diff --git a/libavformat/oggparsetheora.c b/libavformat/oggparsetheora.c
index 8b35a47224..edb823ef5c 100644
--- a/libavformat/oggparsetheora.c
+++ b/libavformat/oggparsetheora.c
@@ -106,6 +106,7 @@ theora_header (AVFormatContext * s, int idx)
 
         st->codec->codec_type = CODEC_TYPE_VIDEO;
         st->codec->codec_id = CODEC_ID_THEORA;
+        st->need_parsing = AVSTREAM_PARSE_HEADERS;
 
     } else if (os->buf[os->pstart] == 0x83) {
         vorbis_comment (s, os->buf + os->pstart + 7, os->psize - 8);