Multiplexing Device NTP Time Rewriting for Digital Broadcasting Delay
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Solution Overview
Problem
The existing multiplexing technologies for digital broadcasting introduce a significant delay of approximately 66 ms between the time written in the Network Time Protocol (NTP) packet and the transmission timing of the Type Length Value (TLV) slot, leading to increased buffer sizes at the receiver and degraded real-time properties during video and audio decoding.
Innovation Solution
A multiplexing device and method that synchronizes the transmission timing of the TMCC information with the main signal by rewriting the NTP packet time to the current time before output, ensuring that the time written in the NTP packet coincides with the system time at the receiver, thereby eliminating the delay and improving real-time performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main signal is delayed by two frames to advance the TMCC information for switching, then the TMCC information can be transmitted in advance for scheme switching, but the delay between NTP packet time and TLV slot transmission time increases by approximately 66 ms
Solution Approach 1:
The patent applies preliminary action by writing the current time into the NTP packet in advance, before the packet is multiplexed into the TLV slot. This ensures that when the TLV slot is transmitted two frames later, the NTP packet already contains the correct current time, eliminating the time delay issue while maintaining the advanced TMCC information transmission for scheme switching reliability
2Device complexity
If the NTP packet time is not synchronized with the transmission timing, then the multiplexing process is simpler, but the buffer size at the receiver increases and real-time properties are degraded
Solution Approach 1:
The patent applies parameter changes by modifying the time parameter in the NTP packet to match the current time at the moment of writing. This simple parameter adjustment synchronizes the NTP packet time with the transmission timing, reducing the receiver buffer size and improving real-time performance without significantly increasing multiplexing process complexity
Data Source
AI summary
According to an embodiment, a multiplexing device includes: a packet generating unit which generates one or more third packets based on at least one of one or more first packets and a second packet; a main signal generating unit which generates from the third packets a main signal; an information generating unit which generates transmission multiplexing control information; a slot generating unit which generates a slot by combining the transmission multiplexing control information and the main signal corresponding to the information described in the transmission multiplexing control information having been generated a predetermined number of frames prior to the currently generated transmission multiplexing control information; and a time writing unit which writes a time in the second packet in the main signal included in the generated slot.