opencv: fix caps issues and extend supported caps for some elements

Some elements had vague caps, such as "video/x-raw-rgb", which caused problems
at least with textwrite. For other elements, the underlying OpenCV functions
support more than just one image type, so I increased the number of supported
caps.

I created a utility function "gst_opencv_caps_from_cv_image_type", so each
element creates caps directly from OpenCV image types, such as CV_8UC1 for
8-bit grayscale. This function uses gstvideo to create uniform caps.

https://bugzilla.gnome.org/show_bug.cgi?id=635304

ext/opencv/gstcvdilateerode.c

@@ -52,6 +52,7 @@
 
 #include <gst/gst.h>
 
+#include "gstopencvutils.h"
 #include "gstcvdilateerode.h"
 
 /*
@@ -59,19 +60,6 @@ GST_DEBUG_CATEGORY_STATIC (gst_cv_dilate_erode_debug);
 #define GST_CAT_DEFAULT gst_cv_dilate_erode_debug
 */
 
-static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
-    GST_PAD_SINK,
-    GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-rgb, depth=(int)24, bpp=(int)24;"
-        "video/x-raw-gray")
-    );
-
-static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
-    GST_PAD_SRC,
-    GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-rgb, depth=(int)24, bpp=(int)24;"
-        "video/x-raw-gray")
-    );
 
 /* Filter signals and args */
 enum
@@ -143,11 +131,21 @@ static void
 gst_cv_dilate_erode_base_init (gpointer gclass)
 {
   GstElementClass *element_class = GST_ELEMENT_CLASS (gclass);
+  GstCaps *caps;
+  GstPadTemplate *templ;
 
-  gst_element_class_add_pad_template (element_class,
+  /* add sink and source pad templates */
-      gst_static_pad_template_get (&src_factory));
+  caps = gst_opencv_caps_from_cv_image_type (CV_16UC1);
-  gst_element_class_add_pad_template (element_class,
+  gst_caps_append (caps, gst_opencv_caps_from_cv_image_type (CV_8UC4));
-      gst_static_pad_template_get (&sink_factory));
+  gst_caps_append (caps, gst_opencv_caps_from_cv_image_type (CV_8UC3));
+  gst_caps_append (caps, gst_opencv_caps_from_cv_image_type (CV_8UC1));
+  templ = gst_pad_template_new ("sink", GST_PAD_SINK, GST_PAD_ALWAYS,
+      gst_caps_ref (caps));
+  gst_element_class_add_pad_template (element_class, templ);
+  gst_object_unref (templ);
+  templ = gst_pad_template_new ("src", GST_PAD_SRC, GST_PAD_ALWAYS, caps);
+  gst_element_class_add_pad_template (element_class, templ);
+  gst_object_unref (templ);
 }
 
 /* initialize the cvdilate_erode's class */

ext/opencv/gstcvequalizehist.c

@@ -47,6 +47,7 @@
 
 #include <gst/gst.h>
 
+#include "gstopencvutils.h"
 #include "gstcvequalizehist.h"
 
 GST_DEBUG_CATEGORY_STATIC (gst_cv_equalize_hist_debug);
@@ -55,12 +56,12 @@ GST_DEBUG_CATEGORY_STATIC (gst_cv_equalize_hist_debug);
 static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-gray, depth=(int)8, bpp=(int)8"));
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_GRAY8));
 
 static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
     GST_PAD_SRC,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-gray, depth=(int)8, bpp=(int)8"));
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_GRAY8));
 
 GST_BOILERPLATE (GstCvEqualizeHist, gst_cv_equalize_hist,
     GstOpencvVideoFilter, GST_TYPE_OPENCV_VIDEO_FILTER);

ext/opencv/gstcvlaplace.c

@@ -47,6 +47,7 @@
 
 #include <gst/gst.h>
 
+#include "gstopencvutils.h"
 #include "gstcvlaplace.h"
 
