Downloads a youtube video with ytdl asyncronously

YoutubeProvider.cs

 class YoutubeProvider
    {
        public float percentage { get; set; }
        public string size { get; set; } = string.Empty;
        public string speed { get; set; } = string.Empty;
        public TimeSpan eta { get; set; }
        public string rawResponse { get; set; } = string.Empty;

        public bool hasFinished { get; private set; }
        public string saveto { get; private set; } = string.Empty;

        public AutoResetEvent waiter { get { return _waiter; } private set { _waiter = value; } }

        Thread _workThread;
        AutoResetEvent _waiter;
        private static Random random = new Random();

        static readonly Regex rgxPercentage = new Regex(@"(\d+\.\d+|\d+)%", RegexOptions.Compiled | RegexOptions.ECMAScript);
        static readonly Regex rgxSize = new Regex(@"of ((\d+\.\d+|\d+).*?) at", RegexOptions.Compiled | RegexOptions.ECMAScript);
        static readonly Regex rgxSpeed = new Regex(@"at[ ]+((\d+\.\d+|\d+).*?\/s)", RegexOptions.Compiled | RegexOptions.ECMAScript);
        static readonly Regex rgxETA = new Regex(@"ETA[ ]+((\d+\:\d+))", RegexOptions.Compiled | RegexOptions.ECMAScript);

        private static string RandomString(int length) { return new string(Enumerable.Repeat("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789", length).Select(s => s[random.Next(s.Length)]).ToArray()); }

        public YoutubeProvider(string uri)
        {
            eta = TimeSpan.FromSeconds(0);
            _waiter = new AutoResetEvent(false);

            hasFinished = false;
            _workThread = new Thread(() =>
            {
                try
                {
                    string tmp = dlVid(uri);
                    lock (rawResponse) { rawResponse = tmp; }
                }
                catch (Exception ex)
                { Console.WriteLine(ex.Message); }
                hasFinished = true;
                _waiter.Set();
            });

            _workThread.Start();
        }

        public void WaitOne()
        {
            _waiter.WaitOne();
        }

        void parseDat(string input)
        {
            try { percentage = Convert.ToSingle(rgxPercentage.Match(input).Groups[1].Value); } catch { }
            lock (size) { try { size = rgxSize.Match(input).Groups[1].Value.Replace(".", ","); } catch { } }
            lock (speed) { try { speed = rgxSpeed.Match(input).Groups[1].Value; } catch { } }
            try { eta = TimeSpan.ParseExact(rgxETA.Match(input).Groups[1].Value, @"mm\:ss", CultureInfo.InvariantCulture); } catch { }
            if (_waiter != null)
                _waiter.Set();
        }

        private string dlVid(string uri)
        {
            List<string> outPutLog = new List<string>();

            lock (saveto)
            {
                while (true)
                {
                    saveto = RandomString(10);
                    if (!File.Exists(saveto + ".mp4") &&
                        !File.Exists(saveto + ".mp3") &&
                        !File.Exists(saveto + ".webm"))
                    {
                        break;
                    }
                    Thread.SpinWait(5);
                }
            }

            string strCommand = string.Format(Settings.ytDLarguments, saveto, uri);

            DataReceivedEventHandler strHand = new DataReceivedEventHandler((sender, e) =>
            {
                string strMessage = e.Data;
                if (strMessage != null && strMessage.Length > 0)
                {
                    outPutLog.Add(strMessage);
                    parseDat(strMessage);
                }
            });

            Process processFfmpeg = new Process()
            {
                EnableRaisingEvents = true,
                StartInfo = new ProcessStartInfo()
                {
                    Arguments = strCommand,
                    FileName = Settings.youtubeDLPath,
                    UseShellExecute = false,
                    RedirectStandardOutput = true,
                    RedirectStandardError = true,
                    CreateNoWindow = true
                }
            };

            processFfmpeg.ErrorDataReceived += strHand;
            processFfmpeg.OutputDataReceived += strHand;

            processFfmpeg.Start();
            processFfmpeg.BeginOutputReadLine();
            processFfmpeg.BeginErrorReadLine();
            processFfmpeg.WaitForExit();

            return string.Join("\n", outPutLog);
        }
    }