Network Clock Synchronization via Extended CRF Frames
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Solution Overview
Problem
In network systems, audio and video data cannot be promptly output before time synchronization protocols are activated, and processing is delayed due to the time required for protocol processing.
Innovation Solution
A network system that uses extended CRF or AVTP frames to transmit and receive data, including a previous frame transmission time and forwarding delay time period, allowing nodes to synchronize their clocks and media clocks without relying on the gPTP protocol, enabling immediate reproduction of audio and video data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a protocol for time synchronization (gPTP) is used to synchronize clocks between nodes, then clock synchronization accuracy is improved, but the time required for protocol processing increases, causing delays in audio and video data output
Solution Approach 1:
The patent performs clock synchronization using extended CRF or AVTP frames before audio and video data processing begins. By establishing time synchronization in advance through these alternative protocols, the system eliminates the need to wait for gPTP protocol completion before outputting media data, thus resolving the contradiction between synchronization accuracy and processing delay
Solution Approach 2:
The patent introduces extended CRF frames or AVTP frames as intermediary mechanisms to achieve clock synchronization without relying on the gPTP protocol. These intermediary protocols carry timing information that enables synchronization while avoiding the processing delays associated with gPTP, allowing audio and video data to be output promptly
2Reliability
If the gPTP protocol is implemented for time synchronization, then system reliability is improved, but device complexity increases due to protocol processing requirements
Solution Approach 1:
The patent extracts the time synchronization function from the gPTP protocol and implements it through extended CRF or AVTP frames. By separating the synchronization mechanism from the complex gPTP protocol stack, the system maintains synchronization reliability while reducing device complexity and processing overhead
Solution Approach 2:
The patent uses lightweight extended CRF or AVTP frames as temporary, simple synchronization carriers instead of implementing the full gPTP protocol stack. These simplified frame structures provide necessary timing information with minimal processing requirements, reducing device complexity while maintaining functional reliability
3Adaptability or versatility
If audio and video data are transmitted through the network, then system versatility is improved, but the time required for data transmission and processing increases
Solution Approach 1:
The patent performs clock synchronization in advance using extended CRF or AVTP frames before audio and video data transmission begins. This preliminary synchronization ensures that when data is transmitted through the network, both transmitting and receiving nodes are already time-synchronized, eliminating delays that would otherwise occur during protocol processing and enabling immediate data reproduction
Data Source
AI summary
According to an embodiment, in a network system 1 in which at least one data of the audio data and the video data is transmitted from a first node to a second node through a network, the second node includes a processor configured to generate a clock signal for reproduction of the audio data and the like. The processor is configured to synchronize a current time in the second node with a current time in the first node, based on a transmission time that is based on the current time in the first node and is contained in a received extended CRF frame, a reception time that is based on the current time in the second node and at which the extended CRF frame is received, and a delay time period occurring while the extended CRF frame is transmitted from the first node to the second node.