UTC-NPT Time Mapping With Leap Second Adjustment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing systems for converting between Coordinated Universal Time (UTC) and Normal Play Time (NPT) are influenced by leap seconds, leading to erroneous calculations, as they cannot distinguish between overlapping seconds during leap second adjustments.
Innovation Solution
Incorporating leap second adjustment information into the mapping information between NPT and UTC times, allowing for accurate adjustment of UTC times corresponding to specific NPT times, thereby mitigating the impact of leap seconds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UTC-NPT reference descriptor is used for time conversion between UTC and NPT times, then time mapping functionality is provided, but erroneous calculation occurs during leap second events
Solution Approach 1:
The patent applies preliminary action by inserting leap second adjustment information into the UTC-NPT reference descriptor before time conversion operations. This allows the reception device to pre-know about upcoming leap seconds and adjust calculations accordingly, preventing erroneous time conversions during leap second events. The adjustment information is prepared in advance and included in the reference descriptor data structure.
2Reliability
If NTP reception is used to obtain leap second information, then leap second awareness is achieved, but system complexity increases due to multiple reception systems
Solution Approach 1:
The patent merges the leap second information delivery mechanism into the existing MMT-SI (MPEG Media Transport - Service Information) system. Instead of relying on separate NTP reception, the leap second adjustment information is embedded within the UTC-NPT reference descriptor that is already part of the MMT-SI structure. This consolidation eliminates the need for parallel NTP reception systems while maintaining leap second handling capability.
3Measurement precision
If the UTC time specified by UTC-NPT reference descriptor avoids leap second target time, then calculation errors are avoided, but time coverage is reduced
Solution Approach 1:
The patent changes the parameter structure of the UTC-NPT reference descriptor by adding leap second adjustment information. This modification enables the system to accurately handle leap second periods without avoiding them. The adjustment information includes indicators that allow the reception device to correctly interpret UTC times during leap second events, thereby maintaining both accuracy and full time range coverage.
Data Source
AI summary
A specific UTC time corresponding to a specific NPT time is appropriately obtained in a reception side without being influenced by occurrence of a leap second.Transmission media of a program are transmitted, and mapping information between an NTP time represented by a relative time from a beginning of a program and a UTC time represented by an absolute time is intermittently transmitted. Leap second adjustment information is included in the mapping information. In the reception side, the specific UTC time corresponding to the specific NPT time obtained on the basis of the mapping information can be adjusted on the basis of the leap second adjustment information, and the influence of occurrence of the leap second can be avoided.