Gif conversion script

convert-to-gif

#!/usr/bin/env node

/*
This script will clip a segment of a video file into a gif, using techniques
described in these resources:

https://engineering.giphy.com/how-to-make-gifs-with-ffmpeg/
https://video.stackexchange.com/questions/4563/how-can-i-crop-a-video-with-ffmpeg
https://askubuntu.com/questions/648603/how-to-create-an-animated-gif-from-mp4-video-via-command-line
https://trac.ffmpeg.org/wiki/HowToBurnSubtitlesIntoVideo
*/

const util = require( 'util' );
const exec = util.promisify( require( 'child_process' ).exec );
const { resolve } = require( 'path' );

// Pad all output with a leading space.
console.log();

// Minified version of https://github.com/substack/minimist
function parseArgs(n,t){t||(t={});var o={bools:{},strings:{},unknownFn:null};"function"==typeof t.unknown&&(o.unknownFn=t.unknown),"boolean"==typeof t.boolean&&t.boolean?o.allBools=!0:[].concat(t.boolean).filter(Boolean).forEach(function(n){o.bools[n]=!0});var e={};Object.keys(t.alias||{}).forEach(function(n){e[n]=[].concat(t.alias[n]),e[n].forEach(function(t){e[t]=[n].concat(e[n].filter(function(n){return t!==n}))})}),[].concat(t.string).filter(Boolean).forEach(function(n){o.strings[n]=!0,e[n]&&(o.strings[e[n]]=!0)});var s=t.default||{},i={_:[]};Object.keys(o.bools).forEach(function(n){a(n,void 0!==s[n]&&s[n])});var r=[];function a(n,t,s){if(!s||!o.unknownFn||(r=n,a=s,o.allBools&&/^--[^=]+$/.test(a)||o.strings[r]||o.bools[r]||e[r])||!1!==o.unknownFn(s)){var r,a,f=!o.strings[n]&&isNumber(t)?Number(t):t;l(i,n.split("."),f),(e[n]||[]).forEach(function(n){l(i,n.split("."),f)})}}function l(n,t,e){var s=n;t.slice(0,-1).forEach(function(n){void 0===s[n]&&(s[n]={}),s=s[n]});var i=t[t.length-1];void 0===s[i]||o.bools[i]||"boolean"==typeof s[i]?s[i]=e:Array.isArray(s[i])?s[i].push(e):s[i]=[s[i],e]}function f(n){return e[n].some(function(n){return o.bools[n]})}-1!==n.indexOf("--")&&(r=n.slice(n.indexOf("--")+1),n=n.slice(0,n.indexOf("--")));for(var c=0;c<n.length;c++){var u=n[c];if(/^--.+=/.test(u)){var b=u.match(/^--([^=]+)=([\s\S]*)$/),h=b[1],p=b[2];o.bools[h]&&(p="false"!==p),a(h,p,u)}else if(/^--no-.+/.test(u)){a(h=u.match(/^--no-(.+)/)[1],!1,u)}else if(/^--.+/.test(u)){h=u.match(/^--(.+)/)[1];void 0===(k=n[c+1])||/^-/.test(k)||o.bools[h]||o.allBools||e[h]&&f(h)?/^(true|false)$/.test(k)?(a(h,"true"===k,u),c++):a(h,!o.strings[h]||"",u):(a(h,k,u),c++)}else if(/^-[^-]+/.test(u)){for(var v=u.slice(1,-1).split(""),d=!1,g=0;g<v.length;g++){var k;if("-"!==(k=u.slice(g+2))){if(/[A-Za-z]/.test(v[g])&&/=/.test(k)){a(v[g],k.split("=")[1],u),d=!0;break}if(/[A-Za-z]/.test(v[g])&&/-?\d+(\.\d*)?(e-?\d+)?$/.test(k)){a(v[g],k,u),d=!0;break}if(v[g+1]&&v[g+1].match(/\W/)){a(v[g],u.slice(g+2),u),d=!0;break}a(v[g],!o.strings[v[g]]||"",u)}else a(v[g],k,u)}h=u.slice(-1)[0];d||"-"===h||(!n[c+1]||/^(-|--)[^-]/.test(n[c+1])||o.bools[h]||e[h]&&f(h)?n[c+1]&&/true|false/.test(n[c+1])?(a(h,"true"===n[c+1],u),c++):a(h,!o.strings[h]||"",u):(a(h,n[c+1],u),c++))}else if(o.unknownFn&&!1===o.unknownFn(u)||i._.push(o.strings._||!isNumber(u)?u:Number(u)),t.stopEarly){i._.push.apply(i._,n.slice(c+1));break}}return Object.keys(s).forEach(function(n){hasKey(i,n.split("."))||(l(i,n.split("."),s[n]),(e[n]||[]).forEach(function(t){l(i,t.split("."),s[n])}))}),t["--"]?(i["--"]=new Array,r.forEach(function(n){i["--"].push(n)})):r.forEach(function(n){i._.push(n)}),i}function hasKey(n,t){var o=n;return t.slice(0,-1).forEach(function(n){o=o[n]||{}}),t[t.length-1]in o}function isNumber(n){return"number"==typeof n||(!!/^0x[0-9a-f]+$/i.test(n)||/^[-+]?(?:\d+(?:\.\d*)?|\.\d+)(e[-+]?\d+)?$/.test(n))}

