Implement the avfilter_default_draw_slice() handler and use it in

avfilter_draw_slice() when the draw_slice callback is not defined in
the input pad.

Originally committed as revision 16554 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavfilter/avfilter.c

@@ -250,6 +250,7 @@ void avfilter_draw_slice(AVFilterLink *link, int y, int h)
 {
     uint8_t *src[4], *dst[4];
     int i, j, hsub, vsub;
+    void (*draw_slice)(AVFilterLink *, int, int);
 
     /* copy the slice if needed for permission reasons */
     if(link->srcpic) {
@@ -279,8 +280,9 @@ void avfilter_draw_slice(AVFilterLink *link, int y, int h)
         }
     }
 
-    if(link_dpad(link).draw_slice)
-        link_dpad(link).draw_slice(link, y, h);
+    if(!(draw_slice = link_dpad(link).draw_slice))
+        draw_slice = avfilter_default_draw_slice;
+    draw_slice(link, y, h);
 }
 
 AVFilter *avfilter_get_by_name(const char *name)

libavfilter/avfilter.h

@@ -23,7 +23,7 @@
 #define AVFILTER_AVFILTER_H
 
 #define LIBAVFILTER_VERSION_MAJOR  0
-#define LIBAVFILTER_VERSION_MINOR  1
+#define LIBAVFILTER_VERSION_MINOR  2
 #define LIBAVFILTER_VERSION_MICRO  0
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
@@ -349,6 +349,8 @@ struct AVFilterPad
 
 /** default handler for start_frame() for video inputs */
 void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
+/** default handler for draw_slice() for video inputs */
+void avfilter_default_draw_slice(AVFilterLink *link, int y, int h);
 /** default handler for end_frame() for video inputs */
 void avfilter_default_end_frame(AVFilterLink *link);
 /** default handler for config_props() for video outputs */

libavfilter/defaults.c

@@ -82,6 +82,17 @@ void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref)
     }
 }
 
+void avfilter_default_draw_slice(AVFilterLink *link, int y, int h)
+{
+    AVFilterLink *out = NULL;
+
+    if(link->dst->output_count)
+        out = link->dst->outputs[0];
+
+    if(out)
+        avfilter_draw_slice(out, y, h);
+}
+
 void avfilter_default_end_frame(AVFilterLink *link)
 {
     AVFilterLink *out = NULL;