Reference Clock Extraction in Broadcast IP Transmission
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Solution Overview
Problem
Conventional MMT schemes require multiple complex processes to acquire high-precision reference clock information on the reception side, leading to increased time and potential jitter due to software-based extraction, especially when reference clock information is stored within the MMT packet layer.
Innovation Solution
The proposed method involves storing reference clock information in the TLV packet at the head of the transfer slot, allowing for simplified acquisition by specifying its position, and potentially using a lower protocol layer for transmission, enabling hardware-based extraction and reducing processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference clock information is stored within the MMT packet layer, then the information can be transmitted through the broadcast channel, but multiple complex software-based processes are required to extract it, increasing acquisition time and introducing jitter
Solution Approach 1:
The patent extracts the reference clock information from the MMT packet layer and places it directly in the transport stream packet header. This extraction moves the clock information to a more accessible location that can be processed by hardware rather than requiring multiple software-based extraction steps from nested packet structures.
Solution Approach 2:
The transport stream packet header serves as an intermediary structure that carries the reference clock information in a format accessible to hardware processors. This intermediate layer enables efficient hardware-based extraction while maintaining the integrity of the broadcast transmission system.
2Measurement precision
If reference clock information is stored within the MMT packet layer, then the information can be transmitted through the broadcast channel, but multiple complex processes are required to acquire it, increasing system complexity
Solution Approach 1:
The reference clock information is extracted from the complex MMT packet structure and placed directly in the transport stream packet header. This eliminates the need for multiple software-based extraction processes through nested packet layers, thereby reducing system complexity while maintaining high-precision clock information transmission.
Solution Approach 2:
The patent replaces software-based extraction processes with hardware-based extraction. By positioning the reference clock information in the transport stream packet header, hardware processors can directly access and process the clock information without requiring complex software parsing of MMT packet structures.
3Measurement precision
If reference clock information is stored within the MMT packet layer, then the information can be transmitted, but software-based extraction is required, introducing jitter in clock reproduction
Solution Approach 1:
The patent substitutes software-based extraction with hardware-based extraction by placing reference clock information in the transport stream packet header. Hardware processors provide deterministic timing and eliminate the jitter inherent in software-based extraction, thereby improving clock reproduction stability while maintaining high precision.
4Productivity
If reference clock information is stored in a lower protocol layer, then hardware-based extraction becomes possible, but the information must be transmitted through multiple packetization layers
Solution Approach 1:
The reference clock information is extracted from deep within the MMT packet structure and placed in the transport stream packet header, which is processed at a lower protocol layer. This enables hardware-based extraction while avoiding the need for complex multi-layer packetization, as the information is made accessible early in the transmission stream.
Data Source
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AI summary
A transmission method in transfer of content using an IP (Internet Protocol) packet performed through broadcast includes a generation step (S151) of generating a transfer frame that stores a plurality of second transfer units that each store one or more first transfer units that each store the IP packet, and a transmission step (S152) of transmitting the generated frame. In the generation step (S151), reference clock information that indicates time for reproduction of the content on a reception side is contained in the first transfer unit positioned at a head within the frame. This provides a transmission method capable of reducing processes for acquiring the reference clock information on a reception side.