2025-04-26
Abstract: With the deepening of smart policing construction, body-worn cameras, as core equipment for frontline law enforcement personnel, have upgraded their functions from traditional audio and video recording to intelligent and networked features. Real-time live streaming and intercom functions, as key technological breakthroughs in body-worn cameras, enable seamless collaboration between on-site law enforcement and the back-end command center, significantly improving law enforcement efficiency and emergency response capabilities. This paper, based on industry standards such as GA/T1400.4-2017 and GB/T28181-2016, and combining 4G/5G communication technology, audio and video encoding and decoding technology, and intelligent interaction technology, systematically analyzes the technical architecture, implementation path, and application scenarios of real-time live streaming and intercom functions in body-worn cameras. It also discusses their value in standardizing law enforcement behavior, strengthening command and dispatch, and ensuring data security, and finally looks forward to future technological optimization directions.
I. Introduction
(I) Research Background
In recent years, the rule of law strategy has propelled the standardization of law enforcement into a new stage. As an important carrier of transparent law enforcement, law enforcement recorders have become standard equipment for departments such as public security, traffic police, and urban management. While traditional law enforcement recorders can capture on-site audio and video, they suffer from problems such as data transmission lag and lack of remote command, making it difficult to meet the real-time collaborative needs of dynamic law enforcement scenarios. With the popularization of 4G/5G networks and the development of smart terminal technology, a new generation of law enforcement recorders with real-time live streaming and intercom functions has emerged, providing technical support for cross-temporal and spatial law enforcement command.
(II) Research Significance
The real-time live streaming function can transmit on-site audio and video data back to the command center in real time, achieving visible remote dispatch; the intercom function supports instant voice interaction between law enforcement personnel and the command center and colleagues, solving the communication problem of being able to connect. The combination of these two functions not only improves the transparency of law enforcement but also shortens response time and reduces law enforcement risks in emergencies. This paper analyzes the technical principles and application practices of real-time live streaming and intercom functions, providing a reference for the intelligent upgrading of law enforcement equipment. (III) Current Status of Domestic and International Research Law enforcement recorders have been developed earlier abroad. For example, NOVESTOM's 4G body camera has achieved 4G live streaming and cloud platform integration. However, due to limitations in communication standards and privacy regulations, its functional compatibility varies regionally. NOVESTOM has also launched a 4G Android body camera that integrates the GB/T28181 protocol and trunking intercom technology, offering advantages in compatibility and localized services. In the academic field, existing research mainly focuses on single-function optimization (such as video compression algorithms and improved positioning accuracy), with less discussion on the collaborative mechanism between live streaming and intercom. This paper aims to fill this gap.
II. Technical Architecture of Real-Time Live Streaming and Intercom Functions in Law Enforcement Recorders
(I) Overall Design Framework The implementation of real-time live streaming and intercom functions relies on a three-layer architecture of terminal-network-platform:
Terminal Layer: The body camera, as the front-end device, integrates a camera, microphone, 4G/5G module, GPS/BeiDou positioning module, and PTT (one-button intercom) button, responsible for audio and video acquisition, encoding, and command transmission. Network Layer: Data transmission is achieved through 4G/5G public networks or dedicated communication networks, supporting dual-stream technology (local high-definition storage + remote low-bitrate transmission) to balance real-time performance and bandwidth costs.
Platform Layer: A command and dispatch platform built on the GB/T28181 protocol, featuring video decoding, device management, user authentication, and data storage functions, supporting multi-terminal access and centralized control.
(II) Real-time Live Streaming Technology Implementation
Audio and Video Acquisition and Encoding: Adopts the H.265/HEVC encoding standard, offering 50% higher compression efficiency compared to H.264, while maintaining 720P/1080P image quality even under low bandwidth.
Wide dynamic range (≥85dB) and infrared night vision (night vision distance ≥7 meters) ensure image clarity in complex lighting conditions.
Real-time Transmission Protocol: Media stream transmission is based on the RTSP/RTMP protocol, using an adaptive bitrate algorithm (such as the dynamic adjustment technology of the SmartGBD SDK) to switch bitrates according to network conditions, avoiding stuttering. Supports GB/T28181 protocol integration with the platform, enabling standardized operations such as device registration, real-time preview, and video playback.
Key Technical Indicators:
Live Stream Latency: ≤3 seconds on 4G networks, ≤1 second on 5G networks;
Frame Rate: 25-30fps, ensuring smooth dynamic images;
Wide-Angle Coverage: 126-degree ultra-wide-angle lens, geometric distortion ≤8%, reducing blind spots.
(III) Intercom Function Technology Implementation
Trunking Intercom Mechanism: Based on PoC (Push-to-Talk over Cellular) technology, it achieves half-duplex voice communication via IP network, supporting group intercom and two-person communication.
PTT physical button design: press to speak, release to listen, convenient operation without affecting core functions such as recording and taking photos.
Multimodal Interaction Expansion: In addition to voice, it supports text chat, local image sending, and real-time location sharing, meeting the information transmission needs in complex law enforcement scenarios. Priority Scheduling Strategy: An emergency call priority mechanism is adopted. When law enforcement personnel trigger a one-click alarm, the intercom channel automatically switches to the highest priority, ensuring that command instructions are transmitted first.
(IV) Data Security Assurance:
Transmission Encryption: TLS 1.3 protocol is used to encrypt live streams and intercom data to prevent eavesdropping or tampering during transmission.
