diff --git a/libavformat/avio_internal.h b/libavformat/avio_internal.h
index a8bcadd38b..f8c9c93a3d 100644
--- a/libavformat/avio_internal.h
+++ b/libavformat/avio_internal.h
@@ -139,4 +139,11 @@ int ffio_open_null_buf(AVIOContext **s);
  */
 int ffio_close_null_buf(AVIOContext *s);
 
+/**
+ * Free a dynamic buffer.
+ *
+ * @param s a pointer to an IO context opened by avio_open_dyn_buf()
+ */
+void ffio_free_dyn_buf(AVIOContext **s);
+
 #endif /* AVFORMAT_AVIO_INTERNAL_H */
diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
index 5f848b20f9..8dc805a3ae 100644
--- a/libavformat/aviobuf.c
+++ b/libavformat/aviobuf.c
@@ -991,6 +991,16 @@ int avio_close_dyn_buf(AVIOContext *s, uint8_t **pbuffer)
     return size - padding;
 }
 
+void ffio_free_dyn_buf(AVIOContext **s)
+{
+    uint8_t *tmp;
+    if (!*s)
+        return;
+    avio_close_dyn_buf(*s, &tmp);
+    av_free(tmp);
+    *s = NULL;
+}
+
 static int null_buf_write(void *opaque, uint8_t *buf, int buf_size)
 {
     DynBuffer *d = opaque;