lite-streaming-client

A lightweight streaming media library written in C++17 for learning purposes.

The goal is to understand and implement streaming protocols (RTSP, RTMP, WebRTC, etc.) from scratch without using FFmpeg, making it easier to learn the underlying mechanisms of streaming media.

Inspired by ZLMediaKit.

Why This Project?

• Learning-oriented: Clean, readable code to understand how streaming protocols work
• No FFmpeg dependency: Implement protocols from scratch for deeper understanding
• Minimal design: Focus on core concepts without complex abstractions

Features

Currently Supported

• RTSP/1.0 client (pull stream)
• Digest authentication
• RTP over TCP (interleaved mode)
• RingBuffer with GOP caching

Planned

• RTMP client
• RTMP server
• WebRTC support
• RTP over UDP
• H.264/H.265 depacketization
• Protocol conversion (RTSP to RTMP, etc.)

Architecture

+---------------------------------------------------+
|              lite-streaming-client                |
+---------------------------------------------------+
|                                                   |
|  +-------------+  +-------------+  +------------+ |
|  | RtspClient  |  | RtmpClient  |  | WebRTC     | |
|  +------+------+  +------+------+  +-----+------+ |
|         |                |               |        |
|         v                v               v        |
|  +---------------------------------------------+  |
|  |              RingBuffer (GOP Cache)         |  |
|  +---------------------------------------------+  |
|                                                   |
+---------------------------------------------------+

RTSP Flow

Client                          Server
   |                               |
   |--- OPTIONS ------------------>|
   |<-- 401 Unauthorized ----------|
   |--- OPTIONS + Authorization -->|
   |<-- 200 OK --------------------|
   |                               |
   |--- DESCRIBE + Auth ---------->|
   |<-- 200 OK + SDP --------------|
   |                               |
   |--- SETUP + Auth ------------->|
   |<-- 200 OK + Session ----------|
   |                               |
   |--- PLAY + Session ----------->|
   |<-- 200 OK --------------------|
   |                               |
   |<== RTP Packets ===============|

Quick Start

Build

mkdir build && cd build
cmake ..
make

Run

./simple_player rtsp://user:password@192.168.1.100:554/stream

Example Code

#include "rtsp/RtspClient.h"

int main() {
    auto client = std::make_shared<RtspClient>();
    
    client->setOnPlayResult([](bool ok, const std::string& msg) {
        std::cout << "Play: " << (ok ? "Success" : "Failed") << std::endl;
    });
    
    client->getRing()->setOnData([](const RtpPacket::Ptr& pkt) {
        std::cout << "RTP seq=" << pkt->seq << std::endl;
    });
    
    client->play("rtsp://admin:123456@192.168.1.64:554/stream");
    
    std::this_thread::sleep_for(std::chrono::seconds(30));
    client->shutdown();
    
    return 0;
}

Project Structure

lite-streaming-client/
├── CMakeLists.txt
├── README.md
└── src/
    ├── main.cpp
    ├── network/
    │   └── TcpClient.h
    ├── rtsp/
    │   ├── RtspClient.h
    │   ├── RtspSplitter.h
    │   └── RtpPacket.h
    └── util/
        └── RingBuffer.h

Dependencies

• C++17
• OpenSSL (for MD5)
• POSIX sockets (Linux/macOS)

References

• ZLMediaKit
• RFC 2326 - RTSP
• RFC 3550 - RTP
• RFC 2617 - HTTP Authentication

License

MIT License