camerabin: Scale incoming frames if their size does not match requested size

If capture preparation in videosrc results in frame size different
from requested size, then we need to scale them.

gst/camerabin/gstcamerabin.c

@@ -1266,24 +1266,75 @@ gst_camerabin_set_capsfilter_caps (GstCameraBin * camera, GstCaps * new_caps)
   g_object_set (G_OBJECT (camera->src_zoom_filter), "caps", new_caps, NULL);
 }
 
+static void
+gst_camerabin_adapt_video_resolution (GstCameraBin * camera, GstCaps * caps)
+{
+  GstStructure *st;
+  gint width = 0, height = 0;
+  GstCaps *filter_caps = NULL;
+
+  /* Get width and height from caps */
+  st = gst_caps_get_structure (caps, 0);
+  gst_structure_get_int (st, "width", &width);
+  gst_structure_get_int (st, "height", &height);
+
+  GST_DEBUG_OBJECT (camera,
+      "changing %dx%d -> %dx%d filter to %" GST_PTR_FORMAT,
+      camera->width, camera->height, width, height, camera->src_filter);
+
+  /* Apply the width and height to filter caps */
+  g_object_get (G_OBJECT (camera->src_filter), "caps", &filter_caps, NULL);
+  filter_caps = gst_caps_make_writable (filter_caps);
+  gst_caps_set_simple (filter_caps, "width", G_TYPE_INT, width,
+      "height", G_TYPE_INT, height, NULL);
+  g_object_set (G_OBJECT (camera->src_filter), "caps", filter_caps, NULL);
+  gst_caps_unref (filter_caps);
+  /* FIXME: implement cropping according to requested aspect ratio */
+}
+
 /*
  * img_capture_prepared:
  * @data: camerabin object
+ * @caps: caps describing the prepared image format
  *
  * Callback which is called after image capture has been prepared.
  */
 static void
-img_capture_prepared (gpointer data)
+img_capture_prepared (gpointer data, GstCaps * caps)
 {
   GstCameraBin *camera = GST_CAMERABIN (data);
+  GstStructure *st, *new_st;
+  gint i;
+  const gchar *field_name;
 
   GST_INFO_OBJECT (camera, "image capture prepared");
 
-  if (camera->image_capture_caps) {
+  /* It is possible we are about to get something else that we requested */
-    /* Set capsfilters to match arriving image data */
+  if (!gst_caps_is_equal (camera->image_capture_caps, caps)) {
-    gst_camerabin_set_capsfilter_caps (camera, camera->image_capture_caps);
+    /* If capture preparation has added new fields to requested caps,
+       we need to copy them */
+    st = gst_caps_get_structure (camera->image_capture_caps, 0);
+    new_st = gst_structure_copy (st);
+    st = gst_caps_get_structure (caps, 0);
+    for (i = 0; i < gst_structure_n_fields (st); i++) {
+      field_name = gst_structure_nth_field_name (st, i);
+      if (!gst_structure_has_field (new_st, field_name)) {
+        GST_DEBUG_OBJECT (camera, "new field in prepared caps: %s", field_name);
+        gst_structure_set_value (new_st, field_name,
+            gst_structure_get_value (st, field_name));
+      }
+    }
+    gst_caps_replace (&camera->image_capture_caps,
+        gst_caps_new_full (new_st, NULL));
   }
 
+  /* Update capsfilters */
+  gst_camerabin_set_capsfilter_caps (camera, camera->image_capture_caps);
+
+  /* If incoming buffer resolution is different from what application
+     requested, then we need to fix this in camerabin */
+  gst_camerabin_adapt_video_resolution (camera, caps);
+
   g_object_set (G_OBJECT (camera->src_out_sel), "resend-latest", FALSE,
       "active-pad", camera->pad_src_img, NULL);
   gst_camerabin_rewrite_tags (camera);
@@ -1300,9 +1351,7 @@ static void
 gst_camerabin_start_image_capture (GstCameraBin * camera)
 {
   GstStateChangeReturn state_ret;
-  gboolean wait_for_prepare = FALSE;
+  gboolean wait_for_prepare = FALSE, ret = FALSE;
-  gint width = 0, height = 0, fps_n = 0, fps_d = 0;
-  GstStructure *st;
 
   GST_INFO_OBJECT (camera, "starting image capture");
 
@@ -1312,17 +1361,6 @@ gst_camerabin_start_image_capture (GstCameraBin * camera)
     /* Start image capture preparations using photography iface */
     wait_for_prepare = TRUE;
     g_mutex_lock (camera->capture_mutex);
-    if (camera->image_capture_caps) {
-      st = gst_caps_get_structure (camera->image_capture_caps, 0);
-    } else {
-      st = gst_caps_get_structure (camera->view_finder_caps, 0);
-    }
-    gst_structure_get_int (st, "width", &width);
-    gst_structure_get_int (st, "height", &height);
-    gst_structure_get_fraction (st, "framerate", &fps_n, &fps_d);
-    /* Set image capture resolution and frame rate */
-    g_signal_emit_by_name (camera->src_vid_src, "user-res-fps",
-        width, height, fps_n, fps_d, 0);
 
     /* Enable still image capture mode in v4l2camsrc */
     if (g_object_class_find_property (G_OBJECT_GET_CLASS (camera->src_vid_src),
@@ -1330,9 +1368,17 @@ gst_camerabin_start_image_capture (GstCameraBin * camera)
       g_object_set (G_OBJECT (camera->src_vid_src), "capture-mode", 1, NULL);
     }
 
+    if (!camera->image_capture_caps) {
+      camera->image_capture_caps = gst_caps_copy (camera->view_finder_caps);
+    }
+
     /* Start preparations for image capture */
-    gst_photography_prepare_for_capture (GST_PHOTOGRAPHY (camera->src_vid_src),
+    GST_DEBUG_OBJECT (camera, "prepare image capture caps %" GST_PTR_FORMAT,
-        (GstPhotoCapturePrepared) img_capture_prepared, camera);
+        camera->image_capture_caps);
+    ret =
+        gst_photography_prepare_for_capture (GST_PHOTOGRAPHY
+        (camera->src_vid_src), (GstPhotoCapturePrepared) img_capture_prepared,
+        camera->image_capture_caps, camera);
     camera->capturing = TRUE;
     g_mutex_unlock (camera->capture_mutex);
   }
@@ -1345,12 +1391,17 @@ gst_camerabin_start_image_capture (GstCameraBin * camera)
       g_object_set (G_OBJECT (camera->src_out_sel), "resend-latest", TRUE,
           "active-pad", camera->pad_src_img, NULL);
       camera->capturing = TRUE;
+      ret = TRUE;
       g_mutex_unlock (camera->capture_mutex);
     } else {
       GST_WARNING_OBJECT (camera, "imagebin state change failed");
       gst_element_set_state (camera->imgbin, GST_STATE_NULL);
     }
   }
+
+  if (!ret) {
+    GST_WARNING_OBJECT (camera, "starting image capture failed");
+  }
 }
 
 /*