Alcatel Lucent

Lucent Technologies Inc.

John P Hearn

Kim N Matthews

Raziel Haimi-Cohen

Lesley Jen-Yuan Wu

Christopher C Yu

A controller in a video headend or other transmission element of a signal distribution system is operative to detect a condition in which unicast transmissions of a given content stream to a plurality of terminals meet a specified threshold. The controller starts a multicast transmission of the given content stream in response to the detected condition, and transitions at least one of the terminals to the multicast transmission. In one embodiment, the controller identifies at least one of the terminals as a terminal that will receive the multicast transmission of the given content stream in place of its unicast transmission prior to one or more of the other terminals receiving the multicast transmission. The controller stops the unicast transmission to the identified terminal if that unicast transmission has already been started, starts the multicast transmission, switches the identified terminal to the multicast transmission, and subsequently transitions one or more of the other terminals to the multicast transmission. The identified terminal may be a leading terminal or a trailing terminal.

Controller providing gradual transition of multiple terminals from unicast transmission

Technology which facilitates a reduction in time of the presentation of video content after a viewer changes channels is described. Frames of a video stream associated with a channel are analyzed to identify locations of access points in the video stream prior to relaying the video stream to a presentation device. Information indicating the locations of access points is stored. The video stream is then time shifted on a continuous basis and is transmitted to the presentation device which made the request for as long as the presentation device remains tuned to the channel corresponding to the request. A first available frame on or before an access point of the time shifted video stream is selected based on the stored information, which is used to commence the transmission of the time shifted video to the presentation device, which facilitates a more immediate presentation of video content.

Reducing channel change delays

In an internet protocol television (IPTV) system, fast channel change (FCC) transactions that experience late multicast joins are handled specially, thereby allowing the system to be provisioned for the vast majority of multicast joins that are within an expected range. During an FCC transaction, the subscriber interface device, such as a set-top box (STB), can determine how long it can wait to join the multicast stream of the new channel before a gap can be predicted to occur in the handover from the FCC unicast to the multicast. If the STB has not joined the multicast stream by the determined time, a recovery procedure is invoked in which the STB sends a RESTART request to the FCC server which, in turn, increases the rate of the FCC unicast as if the FCC transaction were restarted, thus allowing the handover to occur seamlessly. This solution reduces the demands of each FCC transaction, allowing for greater scalability and reduced cost.

Fast channel change handling of late multicast join

The payloads of IP packets are checked to actually determine if a packet contains MPEG-2 video rather than using predefined streams or priority levels that are assumed to contain such information as is done in the prior art. More specifically, the 'sync' bytes of the MPEG-2 stream are searched for within the IP packet payload, and when a pattern indicative of the sync bytes is found the sync bytes are identified and the packet is determined to contain MPEG-2 video. The sync byte was defined in MPEG-2 for over-the-air broadcasting in order that a television receiver be able to synchronize the MPEG-2 transport stream packets. Note that the MPEG-2 video, e.g., the MPEG-2 transport stream packets, may or may not be incorporated within real time protocol (RTP) packets before being incorporated into the IP packets.

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New Providence, NJ, United States of America

John P Hearn