Remote Video Timing Recovery for Negative Phase Jumps
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Solution Overview
Problem
In distributed access architectures for video delivery, maintaining accurate timing information between a video core and remote devices like RPDs or RMDs is challenging, especially during asynchronous operations or loss of synchronization with a grandmaster clock, leading to video quality degradation and network outages.
Innovation Solution
Implementing a dejitter buffer in remote devices to monitor buffer fullness and adjust packet processing (inserting or dropping null packets) to maintain consistent throughput, and a method for detecting and correcting for negative phase jumps without requiring a device reset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If distributed access architecture is used to reduce head end congestion, then device complexity at head end is reduced, but timing synchronization reliability between core and remote devices deteriorates
Solution Approach 1:
The patent applies preliminary action by detecting phase jumps before they cause video quality degradation. The system continuously monitors the phase relationship between core clock and remote device clock, and preemptively adjusts packet timestamps when a phase jump is detected, preventing timing errors from affecting video delivery
Solution Approach 2:
The patent implements feedback mechanisms by continuously monitoring buffer fullness, packet arrival times, and phase relationships between clocks. This feedback is used to dynamically adjust packet processing, null packet insertion, and timestamp modification to maintain synchronization despite distributed architecture challenges
2Stability of the object's composition
If dejitter buffer is used to handle timing variations, then video quality consistency is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by enabling the remote device to autonomously detect phase jumps, determine their direction (positive or negative), and apply appropriate corrections without requiring external control or reset commands. The device independently manages its own synchronization state using the dejitter buffer and phase jump detection logic
3Reliability
If automatic recovery from negative phase jumps is implemented, then network outage time is reduced, but device complexity increases
Solution Approach 1:
The patent implements feedback by continuously monitoring packet timestamps and buffer fullness to detect phase jumps. When a negative phase jump is detected, the system automatically adjusts future packet timestamps to compensate for the timing error, enabling seamless recovery without network outage
Solution Approach 2:
The patent applies parameter changes by modifying packet timestamp values dynamically in response to detected phase jumps. The system changes the timing parameters of video packets to compensate for clock synchronization errors, allowing automatic recovery from negative phase jumps without reset
Data Source
AI summary
Device, systems and methods implemented in a distributed access architecture that allow a remote device to automatically recover from a phase jump event without resetting. A remote device may recover without resetting when a negative phase jump is detected.