Systems and methods for replacing a portion of a broadcast content with a customized, live-streaming alternate media stream are provided. Usable by applications developed for the Web, mobile devices, laptop or desktop computers, or broadcast television, the system includes a broadcast server to prepare customized media streams for a particular broadcast in communication with a client receiver capable of receiving a customized media stream and synching the stream with the particular broadcast of interest. Thus, the user may view the original broadcast with the alternative audio or video stream, in some cases in near real-time, and enjoy the alternative media stream seamlessly with the original broadcast. In order to provide the capabilities disclosed herein, a fingerprinting method is used to analyze the original broadcast and synchronize timing, without modifying the original broadcast data.