Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for power-efficient music playlist identification. In one aspect, a method includes the actions of receiving an audio recording of an item of media content. The actions further include determining, based on the audio recording, an identifier associated with the item of media content, and a timestamp. The actions further include determining, based on the identifier of the item of media content and the timestamp, an amount of remaining time that the item of media content has to play. The actions further include providing an indication for one or more components of a computing device to deactivate. The actions further include determining that the amount of time has elapsed. The actions further include providing an indication for the one or more components of the computing device to reactivate.