SIK Radio Project

Overview

This project implements a multicast internet radio transmitter and receiver. The transmitter sends a stream of audio data to multiple receivers over UDP. Receivers discover available transmitters, request missing packets for retransmission, and output the audio data.

Part A: Transmitter

The transmitter reads an audio stream from standard input, packages it into UDP datagrams, and sends them to a multicast address. It maintains a FIFO queue of the last FSIZE bytes read, allowing for retransmission of requested packets.

Features

• Reads audio data from standard input.
• Sends UDP packets to a specified multicast address and port.
• Maintains a FIFO queue for packet retransmission.
• Listens for control messages on a specified port.

Usage

./sikradio-sender -a MCAST_ADDR -n "Radio Name" -P DATA_PORT -C CTRL_PORT -p PSIZE -f FSIZE -R RTIME

Part B: Receiver

The receiver listens for multicast UDP packets, requests retransmissions for missing packets, and outputs the audio data to standard output. It also provides a simple text-based UI over TCP for switching between stations.

Features

• Discovers active transmitters by sending LOOKUP requests.
• Receives and buffers audio packets.
• Requests retransmission of missing packets.
• Provides a text-based UI for station selection.

Usage

./sikradio-receiver -d DISCOVER_ADDR -C CTRL_PORT -U UI_PORT -b BSIZE -R RTIME -n "Radio Name"

Protocols

Audio Packet Structure

struct __attribute__((packed)) audio_packet {
    uint64_t session_id;
    uint64_t first_byte_num;
    char     audio_data[];
};

Building project

In order to build the project, simply run make command.