ass_to_vtt.js

'use strict';

var fs 			= require('fs'),
	readline 	= require('readline');

var ass_to_vtt = (file_in, file_out, cb)=>{
	var lineReader = readline.createInterface({
  		input: fs.createReadStream(file_in)
  	});
	lineReader.on('line', (line)=>{
		var line_vtt = '';
		var reg = /~(\\\\N)?\{[^}]*\}~/;
		var exp = line.split(reg);
		exp.forEach((part)=>{
			line_vtt += part;
		});
		fs.appendFileSync(file_out, line_vtt + "\n");
	});
	lineReader.on('close', ()=>{
		cb(true);
	});
};

ass_to_vtt('English.ass', 'English.vtt', ()=>{
	console.log('done');
});

Node js function

translate a ass subtitles to vtt subs. nice for html5.