[gst-devel] Fwd: Video processing
Bruno
botte.pub at gmail.com
Tue Aug 26 10:16:31 CEST 2008
Yep that is what I was doing before. Do you think I can draw rectangles over
the cam image when using xvimagesink ?
2008/8/26, Eric Zhang <nicolas.m.zhang at gmail.com>:
>
> Hi, gstreamer-devel:
>
> If you only want to `ximagesink' or `xvimagesink' draws images in
> your GtkDrawingArea, there is a very simple way to achieve this:
>
> Just connect the `expose-event' signal of GtkDrawingArea and pass
> the window ID to the sink element:
>
> // Drawing on our drawing area
> g_signal_connect(G_OBJECT(area), "expose-event", G_CALLBACK(expose_cb),
> NULL);
>
> /* Callback to be called when the drawing area is exposed */
>
> static gboolean expose_cb(GtkWidget * widget, GdkEventExpose * event,
> gpointer data)
> {
>
> // `play-videosink' is your video sink element
> gst_x_overlay_set_xwindow_id(GST_X_OVERLAY(play->videosink),
>
> GDK_WINDOW_XWINDOW(widget->window));
> return FALSE;
> }
>
>
> That's it. If you want to draw the image yourself while not using
> `xvimagesink' or `ximagesink', then I think this is a Gtk+ problem, not
> a gstreamer issue.
>
>
> Eric Zhang
>
>
>
>
> Bruno wrote:
> > Hello all,
> >
> > I still have some questions about gstreamer.
> >
> > Actually I'd like to change the way my program work, in order to
> > display a frame from the camera only once the image processing has
> > been done, and with a rectangle over the face of the person.
> >
> > So I changed my pipeline (removed the screen_sink element), and I'd
> > like to send a buffer from my image processing function to the gtk
> > drawing area where the camera image was displayed before. I tried to
> > do it with gtk drawing area (and with gtk image too with no sucess),
> > but I can't find the way to change the image contained in the drawing
> > area.
> >
> > Here is my code :
> >
> >
> >
> > ///// IMAGE PROCESSING CALLBACK
> >
> > /* Callback to be called when data goes through the pad */
> > static gboolean process_frame(GstElement *video_sink,
> > GstBuffer *buffer, GstPad *pad, AppData *appdata)
> > {
> > int x, y;
> > // getting the pointer to camera buffer
> > unsigned char *data_photo = (unsigned char *)
> > GST_BUFFER_DATA(buffer);
> >
> >
> > // REMOVED PART WHERE THE COORDINATES OF THE POSITION OF THE FACE IS
> > CALCULATED //
> >
> >
> > // THIS PART IS WHAT I TRIED, BUT I HAVE A SEGMENTATION FAULT WHEN
> > CREATING PIXBUF //
> > GdkPixbuf *newscreen;
> > //newscreen = gdk_pixbuf_new_from_data(data_photo,
> > //GDK_COLORSPACE_RGB, /* RGB-colorspace */
> > //FALSE, /* No alpha-channel */
> > //8, /* Bits per RGB-component */
> > //IMAGE_WIDTH, IMAGE_HEIGHT, /* Dimensions */
> > //3*IMAGE_WIDTH, /* Number of bytes between lines
> > (ie stride) */
> > //NULL, NULL); /* Callbacks */
> >
> >
> > gdk_draw_pixmap(GDK_DRAWABLE(appdata->screen),
> > appdata->screen->style->black_gc, GDK_DRAWABLE(newscreen), 0, 0, 0, 0,
> > -1, -1);
> >
> > return TRUE;
> > }
> >
> >
> >
> >
> >
> > /////// PIPELINE
> >
> >
> > /* Initialize the the Gstreamer pipeline. Below is a diagram
> > * of the pipeline that will be created:
> > *
> > * |Camera| |CSP | |Screen| |Screen| |Image |
