c - 我怎样才能摆脱这个警告？在 gstreamer c 语言中

问题描述

我正在尝试用 c 语言处理 gstreamer 并播放 h264 或 mp4。我创建了 decodebin 并运行了以下代码。然后有很多警告。你能告诉我哪里出了问题吗？

    #include <gst/gst.h>
    GstElement *pipeline, *audio;
    
    static void
    cb_newpad (GstElement *decodebin,
           GstPad     *pad,
           gpointer    data)
    {
      GstCaps *caps;
      GstStructure *str;
      GstPad *audiopad;

      /* only link once */
      audiopad = gst_element_get_static_pad (audio, "sink");
      if (GST_PAD_IS_LINKED (audiopad)) {
        g_object_unref (audiopad);
        return;
      }

      /* check media type */
      caps = gst_pad_query_caps (pad, NULL);
      str = gst_caps_get_structure (caps, 0);
      if (!g_strrstr (gst_structure_get_name (str), "audio")) {
        gst_caps_unref (caps);
        gst_object_unref (audiopad);
        return;
      }
      gst_caps_unref (caps);

      /* link'n'play */
      gst_pad_link (pad, audiopad);

      g_object_unref (audiopad);
    }

    gint
    main (gint   argc,
          gchar *argv[])
    {
      GMainLoop *loop;
      GstElement *src, *dec, *conv, *sink;
      GstPad *audiopad;
      GstBus *bus;

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

      /* make sure we have input */
      if (argc != 2) {
        g_print ("Usage: %s <filename>\n", argv[0]);
        return -1;
      }

      /* setup */
      pipeline = gst_pipeline_new ("pipeline");

      bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
      gst_bus_add_watch (bus, my_bus_callback, loop);
      gst_object_unref (bus);

      src = gst_element_factory_make ("filesrc", "source");
      g_object_set (G_OBJECT (src), "location", argv[1], NULL);
      dec = gst_element_factory_make ("decodebin", "decoder");
      g_signal_connect (dec, "pad-added", G_CALLBACK (cb_newpad), NULL);
      gst_bin_add_many (GST_BIN (pipeline), src, dec, NULL);
      gst_element_link (src, dec);

      /* create audio output */
      audio = gst_bin_new ("audiobin");
      conv = gst_element_factory_make ("audioconvert", "aconv");
      audiopad = gst_element_get_static_pad (conv, "sink");
      sink = gst_element_factory_make ("alsasink", "sink");
      gst_bin_add_many (GST_BIN (audio), conv, sink, NULL);
      gst_element_link (conv, sink);
      gst_element_add_pad (audio,
          gst_ghost_pad_new ("sink", audiopad));
      gst_object_unref (audiopad);
      gst_bin_add (GST_BIN (pipeline), audio);

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

      /* cleanup */
      gst_element_set_state (pipeline, GST_STATE_NULL);
      gst_object_unref (GST_OBJECT (pipeline));

      return 0;
    }

以下是警告内容

（a.out：5166）：GLib-GObject-WARNING **：15：28：10.057：无效的不可实例化类型''转换为'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.058: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.058: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.058: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.058: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.059: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.059: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.059: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.059: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.060: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.060: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.060: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.645: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.649: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.649: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.649: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.740: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.741: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.772: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.773: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.793: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.805: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.806: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.943: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

(a.out:5166): GLib-GObject-WARNING **: 15:28:10.944: invalid uninstantiatable type '<invalid>' in cast to 'GstElement'

标签： cvideogstreamerdecode

c - 我怎样才能摆脱这个警告？在 gstreamer c 语言中

问题描述

解决方案

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