diff --git a/ext/opencv/faceblur/gstfaceblur.c b/ext/opencv/faceblur/gstfaceblur.c
index a33a708f72..bceb068cbc 100644
--- a/ext/opencv/faceblur/gstfaceblur.c
+++ b/ext/opencv/faceblur/gstfaceblur.c
@@ -272,6 +272,9 @@ gst_faceblur_chain (GstPad * pad, GstBuffer * buf)
         cvHaarDetectObjects (filter->cvGray, filter->cvCascade,
         filter->cvStorage, 1.1, 2, 0, cvSize (30, 30));
 
+    if (faces && faces->total > 0) {
+      buf = gst_buffer_make_writable (buf);
+    }
     for (i = 0; i < (faces ? faces->total : 0); i++) {
       CvRect *r = (CvRect *) cvGetSeqElem (faces, i);
       cvSetImageROI (filter->cvImage, *r);
@@ -279,11 +282,9 @@ gst_faceblur_chain (GstPad * pad, GstBuffer * buf)
       cvSmooth (filter->cvImage, filter->cvImage, CV_GAUSSIAN, 11, 11, 0, 0);
       cvResetImageROI (filter->cvImage);
     }
-
   }
 
-  gst_buffer_set_data (buf, (guint8 *) filter->cvImage->imageData,
-      filter->cvImage->imageSize);
+  /* these filters operate in place, so we push the same buffer */
 
   return gst_pad_push (filter->srcpad, buf);
 }
diff --git a/ext/opencv/facedetect/gstfacedetect.c b/ext/opencv/facedetect/gstfacedetect.c
index 6494e4399e..660add67d8 100644
--- a/ext/opencv/facedetect/gstfacedetect.c
+++ b/ext/opencv/facedetect/gstfacedetect.c
@@ -284,6 +284,10 @@ gst_facedetect_chain (GstPad * pad, GstBuffer * buf)
         cvHaarDetectObjects (filter->cvGray, filter->cvCascade,
         filter->cvStorage, 1.1, 2, 0, cvSize (30, 30));
 
+    if (filter->display && faces && faces->total > 0) {
+      buf = gst_buffer_make_writable (buf);
+    }
+
     for (i = 0; i < (faces ? faces->total : 0); i++) {
       CvRect *r = (CvRect *) cvGetSeqElem (faces, i);
 
@@ -310,9 +314,6 @@ gst_facedetect_chain (GstPad * pad, GstBuffer * buf)
 
   }
 
-  gst_buffer_set_data (buf, (guint8 *) filter->cvImage->imageData,
-      filter->cvImage->imageSize);
-
   return gst_pad_push (filter->srcpad, buf);
 }
 
diff --git a/ext/opencv/templatematch/gsttemplatematch.c b/ext/opencv/templatematch/gsttemplatematch.c
index 6dad35bb43..3821020b1f 100644
--- a/ext/opencv/templatematch/gsttemplatematch.c
+++ b/ext/opencv/templatematch/gsttemplatematch.c
@@ -310,13 +310,14 @@ gst_templatematch_chain (GstPad * pad, GstBuffer * buf)
   double best_res;
 
   filter = GST_TEMPLATEMATCH (GST_OBJECT_PARENT (pad));
-  buf = gst_buffer_make_writable (buf);
+
+  /* FIXME Why template == NULL returns OK?
+   * shouldn't it be a passthrough instead? */
   if ((!filter) || (!buf) || filter->template == NULL) {
     return GST_FLOW_OK;
   }
   filter->cvImage->imageData = (char *) GST_BUFFER_DATA (buf);
 
-
   if (!filter->cvDistImage) {
     filter->cvDistImage =
         cvCreateImage (cvSize (filter->cvImage->width -
@@ -344,6 +345,9 @@ gst_templatematch_chain (GstPad * pad, GstBuffer * buf)
 
     if (filter->display) {
       CvPoint corner = best_pos;
+
+      buf = gst_buffer_make_writable (buf);
+
       corner.x += filter->cvTemplateImage->width;
       corner.y += filter->cvTemplateImage->height;
       cvRectangle (filter->cvImage, best_pos, corner, CV_RGB (255, 32, 32), 3,
@@ -352,10 +356,6 @@ gst_templatematch_chain (GstPad * pad, GstBuffer * buf)
 
   }
 
-
-  gst_buffer_set_data (buf, (guint8 *) filter->cvImage->imageData,
-      filter->cvImage->imageSize);
-
   return gst_pad_push (filter->srcpad, buf);
 }
 
diff --git a/ext/opencv/textwrite/gsttextwrite.c b/ext/opencv/textwrite/gsttextwrite.c
index 7e5684683b..287de3f43e 100644
--- a/ext/opencv/textwrite/gsttextwrite.c
+++ b/ext/opencv/textwrite/gsttextwrite.c
@@ -384,11 +384,9 @@ gst_textwrite_chain (GstPad * pad, GstBuffer * buf)
  
   cvInitFont(&(filter->font),CV_FONT_VECTOR0, filter->width,filter->height,0,filter->thickness,0);
   
+  buf = gst_buffer_make_writable (buf);
   cvPutText (filter->cvImage,filter->textbuf,cvPoint(filter->xpos,filter->ypos), &(filter->font), cvScalar(filter->colorR,filter->colorG,filter->colorB,0));
 
-  gst_buffer_set_data (buf, (guint8 *) filter->cvImage->imageData,
-      filter->cvImage->imageSize);
- 
   return gst_pad_push (filter->srcpad, buf);
 }