Appsrc example with cairo

[Annick Fron]

Hi,

I have copied from the doc the appsrc example, and tried to create contents using cairo, but the example does not work.

Any idea ?

Annick Fron

/*
============================================================================
Name        : Cairo-src.c

============================================================================
*/


#include <gst/gst.h>
#include <cairo.h>
#include <gst/video/video.h>
#include <stdio.h>

static GMainLoop *loop;

static void
cb_need_data (GstElement *appsrc,
        guint       unused_size,
        gpointer    user_data)
{
static gboolean white = FALSE;
static GstClockTime timestamp = 0;
GstBuffer *buffer;
GstMapInfo info;
guint size;
GstFlowReturn ret;
GstMemory * memory;
cairo_t *  cr;


cairo_surface_t * imageSurface;


size = 640 * 50 * 4;

buffer = gst_buffer_new_allocate (NULL, size, NULL);


memory=gst_buffer_get_all_memory(buffer);
gst_buffer_make_writable(buffer);
gst_buffer_map (buffer, &info, GST_MAP_WRITE);
    printf("buffer \n");
imageSurface = cairo_image_surface_create_for_data (info.data,
        CAIRO_FORMAT_ARGB32,
        640,
        50,
        640*4);
cr = cairo_create(imageSurface);
cairo_set_source_rgb(cr,1.0,0,1.0);
cairo_rectangle(cr, 100.0,20.0,400.0,40.0 );
cairo_fill(cr);

//gst_buffer_unmap (buffer, &info);

GST_BUFFER_PTS (buffer) = timestamp;
GST_BUFFER_DURATION (buffer) = gst_util_uint64_scale_int (1, GST_SECOND, 2);

timestamp += GST_BUFFER_DURATION (buffer);


g_signal_emit_by_name (appsrc, "push-buffer", buffer, &ret);


if (ret != GST_FLOW_OK) {
  /* something wrong, stop pushing */
  g_main_loop_quit (loop);
}
}

gint
main (gint   argc,
    gchar *argv[])
{
GstElement *pipeline, *appsrc, *conv, *videosink;

/* init GStreamer */
gst_init (&argc, &argv);
loop = g_main_loop_new (NULL, FALSE);

/* setup pipeline */
pipeline = gst_pipeline_new ("pipeline");
appsrc = gst_element_factory_make ("appsrc", "source");
conv = gst_element_factory_make ("videoconvert", "conv");
videosink = gst_element_factory_make ("ximagesink", "videosink");

/* setup */
g_object_set (G_OBJECT (appsrc), "caps",
        gst_caps_new_simple ("video/x-raw",
                   "format", G_TYPE_STRING, "ARGB",
                   "width", G_TYPE_INT, 640,
                   "height", G_TYPE_INT, 50,
                   "framerate", GST_TYPE_FRACTION, 15, 1,
                   NULL), NULL);
gst_bin_add_many (GST_BIN (pipeline), appsrc, conv, videosink, NULL);
gst_element_link_many (appsrc, conv, videosink, NULL);

/* setup appsrc */
g_object_set (G_OBJECT (appsrc),
      "stream-type", 0,
      "format", GST_FORMAT_TIME, NULL);
g_signal_connect (appsrc, "need-data", G_CALLBACK (cb_need_data), NULL);

/* play */
gst_element_set_state (pipeline, GST_STATE_PLAYING);
g_main_loop_run (loop);

/* clean up */
gst_element_set_state (pipeline, GST_STATE_NULL);
gst_object_unref (GST_OBJECT (pipeline));
g_main_loop_unref (loop);

return 0;
}