title: Gstreamer playback using typefind
body: <p>To start with I am just a beginner in gstreamer and I am in the process of development of an application which sends video data to the listener and listener decodes it to play. For this am using gstreamer.
  But before that iam trying to understand gstreamer.</p>
  
  <p>I have got a standalone code which generates a pad-added signal and call back is hit.
  Iam using I.MX6 board for playback.</p>
  
  <p>I used gst-launch to playback a "ts file and as well as mp4 file" using the below command and it works.</p>
  
  <pre><code>gst-launch-0.10 filesrc location=/opt/zu/test/stream2.ts typefind=true ! aiurdemux name=demux demux. ! queue ! beepdec ! audioconvert ! autoaudiosink demux. ! queue ! vpudec! mfw_v4lsink
  </code></pre>
  
  <p>which then i brought it into the code with perfectly using the demuxer and the required elements.</p>
  
  <p>Here i find "typefind=true" is set which I am not sure how to bring it to the code. As far i understood typefind sets the src pads after finding the CAP.
  This is what i got using a standalone for typefind.</p>
  
  <pre><code>&lt;?xml version="1.0"?&gt;
  &lt;Capabilities&gt;
   &lt;Caps1&gt;video/mpegts, systemstream=(boolean)true, packetsize=(int)188&lt;/Caps1&gt;
  &lt;/Capabilities&gt;
  </code></pre>
  
  <p>Cap = video/mpegts</p>
  
  <p>While running my gstreamer standalone to playback ts file , I get the below message</p>
  
  <p>"Pipeline state changed from NULL to READY:" and it doesnt playback. It just keeps running. Below is my standalone code</p>
  
  <pre><code>data.source = gst_element_factory_make ("filesrc", "source");
  g_object_set (data.source, "location", argv[1], NULL);
  data.typefind = gst_element_factory_make ("typefind", "typefinder");
  data.demuxer = gst_element_factory_make ("aiurdemux", "demuxer");
  data.audioqueue = gst_element_factory_make("queue","audioqueue");
  data.videoqueue = gst_element_factory_make("queue","videoqueue");
  data.audio_decoder = gst_element_factory_make ("beepdec", "audio_decoder");
  data.audio_convert = gst_element_factory_make ("audioconvert", "audio_convert");
  data.audio_sink = gst_element_factory_make ("autoaudiosink", "audio_sink");
  data.video_decoder = gst_element_factory_make("vpudec","video_decoder");
  data.video_sink = gst_element_factory_make("mfw_v4lsink","video_sink");
  
     if (!gst_element_link(data.source,data.demuxer)) {
                  g_printerr ("Elements could not be linked.\n");
                  gst_object_unref (data.pipeline);
                  return -1;
          }
  
   if (!gst_element_link_many (data.audioqueue,data.audio_decoder,data.audio_convert, data.audio_sink,NULL)) {
                  g_printerr (" audio Elements could not be linked.\n");
                  gst_object_unref (data.pipeline);
                  return -1;
          }
     if (!gst_element_link_many(data.videoqueue,data.video_decoder, data.video_sink,NULL)) {
                  g_printerr("video Elements could not be linked.\n");
                  gst_object_unref(data.pipeline);
                  return -1;
          }
  
   //g_object_set (data.source, "location", argv[1], NULL);
          g_signal_connect (data.demuxer, "pad-added", G_CALLBACK (pad_added_handler), &amp;data);
          /* Start playing */
  
  
  // CALLBACK FUNCTION
  
  static void pad_added_handler (GstElement *src, GstPad *new_pad, CustomData *data) {
          g_print("Inside the pad_added_handler method \n");
          printf("Inside the pad_added_handler method \n");
          GstPad *sink_pad_audio = gst_element_get_static_pad (data-&gt;audioqueue, "sink");
          GstPad *sink_pad_video = gst_element_get_static_pad (data-&gt;videoqueue, "sink");
  
          GstPadLinkReturn ret;
          GstCaps *new_pad_caps = NULL;
          GstStructure *new_pad_struct = NULL;
          const gchar *new_pad_type = NULL;
          g_print ("Received new pad '%s' from '%s':\n", GST_PAD_NAME (new_pad), GST_ELEMENT_NAME (src));
          new_pad_caps = gst_pad_get_caps (new_pad);
          new_pad_struct = gst_caps_get_structure (new_pad_caps, 0);
          new_pad_type = gst_structure_get_name (new_pad_struct);
          if (g_str_has_prefix (new_pad_type,/*"audio/x-vorbis"*/ "audio/mpeg"))
          {
                  ret = gst_pad_link (new_pad, sink_pad_audio);
                  if (GST_PAD_LINK_FAILED (ret))
                  {
                          g_print (" Type is '%s' but link failed.\n", new_pad_type);
                  }
                  else
                  {
                          g_print (" Link succeeded (type '%s').\n", new_pad_type);
                  }
          }
  
          //else if (g_str_has_prefix (new_pad_type, /*"video/x-theora"*/"video/x-h264"))
          else if (g_str_has_prefix (new_pad_type, /*"video/x-theora"*/"video/mpegts"))
          {
                  ret = gst_pad_link (new_pad, sink_pad_video);
  
                  if (GST_PAD_LINK_FAILED (ret))
                  {
                          g_print (" Type is '%s' but link failed.\n", new_pad_type);
                  }
                  else
                  {
                          g_print (" Link succeeded (type '%s').\n", new_pad_type);
                  }
          }
  
  
          else {
                  g_print (" It has type '%s' which is not raw audio. Ignoring.\n", new_pad_type);
                  goto exit;
          }
  exit:
          if (new_pad_caps != NULL)
                  gst_caps_unref (new_pad_caps);
          gst_object_unref (sink_pad_audio);
          gst_object_unref (sink_pad_video);
  
  }
  </code></pre>
  
  <p>I have reduced some of the code. Can you please guide what Iam missing here.?..
  Iam not sure how to bring type find into the code.</p>
  
  <p>Thanks </p>