apple trailer requirement

What are the requirements to view video on apple trailers?

That depends on how you are trying to watch them. The easiest way is to use an Apple device (iPod Touch, iPhone, iPad, TV) with the iTunes "Trailer" app installed. These same devices can normally use the IOS version of Safari to view trailers on the trailers.apple.com web site. In general, any browser and access this web site as long as the web pages are coded for compatibility with the browser in use—which means you can sometimes run into page coding problems. I normally prefer to open such media in the QTX or QT7 players directly using the trailer's URL reference if it can be recovered. Whichever method you use, the playing software must support H.264/AAC media playback which is the default for both the trailer content and Apple player software.