private static ArrayList<TimelineEntry> getSeqTimeline(
      ElementSequentialTimeContainer seq, double offset, double maxOffset) {
    ArrayList<TimelineEntry> timeline = new ArrayList<TimelineEntry>();
    double orgOffset = offset;

    // Set my begin at first
    TimeList myBeginList = seq.getBegin();
    /*
     * Begin list only contain 1 begin time which has been resolved.
     * @see com.irrenhaus.irresms.dom.smil.ElementSequentialTimeContainerImpl#getBegin()
     */
    Time begin = myBeginList.item(0);
    double beginOffset = begin.getResolvedOffset() + offset;
    if (beginOffset > maxOffset) {
      // This element can't be started.
      return timeline;
    }
    TimelineEntry myBegin = new TimelineEntry(beginOffset, seq, TimelineEntry.ACTION_BEGIN);
    timeline.add(myBegin);

    TimeList myEndList = seq.getEnd();
    /*
     * End list only contain 1 end time which has been resolved.
     * @see com.irrenhaus.irresms.dom.smil.ElementSequentialTimeContainerImpl#getEnd()
     */
    Time end = myEndList.item(0);
    double endOffset = end.getResolvedOffset() + offset;
    if (endOffset > maxOffset) {
      endOffset = maxOffset;
    }
    TimelineEntry myEnd = new TimelineEntry(endOffset, seq, TimelineEntry.ACTION_END);

    maxOffset = endOffset;

    // Get children's timelines
    NodeList children = seq.getTimeChildren();
    for (int i = 0; i < children.getLength(); ++i) {
      ElementTime child = (ElementTime) children.item(i);
      ArrayList<TimelineEntry> childTimeline = getTimeline(child, offset, maxOffset);
      timeline.addAll(childTimeline);

      // Since the child timeline has been sorted, the offset of the last one is the biggest.
      offset = childTimeline.get(childTimeline.size() - 1).getOffsetTime();
    }

    // Add end-event to timeline for all active children
    NodeList activeChildrenAtEnd = seq.getActiveChildrenAt((float) (endOffset - orgOffset));
    for (int i = 0; i < activeChildrenAtEnd.getLength(); ++i) {
      timeline.add(
          new TimelineEntry(
              endOffset, (ElementTime) activeChildrenAtEnd.item(i), TimelineEntry.ACTION_END));
    }

    // Set my end at last
    timeline.add(myEnd);

    return timeline;
  }
 public NodeList getActiveChildrenAt(float instant) {
   return mSeqTimeContainer.getActiveChildrenAt(instant);
 }