Stream a buffer in loop.

streamloop.js

const {isBuffer} = Buffer
const {Readable} = require('readable-stream')

class StreamLoop extends Readable {
  constructor(data, options = {}) {
    if (!isBuffer(data)) throw new Error('data must be a Buffer')
    super(options) // Readable opts
    this.data = data
    this.length = data.byteLength
    this.offset = 0
    this.lap = 0
  }


  _read (size) {
    let chunk = this.data.slice(this.offset, this.offset + size)
    if ((this.offset + size) >= this.length) {
      let rest = (this.offset + size) - this.length
      chunk = Buffer.concat([chunk, this.data.slice(0, rest)])
      this.emit('lap', ++this.lap)
      this.offset = rest
    } else {
      this.offset += size
    }
    this.push(chunk)
  }

}

module.exports = StreamLoop

Usage example:

let video = require('fs').readFileSync('/home/user/video.mp4')
let loop = new StreamLoop(video)

loop.on('lap', i => {
  console.error(`Lap ${i}`)
})

loop.pipe(process.stdout)