How much of influence does media have on a court's judgement?

If the media is convinced that someone is guilty they do have the tools to make people believe them. What would happen if a person is charged with something that they have not done and the media portrays him as guilty with the general consensus being the same the court would then have to play the tough part of being impartial listening to all the arguments and making an informed decision. But the person has been pronounced guilty by the media what happens to them then? Can what has been said be taken back? It could be undone in other manners but I doubt it is.