 GST_DEBUG_CATEGORY_STATIC (gst_cv_laplace_debug);
@@ -55,14 +56,19 @@ GST_DEBUG_CATEGORY_STATIC (gst_cv_laplace_debug);
 static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-gray, depth=(int)8, bpp=(int)8")
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_GRAY8)
     );
 
+#if G_BYTE_ORDER == G_BIG_ENDIAN
+  #define BYTE_ORDER_STRING "BIG_ENDIAN"
+#else
+  #define BYTE_ORDER_STRING "LITTLE_ENDIAN"
+#endif
+
 static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
     GST_PAD_SRC,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_GRAY16 (BYTE_ORDER_STRING))
-    ("video/x-raw-gray, depth=(int)16, bpp=(int)16, endianness=(int)4321")
     );
 
 /* Filter signals and args */
@@ -213,14 +219,18 @@ gst_cv_laplace_transform_caps (GstBaseTransform * trans, GstPadDirection dir,
         structure = gst_caps_get_structure (output, i);
         gst_structure_set (structure,
             "depth", G_TYPE_INT, 16,
-            "bpp", G_TYPE_INT, 16, "endianness", G_TYPE_INT, 4321, NULL);
+            "bpp", G_TYPE_INT, 16,
+            "endianness", G_TYPE_INT, G_BYTE_ORDER,
+            NULL);
       }
       break;
     case GST_PAD_SRC:
       for (i = 0; i < gst_caps_get_size (output); i++) {
         structure = gst_caps_get_structure (output, i);
         gst_structure_set (structure,
-            "depth", G_TYPE_INT, 8, "bpp", G_TYPE_INT, 8, NULL);
+            "depth", G_TYPE_INT, 8,
+            "bpp", G_TYPE_INT, 8,
+            NULL);
         gst_structure_remove_field (structure, "endianness");
       }
       break;

ext/opencv/gstcvsmooth.c

@@ -47,25 +47,12 @@
 
 #include <gst/gst.h>
 
+#include "gstopencvutils.h"
 #include "gstcvsmooth.h"
 
 GST_DEBUG_CATEGORY_STATIC (gst_cv_smooth_debug);
 #define GST_CAT_DEFAULT gst_cv_smooth_debug
 
-static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
-    GST_PAD_SINK,
-    GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-rgb, depth=(int)24, bpp=(int)24;"
-        "video/x-raw-gray, depth=(int)8, bpp=(int)8")
-    );
-
-static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
-    GST_PAD_SRC,
-    GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-rgb, depth=(int)24, bpp=(int)24;"
-        "video/x-raw-gray, depth=(int)8, bpp=(int)8")
-    );
-
 /* Filter signals and args */
 enum
 {
@@ -146,17 +133,25 @@ static void
 gst_cv_smooth_base_init (gpointer gclass)
 {
   GstElementClass *element_class = GST_ELEMENT_CLASS (gclass);
-
+  GstCaps *caps;
-  gst_element_class_add_pad_template (element_class,
+  GstPadTemplate *templ;
-      gst_static_pad_template_get (&src_factory));
-  gst_element_class_add_pad_template (element_class,
-      gst_static_pad_template_get (&sink_factory));
 
   gst_element_class_set_details_simple (element_class,
       "cvsmooth",
       "Transform/Effect/Video",
       "Applies cvSmooth OpenCV function to the image",
       "Thiago Santos<thiago.sousa.santos@collabora.co.uk>");
+
+  /* add sink and source pad templates */
+  caps = gst_opencv_caps_from_cv_image_type (CV_8UC3);
+  gst_caps_append (caps, gst_opencv_caps_from_cv_image_type (CV_8UC1));
+  templ = gst_pad_template_new ("sink", GST_PAD_SINK, GST_PAD_ALWAYS,
+      gst_caps_ref (caps));
+  gst_element_class_add_pad_template (element_class, templ);
+  gst_object_unref (templ);
+  templ = gst_pad_template_new ("src", GST_PAD_SRC, GST_PAD_ALWAYS, caps);
+  gst_element_class_add_pad_template (element_class, templ);
+  gst_object_unref (templ);
 }
 
