Project Overview

The video convergence and transcoding platform for the east extension line of a certain Rail Transit Line 2 is a high - performance video processing application platform developed by Beijing CSVision Technology Co., Ltd., specifically designed for multiple fields such as rail transit and digital government. There are approximately 2,500 cameras along the entire extension line of this rail. The platform adopts advanced video codec technology and a distributed architecture design, enabling video convergence and encoding format conversion regardless of brand, encoding format, resolution, or bit rate. It supports lossless local video viewing and intelligent transcoding, and fully supports multiple standard protocols such as GB/T 28181 - 2022, achieving seamless docking with third - party platforms.

Industry Background and Technological Trends

As a core component of the public security video surveillance system, this project has formed a standardized technical system. According to the latest GB/T 28181 - 2022 standard, the current platform adopts an architecture model of four - level platforms and five - level access:

Hierarchical architecture:Provincial platform: 

The general platform for sharing video and image information, integrating all resources within the jurisdiction

Municipal platform: The docking target of this project, realizing unified scheduling and permission allocation.

District - county platform: The regional convergence center, realizing local autonomy and reporting step - by -step.

Township/village platform: The grass - roots collection and prevention nodes.

Technical features:

Full - area coverage: Network sharing of video resources in public areas.

Full - network sharing: Interconnection of resources across departments and regions.

All - time availability: 24/7 uninterrupted service.Full - process controllability: Perfect security auditing and permission control.

With the continuous innovation of video encoding technology, the H.265/HEVC encoding format has been widely used in newly built video surveillance systems due to its higher compression efficiency (saving approximately 50% of bandwidth compared to H.264). However, most of the early - built platforms are mainly based on H.264, resulting in serious compatibility obstacles in encoding formats between the old and new systems.

Key points of the GB/T 28181 - 2022 standard update:

New support for H.265 and AAC audio encoding.

Optimization of the SIP monitoring domain interconnection structure.

Enhancement of PTZ control and device management functions.

Improvement of network transmission security requirements.

Perfection of signaling protocols and interface specifications.

Project Pain - Point Analysis

This project adopts a general - branch management model: All cameras along the entire line are centrally connected to the municipal bureau platform, which realizes unified scheduling, unified video display on the wall, and unified permission allocation. The local rail line has some self - management permissions. Due to the early construction period of the platform, it faces the following core problems in the continuous expansion of the video surveillance scope and the iterative upgrade of video decoding technology:

| Difficulty in video convergence and challenges in heterogeneous device compatibility:

Diverse camera manufacturers (Hikvision, Dahua, Uniview, Huawei, etc.).

Inconsistent resolution specifications (1080P, 4MP, 4K, etc.).

Mixed encoding formats (H.264, H.265, MJPEG, etc.).

Differences in access protocols (ONVIF, GB/T 28181, SDK, etc.).

| Technical generation conflict and difficulty in video display on the wall:

The early - built lines uniformly adopted the H.264 encoding format, meeting the requirements of the superior platform.

The newly built east extension line fully adopts the H.265 encoding format to improve storage and transmission efficiency. However, due to the lagging decoding ability of the platform, it cannot natively support the H.265 format.

A large number of videos cannot be displayed on the wall for viewing, seriously affecting emergency command and daily inspection work.

Project Solutions and Highlights

The platform adopts the design concept of hierarchical decoupling and software - hardware collaboration, constructing a trinity video processing architecture of "access - processing - distribution".

Explanation of the System Architecture Layers

Multi - protocol access capability:

The platform supports full - protocol stack access in the south - bound direction, ensuring seamless compatibility of heterogeneous devices.

It has the full - process device management capabilities of automatic device discovery and batch import, digital management of one device with one file, status inspection and fault alarm, remote configuration, and firmware upgrade.

Technological Innovation Points

Intelligent transcoding engine:

Scene adaptation: Dynamically adjust encoding parameters according to the picture content (low bit rate for static scenes and high bit rate for dynamic scenes).

ROI encoding: Improve the encoding quality of key areas (such as platform edges and entrances/exits).

Temporal filtering: Intelligent noise reduction to improve the transcoding quality in low - light environments.

High - availability architecture:

Load balancing: Multi - node cluster deployment with automatic load sharing.

Fault transfer: Automatic business switching in case of single - node failure (RTO ≤ 30 seconds).

Elastic expansion: Support for horizontal expansion to meet the needs of future line extensions.

Security enhancement:

Signaling encryption: SIP over TLS to ensure the security of control signaling.

Media encryption: SRTP protocol to prevent video stream eavesdropping.

Access authentication: Two - way certificate authentication for strict device identity verification.

Audit log: Complete recording of operation behaviors to meet the requirements of Class 2.0 of the Information Security Level Protection.

Unified Management of Rail Videos

Through the deployment of the video convergence and transcoding platform of Beijing ZhongShengYiHua, the video convergence and transcoding platform project for the east extension line of a certain Rail Transit Line 2 has successfully solved the core technical problems such as multi - brand device compatibility, H.265/H.264 format conversion, and multi - level platform cascading. The project has achieved unified convergence, lossless transcoding, and two - way sharing of 2,500 video resources, providing a successful practical case for the standardized, intelligent, and cloud - based development of the rail transit video surveillance system, and having important industry demonstration significance.