This clip is from film Brgin Agian (2013, John Carney), the scene starts from 1:12 in the video above, and  17:20 in the actual film.

The scene starts with Dan (Mark Ruffalo) comes into the bar and sits down, and immediately cut to the other side of him, from a close-up to a mid-shot. In the mid-shot, the edges of the bar and the shelf forms multiple invisible lines that guide the audience’s attention to the left while the same time the camera pans very shortly pans to the same direction, which is where the stage is at. A non-diegetic sound comes up, which clearly is from the stage. So far with composition, camera movement and sound, the audience becomes aware of the stage while have not even seen it yet.

Then follows a 16-second close-up on Frank to the opposite direction again, this long take on Frank drinking alone expresses the loneliness and internal suffering of Frank until it soaks in to the audience. Then again reverses to a wide shot, but different from the previous shot, the camera is panned a few degrees to left now includes in the shot that Gretta (Keira Knightley) on the stage holding a guitar. When Gretta says “It’s (the song) for anyone who’s ever been alone in the city”, the film instantly cuts back to Frank as if she was talking about him. Since there is another leading character appeared on the opposite side (physically) of Frank, the shot-reverse-shot starts to develop more meaning —— a sort of connection between Frank and Gretta.

But before that connection really happens, there is another close-up on Frank, 30 seconds longer than the last one. In this shot, there is a transition for Frank. The shot starts with Frank burying his head down, drowning in his sorrow, to starting noticing Gretta but still hides half his face behind his arm, then he finishes his drink and reveals his face as Gretta sings gently. Eventually he is attracted, he nods his head with the beat, and his body starts to react as well. Then it cuts to a mid close-up on Gretta, with no establishing shot as if the people filled the bar do not exist, this cut enhances the connection built by the shot-reverse-shot earlier. Frank is reading Gretta while listening to her music.

The highlight begins when it cuts away from Gretta, but cuts between Frank and the instruments on the stage. The instruments are playing by themselves, and their sounds come up as internal diegetic sound because it clearly happens in Frank’s imagination. This part done by special effect is the magical part, it suggests Frank’s professionalism and talent as a music producer, meanwhile enriches the soundtrack, build up to a small climax in the scene. Then follows a ‘dirty’ shot from Gretta’s perspective, Frank is just another man among the crowd, but the ‘invisible lines’ formed by the wall and the people guide the audience to notice Frank. From here the shots are cut between close-ups on Gretta, close-ups on Frank, instruments. Through the editing, each shot is shorter than the last one, in order to build excitement. But in every 3 to 5 shots the film applies a wider shot or a longer take to release that excitement and rebuild. This cycle repeats until the end of the song, handheld camera slowly pulls away from Gretta and Frank, the other instrument goes quiet, the excitement fades.