> > * |src |->|Filter|->|queue |->|sink |-> |processing|-> Display
> > */
> > static gboolean initialize_pipeline(AppData *appdata,
> > int *argc, char ***argv)
> > {
> > GstElement *pipeline, *camera_src, *screen_sink;
> > GstElement *screen_queue;
> > GstElement *csp_filter;
> > GstCaps *caps;
> > GstBus *bus;
> > GstPad *sinkpad;
> >
> > /* Initialize Gstreamer */
> > gst_init(argc, argv);
> >
> > /* Create pipeline and attach a callback to it's
> > * message bus */
> > pipeline = gst_pipeline_new("test-camera");
> >
> > bus = gst_pipeline_get_bus(GST_PIPELINE(pipeline));
> > gst_bus_add_watch(bus, (GstBusFunc)bus_callback, appdata);
> > gst_object_unref(GST_OBJECT(bus));
> >
> > /* Save pipeline to the AppData structure */
> > appdata->pipeline = pipeline;
> >
> > /* Create elements */
> > /* Camera video stream comes from a Video4Linux driver */
> > camera_src = gst_element_factory_make(VIDEO_SRC, "camera_src");
> > /* Colorspace filter is needed to make sure that sinks understands
> > * the stream coming from the camera */
> > csp_filter = gst_element_factory_make("ffmpegcolorspace",
> > "csp_filter");
> > /* Queue creates new thread for the stream */
> > screen_queue = gst_element_factory_make("queue", "screen_queue");
> > /* Sink that shows the image on screen. Xephyr doesn't support XVideo
> > * extension, so it needs to use ximagesink, but the device uses
> > * xvimagesink */
> > //screen_sink = gst_element_factory_make(VIDEO_SINK, "screen_sink");
> >
> > sinkpad = gst_element_get_static_pad(screen_queue,"sink");
> > gst_pad_add_buffer_probe(sinkpad,G_CALLBACK(process_frame), appdata);
> >
> >
> > /* Check that elements are correctly initialized */
> > if(!(pipeline && camera_src /*&& screen_sink*/ && csp_filter &&
> > screen_queue))
> > {
> > g_critical("Couldn't create pipeline elements");
> > return FALSE;
> > }
> >
> >
> > /* Add elements to the pipeline. This has to be done prior to
> > * linking them */
> > gst_bin_add_many(GST_BIN(pipeline), camera_src, csp_filter,
> > screen_queue, /*screen_sink,*/ NULL);
> >
> > /* Specify what kind of video is wanted from the camera */
> > caps = gst_caps_new_simple("video/x-raw-rgb",
> > "width", G_TYPE_INT, IMAGE_WIDTH,
> > "height", G_TYPE_INT, IMAGE_HEIGHT,
> > "framerate", GST_TYPE_FRACTION, FRAMERATE, 1,
> > NULL);
> >
> >
> > /* Link the camera source and colorspace filter using capabilities
> > * specified */
> > if(!gst_element_link_filtered(camera_src, csp_filter, caps))
> > {
> > return FALSE;
> > }
> > gst_caps_unref(caps);
> >
> > /* Connect Colorspace Filter -> Screen Queue -> Screen Sink
> > * This finalizes the initialization of the screen-part of the
> > pipeline */
> > if(!gst_element_link_many(csp_filter, screen_queue, /*screen_sink,
> > */NULL))
> > {
> > return FALSE;
> > }
> >
> > gst_element_set_state(pipeline, GST_STATE_PAUSED);
> >
> > return TRUE;
> > }
> >
> >
> >
> >
> >
> >
> >
> > /////// MAIN FUNCTION
> >
> >
> > int main(int argc, char **argv)
> > {
> > // variables for face detection
> > // main structure for vjdetect
> >
> > pdata = (mainstruct*) calloc(1, sizeof(mainstruct));
> > // Allocate memory for array of face detections returned by
> > facedetector (VjDetect).
