/* expand timeline (cache next/prev page images) */
vtl_start -= visible_video_frames * vtl_dist;
visible_video_frames *=3;
if (vtl_start < video_offset ) {
/* expand timeline (cache next/prev page images) */
vtl_start -= visible_video_frames * vtl_dist;
visible_video_frames *=3;
if (vtl_start < video_offset ) {