Fast channel switching for digital TV

A multicast transmitter, which is operative to transmit a multicast stream over a network, the stream including a sequence of frames encoding video data, the sequence containing anchor points, the multicast transmitter comprising:

• a memory, which is coupled to store the video data;
• and
• boost generation logic, which is coupled to the memory and is arranged to receive, at a time subsequent to a first anchor point and prior to a second anchor point in the multicast stream, a request from a client to begin receiving the multicast stream, and to generate, responsively to the request, a boost stream comprising at least a portion of the video data in the frames between the first and second anchor points, and to convey the boost stream to the client during an interval between the time at which the request was received and the second anchor point in the multicast stream, so as to cause the client to display the video data beginning from the first anchor point, and to cause the transmitter, upon completing transmission of the boost stream, to transmit the multicast stream to the client beginning from the second anchor point.

A computer software product, for use in conjunction with a multicast transmitter, which transmits a multicast stream over a network, the stream including a sequence of frames encoding video data, the sequence containing anchor points, the product comprising a computer-readable medium in which program instructions are stored, wherein the instructions, when read by a computer associated with the transmitter, cause the computer to accept, at a time subsequent to a first anchor point and prior to a second anchor point in the multicast stream, a request from a client to begin receiving the multicast stream, and to generate, responsively to the request, a boost stream comprising at least a portion of the video data in the frames between the first and second anchor points, and to convey the boost stream to the client during an interval between the time at which the request was received and the second anchor point in the multicast stream, so as to cause the client to display the video data beginning from the first anchor point, and to cause the transmitter, upon completing transmission of the boost stream, to transmit the multicast stream to the client beginning from the second anchor point.