const args = parseArgs( process.argv, {
  alias: {
    crop: 'c',
    duration: 't',
    help: [ 'h', '?' ],
    overwrite: 'y',
    start: 'ss',
  },
  string: [
    'crop',
    'duration',
    'scale',
    'start',
  ],
  boolean: [
    'help',
    'overwrite',
    'subtitles',
    'debug',
  ],
  default: {
    scale: '480',
    overwrite: true,
    subtitles: true,
  },
} );

// Check whether help is being invoked and display help text if so.
if ( args._.length < 4 || args.help ) {
  console.log( `How to Convert Video to Gif!

Basic Usage:

  convert-to-gif input-file.mkv output-file.gif

Available Arguments:
${ '' /*                                                   80 char mark here: | */ }
  -ss, --start    Timestamp at which to start the clip
  -t, --duration  Length of the desired clip
  -c, --crop      Crop dimensions (format as "width:height:x:y")
  --scale         Max size of output gif's larger dimension
  --subtitles     Burn in subtitles from input file
  -h, -?, --help  Print this help information` );

  // Options that do not currently work: we HAVE to overwrite
  // or exec() hangs forever.
  // -y, --overwrite Do not ask before overwriting files

  // Quit out after displaying help text.
  process.exit( 0 );
}

const pathEscape = str => str.replace( /([^A-Za-z0-9-.\/_])/g, '\\$1' );

const input = args._[ 2 ];
const output = args._[ 3 ];
const inputFile = resolve( process.cwd(), pathEscape( input ) );
const outputFile = resolve( process.cwd(), pathEscape( output ) )

const tempPalette = '~/tmp.png';
const tempMP4 = '~/tmp.mp4';

// Validate input arguments

const TIMESTAMP_RE = /^\d\d:\d\d:\d\d(\.\d+)?$/;
const CROP_RE = /^.*$/;
// const CROP_RE = /^(:?w=)?\d+:(:?h=)?\d+:(:?x=)?\d+:(:?y=)?\d+$/;
const NUMBER_RE = /^\d+$/;

const argsErrors = {
  'No input file provided': ! input,
  'No output file specified': ! output,
  'No start time specified': ! args.start,
  'No clip duration specified': ! args.duration,
  [
    `Invalid start "${ args.start }"; expected format hh:mm:ss`
  ]: args.start && ! TIMESTAMP_RE.test( args.start ),
  [
    `Invalid duration "${ args.duration }"; expected format hh:mm:ss`
  ]: args.duration && ! TIMESTAMP_RE.test( args.duration ),
  [
    `Invalid crop "${ args.crop }"; expected format width:height:x:y`
  ]: args.crop && ! CROP_RE.test( args.crop ),
  [
    `Invalid scale "${ args.scale }"; expected an integer`
  ]: args.scale && ! NUMBER_RE.test( args.scale ),
};

if ( Object.keys( argsErrors ).reduce( ( hasErrors, errorText ) => {
  if ( argsErrors[ errorText ] ) {
    console.error( errorText );
    return true;
  }
  return hasErrors;
}, false ) ) {
  process.exit( 1 );
}

