camerabin: set camerabin default sources/sinks like in playbin2. Fixes #574434

This uses same approach like in playbin, namely checking for user defined
element, auto{audio,video}{sink,src} and finally DEFAULT_{AUDIO,VIDEO}{SRC,SINK}
defines from config.h.

configure.ac

@@ -246,6 +246,9 @@ AG_GST_SET_ERROR_CXXFLAGS($GST_CVS)
 dnl define correct level for debugging messages
 AG_GST_SET_LEVEL_DEFAULT($GST_CVS)
 
+dnl used in examples
+AG_GST_DEFAULT_ELEMENTS
+
 dnl *** plug-ins to include ***
 
 dnl these are all the gst plug-ins, compilable without additional libs

gst/camerabin/camerabingeneral.c

@@ -117,7 +117,7 @@ gst_camerabin_try_add_element (GstBin * bin, GstElement * new_elem)
 GstElement *
 gst_camerabin_create_and_add_element (GstBin * bin, const gchar * elem_name)
 {
-  GstElement *new_elem = NULL;
+  GstElement *new_elem;
 
   new_elem = gst_element_factory_make (elem_name, NULL);
   if (!new_elem) {
@@ -130,6 +130,53 @@ gst_camerabin_create_and_add_element (GstBin * bin, const gchar * elem_name)
   return new_elem;
 }
 
+/* try to change the state of an element. This function returns the element when
+ * the state change could be performed. When this function returns NULL an error
+ * occured and the element is unreffed if @unref is TRUE. */
+static GstElement *
+try_element (GstElement * bin, GstElement * element, gboolean unref)
+{
+  GstStateChangeReturn ret;
+
+  if (element) {
+    ret = gst_element_set_state (element, GST_STATE_READY);
+    if (ret == GST_STATE_CHANGE_FAILURE) {
+      GST_DEBUG_OBJECT (bin, "failed state change..");
+      gst_element_set_state (element, GST_STATE_NULL);
+      if (unref)
+        gst_object_unref (element);
+      element = NULL;
+    }
+  }
+  return element;
+}
+
+GstElement *
+gst_camerabin_setup_default_element (GstBin * bin, GstElement * user_elem,
+    const gchar * auto_elem_name, const gchar * default_elem_name)
+{
+  GstElement *elem;
+
+  if (user_elem) {
+    GST_DEBUG_OBJECT (bin, "trying configured element");
+    elem = try_element (bin, user_elem, FALSE);
+  } else {
+    /* only try fallback if no specific sink was chosen */
+    GST_DEBUG_OBJECT (bin, "trying %s", auto_elem_name);
+    elem = gst_element_factory_make (auto_elem_name, NULL);
+    elem = try_element (bin, elem, TRUE);
+    if (elem == NULL) {
+      /* if default sink from config.h is different then try it too */
+      if (strcmp (default_elem_name, auto_elem_name)) {
+        GST_DEBUG_OBJECT (bin, "trying %s", default_elem_name);
+        elem = gst_element_factory_make (default_elem_name, NULL);
+        elem = try_element (bin, elem, TRUE);
+      }
+    }
+  }
+  return elem;
+}
+
 /**
  * gst_camerabin_remove_elements_from_bin:
  * @bin: removes all elements from this bin

gst/camerabin/camerabingeneral.h

@@ -27,6 +27,8 @@ gboolean gst_camerabin_try_add_element (GstBin * bin, GstElement * new_elem);
 gboolean gst_camerabin_add_element (GstBin * bin, GstElement * new_elem);
 GstElement *gst_camerabin_create_and_add_element (GstBin * bin, const gchar * elem_name);
 
+GstElement * gst_camerabin_setup_default_element (GstBin * bin, GstElement *user_elem, const gchar *auto_elem_name, const gchar *default_elem_name);
+
 void gst_camerabin_remove_elements_from_bin (GstBin * bin);
 
 gboolean gst_camerabin_drop_eos_probe (GstPad * pad, GstEvent * event, gpointer u_data);

gst/camerabin/camerabinvideo.c

@@ -51,6 +51,9 @@
  * includes
  */
 
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include <gst/gst.h>
 #include "camerabingeneral.h"
@@ -63,7 +66,6 @@
 
