diff --git a/libavformat/au.c b/libavformat/au.c
index 520824fc12..a414292894 100644
--- a/libavformat/au.c
+++ b/libavformat/au.c
@@ -86,6 +86,8 @@ static int au_read_annotation(AVFormatContext *s, int size)
     av_bprint_init(&bprint, 64, AV_BPRINT_SIZE_UNLIMITED);
 
     while (size-- > 0) {
+        if (avio_feof(pb))
+            return AVERROR_EOF;
         c = avio_r8(pb);
         switch(state) {
         case PARSE_KEY: