[gst-devel] Fwd: Video processing
Eric Zhang
nicolas.m.zhang at gmail.com
Tue Aug 26 11:17:04 CEST 2008
Hi, gstreamer-devel:
Oh, I think you can use a buffer/data probe to achieve this. Modify the
buffer, add a rectangle on every frame. Or, modify the xvimagesink. :)
Eric Zhang
2008/8/26 Bruno <botte.pub at gmail.com>
> 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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