Display rectangle on deepstream-app c program

Accelerated Computing Intelligent Video Analytics DeepStream SDK
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1

Please provide complete information as applicable to your setup.

• Hardware Platform (Jetson / GPU) Orin nano
• DeepStream Version 6.3
This time is for c program.
I tried to display rectangle on image in deepstream-app.
But it doesn’t display.
My code is as follows.

static void
write_kitti_output (AppCtx * appCtx, NvDsBatchMeta * batch_meta)
{
  gchar bbox_file[1024] = { 0 };
  FILE *bbox_params_dump_file = NULL;

  //if (!appCtx->config.bbox_dir_path)
  //  return;

  for (NvDsMetaList * l_frame = batch_meta->frame_meta_list; l_frame != NULL;
      l_frame = l_frame->next) {
    NvDsFrameMeta *frame_meta = (NvDsFrameMeta *) l_frame->data;   
    g_print("test print here\n");
    NvDsDisplayMeta *disp_meta = nvds_acquire_display_meta_from_pool(batch_meta);
    disp_meta->rect_params[0].left = 50;
    disp_meta->rect_params[0].top = 50;
    disp_meta->rect_params[0].width = 1000;
    disp_meta->rect_params[0].height = 500;
    disp_meta->rect_params[0].border_width = 2;
    disp_meta->rect_params[0].border_color.red = 1.0;
    disp_meta->rect_params[disp_meta->num_rects].border_color.green = 1.0;
    disp_meta->rect_params[disp_meta->num_rects].border_color.blue = 0.0;
    disp_meta->rect_params[disp_meta->num_rects].border_color.alpha = 0.5;
    nvds_add_display_meta_to_frame (frame_meta, disp_meta);
  }
}

Why a rectangle doesn’t display on image?

3 
NvDsDisplayMeta *disp_meta = nvds_acquire_display_meta_from_pool(batch_meta);
disp_meta->num_rects = 1;
disp_meta->rect_params[0].left = 50;

In addition, we usually recommend adding displaymeta to the osd sink pad probe function to avoid being dropped during metadata copy.

4

As suggested I am adding osd_sink_pad_buffer_probe to deepstream_app.c. Implementation in deepstream_test1_app is straightforward. All elements are added one by one. But in deepstream_app.c is different.

Added the osd_sink_pad_buffer_probe to deepstream_app.c

static GstPadProbeReturn
osd_sink_pad_buffer_probe (GstPad * pad, GstPadProbeInfo * info,
    gpointer u_data)
{
    GstBuffer *buf = (GstBuffer *) info->data;
    guint num_rects = 0;
    NvDsObjectMeta *obj_meta = NULL;
    guint vehicle_count = 0;
    guint person_count = 0;
    NvDsMetaList * l_frame = NULL;
    NvDsMetaList * l_obj = NULL;
    NvDsDisplayMeta *display_meta = NULL;

    NvDsBatchMeta *batch_meta = gst_buffer_get_nvds_batch_meta (buf);

    for (l_frame = batch_meta->frame_meta_list; l_frame != NULL;
      l_frame = l_frame->next) {
        NvDsFrameMeta *frame_meta = (NvDsFrameMeta *) (l_frame->data);
       

        nvds_add_display_meta_to_frame(frame_meta, display_meta);
    }
    
    
    return GST_PAD_PROBE_OK;
}

Then added

GstPad *osd_sink_pad = gst_element_get_static_pad (nvosd, "sink");
  if (!osd_sink_pad)
    g_print ("Unable to get sink pad\n");
  else
    gst_pad_add_probe (osd_sink_pad, GST_PAD_PROBE_TYPE_BUFFER,
        osd_sink_pad_buffer_probe, NULL, NULL);
  gst_object_unref (osd_sink_pad);

to static

gboolean
create_processing_instance (AppCtx * appCtx, guint index)

But I don’t have nvosd made in deepstream_app.c. How can I add osd probe in deepstream_app.c.

5

Refer to the overlay_graphics functions in /opt/nvidia/deepstream/deepstream/sources/apps/sample_apps/deepstream-app/deepstream_app_main.c

6

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