fm-dx-webserver/stream/index.js

const { spawn } = require('child_process');
const fs = require('fs');
const consoleCmd = require('../console.js');

let serverConfig = {
    webserver: {
        audioPort: "8081"
    },
    audio: {
      audioDevice: "Microphone (High Definition Audio Device)",
      audioChannels: 2,
      audioBitrate: "128k"
    },
};

if(fs.existsSync('./config.json')) {
    const configFileContents = fs.readFileSync('./config.json', 'utf8');
    serverConfig = JSON.parse(configFileContents);
}

function enableAudioStream() {
    var ffmpegCommand;
    // Specify the command and its arguments
    const command = 'ffmpeg';
    const flags = `-fflags +nobuffer+flush_packets -flags low_delay -rtbufsize 6192 -probesize 32`;
    const codec = `-acodec pcm_s16le -ar 32000 -ac ${serverConfig.audio.audioChannels}`;
    const output = `-f s16le -fflags +nobuffer+flush_packets -packetsize 384 -flush_packets 1 -bufsize 960`;
    // Combine all the settings for the ffmpeg command
    if (process.platform === 'win32') {
        // Windows
        ffmpegCommand = `${flags} -f dshow -i audio="${serverConfig.audio.audioDevice}" ${codec} ${output} pipe:1 | node stream/3las.server.js -port ${serverConfig.webserver.audioPort} -samplerate 32000 -channels ${serverConfig.audio.audioChannels}`;
      } else {
        // Linux
        ffmpegCommand = `${flags} -f alsa -i "${serverConfig.audio.audioDevice}" ${codec} ${output} pipe:1 | node stream/3las.server.js -port ${serverConfig.webserver.audioPort} -samplerate 32000 -channels ${serverConfig.audio.audioChannels}`;
    } 

    consoleCmd.logInfo("Using audio device: " + serverConfig.audio.audioDevice);
    consoleCmd.logInfo("Launching audio stream on port " + serverConfig.webserver.audioPort + ".");
    // Spawn the child process

    if(serverConfig.audio.audioDevice.length > 2) {
        const childProcess = spawn(command, [ffmpegCommand], { shell: true });

        // Handle the output of the child process (optional)
        childProcess.stdout.on('data', (data) => {
            consoleCmd.logDebug(`stdout: ${data}`);
        });

        childProcess.stderr.on('data', (data) => {
            consoleCmd.logDebug(`stderr: ${data}`);
        });
    
        // Handle the child process exit event
        childProcess.on('close', (code) => {
            consoleCmd.logDebug(`Child process exited with code ${code}`);
        });
    
        // You can also listen for the 'error' event in case the process fails to start
        childProcess.on('error', (err) => {
            consoleCmd.logError(`Error starting child process: ${err}`);
        });
    }
}

module.exports = {
    enableAudioStream
}