 /* internal element names */
 
-#define DEFAULT_AUD_SRC "pulsesrc"
 #define DEFAULT_AUD_ENC "vorbisenc"
 #define DEFAULT_VID_ENC "theoraenc"
 #define DEFAULT_MUX "oggmux"
@@ -616,14 +618,13 @@ gst_camerabin_video_create_elements (GstCameraBinVideo * vid)
       NULL);
 
   /* Add user set or default audio source element */
-  if (vid->user_aud_src) {
-    vid->aud_src = vid->user_aud_src;
-    if (!gst_camerabin_add_element (vidbin, vid->aud_src)) {
-      goto error;
-    }
-  } else if (!(vid->aud_src =
-          gst_camerabin_create_and_add_element (vidbin, DEFAULT_AUD_SRC))) {
+  if (!(vid->aud_src = gst_camerabin_setup_default_element (vidbin,
+              vid->user_aud_src, "autoaudiosrc", DEFAULT_AUDIOSRC))) {
+    vid->aud_src = NULL;
     goto error;
+  } else {
+    if (!gst_camerabin_add_element (vidbin, vid->aud_src))
+      goto error;
   }
 
   /* Add queue element for audio */

gst/camerabin/gstcamerabin.c

@@ -226,12 +226,6 @@ static guint camerabin_signals[LAST_SIGNAL];
 //#define USE_VIEWFINDER_COLOR_CONVERTER 1
 //#define USE_VIEWFINDER_SCALE 1
 
-/* internal element names */
-
-/* FIXME: Make sure this can work with autovideosrc and use that. */
-#define DEFAULT_SRC_VID_SRC "v4l2src"
-#define DEFAULT_VIEW_SINK "autovideosink"
-
 /* message names */
 #define PREVIEW_MESSAGE_NAME "preview-image"
 #define IMG_CAPTURED_MESSAGE_NAME "image-captured"
@@ -558,16 +552,15 @@ camerabin_create_src_elements (GstCameraBin * camera)
   GstBin *cbin = GST_BIN (camera);
   gchar *driver_name = NULL;
 
-  if (camera->user_vid_src) {
-    camera->src_vid_src = camera->user_vid_src;
-
-    if (!gst_camerabin_add_element (cbin, camera->src_vid_src)) {
-      camera->src_vid_src = NULL;
-      goto done;
-    }
-  } else if (!(camera->src_vid_src =
-          gst_camerabin_create_and_add_element (cbin, DEFAULT_SRC_VID_SRC)))
+  /* Add user set or default video src element */
+  if (!(camera->src_vid_src = gst_camerabin_setup_default_element (cbin,
+              camera->user_vid_src, "autovideosrc", DEFAULT_VIDEOSRC))) {
+    camera->src_vid_src = NULL;
     goto done;
+  } else {
+    if (!gst_camerabin_add_element (cbin, camera->src_vid_src))
+      goto done;
+  }
 #ifdef USE_COLOR_CONVERTER
   if (!gst_camerabin_create_and_add_element (cbin, "ffmpegcolorspace"))
     goto done;
@@ -646,10 +639,10 @@ static gboolean
 camerabin_create_view_elements (GstCameraBin * camera)
 {
   const GList *pads;
+  GstBin *cbin = GST_BIN (camera);
 
   if (!(camera->view_in_sel =
-          gst_camerabin_create_and_add_element (GST_BIN (camera),
-              "input-selector"))) {
+          gst_camerabin_create_and_add_element (cbin, "input-selector"))) {
     goto error;
   }
 
@@ -664,33 +657,29 @@ camerabin_create_view_elements (GstCameraBin * camera)
 #ifdef USE_VIEWFINDER_CONVERTERS
   /* Add videoscale in case we need to downscale frame for view finder */
   if (!(camera->view_scale =
-          gst_camerabin_create_and_add_element (GST_BIN (camera),
-              "videoscale"))) {
+          gst_camerabin_create_and_add_element (cbin, "videoscale"))) {
     goto error;
   }
 
