v4l2src: add controlable colorbalance parameters

Expose colorbalance controls as object properties (like we do on xvimagesink).
Make them controlable.

sys/v4l2/Makefile.am

@@ -23,6 +23,7 @@ libgstvideo4linux2_la_SOURCES = gstv4l2.c \
 
 libgstvideo4linux2_la_CFLAGS =   $(GST_PLUGINS_BASE_CFLAGS) \
 				 $(GST_BASE_CFLAGS) \
+				 $(GST_CONTROLLER_CFLAGS) \
 				 $(GST_CFLAGS) \
 				 $(X_CFLAGS) \
 				 $(LIBV4L2_CFLAGS) \
@@ -33,7 +34,9 @@ libgstvideo4linux2_la_LIBTOOLFLAGS = --tag=disable-static
 
 libgstvideo4linux2_la_LIBADD =   $(GST_PLUGINS_BASE_LIBS) \
 				 $(GST_BASE_LIBS) \
-				 $(GST_PLUGINS_BASE_LIBS) -lgstvideo-$(GST_MAJORMINOR) \
+				 $(GST_CONTROLLER_LIBS) \
+				 $(GST_PLUGINS_BASE_LIBS) \
+				 -lgstvideo-$(GST_MAJORMINOR) \
 				 -lgstinterfaces-$(GST_MAJORMINOR) \
 				 $(GST_LIBS) \
 				 $(xv_libs) \

sys/v4l2/gstv4l2.c

@@ -28,6 +28,7 @@
 #include "gst/gst-i18n-plugin.h"
 
 #include <gst/gst.h>
+#include <gst/controller/gstcontroller.h>
 
 #include "gstv4l2object.h"
 #include "gstv4l2src.h"
@@ -46,6 +47,9 @@ plugin_init (GstPlugin * plugin)
   GST_DEBUG_CATEGORY_INIT (v4l2_debug, "v4l2", 0, "V4L2 API calls");
   GST_DEBUG_CATEGORY_GET (GST_CAT_PERFORMANCE, "GST_PERFORMANCE");
 
+  /* initialize gst controller library */
+  gst_controller_init (NULL, NULL);
+
   if (!gst_element_register (plugin, "v4l2src", GST_RANK_PRIMARY,
           GST_TYPE_V4L2SRC) ||
       !gst_element_register (plugin, "v4l2sink", GST_RANK_NONE,

sys/v4l2/gstv4l2object.c

@@ -328,6 +328,27 @@ gst_v4l2_object_install_properties_helper (GObjectClass * gobject_class,
       g_param_spec_flags ("flags", "Flags", "Device type flags",
           GST_TYPE_V4L2_DEVICE_FLAGS, DEFAULT_PROP_FLAGS,
           G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (gobject_class, PROP_BRIGHTNESS,
+      g_param_spec_int ("brightness", "Brightness",
+          "Picture brightness, or more precisely, the black level", G_MININT,
+          G_MAXINT, 0,
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | GST_PARAM_CONTROLLABLE));
+  g_object_class_install_property (gobject_class, PROP_CONTRAST,
+      g_param_spec_int ("contrast", "Contrast",
+          "Picture contrast or luma gain", G_MININT,
+          G_MAXINT, 0,
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | GST_PARAM_CONTROLLABLE));
+  g_object_class_install_property (gobject_class, PROP_SATURATION,
+      g_param_spec_int ("saturation", "Saturation",
+          "Picture color saturation or chroma gain", G_MININT,
+          G_MAXINT, 0,
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | GST_PARAM_CONTROLLABLE));
+  g_object_class_install_property (gobject_class, PROP_HUE,
+      g_param_spec_int ("hue", "Hue",
+          "Hue or color balance", G_MININT,
+          G_MAXINT, 0,
+          G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS | GST_PARAM_CONTROLLABLE));
 }
 
 GstV4l2Object *
@@ -405,6 +426,30 @@ gst_v4l2_object_clear_format_list (GstV4l2Object * v4l2object)
   return TRUE;
 }
 
+static gint
+gst_v4l2_object_prop_to_cid (guint prop_id)
+{
+  gint cid = -1;
+
+  switch (prop_id) {
+    case PROP_BRIGHTNESS:
+      cid = V4L2_CID_BRIGHTNESS;
+      break;
+    case PROP_CONTRAST:
+      cid = V4L2_CID_CONTRAST;
+      break;
+    case PROP_SATURATION:
+      cid = V4L2_CID_SATURATION;
+      break;
+    case PROP_HUE:
+      cid = V4L2_CID_HUE;
+      break;
+    default:
+      GST_WARNING ("unmapped property id: %d", prop_id);
+  }
+  return cid;
+}
+
 
