diff --git a/libavformat/dashdec.c b/libavformat/dashdec.c
index 983dc85d65..ab61c28296 100644
--- a/libavformat/dashdec.c
+++ b/libavformat/dashdec.c
@@ -1402,6 +1402,9 @@ static int64_t calc_cur_seg_no(AVFormatContext *s, struct representation *pls)
                 } else {
                     num = pls->first_seq_no + (((c->publish_time - c->time_shift_buffer_depth + pls->fragment_duration) - c->suggested_presentation_delay) * pls->fragment_timescale) / pls->fragment_duration;
                 }
+            } else if (c->period_start && c->availability_start_time && pls->fragment_timescale) {
+				num = pls->first_seq_no + ((( get_current_time_in_sec() - (c->availability_start_time + c->period_start)) * pls->fragment_timescale) - pls->fragment_duration)/ pls->fragment_duration;
+
             } else {
                 num = pls->first_seq_no + (((get_current_time_in_sec() - c->availability_start_time) - c->suggested_presentation_delay) * pls->fragment_timescale) / pls->fragment_duration;
             }