camerabin: add video-source-filter property

Add video-source-filter property that can be used to inject application
specific gstreamer element to camerabin pipeline. The video-source-filter
element will process all frames coming from video source.

One could add image analyzers to collect information about the stream,
or add image enhancers to improve capture quality, for example.

diff --git a/gst/camerabin/gstcamerabin-enum.h b/gst/camerabin/gstcamerabin-enum.h
index 3794201..776a774 100644 (file)
--- a/gst/camerabin/gstcamerabin-enum.h
+++ b/gst/camerabin/gstcamerabin-enum.h
@@ -55,7 +55,8 @@ enum
   ARG_EV_COMP,
   ARG_ISO_SPEED,
   ARG_APERTURE,
-  ARG_EXPOSURE
+  ARG_EXPOSURE,
+  ARG_VIDEO_SOURCE_FILTER
 };
 
 /**

diff --git a/gst/camerabin/gstcamerabin.c b/gst/camerabin/gstcamerabin.c
index 66ea55f..fdadfb4 100644 (file)
--- a/gst/camerabin/gstcamerabin.c
+++ b/gst/camerabin/gstcamerabin.c
@@ -125,7 +125,7 @@
  * The pipeline in the camerabin is
  *
  * videosrc [ ! ffmpegcsp ] ! capsfilter ! crop ! scale ! capsfilter ! \
- *     out-sel name=osel ! queue name=img_q
+ *     [ video_filter ! ] out-sel name=osel ! queue name=img_q
  *
  * View finder:
  * osel. ! in-sel name=isel ! scale ! capsfilter [ ! ffmpegcsp ] ! vfsink
@@ -583,6 +583,11 @@ camerabin_create_src_elements (GstCameraBin * camera)
             gst_camerabin_create_and_add_element (cbin, "capsfilter")))
       goto done;
   }
+  if (camera->app_video_filter) {
+    if (!gst_camerabin_add_element (cbin, camera->app_video_filter)) {
+      goto done;
+    }
+  }
   if (!(camera->src_out_sel =
           gst_camerabin_create_and_add_element (cbin, "output-selector")))
     goto done;
@@ -883,6 +888,11 @@ camerabin_dispose_elements (GstCameraBin * camera)
     camera->user_vid_src = NULL;
   }
 
+  if (camera->app_video_filter) {
+    gst_object_unref (camera->app_video_filter);
+    camera->app_video_filter = NULL;
+  }
+
   /* Free caps */
   gst_caps_replace (&camera->image_capture_caps, NULL);
   gst_caps_replace (&camera->view_finder_caps, NULL);
@@ -2581,6 +2591,23 @@ gst_camerabin_class_init (GstCameraBinClass * klass)
           GST_TYPE_ELEMENT, G_PARAM_READWRITE));
 
   /**
+   *  GstCameraBin:video-source-filter:
+   *
+   * Set up optional video filter element, all frames from video source
+   * will be processed by this element. e.g. An application might add
+   * image enhancers/parameter adjustment filters here to improve captured
+   * image/video results, or add analyzers to give feedback on capture
+   * the application.
+   * 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_SOURCE_FILTER,
+      g_param_spec_object ("video-source-filter", "video source filter element",
+          "Optional video filter GStreamer element, filters all frames from"
+          "the video source", GST_TYPE_ELEMENT, G_PARAM_READWRITE));
+
+  /**
    * GstCameraBin:video-source-caps:
    *
    * The allowed modes of operation of the video source. Have in mind that it
@@ -2825,6 +2852,7 @@ gst_camerabin_init (GstCameraBin * camera, GstCameraBinClass * gclass)
   camera->src_zoom_filter = NULL;
   camera->src_out_sel = NULL;
 
+  camera->app_video_filter = NULL;
   camera->user_vid_src = NULL;
 
   camera->active_bin = NULL;
@@ -3007,6 +3035,17 @@ gst_camerabin_set_property (GObject * object, guint prop_id,
       gst_camerabin_video_set_audio_src (GST_CAMERABIN_VIDEO (camera->vidbin),
           g_value_get_object (value));
       break;
+    case ARG_VIDEO_SOURCE_FILTER:
+      if (GST_STATE (camera) != GST_STATE_NULL) {
+        GST_ELEMENT_ERROR (camera, CORE, FAILED,
+            ("camerabin must be in NULL state when setting the video filter element"),
+            (NULL));
+      } else {
+        if (camera->app_video_filter)
+          gst_object_unref (camera->app_video_filter);
+        camera->app_video_filter = g_value_dup_object (value);
+      }
+      break;
     case ARG_FILTER_CAPS:
       GST_OBJECT_LOCK (camera);
       gst_caps_replace (&camera->view_finder_caps,
@@ -3125,6 +3164,9 @@ gst_camerabin_get_property (GObject * object, guint prop_id,
           gst_camerabin_video_get_audio_src (GST_CAMERABIN_VIDEO
               (camera->vidbin)));
       break;
+    case ARG_VIDEO_SOURCE_FILTER:
+      g_value_set_object (value, camera->app_video_filter);
+      break;
     case ARG_INPUT_CAPS:
       gst_value_set_caps (value, gst_camerabin_get_allowed_input_caps (camera));
       break;

diff --git a/gst/camerabin/gstcamerabin.h b/gst/camerabin/gstcamerabin.h
index 58350c3..a7dd674 100644 (file)
--- a/gst/camerabin/gstcamerabin.h
+++ b/gst/camerabin/gstcamerabin.h
@@ -137,6 +137,7 @@ struct _GstCameraBin
   /* User configurable elements */
   GstElement *user_vid_src;
   GstElement *user_vf_sink;
+  GstElement *app_video_filter;
 
   /* Night mode handling */
   gboolean night_mode;