RoomRTC

Final project for the Programming Workshop (FIUBA) developed by the RoomRTC group.

RoomRTC is a video conferencing application written in Rust. It uses a central server for authentication and signaling, and establishes a peer-to-peer (P2P) connection between clients to transport audio, video, and files.

Quick Start: Build & Run

Compilation

cargo build

1. Running the Server

cargo run --bin server room_rtc.conf

The server uses the configuration from the config file and writes logs to room_rtc.server.log.

2. Running a Client

cargo run --bin client room_rtc.conf 127.0.0.1:8080

The second argument is the address of the signaling server (client_server_addr). The client writes logs to room_rtc.log.

Recommended Order

1. Start the server.
2. Open one or more clients.
3. Register or log in.
4. Select an available user and start the call.

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Features

• User registration and login.
• List of available users.
• Peer-to-peer calls with SDP and ICE exchange.
• Real-time audio and video transport.
• Encrypted communication using DTLS/SRTP.
• File transfer during calls via Data Channels over SCTP.
• Desktop graphical interface built with eframe/egui.

Architecture (App Flow)

• Central Server: Handles users, login, and signaling over TCP/TLS.
• Client: Handles the GUI, audio/video capture, and call control.
• P2P Connection: Once the call is negotiated, peers exchange media and data directly over UDP.

graph TD
    subgraph Local Network / Internet
        S[Central Server<br/>TCP/TLS Signaling]
        C1[Client 1]
        C2[Client 2]
    end

    C1 <==>|Login / SDP / Signaling| S
    C2 <==>|Login / SDP / Signaling| S
    C1 <.->|UDP ICE Checks| C2
    C1 <==>|P2P Media & Data<br/>DTLS / SRTP / SCTP| C2

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Call Flow

The call establishment flow follows the WebRTC specification adapted to RoomRTC's client-server protocol.

sequenceDiagram
    participant C1 as Client 1 (Caller)
    participant S as Central Server
    participant C2 as Client 2 (Callee)

    C1->>S: LogIn
    C2->>S: LogIn
    
    Note over C1,C2: Call Initiation
    C1->>S: CallRequest (SDP Offer)
    S->>C2: CallIncoming (SDP Offer)
    
    C2->>S: CallAccept (SDP Answer)
    S->>C1: CallAccepted (SDP Answer)
    
    Note over C1,C2: Peer-to-Peer Connection
    C1-->>C2: ICE Connectivity Checks (UDP Ping/Pong)
    C1-->>C2: DTLS Handshake
    C1-->>C2: Media Transport (SRTP) / Files (SCTP)
    
    Note over C1,C2: End of Call
    C1->>S: CallHangup
    S->>C2: UserStatusUpdate (Available)

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Client Internal Components

The application is modularly designed, featuring a central controller that orchestrates the UI, sessions, and network transport, using standard library threads instead of async tools like Tokio.

graph LR
    UI[Graphical Interface<br/>egui] --> CTRL[Controller]
    
    subgraph Core
        CTRL --> CS[Call Session<br/>SDP / ICE]
        CTRL --> MT[Media Transport]
        CTRL --> FT[File Transferer<br/>SCTP]
        CTRL --> MP[Media Pipeline<br/>OpenCV / Opus]
    end
    
    subgraph Network["Network (UDP)"]
        MT --> SRTP[SRTP Context]
        MT --> RTP[RTP Sender/Receiver]
        MT --> RTCP[RTCP Report Handler]
    end

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Requirements

• Stable Rust.
• OpenCV 4 with development headers.
• OpenSSL with development headers.
• clang, llvm, pkg-config.

For Ubuntu/Debian, there is a base script to install environment dependencies:

bash ./scripts/dependencies.sh

Depending on your system, you may also need to install libssl-dev.

Configuration

The room_rtc.conf file includes the main sections of the system:

• [network]: Sockets and maximum UDP packet size.
• [media]: Camera, H.264 video, Opus audio, and RTP parameters.
• [rtcp] & [rtp]: Reports, timeouts, and packet sizes.
• [sdp] & [ice]: Session negotiation and candidates.
• [server]: Server addresses, TLS files, and users file.
• [dcep]: Timeouts for data channels.

The example configuration file already points to:

• Signaling server at 0.0.0.0:8080.
• Server-client channel at 0.0.0.0:8081.
• TLS certificates in tls_server/.
• Simple user database in src/server/data.txt.

Testing and Quality

cargo test

cargo clippy --all-targets --all-features

Documentation

cargo doc --open

Useful Files

• room_rtc.conf: Example configuration.
• src/bin/server/main.rs: Server entry point.
• src/bin/client/main.rs: Client entry point.
• docs/Informe.md: Technical project report.

*** Let me know if you'd like to tweak any other part of the documentation!