Video Camera Multiplexing Control Signals in Serial Digital Video
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Solution Overview
Problem
In pool coverage systems, noise interference can cause video recording apparatuses to incorrectly interpret trigger pulses, leading to unreliable recording operations, and the physical constraints of the 26-pin connector cables limit the placement of VTRs, making it difficult to manage equipment in restricted spaces.
Innovation Solution
A video recording system where the video camera generates control information at predetermined intervals and multiplexes it with the video signal into a serial digital signal, which is transmitted to the recording apparatus, allowing for reliable control and operation of the recording system, even in tight spaces, by using HD-SDI signals and ancillary data packets to manage recording, playback, and equipment operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trigger pulses are transmitted through cables to control video recording apparatus, then recording operations can be performed, but noise interference causes incorrect interpretation of trigger pulses leading to unreliable recording operations
Solution Approach 1:
The patent replaces the mechanical/electrical trigger pulse transmission system with a digital control signal system. Instead of sending analog trigger pulses through cables that are susceptible to noise, the system encodes control information (including recording start/stop commands) into digital control signals that are multiplexed with the video signal. This digital encoding makes the control information immune to noise interference during transmission.
Solution Approach 2:
The patent introduces an intermediary encoding process where control information is converted into a standardized digital format (such as SMPTE 291M ancillary data packets) before transmission. This intermediary digital representation acts as a mediator between the camera operator's intentions and the recording apparatus, ensuring accurate interpretation regardless of transmission conditions.
2Ease of operation
If 26-pin connector cables are used to connect video camera and VTRs, then control signals can be transmitted, but cable length limitations restrict placement of VTRs making equipment management difficult in restricted spaces
Solution Approach 1:
The patent makes the video signal transmission system multi-functional by embedding control information within the video signal itself. The same SDI cable that carries the video signal also carries the control information for recording operations, eliminating the need for separate control cables and extending the system's operational range beyond cable length limitations.
Solution Approach 2:
The patent merges the video signal transmission and control signal transmission into a single integrated digital signal. By multiplexing control information with the video signal in the time or frequency domain, the system uses one cable for both purposes, thereby overcoming the physical length constraints of traditional separate control cables.
3Reliability
If control information is transmitted separately from video signal, then control functions can be performed, but system complexity increases and reliability decreases due to additional connection points
Solution Approach 1:
The patent combines separate control signal transmission and video signal transmission into a single integrated digital signal transmission system. Control information is multiplexed with the video signal, reducing the number of connection points and interfaces, thereby simplifying the system and improving reliability by eliminating additional potential failure points.
Data Source
AI summary
A video recording system is provided in which reliability of information supplied from a video camera to control recording and the like is improved when video being obtained by a video camera is recorded in one or more VTRs. In the video recording system, the video camera multiplexes: control information to control the VTR in accordance with an operational status of an operation unit of the video camera and a video signal from an imaging unit of the video camera, and transmits the result to the VTR as a transmission serial digital signal. The VTR separates the video signal and the control information from the serial digital signal and controls a video recording system of the VTR based on the control information.