widget_set_size_request(video_drawing_area, 800, 600);
    gtk_container_add(GTK_CONTAINER(root_pane), video_drawing_area);

    GtkWidget *play_button = gtk_button_new_with_label("Play");
    gtk_overlay_add_overlay(GTK_OVERLAY(root_pane), play_button);
    gtk_widget_set_halign(play_button, GTK_ALIGN_END);
    gtk_widget_set_valign(play_button, GTK_ALIGN_END);
    gtk_widget_set_margin_end(play_button, 20);
    gtk_widget_set_margin_bottom(play_button, 20);
    g_signal_connect(G_OBJECT(play_button), "clicked", G_CALLBACK(play), NULL);

    gtk_widget_show_all(window);

}

int main(int argc, char **argv) {

    gst_init(&argc, &argv);
    playbin = gst_element_factory_make("playbin", NULL);
    g_object_set(playbin, "uri", "http://techslides.com/demos/sample-videos/small.ogv", NULL);

    sink = gst_element_factory_make ("gtksink", NULL);
    g_object_set(playbin, "video-sink", sink, NULL);


    GtkApplication *app = gtk_application_new("com.techn.videotest", G_APPLICATION_FLAGS_NONE);
    g_signal_connect(app, "activate", G_CALLBACK(activate), NULL);
    return g_application_run(G_APPLICATION(app), argc, argv);

}

用以下代码编译：

gcc videotest.c -o videotest `pkg-config --cflags --libs gtk+-3.0 gstreamer-video-1.0`

或尝试：

#include <gtk/gtk.h>
#include <gst/gst.h>

GstElement *pipeline, *src, *sink;

int main (int argc, char **argv)
{
    gst_init (&argc, &argv);
    gtk_init (&argc, &argv);

    pipeline = gst_pipeline_new ("xvoverlay");
    src = gst_element_factory_make ("videotestsrc", NULL);
    sink = gst_element_factory_make ("gtksink", NULL);

    gst_bin_add_many (GST_BIN (pipeline), src, sink, NULL);
    gst_element_link (src, sink);

    GtkWidget *window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    GtkWidget *area;
    g_object_get (sink, "widget", &area, NULL);
    gtk_container_add (GTK_CONTAINER (window), area);

    gtk_widget_realize(area);

    gtk_widget_show_all (window);
    gst_element_set_state (pipeline, GST_STATE_PLAYING);

    gtk_main ();
    return 0;
}

这个答案让我找到了解决方案： https://stackoverflow.com/a/32695253

Answer 2

我刚刚发现了这个问题。在我的情况下，使用gtksink根本不适合。

我发现一切都可以防止Windows Aero主题被关闭。进一步调查指出，这是因为'分层'W7窗口（WS_EX_LAYERED窗口属性）。

因此，从GDK源代码开始，有一个很好的规定解决方案：

如果环境变量GDK_WIN32_LAYERED设置为0，则GDK根本不使用分层窗口。它也可以通过编程方式完成：

#ifdef WIN32
Glib::setenv ("GDK_WIN32_LAYERED", "0", false) ;
#endif

无法在GTK +窗口中嵌入Gstreamer视频

2 个答案: