In multicast-based IPTV distribution networks, when an IPTV viewer tunes to a new channel, the IP set-top box (STB) joins a new multicast session. Upon join, the IP STB needs to acquire and parse certain key information before it can process any data sent in the multicast session. Depending on the join time, length of the key information repetition interval, size of the key information as well as the application and transport properties, the time lag before the IP STB can usefully consume the multicast data, which we refer to as the synchronization delay, varies and may be large. This is an undesirable phenomenon and degrades the quality of experience perceived by the IPTV viewers. In this study, we describe a unified standards-based approach that can be used both to repair lost packets in real time and reduce the synchronization delay.

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