diff --git a/libavcodec/png_parser.c b/libavcodec/png_parser.c
index 74f2964118..9ec8551a1b 100644
--- a/libavcodec/png_parser.c
+++ b/libavcodec/png_parser.c
@@ -45,6 +45,7 @@ static int png_parse(AVCodecParserContext *s, AVCodecContext *avctx,
     s->pict_type = AV_PICTURE_TYPE_NONE;
 
     *poutbuf_size = 0;
+    *poutbuf = NULL;
 
     if (!ppc->pc.frame_start_found) {
         uint64_t state64 = ppc->pc.state64;