Synchronized Multimedia Transmission Over Asynchronous Networks
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Solution Overview
Problem
In asynchronous packet transport networks, such as the internet and local area networks, it is challenging to maintain high precision synchronization between video camera and camera control unit reference signals and ensure video signal transport delays are within the video frame interval, leading to potential interference in video and audio processing.
Innovation Solution
A synchronous transport system that employs compression coding, packetization using RTP, high precision clock synchronization via IEEE1588 PTP, and media phase correction to synchronize and adjust the video signal transport, ensuring the video signal is transmitted with minimal delay and phase alignment across the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If video signal is transmitted over asynchronous packet transport network, then transmission distance is extended and network flexibility is improved, but transport delay increases and synchronization precision deteriorates
Solution Approach 1:
The patent applies preliminary action by measuring the transport delay before video signal transmission and using this measured value to pre-calculate and set the media phase correction amount. This allows the transmission side to compensate for the asynchronous nature of packet networks in advance, ensuring that even though transport delay varies in asynchronous networks, the synchronization is maintained by having the correction value ready before transmission begins.
Solution Approach 2:
The patent implements feedback by having the reception side measure the actual transport delay of received video packets and communicate this information back to the transmission side. The transmission side then uses this feedback to adjust the media phase correction amount dynamically, creating a closed-loop system that adapts to changing network conditions and maintains synchronization despite the asynchronous nature of packet transport.
2Reliability
If transport delay is reduced to maintain synchronization, then video and audio processing quality is improved, but transmission distance is limited and network versatility is reduced
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the media phase correction amount based on the measured transport delay. Instead of fixing the transmission parameters, the system continuously monitors the actual transport delay and modifies the media phase parameter accordingly. This allows the system to maintain high synchronization precision regardless of transmission distance or network conditions, as the correction parameter adapts to compensate for variations in transport delay.
3Device complexity
If media phase is not corrected, then system complexity is reduced, but video and audio interference occurs and processing quality deteriorates
Solution Approach 1:
The patent introduces an intermediary element - the media phase correction amount - that acts as a mediator between the asynchronous packet transport network and the synchronous video/audio processing requirements. This correction value, calculated based on measured transport delay, serves as a buffer that translates the asynchronous network timing into synchronous processing timing, eliminating video and audio interference without requiring complex real-time synchronization mechanisms at every processing stage.
Data Source
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AI summary
An apparatus includes a receiver (21), a delay value receiver (25), a time stamp calculation unit (29), and a transmitter (25). The receiver (21) is configured to receive a content signal. The delay value receiver (25) is configured to receive a delay value from another apparatus (13). The time stamp calculation unit (29) is configured to determine a time stamp based on the delay value. The transmitter (25) is configured to send the content signal including the time stamp to the another apparatus (13).