Method for synchronising a reference audio-visual content with an altered version thereof broadcast through television, comprising the following steps: • Creation, prior to the broadcast, of a trace of the reference content, where the necessary transformations of the reference content are performed, • Creation, in real time, of a trace of the broadcast content by extracting the characteristics of the image corresponding to a series of frames; Where, in the process of creating the traces of both the reference content and the broadcast content, the following actions are performed: • Partitioning of the image corresponding to a frame of the broadcast by dividing the image into smaller pieces or partitions, • Extraction of the Colour histogram corresponding to each of the partitioned pieces, • Searching for significant points by searching shapes or the boundary points of the image in each of the frames analysed; The method continues with the following steps: • Detection of an advertisement broadcasting period during the broadcasting of the content, • Comparison between the traces created from the broadcast content and the reference content until a certain degree of correspondence is achieved, within a given threshold, • Where the number of frames wherefrom a trace of the broadcast content is created matches a browser window located around the time of broadcasting, • the browser window is adaptive, in such a way that the greater the degree of correspondence achieved when comparing the frames, the browser window may be reduced, while if the degree of correspondence between the frames decreases, the length of the browser window increases, in the event that the degree of correspondence should progressively decrease, the number of seconds browsed in the browser window doubles each time that the degree of correspondence decreases, up to a configurable maximum and, once this maximum has been reached, the window commences a search in a forward direction until synchronisation is achieved. • Creation, prior to the broadcast, of a trace of the reference content, where the necessary transformations of the reference content are performed, • Creation, in real time, of a trace of the broadcast content by extracting the characteristics of the image corresponding to a series of frames; • Partitioning of the image corresponding to a frame of the broadcast by dividing the image into smaller pieces or partitions, • Extraction of the Colour histogram corresponding to each of the partitioned pieces, • Searching for significant points by searching shapes or the boundary points of the image in each of the frames analysed; • Detection of an advertisement broadcasting period during the broadcasting of the content, • Comparison between the traces created from the broadcast content and the reference content until a certain degree of correspondence is achieved, within a given threshold, • Where the number of frames wherefrom a trace of the broadcast content is created matches a browser window located around the time of broadcasting, • the browser window is adaptive, in such a way that the greater the degree of correspondence achieved when comparing the frames, the browser window may be reduced, while if the degree of correspondence between the frames decreases, the length of the browser window increases,