Nikon RAW files converted to JPEG using mogrify with 'multithreading'

convertNEF.js

const fs = require('fs')
const cp = require('child_process')

const vamuved = require('vamuved')

function exec (command) {
  return new Promise((resolve, reject) => {
    cp.exec(command, (error, stdout, stderr) => {
      if (error) {
        reject(error.message)
        return
      }
      if (stderr) {
        reject(stderr)
        return
      }
      resolve(stdout)
    })
  })
}

const outDir = 'out'

if (!fs.existsSync(outDir)) {
  fs.mkdirSync(outDir)
}

class Converter {
  constructor (threads) {
    this.threads = threads

    this.tasks = []
    this.left = 0
    this.next = 1

    this.notified = false

    this.times = []
  }

  addTask (task) {
    this.tasks.push(task)
  }

  startConverting () {
    this.next = 0
    this.left = this.tasks.length

    for (let i = 0; i < this.threads; i += 1) {
      this.convert(i)
    }
  }

  async convert (threadId) {
    while (this.left !== 0) {
      // take task
      const task = this.tasks[this.next]
      this.next += 1
      this.left -= 1

      // handle task
      const index = parseInt(
        task.match(/(?<=DSC_)\d+(?=\.NEF)/)[0]
      )

      const outIndex = index.toString().padStart(4, '0')
      const outPath = `${outDir}/${outIndex}.jpg`

      const command = `mogrify -normalize -format JPG -write ${outPath} ${task}`

      const start = new Date()
      await exec(command)
      const finish = new Date()

      // report
      this.times.push(finish.valueOf() - start.valueOf())

      if (this.times.length > 10) {
        this.times.shift()
      }

      const avgTimeMs = this.times.reduce((acc, curr) => acc + curr, 0) / this.times.length
      const leftS = avgTimeMs * this.left / this.threads / 1000

      const left = {
        s: Math.floor(leftS % 60).toString().padStart(2, '0'),
        m: Math.floor(leftS % 3600 / 60).toString().padStart(2, '0'),
        h: Math.floor(leftS / 3600).toString().padStart(2, '0')
      }

      const pct = Math.round(100 * (1 - this.left / this.tasks.length)).toString().padStart(3, ' ')

      console.log(`th#${threadId}: ${pct}% — ${this.left} left ~ ${left.h}:${left.m}:${left.s}`)
    }

    if (!this.notified) {
      this.notified = true

      await vamuved.send('5fc4f28dceedc00011653934')
    }
  }
}

const files = fs.readdirSync('.')

const photos = files.filter(fileName => /.*\.NEF/i.test(fileName))

const threads = 4

const converter = new Converter(threads)

converter.tasks = photos

converter.startConverting()