gaudieffects: Avoid divide by 0 in burn element

2 files changed, 34 insertions, 20 deletions

diff --git a/gst/gaudieffects/burn-example.py b/gst/gaudieffects/burn-example.py
new file mode 100644
index 000000000..01080b909
--- /dev/null
+++ b/gst/gaudieffects/burn-example.py
@@ -0,0 +1,23 @@
+#!/usr/bin/python
+import gobject; gobject.threads_init()
+import pygst; pygst.require("0.10")
+import gst
+
+p = gst.parse_launch ("""
+   v4l2src !
+   ffmpegcolorspace ! queue ! video/x-raw-rgb,width=320,height=240,framerate=30/1 ! burn qos=true name=vf ! ffmpegcolorspace !
+   timeoverlay ! xvimagesink
+   """)
+
+m = p.get_by_name ("vf")
+m.set_property ("adjustment", 128)
+
+control = gst.Controller(m, "adjustment")
+control.set_interpolation_mode("adjustment", gst.INTERPOLATE_LINEAR)
+control.set("adjustment", 0 * gst.SECOND, 128)
+control.set("adjustment", 5 * gst.SECOND, 256)
+control.set("adjustment", 25 * gst.SECOND, 0)
+
+p.set_state (gst.STATE_PLAYING)
+
+gobject.MainLoop().run()
diff --git a/gst/gaudieffects/gstburn.c b/gst/gaudieffects/gstburn.c
index 582d5e85b..3d769356a 100644
--- a/gst/gaudieffects/gstburn.c
+++ b/gst/gaudieffects/gstburn.c
@@ -96,7 +96,6 @@ enum
 
 #define DEFAULT_ADJUSTMENT 175
 
-static gint gate_int (gint value, gint min, gint max);
 static void transform (guint32 * src, guint32 * dest, gint video_area,
     gint adjustment);
 
@@ -289,24 +288,13 @@ gst_burn_plugin_init (GstPlugin * burn)
 }
 
 /*** Now the image processing work.... ***/
-/* Keep the values inbounds. */
-static gint
-gate_int (gint value, gint min, gint max)
-{
-  if (value < min) {
-    return min;
-  } else if (value > max) {
-    return max;
-  } else {
-    return value;
-  }
-}
 
 /* Transform processes each frame. */
 static void
 transform (guint32 * src, guint32 * dest, gint video_area, gint adjustment)
 {
-  guint32 in, red, green, blue;
+  guint32 in;
+  gint red, green, blue, c;
   gint x;
 
   for (x = 0; x < video_area; x++) {
@@ -316,13 +304,16 @@ transform (guint32 * src, guint32 * dest, gint video_area, gint adjustment)
     green = (in >> 8) & 0xff;
     blue = (in) & 0xff;
 
-    red = 256 - ((256 * (255 - red)) / (red + adjustment));
-    green = 256 - ((256 * (255 - green)) / (green + adjustment));
-    blue = 256 - ((256 * (255 - blue)) / (blue + adjustment));
+    c = (red + adjustment);
+    red = c ? (256 - (256 * (255 - red) / c)) : 0;
+    c = (green + adjustment);
+    green = c ? (256 - (256 * (255 - green) / c)) : 0;
+    c = (blue + adjustment);
+    blue = c ? (256 - (256 * (255 - blue) / c)) : 0;
 
-    red = gate_int (red, 0, 255);
-    green = gate_int (green, 0, 255);
-    blue = gate_int (blue, 0, 255);
+    red = CLAMP (red, 0, 255);
+    green = CLAMP (green, 0, 255);
+    blue = CLAMP (blue, 0, 255);
 
     *dest++ = (red << 16) | (green << 8) | blue;
   }