Abstract: A television program stream that includes television programs and at least one original commercial, and a commercial replacement stream that includes at least one replacement commercial, are received simultaneously such that a respective replacement commercial is approximately synchronized in time with a respective original commercial. The television program stream and/or the commercial replacement stream is buffered to substantially synchronize a respective replacement commercial with a respective original commercial. Selective switching is performed between the television program stream and the commercial replacement stream, to provide a television program output that includes the television programs and the at least one replacement commercial instead of the at least one original commercial. Accordingly, commercial replacement may be provided in set top boxes without the need for mass storage devices to store the replacement commercials.

Abstract: A method for digital data distribution or broadcasting that takes advantage of non-deterministic (or “opportunistic”) unused bandwidth in dynamically optimized broadband digital broadcast systems. Digital data files received from broadcasts are stored in mass storage devices for viewing at a later time at high speed, overcoming “last mile” narrow bandwidth issues. Instead of reserving a particular communications channel or data transfer spectrum, data is opportunistically “piggybacked” onto unrelated broadcasts, using otherwise unused bandwidth within existing broadcast channels or spectrums. The broadcast source does not target the digital files at specific identifiable users or broadcast contents based on their interactive requests. Data broadcasting in accordance with the present invention may be implemented to work with any medium which allows the delivery of large files in a one-to-many fashion (i.e.