Fix some issues with shmsrc pipeline and video dimensions (bug #29)

Shmsrc seems to work with a gstreamer 1.4 build, but not with distro gstreamer
(segfault due to missing fix https://bugzilla.gnome.org/show_bug.cgi?id=731093)
Reader / writer of live source need to be using same gstreamer build, otherwise
some pipeline problems appear in deserializing and caps detection.

Playback of the first shape mapped with the live source doesn't seem to work (?),
so this bug stiil needs investigation.

MediaImpl.cpp

@@ -103,6 +103,19 @@ bool MediaImpl::_videoPull()
     // Pull current frame buffer.
     GstBuffer *buffer = gst_sample_get_buffer(sample);
 
+    // for live sources, video dimensions have not been set, because
+    // gstPadAddedCallback is never called. Fix dimensions from first sample /
+    // caps we receive
+    if (_isSharedMemorySource && ( _padHandlerData.width == -1 ||
+          _padHandlerData.height == -1)) {
+      GstCaps *caps = gst_sample_get_caps(sample);
+      GstStructure *structure;
+      structure = gst_caps_get_structure(caps, 0);
+      gst_structure_get_int(structure, "width",  &_padHandlerData.width);
+      gst_structure_get_int(structure, "height", &_padHandlerData.height);
+      // g_print("Size is %u x %u\n", _padHandlerData.width, _padHandlerData.height);
+    }
+
     GstMapInfo map; 
     if (gst_buffer_map(buffer, &map, GST_MAP_READ))
     { 
@@ -347,14 +360,14 @@ bool MediaImpl::loadMovie(QString filename)
   // Build the pipeline. Note that we are NOT linking the source at this
   // point. We will do it later.
   gst_bin_add_many (GST_BIN (_pipeline),
-    _uridecodebin0, _queue0, _videoconvert0,
-    videoscale0, capsfilter0, _appsink0, NULL);
+    _isSharedMemorySource ? _shmsrc0 : _uridecodebin0, _queue0,
+    _videoconvert0, videoscale0, capsfilter0, _appsink0, NULL);
 
   // special case for shmsrc
   if (_isSharedMemorySource)
   {
     gst_bin_add (GST_BIN(_pipeline), _gdpdepay0);
-    if (! gst_element_link_many (_uridecodebin0, _gdpdepay0, _queue0, NULL))
+    if (! gst_element_link_many (_shmsrc0, _gdpdepay0, _queue0, NULL))
     {
       g_printerr ("Could not link shmsrc, deserializer and video queue.\n");
     }
@@ -410,8 +423,8 @@ bool MediaImpl::loadMovie(QString filename)
   else
   {
     //qDebug() << "LIVE mode" << uri;
-    g_object_set (_uridecodebin0, "socket-path", uri, NULL);
-    g_object_set (_uridecodebin0, "is-live", TRUE, NULL);
+    g_object_set (_shmsrc0, "socket-path", uri, NULL);
+    g_object_set (_shmsrc0, "is-live", TRUE, NULL);
     _padHandlerData.videoIsConnected = true;
   }
 
@@ -448,7 +461,6 @@ bool MediaImpl::loadMovie(QString filename)
   {
     return false;
   }
-
   qDebug() << "Pipeline started.";
 
   //_movieReady = true;