lavfi: add avfilter_unref_bufferp()

Signed-off-by: Anton Khirnov <anton@khirnov.net>

2 files changed, 18 insertions, 0 deletions

diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index 10d64ad614..7fbdd8a2fb 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -195,9 +195,21 @@ AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);
  * buffer, the buffer itself is also automatically freed.
  *
  * @param ref reference to the buffer, may be NULL
+ *
+ * @note it is recommended to use avfilter_unref_bufferp() instead of this
+ * function
  */
 void avfilter_unref_buffer(AVFilterBufferRef *ref);
 
+/**
+ * Remove a reference to a buffer and set the pointer to NULL.
+ * If this is the last reference to the buffer, the buffer itself
+ * is also automatically freed.
+ *
+ * @param ref pointer to the buffer reference
+ */
+void avfilter_unref_bufferp(AVFilterBufferRef **ref);
+
 #if FF_API_AVFILTERPAD_PUBLIC
 /**
  * A filter pad used for either input or output.
diff --git a/libavfilter/buffer.c b/libavfilter/buffer.c
index be0da26ea1..e3ebc9b8c7 100644
--- a/libavfilter/buffer.c
+++ b/libavfilter/buffer.c
@@ -84,6 +84,12 @@ void avfilter_unref_buffer(AVFilterBufferRef *ref)
     av_free(ref);
 }
 
+void avfilter_unref_bufferp(AVFilterBufferRef **ref)
+{
+    avfilter_unref_buffer(*ref);
+    *ref = NULL;
+}
+
 int avfilter_copy_frame_props(AVFilterBufferRef *dst, const AVFrame *src)
 {
     dst->pts    = src->pts;