Abstract: A method of playing audio content to a viewer in synchronization with a video content. The method comprises receiving and digitizing an ultrasonic signal comprising ultrasonic synchronization signal(s), the ultrasonic synchronization signal(s) comprising a timecode-carrying part that encodes a respective timecode through modulation of ultrasonic carrier signal(s), the ultrasonic synchronization signal(s) comprising further an ultrasonic marker signal conterminous with the timecode-carrying part. The timecode-carrying part is identified based on a received ultrasonic marker signal and decoded to determine the corresponding timecode. The stored audio content is played back from a playback point determined based on the timecode.

Abstract: A method of playing audio content to a viewer in synchronisation with a video content. The method comprises receiving and digitising an ultrasonic signal comprising ultrasonic synchronisation signal(s) which encode a respective timecode through modulation of ultrasonic carrier signal(s), and identifying digitised ultrasonic synchronisation signals which are decoded to determine the corresponding timecode by sampling the digitised ultrasonic signal and eliminating estimated background noise component(s) from the frequency spectrum of the samples, binarising the corrected frequency spectrum corresponding to the timecode-carrying part of the digitised ultrasonic synchronisation signal to generate a representation of the timecode, and determining the corresponding timecode from the representation. A stored audio content is played back from a playback point determined based on the timecode.

Abstract: A method of playing audio content to a viewer in synchronisation with a video content. The method comprises receiving and digitising an ultrasonic signal comprising ultrasonic synchronisation signal(s) encoding a respective timecode through modulation of ultrasonic carrier signal(s), a first ultrasonic carrier signal having been amplitude modulated to encode logical “1” or “0” in data-carrying segments, each data-carrying segments being followed by non-data-carrying segments in which the amplitude of the ultrasonic carrier signal does not exceed a predetermined threshold. A digitised ultrasonic synchronisation signal is processed to identify the data-carrying segments, and the corresponding timecode is extracted from the data-carrying segments. A stored audio content is played back from a playback point determined based on the timecode.

Abstract: A method of playing audio content to a viewer in synchronisation with a video content. The method comprises receiving and digitising an ultrasonic signal comprising ultrasonic synchronisation signal(s) which encode a respective timecode through modulation of ultrasonic carrier signal(s), and identifying digitised ultrasonic synchronisation signals which are decoded to determine the corresponding timecode by sampling the digitised ultrasonic signal and eliminating estimated background noise component(s) from the frequency spectrum of the samples, binarising the corrected frequency spectrum corresponding to the timecode-carrying part of the digitised ultrasonic synchronisation signal to generate a representation of the timecode, and determining the corresponding timecode from the representation. A stored audio content is played back from a playback point determined based on the timecode.

Abstract: A method of playing audio content to a viewer in synchronisation with a video content. The method comprises receiving and digitising an ultrasonic signal comprising ultrasonic synchronisation signal(s) encoding a respective timecode through modulation of ultrasonic carrier signal(s), a first ultrasonic carrier signal having been amplitude modulated to encode logical “1” or “0” in data-carrying segments, each data-carrying segments being followed by non-data-carrying segments in which the amplitude of the ultrasonic carrier signal does not exceed a predetermined threshold. A digitised ultrasonic synchronisation signal is processed to identify the data-carrying segments, and the corresponding timecode is extracted from the data-carrying segments. A stored audio content is played back from a playback point determined based on the timecode.

Abstract: A method of playing audio content to a viewer in synchronisation with a video content. The method comprises receiving and digitising an ultrasonic signal comprising ultrasonic synchronisation signal(s), the ultrasonic synchronisation signal(s) comprising a timecode-carrying part that encodes a respective timecode through modulation of ultrasonic carrier signal(s), the ultrasonic synchronisation signal(s) comprising further an ultrasonic marker signal conterminous with the timecode-carrying part. The timecode-carrying part is identified based on a received ultrasonic marker signal and decoded to determine the corresponding timecode. The stored audio content is played back from a playback point determined based on the timecode.