   /* Add capsfilter to maintain aspect ratio while scaling */
   if (!(camera->aspect_filter =
-          gst_camerabin_create_and_add_element (GST_BIN (camera),
-              "capsfilter"))) {
+          gst_camerabin_create_and_add_element (cbin, "capsfilter"))) {
     goto error;
   }
 #endif
 #ifdef USE_VIEWFINDER_COLOR_CONVERTER
-  if (!gst_camerabin_create_and_add_element (GST_BIN (camera),
-          "ffmpegcolorspace")) {
+  if (!gst_camerabin_create_and_add_element (cbin, "ffmpegcolorspace")) {
     goto error;
   }
 #endif
-  if (camera->user_vf_sink) {
-    camera->view_sink = camera->user_vf_sink;
-    if (!gst_camerabin_add_element (GST_BIN (camera), camera->view_sink)) {
-      goto error;
-    }
-  } else if (!(camera->view_sink =
-          gst_camerabin_create_and_add_element (GST_BIN (camera),
-              DEFAULT_VIEW_SINK))) {
+  /* Add user set or default video sink element */
+  if (!(camera->view_sink = gst_camerabin_setup_default_element (cbin,
+              camera->user_vf_sink, "autovideosink", DEFAULT_VIDEOSINK))) {
+    camera->view_sink = NULL;
     goto error;
+  } else {
+    if (!gst_camerabin_add_element (cbin, camera->view_sink))
+      goto error;
   }
 
   return TRUE;
@@ -1652,8 +1641,7 @@ gst_camerabin_send_video_eos (GstCameraBin * camera)
     gst_pad_send_event (videopad, gst_event_new_eos ());
     gst_object_unref (videopad);
     camera->eos_handled = TRUE;
-  }
-  else {
+  } else {
     GST_INFO_OBJECT (camera, "dropping duplicate EOS");
   }
 }
@@ -2472,41 +2460,41 @@ gst_camerabin_class_init (GstCameraBinClass * klass)
    *  GstCameraBin:vfsink:
    *
    * Set up a sink element to render frames in view finder.
-   * By default "autovideosink" will be the sink element.
+   * By default "autovideosink" or DEFAULT_VIDEOSINK will be used.
    * This property can only be set while #GstCameraBin is in NULL state.
    * The ownership of the element will be taken by #GstCameraBin.
    */
 
   g_object_class_install_property (gobject_class, ARG_VF_SINK,
       g_param_spec_object ("vfsink", "View finder sink",
-          "View finder sink GStreamer element (default is " DEFAULT_VIEW_SINK
-          ")", GST_TYPE_ELEMENT, G_PARAM_READWRITE));
+          "View finder sink GStreamer element (NULL = default video sink)",
+          GST_TYPE_ELEMENT, G_PARAM_READWRITE));
 
   /**
    *  GstCameraBin:videosrc:
    *
    * Set up a video source element.
-   * By default "v4l2src" will be the src element.
+   * By default "autovideosrc" or DEFAULT_VIDEOSRC will be used.
    * This property can only be set while #GstCameraBin is in NULL state.
    * The ownership of the element will be taken by #GstCameraBin.
    */
 
   g_object_class_install_property (gobject_class, ARG_VIDEO_SRC,
       g_param_spec_object ("videosrc", "Video source element",
-          "Video source GStreamer element (default is " DEFAULT_SRC_VID_SRC ")",
+          "Video source GStreamer element (NULL = default video src)",
           GST_TYPE_ELEMENT, G_PARAM_READWRITE));
   /**
    *  GstCameraBin:audiosrc:
    *
    * Set up an audio source element.
-   * By default "pulsesrc" will be the source element.
+   * By default "autoaudiosrc" or DEFAULT_AUDIOSRC will be used.
    * This property can only be set while #GstCameraBin is in NULL state.
    * The ownership of the element will be taken by #GstCameraBin.
    */
 
   g_object_class_install_property (gobject_class, ARG_AUDIO_SRC,
       g_param_spec_object ("audiosrc", "Audio source element",
-          "Audio source GStreamer element (default is pulsesrc)",
+          "Audio source GStreamer element (NULL = default audio src)",
           GST_TYPE_ELEMENT, G_PARAM_READWRITE));
 
   /**
@@ -2898,7 +2886,7 @@ gst_camerabin_set_property (GObject * object, guint prop_id,
         new_caps = (GstCaps *) gst_value_get_caps (value);
         GST_DEBUG_OBJECT (camera,
             "setting preview caps: %" GST_PTR_FORMAT " -> %" GST_PTR_FORMAT,
-             camera->preview_caps, new_caps);
+            camera->preview_caps, new_caps);
 
         if (!gst_caps_is_equal (camera->preview_caps, new_caps)) {
           GST_OBJECT_LOCK (camera);