 /* initialize the cvsmooth's class */

ext/opencv/gstcvsobel.c

@@ -47,6 +47,7 @@
 
 #include <gst/gst.h>
 
+#include "gstopencvutils.h"
 #include "gstcvsobel.h"
 
 GST_DEBUG_CATEGORY_STATIC (gst_cv_sobel_debug);
@@ -55,14 +56,19 @@ GST_DEBUG_CATEGORY_STATIC (gst_cv_sobel_debug);
 static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-gray, depth=(int)8, bpp=(int)8")
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_GRAY8)
     );
 
+#if G_BYTE_ORDER == G_BIG_ENDIAN
+  #define BYTE_ORDER_STRING "BIG_ENDIAN"
+#else
+  #define BYTE_ORDER_STRING "LITTLE_ENDIAN"
+#endif
+
 static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
     GST_PAD_SRC,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_GRAY16 (BYTE_ORDER_STRING))
-    ("video/x-raw-gray, depth=(int)16, bpp=(int)16, endianness=(int)4321")
     );
 
 /* Filter signals and args */
@@ -188,14 +194,18 @@ gst_cv_sobel_transform_caps (GstBaseTransform * trans, GstPadDirection dir,
         structure = gst_caps_get_structure (output, i);
         gst_structure_set (structure,
             "depth", G_TYPE_INT, 16,
-            "bpp", G_TYPE_INT, 16, "endianness", G_TYPE_INT, 4321, NULL);
+            "bpp", G_TYPE_INT, 16,
+            "endianness", G_TYPE_INT, G_BYTE_ORDER,
+            NULL);
       }
       break;
     case GST_PAD_SRC:
       for (i = 0; i < gst_caps_get_size (output); i++) {
         structure = gst_caps_get_structure (output, i);
         gst_structure_set (structure,
-            "depth", G_TYPE_INT, 8, "bpp", G_TYPE_INT, 8, NULL);
+            "depth", G_TYPE_INT, 8,
+            "bpp", G_TYPE_INT, 8,
+            NULL);
         gst_structure_remove_field (structure, "endianness");
       }
       break;

ext/opencv/gstedgedetect.c

@@ -62,6 +62,7 @@
 
 #include <gst/gst.h>
 
+#include "gstopencvutils.h"
 #include "gstedgedetect.h"
 
 GST_DEBUG_CATEGORY_STATIC (gst_edgedetect_debug);
@@ -90,13 +91,13 @@ enum
 static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-rgb")
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_RGB)
     );
 
 static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
     GST_PAD_SRC,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-rgb")
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_RGB)
     );
 
 GST_BOILERPLATE (Gstedgedetect, gst_edgedetect, GstElement, GST_TYPE_ELEMENT);

ext/opencv/gstfaceblur.c

@@ -62,6 +62,7 @@
 
 #include <gst/gst.h>
 
+#include "gstopencvutils.h"
 #include "gstfaceblur.h"
 
 GST_DEBUG_CATEGORY_STATIC (gst_faceblur_debug);
@@ -87,13 +88,13 @@ enum
 static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-rgb")
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_RGB)
     );
 
 static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
     GST_PAD_SRC,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-rgb")
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_RGB)
     );
 
 GST_BOILERPLATE (Gstfaceblur, gst_faceblur, GstElement, GST_TYPE_ELEMENT);

