Critical errors when adding call back

rottnest · September 30, 2024, 2:22pm

First thankyou for the handholding when I was out of my depth.
I am doing my preview and dynamic recording with 2 pipes intervideosink/src.
The system is working but I would like to log/respond to BOTH pipes. I add a callback (so far on 1 pipe)

// Create bus and add watch
GstBus *bus1 = gst_pipeline_get_bus (GST_PIPELINE (mainPipe));
gst_bus_add_signal_watch (bus1);
g_signal_connect (bus1, "message", G_CALLBACK (messageHandler), NULL);

Which unleaches a storm:

lots of same
(dvrPR:121489): GStreamer-CRITICAL **: 21:33:30.875: gst_mini_object_unref: assertion ‘GST_MINI_OBJECT_REFCOUNT_VALUE (mini_object) > 0’ failed

(dvrPR:121489): GStreamer-CRITICAL **: 21:33:30.875: gst_mini_object_unref: assertion ‘GST_MINI_OBJECT_REFCOUNT_VALUE (mini_object) > 0’ failed

(dvrPR:121489): GStreamer-CRITICAL **: 21:33:30.875: gst_mini_object_unref: assertion ‘GST_MINI_OBJECT_REFCOUNT_VALUE (mini_object) > 0’ failed
malloc(): unsorted double linked list corrupted
Aborted (core dumped)

All caused by the g_signal_connect (…)
How would I set about trying to debug this. Is not the malloc/linked list bit indicative of a bug

slomo · October 1, 2024, 6:52am

Can you show the complete code, especially the messageHandler callback?

rottnest · October 1, 2024, 8:39am

#include <gst/gst.h>

GstElement *mainPipe;
GstElement *recordPipe;

static void messageHandler (GstBus *bus, GstMessage *msg, gpointer user_data)
{
    GMainLoop *loop = (GMainLoop *)user_data;

    GError *err;
    gchar *debug_info;
    switch (GST_MESSAGE_TYPE (msg)) {
        case GST_MESSAGE_ERROR:
            gst_message_parse_error (msg, &err, &debug_info);
            g_printerr("----[error] %s\n", err->message);
            g_printerr("    %s\n", debug_info ? debug_info : "none");
            g_clear_error (&err);
            g_free (debug_info);
            break;

        case GST_MESSAGE_WARNING:
            gst_message_parse_error (msg, &err, &debug_info);
            g_printerr("----[warning] %s\n", err->message);
            g_printerr("    %s\n", debug_info ? debug_info : "none");
            g_clear_error (&err);
            g_free (debug_info);
            break;
        case GST_MESSAGE_INFO:
            gst_message_parse_error (msg, &err, &debug_info);
            g_printerr("----[info] %s\n", err->message);
            g_printerr("    %s\n", debug_info ? debug_info : "none");
            g_clear_error (&err);
            g_free (debug_info);
            break;
        case GST_MESSAGE_EOS:
            g_print("----End-Of-Stream reached.\n");
            //g_main_loop_quit(loop);
            break;
        default:
            break;
    }

    gst_message_unref (msg);
}

int main(int argc, char *argv[]) {
//    GstBus *bus;
//    GMainLoop *loop1;
    GstMessage *msg;

    g_print ("--dvrRecord\n");
    if (argc < 4) {
        g_printerr ("usage: dvrPreview CardNo mainPipe recordPipe recordName\n");
        //                      0        1       2        3           4
        exit (1);
    }

    // Initialize GStreamer
    gst_init (&argc, &argv);

    // Create pipelines
    mainPipe  = gst_pipeline_new ("mainPipe");
    recordPipe = gst_pipeline_new ("recordPipe");

    // Create pipeline from string
    mainPipe = gst_parse_launch (argv[2], NULL);
    recordPipe = gst_parse_launch (argv[3], NULL);

    if (mainPipe == 0) {
        g_printerr ("Failed to create  mainPipe.\n");
        return -1;
    }
    if (recordPipe == 0) {
        g_printerr ("Failed to create  recordPipe.\n");
        return -1;
    }

    // Create bus and add watch
    GstBus *bus1 = gst_pipeline_get_bus (GST_PIPELINE (mainPipe));
    gst_bus_add_signal_watch (bus1);
    g_signal_connect (bus1, "message", G_CALLBACK (messageHandler), NULL);

    // Create main loop
    GMainLoop *loop1 = g_main_loop_new (NULL, FALSE);

    // Start pipeline
    gst_element_set_state (mainPipe, GST_STATE_PLAYING);

    // Run main loop
    g_main_loop_run (loop1);

    // Wait for EOS or error
    //msg1 = gst_bus_timed_pop_filtered(bus, GST_CLOCK_TIME_NONE, GST_MESSAGE_EOS | GST_MESSAGE_ERROR);

    // Free resources
    //if (msg) {
    //    gst_message_unref (msg);
    //}
    gst_object_unref (bus1);
    gst_object_unref (mainPipe);
    g_main_loop_unref (loop1);

    // Deinitialize GStreamer
    gst_deinit();

    return 0;
}

slomo · October 1, 2024, 2:10pm

Don’t unref the message at the end of your callback. You don’t own the reference

rottnest · October 1, 2024, 2:23pm

Thankyou, that makes sense! I’ll try