https://github.com/illuspas/Node-Media-Server/blob/master/README_CN.md

const NodeMediaServer = require('node-media-server');
const { exec } = require('child_process');

const config = {
    rtmp: {
        port: 1935,
        chunk_size: 60000,
        gop_cache: true,
        ping: 30,
        ping_timeout: 60
    },
    auth: {play: true, publish: true, secret: '123456789'},
    http: {
        port: 8000,
        mediaroot: './media',
        allow_origin: '*'
    },
    trans: {
        ffmpeg: 'd:/ffmpeg/bin/ffmpeg.exe',
        tasks: [{
            app: 'live',
            hls: true,
            hlsFlags: '[hls_time=2:hls_list_size=3:hls_flags=delete_segments]',
            dash: true,
            dashFlags: '[f=dash:window_size=3:extra_window_size=5]'
        }]
    }
};

var nms = new NodeMediaServer(config)
nms.run();
nms.on('prePublish', (id, StreamPath, args) => {
    //console.log(`[NodeEvent on prePublish] ${id} ${StreamPath} ${args}`);

    const outputFilePath = `./media/${StreamPath}.mp4`;

    const ffmpegCommand = `d:/ffmpeg/bin/ffmpeg.exe -i rtmp://localhost:1935${StreamPath} -c:v copy -c:a copy ${outputFilePath}`;

    exec(ffmpegCommand, (error, stdout, stderr) => {
        if (error) {
            console.error(`exec error: ${error}`);
            return;
        }
        console.log(`stdout: ${stdout}`);
        console.error(`stderr: ${stderr}`);
    });
});