Originally committed as revision 12176 to svn://svn.ffmpeg.org/ffmpeg/trunk
*/
void avfilter_formats_unref(AVFilterFormats **ref);
+/**
+ *
+ * Before After
+ * ________ ________
+ * | f |<---------. | f |<---------.
+ * | ____ | ___|___ | ____ | ___|___
+ * | |refs| | | | | | |refs| | | | | NULL
+ * | |* *--------->|*oldref| | |* *--------->|*newref| ^
+ * | |* * | | |_______| | |* * | | |_______| ___|___
+ * | |____| | | |____| | | | |
+ * |________| |________| |*oldref|
+ * |_______|
+ */
void avfilter_formats_changeref(AVFilterFormats **oldref,
AVFilterFormats **newref);