I'm currently an AS media studies student and am predicted an A grade so I am the best person to ask about this (I didn't do GCSE media)
AS media is 50% exam and50% coursework.
The first part of the exam is all about the way media texts are formed, represented, consumed by their audience and the institutions that govern and regulate the media. The first part of the exam is based on watching, reading or listening to a media text (television show, magazine etc.) and by using the four key concepts of form, representation, audience and institution to answer four short essays on the media texts using the four key concepts.
I'm not sure about the second part of the media exam.
In the coursework you have to produce a magazine and a short moving image piece which can be challenging if you don't manage your time well or if you have a s**t group.