[gst-devel] removed objects destroyed after pipeline unref

[Dan Taylor]

I am trying to use multiple frontends to feed an audio/video backend
pair.

When I switch frontends, I unlink the front/back ends, remove them from
their respective pipelines and unref the pipelines.  After I have done
that,
the backend object has been destroyed.

I've attached a code snippet and XML dumps of an affected object before
it
is removed from the pipeline, the pipeline after removal, and the
complaint
about the object after it is removed.

With the object removed from the pipeline, unreffing the pipeline
shouldn't
change any of the objects it used to contain.  Any hints about what I've
missed?

Sorry about the length of the xml.

Code:

    gst_element_set_state (GST_ELEMENT (audio_pipeline),
GST_STATE_NULL);

    /* unlink ends */
    unlink_backend_sink(audio_backend);

    if (dump_xml) gst_xml_write_file (GST_ELEMENT (audio_backend),
stdout);

    /* remove them from bin, so they are not freed */
    gst_bin_remove_many(GST_BIN (audio_pipeline), audio_frontend,
audio_backend, NULL);

    if (dump_xml) gst_xml_write_file (GST_ELEMENT (audio_pipeline),
stdout);

    gst_object_unref (audio_pipeline);
    audio_pipeline = NULL;

    if (dump_xml) gst_xml_write_file (GST_ELEMENT (audio_backend),
stdout);

Messages and debug prints:

backend audio_backend
backend unlink successful

<?xml version="1.0"?>
<gstreamer xmlns:gst="http://gstreamer.net/gst-core/1.0/">
  <gst:element>
    <gst:name>audio_backend</gst:name>
    <gst:type>bin</gst:type>
    <gst:param>
      <gst:name>name</gst:name>
      <gst:value>audio_backend</gst:value>
    </gst:param>
    <gst:param>
      <gst:name>async-handling</gst:name>
      <gst:value>FALSE</gst:value>
    </gst:param>
    <gst:pad>
      <gst:ghostpad>
        <gst:name>ghost3</gst:name>
        <gst:parent>audio_backend</gst:parent>
        <gst:direction>sink</gst:direction>
        <gst:peer>audio_frontend.ghost2</gst:peer>
      </gst:ghostpad>
    </gst:pad>
    <gst:children>
      <gst:element>
        <gst:name>alsasink0</gst:name>
        <gst:type>alsasink</gst:type>
        <gst:param>
          <gst:name>name</gst:name>
          <gst:value>alsasink0</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>preroll-queue-len</gst:name>
          <gst:value>0</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>sync</gst:name>
          <gst:value>TRUE</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>max-lateness</gst:name>
          <gst:value>-1</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>qos</gst:name>
          <gst:value>FALSE</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>async</gst:name>
          <gst:value>TRUE</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>ts-offset</gst:name>
          <gst:value>0</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>last-buffer</gst:name>
          <gst:value>NULL</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>buffer-time</gst:name>
          <gst:value>200000</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>latency-time</gst:name>
          <gst:value>10000</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>provide-clock</gst:name>
          <gst:value>TRUE</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>slave-method</gst:name>
          <gst:value>1</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>device</gst:name>
          <gst:value>default</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>device-name</gst:name>
          <gst:value/>
        </gst:param>
        <gst:pad>
          <gst:name>sink</gst:name>
          <gst:direction>sink</gst:direction>
          <gst:peer>audioconvert0.src</gst:peer>
        </gst:pad>
      </gst:element>
      <gst:element>
        <gst:name>audioconvert0</gst:name>
        <gst:type>audioconvert</gst:type>
        <gst:param>
          <gst:name>name</gst:name>
          <gst:value>audioconvert0</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>qos</gst:name>
          <gst:value>FALSE</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>dithering</gst:name>
          <gst:value>2</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>noise-shaping</gst:name>
          <gst:value>0</gst:value>
        </gst:param>
        <gst:pad>
          <gst:name>src</gst:name>
          <gst:direction>source</gst:direction>
          <gst:peer>alsasink0.sink</gst:peer>
        </gst:pad>
        <gst:pad>
          <gst:name>sink</gst:name>
          <gst:direction>sink</gst:direction>
          <gst:peer>audio_q.src</gst:peer>
        </gst:pad>
      </gst:element>
      <gst:element>
        <gst:name>audio_q</gst:name>
        <gst:type>queue</gst:type>
        <gst:param>
          <gst:name>name</gst:name>
          <gst:value>audio_q</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>current-level-buffers</gst:name>
          <gst:value>0</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>current-level-bytes</gst:name>
          <gst:value>0</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>current-level-time</gst:name>
          <gst:value>0</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>max-size-buffers</gst:name>
          <gst:value>0</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>max-size-bytes</gst:name>
          <gst:value>10485760</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>max-size-time</gst:name>
          <gst:value>0</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>min-threshold-buffers</gst:name>
          <gst:value>0</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>min-threshold-bytes</gst:name>
          <gst:value>0</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>min-threshold-time</gst:name>
          <gst:value>0</gst:value>
        </gst:param>
        <gst:param>
          <gst:name>leaky</gst:name>
          <gst:value>0</gst:value>
        </gst:param>
        <gst:pad>
          <gst:name>src</gst:name>
          <gst:direction>source</gst:direction>
          <gst:peer>audioconvert0.sink</gst:peer>
        </gst:pad>
        <gst:pad>
          <gst:name>sink</gst:name>
          <gst:direction>sink</gst:direction>
          <gst:peer/>
        </gst:pad>
      </gst:element>
    </gst:children>
  </gst:element>
</gstreamer>

<?xml version="1.0"?>
<gstreamer xmlns:gst="http://gstreamer.net/gst-core/1.0/">
  <gst:element>
    <gst:name>audio_pipeline</gst:name>
    <gst:type>pipeline</gst:type>
    <gst:param>
      <gst:name>name</gst:name>
      <gst:value>audio_pipeline</gst:value>
    </gst:param>
    <gst:param>
      <gst:name>async-handling</gst:name>
      <gst:value>FALSE</gst:value>
    </gst:param>
    <gst:param>
      <gst:name>delay</gst:name>
      <gst:value>0</gst:value>
    </gst:param>
    <gst:param>
      <gst:name>auto-flush-bus</gst:name>
      <gst:value>TRUE</gst:value>
    </gst:param>
    <gst:children/>
  </gst:element>
</gstreamer>

(avMediaDaemon:22708): GLib-GObject-WARNING **: invalid uninstantiatable
type `(null)' in cast to `GstElement'

(avMediaDaemon:22708): GLib-GObject-WARNING **: invalid uninstantiatable
type `(null)' in cast to `GstObject'

(avMediaDaemon:22708): GStreamer-CRITICAL **: gst_object_save_thyself:
assertion `GST_IS_OBJECT (object)' failed

<?xml version="1.0"?>
<gstreamer xmlns:gst="http://gstreamer.net/gst-core/1.0/">
  <gst:element/>
</gstreamer>