diff --git a/libavformat/img2.c b/libavformat/img2.c
index 77145cb1cf..a2a4a017d5 100644
--- a/libavformat/img2.c
+++ b/libavformat/img2.c
@@ -436,6 +436,8 @@ static int write_packet(AVFormatContext *s, AVPacket *pkt)
                 avio_wb32(pb[0], 0);
                 ffio_wfourcc(pb[0], "jp2 ");
                 avio_write(pb[0], st->codec->extradata, st->codec->extradata_size);
+            }else if(pkt->size >= 8 && AV_RB32(pkt->data) == 0xFF4FFF51){
+                //jpeg2000 codestream
             }else if(pkt->size < 8 ||
                      (!st->codec->extradata_size &&
                       AV_RL32(pkt->data+4) != MKTAG('j','P',' ',' '))){ // signature