Set-Top Box Offset Calculation for Seamless IPTV Transition
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Solution Overview
Problem
Current IPTV systems experience delays and inaccuracies when resuming a paused live broadcast due to network delays in calculating the restart position, leading to a jump in the media stream and an unsatisfactory transition from multicast to unicast streams.
Innovation Solution
Incorporating a parameter in SIP/SDP signaling to enable accurate computation of the time offset by either the network side providing the start time of the media stream or the client side providing the pause time, allowing the set-top box to calculate a precise offset for seamless media transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the network side calculates the restart position using current SIP/SDP signaling, then the system can resume paused broadcasts, but network delays cause inaccuracies in offset calculation leading to jump discontinuities
Solution Approach 1:
The patent applies preliminary action by having the client side (set-top box) determine the pause time immediately when the user pauses the broadcast, rather than waiting for network side calculation. The client side uses local timing information to calculate the offset value right away, eliminating the network delay that would otherwise occur during the resume operation. This pre-calculation of the offset value ensures accurate media stream resumption without jump discontinuities.
2Ease of operation
If the system uses current offset calculation methods, then media stream resumption is possible, but the transition from multicast to unicast streams exhibits jump discontinuities
Solution Approach 1:
The patent applies self-service by enabling the client side (set-top box) to autonomously determine the pause time and calculate the offset value without relying on network side processing. The set-top box uses its own local timing information and the media stream start time to compute the offset, making the system self-sufficient for this critical calculation. This eliminates network delay dependencies and ensures precise restart position determination for seamless media transition.
3Adaptability or versatility
If network delays are present in SIP/SDP signaling, then basic time-shift functionality can be implemented, but the user experience deteriorates due to inaccurate offset values
Solution Approach 1:
The patent applies inversion by reversing the traditional approach where the network side calculates the offset. Instead, the client side (set-top box) performs the offset calculation using local timing information. This inversion of the calculation responsibility eliminates the network delay bottleneck and provides accurate offset values even in the presence of network delays, thereby maintaining reliable time-shift functionality with improved user experience.
Data Source
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Figure 4A
AI summary
Effects of a network delay in handling messages in time-shifting media information streams are eliminated by either the network side's providing a media stream start time to the client side, which uses the media start time to compute a correct time offset for restarting the media stream after a pause, or by the client side's providing the time of a pause request to the network side, which uses the pause request time to compute the correct time offset and provides the offset to the client side.