Appsrc simple 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;
 }