@@ -70,6 +70,8 @@ AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask)

 void avfilter_unref_buffer(AVFilterBufferRef *ref)

 {

+    if (!ref)

+        return;

     if (!(--ref->buf->refcount))

         ref->buf->free(ref->buf);

     av_free(ref->video);

@@ -28,7 +28,7 @@

 #define LIBAVFILTER_VERSION_MAJOR  1

 #define LIBAVFILTER_VERSION_MINOR 73

-#define LIBAVFILTER_VERSION_MICRO  1

+#define LIBAVFILTER_VERSION_MICRO  2

 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

                                                LIBAVFILTER_VERSION_MINOR, \

@@ -177,7 +177,7 @@ AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);

  * Remove a reference to a buffer. If this is the last reference to the

  * buffer, the buffer itself is also automatically freed.

  *

- * @param ref reference to the buffer

+ * @param ref reference to the buffer, may be NULL

  */

 void avfilter_unref_buffer(AVFilterBufferRef *ref);