ZLMediaKit — High-Performance Streaming Media Server in C++

Introduction

ZLMediaKit is a high-performance, cross-platform streaming media server framework written in C++11. It provides a unified server that handles nearly every streaming protocol used in production — from traditional RTSP/RTMP to modern WebRTC and SRT — making it suitable for live broadcasting, video surveillance, and real-time communication systems.

What ZLMediaKit Does

• Receives and distributes live streams across multiple protocols simultaneously
• Converts between protocols on-the-fly (e.g., RTSP input to HLS/WebRTC output)
• Records streams to MP4 or HLS segments for later playback
• Provides a RESTful API for stream management and server control
• Supports cluster deployment with origin-edge architecture

Architecture Overview

ZLMediaKit is built on an event-driven, multi-threaded networking framework (ZLToolKit). Each incoming stream is demuxed into a protocol-agnostic internal frame queue, then remuxed on demand into any output protocol requested by viewers. This design enables zero-copy protocol conversion. The server manages sessions via a thread-pool model with lock-free queues for high concurrency.

Self-Hosting & Configuration

• Compile from source with CMake on Linux, macOS, or Windows
• Docker images available for quick deployment
• Configure listening ports and protocol options in config.ini
• Enable HTTPS/WSS with your own TLS certificates
• Set up hook URLs for stream publish/play authentication callbacks

Key Features

• Multi-protocol: WebRTC, RTSP, RTMP, HLS, HTTP-FLV, SRT, GB28181 in one binary
• Sub-second latency with WebRTC and HTTP-FLV delivery
• On-the-fly transcoding-free protocol conversion
• RESTful API for programmatic stream management
• Cluster support with configurable origin-edge relay

Comparison with Similar Tools

• Nginx-RTMP — RTMP-only module; ZLMediaKit handles many more protocols natively
• SRS (Simple RTMP Server) — similar goals but ZLMediaKit adds GB28181 and broader WebRTC
• Janus — WebRTC gateway focus; ZLMediaKit covers traditional streaming protocols too
• MediaSoup — WebRTC SFU library; ZLMediaKit is a full-featured standalone server
• Wowza — commercial streaming server; ZLMediaKit is free and open source

FAQ

Q: Can it handle thousands of concurrent viewers? A: Yes, its event-driven architecture and edge-relay support allow scaling to large audiences.

Q: Does it support recording? A: Yes, streams can be recorded as MP4 files or HLS segments with configurable retention.

Q: Is GPU transcoding supported? A: ZLMediaKit focuses on protocol conversion without transcoding. For transcoding, pair it with FFmpeg.

Q: What is GB28181 support? A: GB28181 is a Chinese national standard for video surveillance systems. ZLMediaKit can ingest and serve streams from GB28181-compliant cameras.

Sources

• https://github.com/ZLMediaKit/ZLMediaKit
• https://docs.zlmediakit.com