Sometimes it seems that editors are like the drummers in a rock band. Hidden away at the back of the stage behind too much kit, contributing an essential part to the proceedings but never recognized. Unless they drive their Bentley into a swimming pool. So, in an effort to better understand what a good editor brings to the party, let's look at Reebok's "Sofa," directed by Frank Budgen.

This film made me laugh. It's the story of one man's fight with his furniture - a sofa that is trying to prevent him going to the gym. The cutting is excellent, employing a whole bag of tricks. It builds tension while keeping the humor alive. It never bores or overexplains. It's fast and funny and accompanied by a great music score, which captures a psychological tone while enhancing the exciting action the same way that John Williams' soundtrack works for Jaws.

It opens with a guy watching TV in a dimly lit apartment. He turns the TV off, discards the remote control and stands up. This is the first good choice made by the editor. He resists the urge to cut in a POV shot of the guy's gym bag to explain his motivation. In too many films, you see bad commercials acting trying to show some internal process and too many shots attempting to explain everything. As he gets up, the sofa lurches forward and knocks him back into its confines. This is followed by a rare thing in the modern commercial: a pause. Think about it. Your sofa has just tripped you up - it deserves a pause. As clients ask for more time for the product shot, the pause comes under siege. In a medium where impact is paramount, a pause can sometimes appear like a luxury instead of what it is - a vital part of film grammar, giving the film a dynamic, and in this case adding to the sense of paranoia that fills the spot.

With the tone established, it's time to get on with action. The man tries to stand up again. This time, in a sequence of quick cuts, the sofa smothers him with its armrest and slams him into the corner before spitting him back out onto the floor. The achievement of this sequence is the fluid action cuts that link one shot seamlessly with another. The man stares in disbelief as the sofa breathes heavily in the corner, the two eyeing each other before the next round.

Now, the man grabs his gym bag and makes for the door at the other side of the room. But the sofa trips him again. The sofa's appearance on the opposite side of the room from where we last saw it is a huge leap in continuity. The editor has made no attempt to disguise this. Continuity is one of the most overestimated ingredients in an edit. On this occasion, the jump from one side of the room to the other makes the sofa feel omnipresent. The guy is dragged back into the room, losing his trousers in the process. In a group of jump cuts, he now starts to fight back, punching the sofa and spinning it around the room on his head as loose change falls from its depths. Throughout, the rhythm and movement maintained by the editor is excellent, directing your eye to exactly the right moments. A quick cut of his face under the sofa shows his determination. This is followed by a quick cut of his pants around his ankles, reminding us how silly the scenario is. This juxtaposition is the DNA of this commercial. Dark and light playing off each other. The man trashes his room and finally throws the sofa onto the floor, grabs his gym bag and makes for the stairs, followed by you-know-what. The man falls over and lands at the bottom of the stairs. In a brilliant piece of intercutting between the furious furniture and the terrified man, we see the two get closer and closer as the guy fumbles with a locked door at the bottom of the stairs. The sofa crashes through the door but the guy is nowhere to be seen. Then his head appears from below the sofa; he has survived.

My only criticism of the editing in the entire film is that I would have liked to have held the shot a beat longer before his head appears. That way, we might believe the sofa had really flattened him and won the fight, before we rediscover him. I think the film's dark humor could have supported that. Anyway, the sofa is wedged in the doorway, the guy grabs his Reebok bag and heads for the gym while a title advises us to "Escape the sofa."

This film does not patronize the viewer; rather it invites its audience to participate. For me, one of the best ways to gauge a good film is to see how jealous I am that I didn't cut it. On this occasion, Othello looks well adjusted compared to me.