@@ -169,6 +169,7 @@ static int smacker_read_header(AVFormatContext *s, AVFormatParameters *ap)

     tbase = 100000;

     av_reduce(&tbase, &smk->pts_inc, tbase, smk->pts_inc, (1UL<<31)-1);

     av_set_pts_info(st, 33, smk->pts_inc, tbase);

+    st->duration = smk->frames;

     /* handle possible audio streams */

     for(i = 0; i < 7; i++) {

         smk->indexes[i] = -1;