In the most recent issue of ABC.net.au's Mediawatch (not to be confused with
the RNZ version, totally different) -- an Australian network tried to insert
ads (duration of under ~1.1s) into its PAL programming. However, HD viewers
may have noticed the immediate macroblock effects of the inserted ads.
http://www.abc.net.au/tv/video/downloads.htm#?vid=mediawatch
http://abc.net.au/mediawatch/vodcast/mediawatch_mp4.xml
http://abc.net.au/mediawatch/vodcast/mediawatch_wmv.xml