Copyright: Copyright 1998-2005  W3C (MIT, ERCIM, Keio), All Rights Reserved.
See http://www.w3.org/Consortium/Legal/.
Author: Aaron Cohen (Intel), Jeff Boston (IBM)
           Version: May 1, 2001
            Module: Timing and Synchronization
           Feature: Interval logic events and pruning
         File Name: interval_logic_events_pruning_1.smil
  Media Components: 1 QT, 1 JPG
 Expected Behavior: at t=5  video1 starts from the beginning.
                          at t=7  video1 disappears.
                          at t=10 smile appears.
                          at t=10 video2 starts from the beginning.
                          at t=11 smile disappears.
                        at t=12 video2 disappears.
                        at t=13 smile appears.
                        at t=13 video1 starts from the beginning again.
                          at t=13 video2 starts from the beginning again.
                          at t=15 video1 disappears.
                        at t=15 video2 disappears.
                        at t=19 smile disappears.
This is a modification of example in SMIL 2.1 spec section:
        10.5.2 Events and event model.
        Modified the duration of the smile image.
<smil xmlns="http://www.w3.org/2005/SMIL21/Language">
                <par id="par1" begin="10s">
                        <img id="smile" begin="-5;3s" dur="6s"
                <video id="video1" begin="smile.begin" dur="2s"
                <video id="video2" begin="smile.beginEvent" dur="2s"