Media Unit Timing with Leap Second Synchronization

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Solution Overview

Problem

Decoding ultra-high definition moving images such as 8K and 4K in real time is challenging due to high processing loads, and leap second adjustments in reference time information complicate the decoding or presentation of media presentation units (MPUs) in MMT/TLV schemes.

Innovation Solution

A transmitting method that stores data in predetermined data units and generates time specification information, transmitting both the data units and control information indicating the time specification information, including identification of whether it is before a leap second adjustment, allowing the receiving device to execute applications at intended times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If MMT/TLV scheme is used with reference clock synchronized to NTP, then time synchronization between transmission and receiving devices is improved, but decoding or presentation of media presentation units cannot be performed at intended time when leap second adjustment is made

Engineering Contradiction:

Improvetime synchronizationVSAvoiddecoding timing accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent segments time specification information into multiple parts: basic time information and leap second adjustment information. By dividing the time representation into these separate components, the system can handle leap second adjustments without disrupting the overall time synchronization mechanism, allowing accurate decoding timing to be maintained even when leap seconds occur.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary element (the time specification information structure with leap second flags) that mediates between the NTP reference clock and the decoding timing. This intermediary allows the system to translate NTP time (which may include leap seconds) into accurate decoding timestamps by detecting and compensating for leap second adjustments, thus resolving the timing discrepancy.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If leap second adjustment is made to reference time information, then time accuracy is improved, but receiving device cannot execute applications at intended time

Engineering Contradiction:

Improvetime accuracyVSAvoidapplication execution timing

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary action by embedding leap second adjustment information in advance within the time specification data structure. The receiving device can detect the upcoming leap second adjustment before it occurs and proactively adjust its timing calculations, ensuring that application execution timing remains accurate despite the leap second insertion in the NTP time scale.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If parallelized decoding processing by using plurality of decoders is implemented, then processing load of one decoder is reduced, but system complexity increases

Engineering Contradiction:

Improvedecoding speedVSAvoiddecoder system complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the decoding task by assigning different media presentation units or time intervals to different decoders. Each decoder handles a specific portion of the decoding workload, which distributes the processing load and enables real-time decoding of ultra-high definition content. The segmentation is managed through the time specification information that coordinates the parallel decoders.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a universal time specification information structure that can be used across multiple decoders and different media types. This multi-functional time specification mechanism allows the same timing and synchronization approach to work across the entire parallel decoder system, reducing the complexity that would otherwise arise from managing multiple separate timing systems.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12489931B2Transmitting method, receiving method, transmitting device, and receiving device

Publication Date: 2025.12.02 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA

AI summary

A transmitting method stores data making up a coded stream into a predetermined data unit and transmits the stored data in the predetermined data unit. The transmitting method further generates presentation time information indicating a presentation time of the predetermined data unit, based on reference time information received from an external source; and transmits the predetermined data unit, first control information which includes the generated presentation time information, and second control information which includes leap second information indicating whether or not the presentation time information is a time that is before a leap second adjustment. A receiving method receives the predetermined data unit, first control information, and second control information; and reproduces the received predetermined data unit based on the first and second control information that are received.