mergeChunks.js

import { spawn } from 'node:child_process'
import { readdir } from 'node:fs/promises'

export default async function mergeChunks(dirname) {
    // construct merge command
    // const watermarkSize = 20
    // const mergeChunksCmd = `ffmpeg -i "concat:$(ls -v ${dirname}/*.ts | tr '\n' '|')" -vf "drawtext=text='PYONERIP.COM':x=10:y=h-th-10:fontcolor=white@0.5:fontsize=${watermarkSize}:alpha=0.5" -c:v libx264 -preset medium -crf 23 -c:a aac -b:a 128k ${dirname}/${dirname}.mp4`
    const getOrderNo = (chunkName) => parseInt(chunkName.match(/video(\d+)\.ts/)[1])
    const sortByNumber = (a, b) => {
        const chunkA = getOrderNo(a)
        const chunkB = getOrderNo(b)
        return chunkA - chunkB
    }
    const dirContents = await readdir(dirname)
    const tsFiles = dirContents
        .filter(file => file.endsWith('.ts'))
        .map(file => `${dirname}/${file}`)
        .sort(sortByNumber)
        .join('|')

    const ffmpegOptions = ['-i', `concat:${tsFiles}`, '-c', 'copy', `${dirname}/${dirname}.mp4`]
    // run merge command
    return new Promise((resolve, reject) => {

        const cp = spawn('ffmpeg', ffmpegOptions, { stdio: 'inherit' })
        cp.on('spawn', () => console.log('spawned', process.pid))
        cp.on('exit', (code) => code != 0 ? reject(code) : resolve(`${dirname}/${dirname}.mp4`))
    })
}