Group Video Synchronization via LMR Feedback

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Solution Overview

Problem

Public-safety officers experience confusion due to latency differences in video sharing over LTE networks, causing asynchronous viewing of video among officers discussing the same content via Land Mobile Radio, despite instantaneous voice communications.

Innovation Solution

A method and apparatus for synchronizing group video by transmitting synchronization information, such as frame numbers or timestamps, over an LMR and/or LTE network upon a triggering event like a Push-to-Talk button press or touchscreen touch, ensuring all users view the same spot in the video.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If video is shared over LTE network, then large data rates are achieved, but viewers receive video at different latencies due to differing channel conditions

Engineering Contradiction:

Improvedata rateVSAvoidvideo latency

Core Design Contradiction:

PowerVSLoss of time

Solution Approach 1:

The system transmits synchronization information (frame numbers, timestamps) from one user device to other user devices via LMR network. Each user device receives this feedback information and adjusts its video playback position accordingly to synchronize with the reference device, compensating for the latency differences caused by varying LTE channel conditions.

Inventive Principle:

Principle #23Feedback

2Ease of operation

If users pause and resume video independently, then individual viewing control is achieved, but viewers simultaneously watch different parts of the same video

Engineering Contradiction:

Improveviewing controlVSAvoidvideo synchronization

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

When a user pauses or resumes video, the system transmits synchronization information indicating the current video position (frame number or timestamp) to all other user devices. This feedback mechanism ensures that all viewers remain synchronized at the same video position, maintaining group viewing coherence while still allowing individual pause/resume control.

Inventive Principle:

Principle #23Feedback

3Speed

If LMR network is used for voice communications, then instantaneous communication is achieved, but video and voice become asynchronous when discussing video content

Engineering Contradiction:

Improvevoice communication speedVSAvoidsynchronization information

Core Design Contradiction:

SpeedVSLoss of information

Solution Approach 1:

The system introduces synchronization information as an intermediary element that bridges the LMR voice communication network and the LTE video sharing network. This synchronization data (frame numbers, timestamps) acts as a mediator that allows voice discussions to be properly aligned with the corresponding video content being viewed, resolving the asynchrony between instantaneous voice communication and delayed video delivery.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10250936B1Transmission of group video synchronization to other radios

Publication Date: 2019.04.02 MOTOROLA SOLUTIONS INC

AI summary

A method and apparatus for synchronizing group video is provided herein. Upon a triggering event, users viewing a video over an LTE network will transmit synchronization information (e.g., a frame number, or a time stamp of the video frame, . . . , etc.) over an LMR and/or LTE network. In response, user devices will synchronize to the same spot in the video.