Network Video Recorder Multi-Stream Recording Delay Handling
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Solution Overview
Problem
In a multi-stream recording environment, network video recorders face issues with video omission due to transmission delays when performing low-quality time-lapse and high-quality event stream recordings simultaneously, as they use different streams and are prone to overlapping and omission problems.
Innovation Solution
A network video recorder with a multi-stream recording function that includes a time-lapse recorder, an event recorder, and a recording controller to manage switching between modes, adjust recording times, and delete redundant data to prevent video omission by synchronizing the recording and reproduction of time-lapse and event streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multi-stream recording is implemented with separate time-lapse and event streams, then recording quality for events is improved, but video omission occurs due to transmission delay
Solution Approach 1:
The system performs preliminary actions by continuously recording time-lapse streams at low quality before events occur, and maintains buffer storage ready to capture event streams. When an event is detected, the system has already prepared the recording infrastructure and can immediately switch to high-quality event recording without loss, ensuring video completeness while maintaining high recording quality.
Solution Approach 2:
The patent introduces a stream selector as an intermediary component that manages multiple streams (time-lapse and event streams) and selects which stream to record based on event detection. This intermediary resolves the contradiction by coordinating between the two separate streams, ensuring that the high-quality event stream is captured without omission while the low-quality time-lapse stream provides continuous coverage.
2Adaptability or versatility
If separate streams are used for time-lapse and event recording, then recording flexibility is improved, but overlapping recording and omission occur due to transmission delay
Solution Approach 1:
The system implements dynamic switching between time-lapse recording mode and event recording mode based on real-time event detection. The stream selector dynamically adjusts which stream is being recorded, and the recording controller dynamically changes recording parameters. This dynamic adaptation maintains recording flexibility while ensuring continuity by seamlessly transitioning between modes without gaps or overlaps.
Solution Approach 2:
The system uses feedback from event detection to control the recording process. When an event is detected in the time-lapse stream, this feedback triggers the stream selector to switch to the event stream for high-quality recording. This feedback mechanism ensures recording continuity by automatically adjusting the recording mode based on actual conditions, preventing both overlapping and omission issues.
3Productivity
If event stream recording starts from reference frame position, then recording efficiency is improved, but video omission occurs in compressed video
Solution Approach 1:
The system performs preliminary analysis to identify key frame positions in the event stream before starting recording. By pre-determining the optimal starting position (key frame) and preparing the recording buffer in advance, the system can efficiently record from the correct position without omission, maintaining both recording efficiency and video completeness in compressed video formats.
Data Source
AI summary
A network video recorder having a multi-stream recording function which is robust to event stream delay is provided. An event stream is recorded by adjusting a time-lapse recording end time and an event recording time to prevent omission of a video, caused by transmission delay of a high-quality event stream during the recording of the event stream.