simplevideomarkdetect: move offset calculations out of inner loops

the calculations for detecting the videomark is being repeated
in for loop unnecessarily. Moving this outside of for loop
such that the code need not be executed evertime the loop is executed.

https://bugzilla.gnome.org/show_bug.cgi?id=744778

diff --git a/gst/videosignal/gstsimplevideomarkdetect.c b/gst/videosignal/gstsimplevideomarkdetect.c
index fca367e..c04d90b 100644 (file)
--- a/gst/videosignal/gstsimplevideomarkdetect.c
+++ b/gst/videosignal/gstsimplevideomarkdetect.c
@@ -463,15 +463,13 @@ gst_video_detect_yuv (GstSimpleVideoMarkDetect * simplevideomarkdetect,
     goto no_pattern;
   }
 
+  d = GST_VIDEO_FRAME_COMP_DATA (frame, 0);
+  /* move to start of bottom left, adjust for offsets */
+  d += row_stride * (height - ph - simplevideomarkdetect->bottom_offset) +
+      pixel_stride * simplevideomarkdetect->left_offset;
+
   /* analyse the bottom left pixels */
   for (i = 0; i < simplevideomarkdetect->pattern_count; i++) {
-    d = GST_VIDEO_FRAME_COMP_DATA (frame, 0);
-    /* move to start of bottom left, adjust for offsets */
-    d += row_stride * (height - ph - simplevideomarkdetect->bottom_offset) +
-        pixel_stride * simplevideomarkdetect->left_offset;
-    /* move to i-th pattern */
-    d += pixel_stride * pw * i;
-
     /* calc brightness of width * height box */
     brightness =
         gst_video_detect_calc_brightness (simplevideomarkdetect, d, pw, ph,
@@ -494,6 +492,9 @@ gst_video_detect_yuv (GstSimpleVideoMarkDetect * simplevideomarkdetect,
               simplevideomarkdetect->pattern_sensitivity))
         goto no_pattern;
     }
+
+    /* move to i-th pattern */
+    d += pixel_stride * pw;
   }
   GST_DEBUG_OBJECT (simplevideomarkdetect, "found pattern");
 
@@ -501,15 +502,6 @@ gst_video_detect_yuv (GstSimpleVideoMarkDetect * simplevideomarkdetect,
 
   /* get the data of the pattern */
   for (i = 0; i < simplevideomarkdetect->pattern_data_count; i++) {
-    d = GST_VIDEO_FRAME_COMP_DATA (frame, 0);
-    /* move to start of bottom left, adjust for offsets */
-    d += row_stride * (height - ph - simplevideomarkdetect->bottom_offset) +
-        pixel_stride * simplevideomarkdetect->left_offset;
-    /* move after the fixed pattern */
-    d += pixel_stride * (simplevideomarkdetect->pattern_count * pw);
-    /* move to i-th pattern data */
-    d += pixel_stride * pw * i;
-
     /* calc brightness of width * height box */
     brightness =
         gst_video_detect_calc_brightness (simplevideomarkdetect, d, pw, ph,
@@ -518,6 +510,8 @@ gst_video_detect_yuv (GstSimpleVideoMarkDetect * simplevideomarkdetect,
     pattern_data <<= 1;
     if (brightness > simplevideomarkdetect->pattern_center)
       pattern_data |= 1;
+    /* move to i-th pattern data */
+    d += pixel_stride * pw;
   }
 
   GST_DEBUG_OBJECT (simplevideomarkdetect, "have data %" G_GUINT64_FORMAT,