Reference Clock Acquisition in MMT Broadcast Transmission
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Solution Overview
Problem
Conventional MMT schemes face challenges in acquiring high-precision reference clock information due to complex processes and potential jitter in software-based extraction, especially when reference clock information is stored in MMT packets and requires extraction through multiple layers, leading to longer acquisition times and lower precision.
Innovation Solution
The method involves generating transfer frames that store IP packets with reference clock information at the head of streams, allowing for simplified acquisition by positioning the reference clock information in TLV packets or control information, reducing the number of processes required for the reception apparatus to extract and reproduce the clock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference clock information is stored in MMT packets and extracted through multiple layers, then the information can be obtained, but the acquisition process becomes complex and time-consuming
Solution Approach 1:
The patent extracts reference clock information from deep within the MMT packet structure and places it at the head of IP packets. This allows the reception apparatus to acquire the information without complex multi-layer extraction processes, directly resolving the contradiction between obtaining the information and the complexity of the extraction process.
Solution Approach 2:
The transmission apparatus performs preliminary action by positioning the reference clock information at the head of IP packets before transmission. This pre-positioning eliminates the need for complex extraction processes at the reception end, as the information is already in the optimal location for quick acquisition.
2Adaptability or versatility
If reference clock information is extracted through software-based processes, then flexibility is maintained, but jitter increases and precision decreases
Solution Approach 1:
The patent enables hardware-based extraction by positioning reference clock information at the IP packet level, which can be processed by hardware components. This substitutes software-based extraction with hardware-based processing, eliminating jitter and precision losses while maintaining flexibility through the standardized IP packet structure.
3Stability of the object's composition
If reference clock information is positioned deep in the packet structure, then data organization is maintained, but acquisition time increases
Solution Approach 1:
The transmission apparatus performs preliminary action by pre-positioning reference clock information at the head of IP packets. This ensures the information is immediately accessible upon packet reception without requiring deep structure traversal, thus reducing acquisition time while maintaining organized packet structure through standardized formatting.
Data Source
AI summary
A transmission method includes: generating one or more transfer frames that each store one or more streams used for content transfer; and transmitting the one or more generated frames through broadcast, each of the one or more streams storing one or more second transfer units, each of the one or more second transfer units storing one or more first transfer units, and each of the one or more first transfer units storing one or more Internet Protocol (IP) packets. In at least one stream among the one or more streams, each of the first transfer units positioned at a head contains reference clock information indicating time used for reproduction of the content.