diff --git a/libavformat/nut.c b/libavformat/nut.c
index 4c41db35dc..91509afbd8 100644
--- a/libavformat/nut.c
+++ b/libavformat/nut.c
@@ -35,3 +35,10 @@ void ff_nut_reset_ts(NUTContext *nut, AVRational time_base, int64_t val){
             AV_ROUND_DOWN);
     }
 }
+
+int64_t ff_lsb2full(StreamContext *stream, int64_t lsb){
+    int64_t mask = (1<<stream->msb_pts_shift)-1;
+    int64_t delta= stream->last_pts - mask/2;
+    return  ((lsb - delta)&mask) + delta;
+}
+
diff --git a/libavformat/nut.h b/libavformat/nut.h
index a96d111d50..3c518acd4e 100644
--- a/libavformat/nut.h
+++ b/libavformat/nut.h
@@ -94,5 +94,6 @@ typedef struct {
 
 unsigned long av_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf, unsigned int len);
 void ff_nut_reset_ts(NUTContext *nut, AVRational time_base, int64_t val);
+int64_t ff_lsb2full(StreamContext *stream, int64_t lsb);
 
 #endif /* AVFORMAT_NUT_H */
diff --git a/libavformat/nutdec.c b/libavformat/nutdec.c
index 322ed2518e..3143f384d0 100644
--- a/libavformat/nutdec.c
+++ b/libavformat/nutdec.c
@@ -155,12 +155,6 @@ static int64_t find_startcode(ByteIOContext *bc, uint64_t code, int64_t pos){
     }
 }
 
-static int64_t lsb2full(StreamContext *stream, int64_t lsb){
-    int64_t mask = (1<<stream->msb_pts_shift)-1;
-    int64_t delta= stream->last_pts - mask/2;
-    return  ((lsb - delta)&mask) + delta;
-}
-
 static int nut_probe(AVProbeData *p){
     int i;
     uint64_t code= 0;
@@ -655,7 +649,7 @@ static int decode_frame_header(NUTContext *nut, int64_t *pts, int *stream_id, in
         int coded_pts= get_v(bc);
 //FIXME check last_pts validity?
         if(coded_pts < (1<<stc->msb_pts_shift)){
-            *pts=lsb2full(stc, coded_pts);
+            *pts=ff_lsb2full(stc, coded_pts);
         }else
             *pts=coded_pts - (1<<stc->msb_pts_shift);
     }else