index.js

var fs = require('fs')
var path = require('path')
var subtitlesParser = require('subtitles-parser')
var childProcess = require('child_process')
var moment = require('moment')
var mkdirp = require('mkdirp')
var debug = require('debug')('gilmarkgifs')

function generateGifForEachSubtitle (filePath) {
  var identifier = getSeasonEpisodeIdentifierFromFilePath(filePath)
  debug('Generating GIFs for Gilmore Girls ' + identifier)
  extractSubtitlesFromFile(filePath, function (err, subtitles) {
    var destFolder = path.join(__dirname, 'data', 'frames', identifier)

    mkdirp.sync(destFolder)
    var parsedSubtitles = subtitlesParser.fromSrt(subtitles)
    parsedSubtitles.forEach(function (subtitleData) {
      var timestampMs = convertTimeToTimestamp(subtitleData.endTime) - convertTimeToTimestamp(subtitleData.startTime)
      subtitleData.duration = convertTimestampToTime(timestampMs)
      var gifPath = generateGifForSubtitle(filePath, subtitleData, destFolder)
      addSubtitleToGif(filePath, gifPath, subtitleData)
    })
  })
}

function generateGifForSubtitle (filePath, subtitleData, destFolder) {
  debug('Generate frames GIF for subtitle #' + subtitleData.id)
  var scriptPath = path.join(__dirname, 'script', 'extract-gif')
  var destPath = path.join(destFolder, subtitleData.id + '.gif')
  var identifier = getSeasonEpisodeIdentifierFromFilePath(filePath)
  var cmd = [
    'bash',
    scriptPath,
    filePath,
    destPath,
    subtitleData.startTime.replace(',','.'),
    subtitleData.duration.replace(',','.')
  ].join(' ')
  childProcess.execSync(cmd)
  debug('Saved frames GIF to ' + destPath)
  return destPath
}

function addSubtitleToGif (filePath, gifPath, subtitleData) {
  var identifier = getSeasonEpisodeIdentifierFromFilePath(filePath)
  var destFolder = path.join(__dirname, 'data', 'annotated', identifier)
  var destPath = path.join(destFolder, subtitleData.id + '.gif')

  debug('Generate annoted GIF for subtitle #' + subtitleData.id)

  mkdirp.sync(destFolder)
  var subtitleText = '"' + subtitleData.text.replace(/"/g, "'") + '"'
  var cmd = [
    'convert',
    gifPath,
    '-gravity south',
    '-font Helvetica',
    '-pointsize 14',
    '-stroke \'#000C\'',
    '-strokewidth 3',
    '-annotate 0',
    subtitleText,
    '-stroke none',
    '-fill white',
    '-annotate 0',
    subtitleText,
    destPath
  ].join(' ')
  childProcess.execSync(cmd)
  debug('Saved annoted GIF to ' + destPath)
}

function convertTimeToTimestamp (time) {
  return moment.utc(time, "HH:mm:ss,SSS").set({'year':1970, 'month':0, 'date':1}).valueOf()
}

function convertTimestampToTime (timestamp) {
  return moment.utc(timestamp, 'x').format("HH:mm:ss,SSS")
}

function extractSubtitlesFromFile (filePath, cb) {
  var identifier = getSeasonEpisodeIdentifierFromFilePath(filePath)
  var subtitleDestinationPath = path.join(__dirname, 'data', 'subtitles', identifier + '.srt')

  getMkvInfo(filePath, function(err, info) {
    var subtitleExtractId = getExtractIdForSubtitleTrack(info)
    var cmd = [
      'mkvextract',
      'tracks',
      filePath,
      subtitleExtractId + ':' + subtitleDestinationPath
    ].join(' ')
    childProcess.exec(cmd, function (err, output) {
      if (err) throw new Error('Failed to extract subtitles')
      var subtitles = fs.readFileSync(subtitleDestinationPath, 'utf8')
      cb(null, subtitles)
    })
  })
}

function getSeasonEpisodeIdentifierFromFilePath (filePath) {
  return filePath.match(/S\d+E\d+/)[0]
}

function getMkvInfo (filePath, cb) {
  childProcess.exec('mkvinfo ' + filePath, function(err, info) {
    if (err) throw new Error('Could not get info for file')
    cb(null, info)
  })
}

function getExtractIdForSubtitleTrack (mkvinfoOutput) {
  var arr = mkvinfoOutput.split('\n')
  var typeLine = arr.indexOf('|  + Track type: subtitles')
  if (!typeLine) throw new Error('Could not find subtitle track type')
  var targetLine = typeLine - 2
  var id = arr[targetLine].match(/mkvextract: (\d)/)[1]
  return parseInt(id)
}

module.exports = generateGifForEachSubtitle