Storage Encryption: Local video files are encrypted using the AES-256 algorithm, and only authorized devices (such as acquisition stations) can decrypt them, preventing data leakage (Reference 8).
Access Control: The platform layer uses triple authentication of username + password + device SN code to restrict unauthorized terminal access. The log system records all operational behaviors.
III. Functional Application Scenarios and Practical Cases
(I) Daily Patrol Enforcement: In scenarios such as traffic violation investigation and community security patrols, after law enforcement personnel start live streaming, the command center can remotely monitor the enforcement process and promptly correct any irregularities. For example, when traffic police are investigating drunk driving, if the driver resists enforcement, the command center can assess the situation through live video and dispatch nearby police support; simultaneously, it can issue enforcement guidelines directly through the intercom function to prevent escalation of conflict.
(II) Emergency Response to Sudden Incidents In emergency scenarios such as mass incidents and violent crimes, the synergy between live streaming and intercom functions is particularly crucial:
Live Streaming: Live video feeds back in real time, allowing the command center to formulate response plans based on the density and emotional state of people in the video;
Group Intercom: Multiple groups of law enforcement personnel can clearly define their roles through group intercom (e.g., control group, negotiation group), and the PTT button ensures immediate transmission of voice commands;
Location Linkage: Combined with GPS/BeiDou positioning, the platform can mark the location of law enforcement personnel on an electronic map, optimizing police deployment routes.
Case Study: In a 2023 pilot project for smart policing in a certain province, law enforcement recorders equipped with live streaming functions played a role in forest fire rescue. Firefighters transmitted video of the fire scene via 4G network, and the command center remotely planned firefighting routes based on the fire's spread. They also coordinated ground and air rescue forces through intercom, reducing fire control time by 40%.
(III) Cross-departmental Collaborative Enforcement
In joint enforcement (such as joint anti-counterfeiting operations by public security and market supervision departments), law enforcement recorders from different departments can be connected to the same command platform, enabling the sharing of live footage and intercom channels. For example, after discovering a warehouse of counterfeit goods, market supervision personnel can use the live footage to allow public security personnel to remotely confirm the situation, simultaneously coordinating arrest plans through intercom, thus avoiding information transmission distortion.
(I) Technical Bottlenecks
Strong Network Dependence: In remote areas or environments with signal blockage, insufficient 4G/5G network coverage may lead to live broadcast interruptions and intercom delays.
Insufficient Battery Life: Real-time live streaming and network communication consume a lot of power. The existing 3600mAh battery provides approximately 8 hours of battery life in 1080P live streaming mode, which is insufficient to meet the needs of all-weather enforcement (Reference 8). High Algorithm Complexity: In dynamic scenes (such as rapid movement or sudden changes in lighting), video encoding algorithms are prone to pixelation and frame drops, affecting image quality.
(II) Optimization Strategies
Multi-Network Integration: Introducing a satellite communication backup module automatically switches to satellite transmission in areas without public network coverage, ensuring communication continuity in extreme environments.
Low Power Consumption Design: Employing energy-saving chips (such as the Qualcomm Snapdragon 690) and dynamic sleep technology, some modules are shut down during non-live broadcast periods, extending battery life to over 12 hours.
AI-Assisted Encoding: Integrating an edge computing chip, AI algorithms analyze scene complexity in real time and dynamically adjust encoding parameters (such as increasing bitrate in moving areas and decreasing bitrate in static areas) to improve compression efficiency.
(III) Policy and Standard Recommendations
Improve Industry Standards: Promote the development of technical specifications for real-time live streaming and intercom functions, unifying interface protocols and performance indicators (such as latency thresholds and encryption algorithms) to avoid device compatibility issues. Data Privacy Protection: Clearly define the storage period and access permissions for live streaming data, and automatically anonymize footage involving citizens' privacy (such as residential buildings and minors).
V.Conclusions and Outlook
(I) Research Conclusions
Real-time live streaming and intercom functions are the core hallmarks of the upgrade of law enforcement recorders from standalone data collection to intelligent interconnection. Their technological implementation relies on the integration of multiple technologies such as audio and video encoding/decoding, 4G/5G communication, and trunking intercom. Application scenarios cover daily law enforcement, emergency response, and cross-departmental collaboration, significantly improving law enforcement efficiency and standardization.
(II) Future Outlook
Deep Integration of 5G and AI: The low latency (≤1ms) of 5G networks will further improve the smoothness of live streaming. AI algorithms can achieve real-time facial recognition, behavior analysis, and automatic early warning of abnormal law enforcement behavior.
Lightweight and Modular Design: body camera will develop towards miniaturization and wearability, supporting on-demand expansion of functional modules (such as external infrared thermal imaging lenses and gas sensors) to adapt to diverse law enforcement scenarios. Blockchain-based evidence storage: Utilizing blockchain technology to achieve the immutability and full traceability of law enforcement data, providing technical endorsement for the judicial evidence chain.
(III) Conclusion
The widespread adoption of real-time live streaming and intercom functions in body camera is not only a result of technological innovation but also a reflection of the shift in law enforcement philosophy from post-event retrospection to in-event intervention. In the future, a balance needs to be struck between technological optimization, standards development, and privacy protection, ensuring that intelligent equipment truly becomes the eyes and ears of law enforcement personnel, providing solid support for building a society governed by the rule of law.