 gboolean
 gst_v4l2_object_set_property_helper (GstV4l2Object * v4l2object,
@@ -415,6 +460,21 @@ gst_v4l2_object_set_property_helper (GstV4l2Object * v4l2object,
       g_free (v4l2object->videodev);
       v4l2object->videodev = g_value_dup_string (value);
       break;
+    case PROP_BRIGHTNESS:
+    case PROP_CONTRAST:
+    case PROP_SATURATION:
+    case PROP_HUE:
+    {
+      gint cid = gst_v4l2_object_prop_to_cid (prop_id);
+
+      if (cid != -1) {
+        if (GST_V4L2_IS_OPEN (v4l2object)) {
+          gst_v4l2_set_attribute (v4l2object, cid, g_value_get_int (value));
+        }
+      }
+      return TRUE;
+    }
+      break;
 #if 0
     case PROP_NORM:
       if (GST_V4L2_IS_OPEN (v4l2object)) {
@@ -518,6 +578,24 @@ gst_v4l2_object_get_property_helper (GstV4l2Object * v4l2object,
       g_value_set_flags (value, flags);
       break;
     }
+    case PROP_BRIGHTNESS:
+    case PROP_CONTRAST:
+    case PROP_SATURATION:
+    case PROP_HUE:
+    {
+      gint cid = gst_v4l2_object_prop_to_cid (prop_id);
+
+      if (cid != -1) {
+        if (GST_V4L2_IS_OPEN (v4l2object)) {
+          gint v;
+          if (gst_v4l2_get_attribute (v4l2object, cid, &v)) {
+            g_value_set_int (value, v);
+          }
+        }
+      }
+      return TRUE;
+    }
+      break;
     default:
       return FALSE;
       break;

sys/v4l2/gstv4l2object.h

@@ -49,6 +49,7 @@
 
 #include <gst/gst.h>
 #include <gst/base/gstpushsrc.h>
+#include <gst/controller/gstcontroller.h>
 
 #include <gst/interfaces/propertyprobe.h>
 
@@ -132,7 +133,11 @@ GType gst_v4l2_object_get_type (void);
     PROP_DEVICE,			\
     PROP_DEVICE_NAME,			\
     PROP_DEVICE_FD,			\
-    PROP_FLAGS
+    PROP_FLAGS,			\
+    PROP_BRIGHTNESS,			\
+    PROP_CONTRAST,			\
+    PROP_SATURATION,			\
+    PROP_HUE
 
 /* create/destroy */
 GstV4l2Object *	gst_v4l2_object_new 		 (GstElement * element,

sys/v4l2/gstv4l2src.c

@@ -626,7 +626,7 @@ gst_v4l2src_set_caps (GstBaseSrc * src, GstCaps * caps)
   /* we want our own v4l2 type of fourcc codes */
   if (!gst_v4l2_object_get_caps_info (v4l2src->v4l2object, caps, &format, &w,
           &h, &fps_n, &fps_d, &size)) {
-    GST_DEBUG_OBJECT (v4l2src,
+    GST_INFO_OBJECT (v4l2src,
         "can't get capture format from caps %" GST_PTR_FORMAT, caps);
     return FALSE;
   }
@@ -723,6 +723,10 @@ gst_v4l2src_start (GstBaseSrc * src)
 
   v4l2src->offset = 0;
 
+  /* activate settings for first frame */
+  v4l2src->ctrl_time = 0;
+  gst_object_sync_values (G_OBJECT (src), v4l2src->ctrl_time);
+
   return TRUE;
 }
 
@@ -945,6 +949,7 @@ gst_v4l2src_create (GstPushSrc * src, GstBuffer ** buf)
     GST_BUFFER_OFFSET_END (*buf) = v4l2src->offset;
 
     /* timestamps, LOCK to get clock and base time. */
+    /* FIXME: element clock and base_time is rarely changing */
     GST_OBJECT_LOCK (v4l2src);
     if ((clock = GST_ELEMENT_CLOCK (v4l2src))) {
       /* we have a clock, get base time and ref clock */
@@ -970,6 +975,19 @@ gst_v4l2src_create (GstPushSrc * src, GstBuffer ** buf)
       }
     }
 
+    /* activate settings for next frame */
+    if (GST_CLOCK_TIME_IS_VALID (v4l2src->duration)) {
+      v4l2src->ctrl_time += v4l2src->duration;
+    } else {
+      /* this is not very good (as it should be the next timestamp),
+       * still good enough for linear fades (as long as it is not -1) 
+       */
+      v4l2src->ctrl_time = timestamp;
+    }
+    gst_object_sync_values (G_OBJECT (src), v4l2src->ctrl_time);
+    GST_INFO_OBJECT (src, "sync to %" GST_TIME_FORMAT,
+        GST_TIME_ARGS (v4l2src->ctrl_time));
+
     /* FIXME: use the timestamp from the buffer itself! */
     GST_BUFFER_TIMESTAMP (*buf) = timestamp;
     GST_BUFFER_DURATION (*buf) = v4l2src->duration;

sys/v4l2/gstv4l2src.h

@@ -84,6 +84,8 @@ struct _GstV4l2Src
   gint     fps_d, fps_n;       /* framerate if device is open */
   GstClockTime duration;       /* duration of one frame */
   
+  GstClockTime ctrl_time;
+
   GstV4l2SrcGetFunc get_frame;
 };