Decoding Device Leap Second Handling MMT Broadcasting
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Solution Overview
Problem
Receivers face difficulties in accurately decoding and reproducing television program information due to changes in weather conditions and leap second adjustments, which affect the timing of video and audio reproduction in MMT-based digital broadcasting systems.
Innovation Solution
A decoding apparatus and method that determines decoding timings based on adjustment information and processing interval information included in packets, ensuring sequential decoding of packets at appropriate intervals, even during leap second adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If television program information is transmitted via radio waves, then coverage area is expanded, but reception reliability deteriorates due to weather conditions
Solution Approach 1:
The patent introduces a communication line as an intermediary transmission path to supplement radio wave transmission. When radio wave reception is difficult, the system switches to or combines with communication line transmission, ensuring continuous reliable delivery of television program information while maintaining wide coverage through radio waves.
2Measurement precision
If leap second adjustment is performed in NTP time stamps, then time accuracy is improved, but decoding timing determination becomes difficult
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing adjusted presentation times in a table before leap second adjustments occur. The timing adjustment unit references this pre-prepared table to determine correct decoding timings, avoiding complex real-time calculations during actual leap second events and simplifying the decoding timing determination process.
Solution Approach 2:
The patent prepares for potential leap second adjustments in advance by creating a presentation time adjustment table that accounts for possible time stamp duplications or eliminations. This beforehand cushioning allows the system to handle time accuracy requirements without encountering decoding timing difficulties when leap seconds actually occur.
3Reliability
If packets are transmitted via multiple transmission paths, then transmission reliability is improved, but synchronization of decoding timings becomes difficult
Solution Approach 1:
The patent uses feedback mechanisms where the timing adjustment unit continuously monitors presentation time information from multiple transmission paths and adjusts decoding timings based on this feedback. The system compares expected timing with actual reception timing and makes real-time adjustments to maintain synchronization across different transmission paths, preventing time loss and ensuring coordinated decoding.
Data Source
AI summary
A method for receiving data, the method includes receiving a plurality of assets, each asset including a Media Processing Unit (MPU); receiving a packet identification for each asset among the plurality of assets via respective Moving Picture Experts Group (MPEG) Media Transport Protocol (MMTP) packets; receiving a time stamp information referencing UTC (Coordinated Universal Time) in the MPU, the time stamp information representing a presentation time of a first access unit in presentation order in the MPU; and receiving a leap second insertion flag indicating when a leap second will be inserted, and receiving a leap second deletion flag indicating when a leap second will be deleted, the leap second insertion flag and the leap second deletion flag indicating a presence of a leap second event, wherein the first access unit in the MPU is presented at the time signaled in reference to the time stamp information.