youtube-terminal/lib/ascii-video.js

Stream YouTube videos as ascii art in the terminal!

var ffmpeg = require('./ffmpeg')
var through2 = require('through2')
var TokenBucket = require('limiter').TokenBucket
var asciiPixels = require('ascii-pixels')
var ChopStream = require('chop-stream')
var charm = require('charm')

function ThrottleStream (chunksPerSecond) {
  var bucket = new TokenBucket(chunksPerSecond, chunksPerSecond, 'second', null)

  return through2(function (chunk, _, next) {
    bucket.removeTokens(1, function (err) {
      next(err, chunk)
    })
  })
}

function AsciiStream (frameWidth, frameHeight, options) {
  return through2(function (frameData, _, next) {
    var imageData = {
      data: frameData,
      width: frameWidth,
      height: frameHeight,
      format: 'RGB24'
    }

    // convert to ascii art
    var ascii = asciiPixels(imageData, options)

    next(null, ascii)
  })
}

function TerminalStream () {
  var term = charm(process)

  term.removeAllListeners('^C')
  term.on('^C', function () {
    term.cursor(true).end()
    process.exit()
  })

  term.reset()
  term.cursor(false)

  return through2(function (text, _, next) {
    var boldText = '\u001B[1m' + text + '\u001B[22m'
    term.erase('screen').position(0, 0).write(boldText)
    next()
  }).on('end', function () {
    term.cursor(true).end()
  })
}

// render video as ascii characters
module.exports = function (video, options) {
  // set the dimensions for the scaled video
  var frameWidth = Math.round(options.width)
  var frameHeight = Math.round(video.height / (video.width / frameWidth))
  var frameBytes = frameWidth * frameHeight * 3 // rgb24

  ffmpeg
    .rawImageStream(video.url, options)
    .pipe(new ChopStream(frameBytes))
    .pipe(new ThrottleStream(options.fps))
    .pipe(new AsciiStream(frameWidth, frameHeight, options))
    .pipe(new TerminalStream())
    .resume() // TODO: makes TerminalStream end (should probably be a writable/output stream instead)
}