ext/opencv/gstopencvutils.c

@@ -92,3 +92,33 @@ gst_opencv_parse_iplimage_params_from_caps (GstCaps * caps, gint * width,
       gst_opencv_parse_iplimage_params_from_structure (gst_caps_get_structure
       (caps, 0), width, height, ipldepth, channels, err);
 }
+
+GstCaps *
+gst_opencv_caps_from_cv_image_type (int cv_type)
+{
+  GstCaps * caps = gst_caps_new_empty ();
+  switch (cv_type) {
+    case CV_8UC1:
+      gst_caps_append (caps, gst_caps_from_string (GST_VIDEO_CAPS_GRAY8));
+      break;
+    case CV_8UC3:
+      gst_caps_append (caps, gst_caps_from_string (GST_VIDEO_CAPS_RGB));
+      gst_caps_append (caps, gst_caps_from_string (GST_VIDEO_CAPS_BGR));
+      break;
+    case CV_8UC4:
+      gst_caps_append (caps, gst_caps_from_string (GST_VIDEO_CAPS_RGBx));
+      gst_caps_append (caps, gst_caps_from_string (GST_VIDEO_CAPS_xRGB));
+      gst_caps_append (caps, gst_caps_from_string (GST_VIDEO_CAPS_BGRx));
+      gst_caps_append (caps, gst_caps_from_string (GST_VIDEO_CAPS_xBGR));
+      gst_caps_append (caps, gst_caps_from_string (GST_VIDEO_CAPS_RGBA));
+      gst_caps_append (caps, gst_caps_from_string (GST_VIDEO_CAPS_ARGB));
+      gst_caps_append (caps, gst_caps_from_string (GST_VIDEO_CAPS_BGRA));
+      gst_caps_append (caps, gst_caps_from_string (GST_VIDEO_CAPS_ABGR));
+      break;
+    case CV_16UC1:
+      gst_caps_append (caps, gst_caps_from_string (GST_VIDEO_CAPS_GRAY16("1234")));
+      gst_caps_append (caps, gst_caps_from_string (GST_VIDEO_CAPS_GRAY16("4321")));
+      break;
+  }
+  return caps;
+}

ext/opencv/gstopencvutils.h

@@ -27,6 +27,8 @@
 #endif
 
 #include <gst/gst.h>
+#include <gst/video/video.h>
+
 #include <cv.h>
 
 gboolean
@@ -39,4 +41,6 @@ gboolean gst_opencv_parse_iplimage_params_from_structure
     (GstStructure * structure, gint * width, gint * height, gint * depth,
     gint * channels, GError ** err);
 
+GstCaps * gst_opencv_caps_from_cv_image_type (int cv_type);
+
 #endif /* __GST_OPENCV_UTILS__ */

ext/opencv/gstpyramidsegment.c

@@ -62,6 +62,7 @@
 
 #include <gst/gst.h>
 
+#include "gstopencvutils.h"
 #include "gstpyramidsegment.h"
 
 #define BLOCK_SIZE 1000
@@ -92,13 +93,13 @@ enum
 static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-rgb")
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_RGB)
     );
 
 static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
     GST_PAD_SRC,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-rgb")
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_RGB)
     );
 
 GST_BOILERPLATE (Gstpyramidsegment, gst_pyramidsegment, GstElement,

ext/opencv/gsttemplatematch.c

@@ -63,6 +63,7 @@
 
 #include <gst/gst.h>
 
+#include "gstopencvutils.h"
 #include "gsttemplatematch.h"
 
 GST_DEBUG_CATEGORY_STATIC (gst_templatematch_debug);
@@ -90,13 +91,13 @@ enum
 static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-rgb")
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_RGB)
     );
 
 static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
     GST_PAD_SRC,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-rgb")
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_RGB)
     );
 
 GST_BOILERPLATE (GstTemplateMatch, gst_templatematch, GstElement,

ext/opencv/gsttextwrite.c

@@ -62,6 +62,7 @@
 
 #include <gst/gst.h>
 
+#include "gstopencvutils.h"
 #include "gsttextwrite.h"
 
 GST_DEBUG_CATEGORY_STATIC (gst_textwrite_debug);
@@ -104,13 +105,13 @@ enum
 static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw-rgb")
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_RGB)
     );
 
 static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
     GST_PAD_SRC,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("ANY")
+    GST_STATIC_CAPS (GST_VIDEO_CAPS_RGB)
     );
 
 GST_BOILERPLATE (Gsttextwrite, gst_textwrite, GstElement, GST_TYPE_ELEMENT);