> > pdata->pFaceDetections = (FLY_Rect
> > *)calloc(MAX_NUMBER_OF_FACE_DETECTIONS, sizeof(FLY_Rect));
> > init(pdata);
> >
> > AppData appdata;
> > appdata.expression = 0;
> > GtkWidget *hbox, *vbox_button, *vbox, *button1, *button2;
> >
> >
> > /* Initialize and create the GUI */
> >
> > example_gui_initialize(
> > &appdata.program, &appdata.window,
> > &argc, &argv, "Expression Detector");
> >
> > vbox = gtk_vbox_new(FALSE, 0);
> > hbox = gtk_hbox_new(FALSE, 0);
> > vbox_button = gtk_vbox_new(FALSE, 0);
> >
> > gtk_box_pack_start(GTK_BOX(hbox), vbox, FALSE, FALSE, 0);
> > gtk_box_pack_start(GTK_BOX(hbox), vbox_button, FALSE, FALSE, 0);
> >
> > appdata.screen = gtk_drawing_area_new();
> > gtk_widget_set_size_request(appdata.screen, 500, 380);
> > gtk_box_pack_start(GTK_BOX(vbox), appdata.screen, FALSE, FALSE, 0);
> >
> > button1 = gtk_toggle_button_new_with_label("Run/Stop");
> > gtk_widget_set_size_request(button1, 170, 75);
> > gtk_box_pack_start(GTK_BOX(vbox_button), button1, FALSE, FALSE, 0);
> >
> > button2 = gtk_toggle_button_new_with_label("Expressions ON/OFF");
> > gtk_widget_set_size_request(button2, 170, 75);
> > gtk_box_pack_start(GTK_BOX(vbox_button), button2, FALSE, FALSE, 0);
> >
> >
> > appdata.anger = gtk_image_new_from_file("./smileys/anger.jpg");
> > gtk_widget_set_size_request(appdata.anger, 160, 180);
> > appdata.disgust = gtk_image_new_from_file("./smileys/disgust.jpg");
> > gtk_widget_set_size_request(appdata.disgust, 160, 180);
> > appdata.fear = gtk_image_new_from_file("./smileys/fear.jpg");
> > gtk_widget_set_size_request(appdata.fear, 160, 180);
> > appdata.happy = gtk_image_new_from_file("./smileys/happy.jpg");
> > gtk_widget_set_size_request(appdata.happy, 160, 180);
> > appdata.neutral = gtk_image_new_from_file("./smileys/neutral.jpg");
> > gtk_widget_set_size_request(appdata.neutral, 160, 180);
> > appdata.sad = gtk_image_new_from_file("./smileys/sad.jpg");
> > gtk_widget_set_size_request(appdata.sad, 160, 180);
> > appdata.surprise = gtk_image_new_from_file("./smileys/surprise.jpg");
> > gtk_widget_set_size_request(appdata.surprise, 160, 180);
> > appdata.unknown = gtk_image_new_from_file("./smileys/unknown.jpg");
> > gtk_widget_set_size_request(appdata.unknown, 160, 180);
> >
> > appdata.smiley = gtk_image_new_from_file("./smileys/unknown.jpg");
> > gtk_widget_set_size_request(appdata.smiley, 160, 180);
> > gtk_box_pack_start(GTK_BOX(vbox_button), appdata.smiley, FALSE,
> > FALSE, 0);
> >
> > g_signal_connect(G_OBJECT(button1), "clicked",
> > G_CALLBACK(button1_pressed), &appdata);
> >
> > g_signal_connect(G_OBJECT(button2), "clicked",
> > G_CALLBACK(button2_pressed), &appdata);
> >
> >
> > gtk_container_add(GTK_CONTAINER(appdata.window), hbox);
> >
> > /* Initialize the GTK pipeline */
> > if(!initialize_pipeline(&appdata, &argc, &argv))
> > {
> > hildon_banner_show_information(
> > GTK_WIDGET(appdata.window),
> > "gtk-dialog-error",
> > "Failed to initialize pipeline");
> > }
> >
> >
> >
> > g_signal_connect(G_OBJECT(appdata.window), "destroy",
> > G_CALLBACK(destroy_pipeline), &appdata);
> >
> >
> > /* Begin the main application */
> > example_gui_run(appdata.program, appdata.window);
> >
> > /* Free the gstreamer resources. Elements added
> > * to the pipeline will be freed automatically */
> >
> > return 0;
> > }
> >
> >
> > What I'd like to do is to modify the data_photo buffer to draw a
> > rectangle in it (in the process_frame function), and draw the content
> > in the appdata.screen GtkWidget. (by the way screen is declared as a
> > GtkWidget * in the appdata structure).
> >
> > Thanks in advance for your help !
> > Bruno
> >
>
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>
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> >
>
>
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