1 <par> 
2 <switch> 
3 <img src="slideshow_hires.rp" region="full" fill="freeze"
   system-bit-rate="20000"/> 
4 <img src="slideshow_lowres.rp" region="full" fill="freeze"
   system-bit-rate="45000"/> 
5 </switch> 
6 <audio src="video_narration.ra"/> 
7 </par>