// Define helper functions for executing commands

const outputOf = command => exec( command ).then( ( { stdout } ) => stdout );

const ensureFFMpeg = async () => {
  const ffmpegInstalled = await outputOf( 'which ffmpeg' ).catch( () => undefined );
  if ( ! ffmpegInstalled ) {
    console.error( '\nError! Could not detect ffmpeg.' );
    console.error( 'Ensure "ffmpeg" is installed and available in your path to proceed.' );
    process.exit( 1 );
  }
};

const hasSubitles = async inputFile => {
  const { stdout } = await exec( `ffprobe -loglevel error -select_streams s:0 -show_entries stream=codec_type -of csv=p=0 ${
    inputFile
  }` );
  return ! ! stdout.trim();
};

const ffmpeg = ( options, outputFile ) => {
  const command = `ffmpeg ${
    Object.keys( options )
      .filter( key => Boolean( options[ key ] ) )
      .map( key => {
        if ( Array.isArray( options[ key ] ) ) {
          // Format as `-key value1 -key value2`.
          return options[ key ]
            .map( value => `${ key } ${ value }` )
            .join( ' ' );
        }
        if ( options[ key ] === true ) {
          // ffmpeg expects boolean arguments to be passed as simple flags.
          return key;
        }
        // Format as `-key value`.
        return `${ key } ${ options[ key ] }`;
      } )
      .join( ' ' )
  } ${ outputFile }`;
  if ( args.debug ) {
    console.log( command );
  }
  return exec( command );
};

const spinner = {
  spinning: false,
  // Thank you cli-spinner for the ASCII.
  frames: [ '⠋', '⠙', '⠹', '⠸', '⠼', '⠴', '⠦', '⠧', '⠇', '⠏' ],
  start( message = '' ) {
    this.spinning = setInterval( () => {
      process.stdout.clearLine();
      process.stdout.cursorTo( 0 );
      process.stdout.write( `${ this.frames[ 0 ] } ${ message }`)
      this.frames.push( this.frames.shift() );
    }, 200 );
  },
  stop( message = '' ) {
    clearInterval( this.spinning );
    this.spinning = false;
    process.stdout.clearLine();
    process.stdout.cursorTo( 0 );
    console.log( message );
  },
  abort() {
    clearInterval( this.spinning );
  }
};

( async () => {
  await ensureFFMpeg();
  try {
    spinner.start( 'Extracting video clip...' );
    const subtitles = args.subtitles && await hasSubitles( inputFile );
    const filters = ( args.crop || subtitles ) ? [
      args.crop ? `crop=${ args.crop }` : null,
      // See http://ffmpeg.org/ffmpeg-filters.html#Notes-on-filtergraph-escaping
      subtitles ? `subtitles=${ inputFile.replace( /\'/g, '\\\\\\\\\\\'' ) }` : null,
    ].filter( Boolean ).join( ', ' ) : false;
    await ffmpeg( {
      '-i': inputFile,
      '-ss': args.start,
      '-t': args.duration,
      '-vf': filters && `"${ filters }"`,
      '-y': true,
      '-async': 1,
    }, tempMP4 );
    spinner.stop( '✓ Movie clip created successfully.' );

    spinner.start( 'Extracting color palette...' );
    await ffmpeg( {
      '-i': tempMP4,
      '-filter_complex': '"[0:v] palettegen"',
      '-y': true,
    }, tempPalette );
    spinner.stop( '✓ Palette extracted successfully.' );

    spinner.start( 'Creating gif...' );
    await ffmpeg( {
      '-i': [
        tempMP4,
        tempPalette,
      ],
      '-filter_complex': `"${ [
        `[0:v] fps=12,scale=${ args.scale }:-1,split [a][b]`,
        '[a] palettegen [p]',
        '[b][p] paletteuse',
      ].join( ';' ) }"`,
      '-y': args.overwrite,
    }, outputFile );
    spinner.stop( `✓ ${ outputFile } created successfully.` );

    spinner.start( 'Cleaning up temporary files...' );
    await exec( `rm ${ tempMP4 }` );
    await exec( `rm ${ tempPalette }` );
    spinner.stop();

    console.log( 'Enjoy!' );
  } catch ( e ) {
    spinner.abort();

    if ( e.stderr ) {
      console.error( e.stderr );
    } else {
      console.error( e );
    }
    process.exit( 1 );
  }
} )();