public void renameSubfile(string folderPath)
        {
            List<string> subFiles = new List<string>();
            MatchSubs m = new MatchSubs();

            var subFilesOnDisk = Directory.GetFiles(folderPath, "*.srt");
            foreach (var file in subFilesOnDisk)
            {
                subFiles.Add(Path.GetFileName(file));
            }

            string[] videoExt = _videoExt.ToString().Split(new char[] { ';' });

            foreach (string ext in videoExt)
            {
                var matchingFiles = Directory.GetFiles(folderPath, "*" + ext);

                foreach (var file in matchingFiles)
                {
                    string filename = Path.GetFileName(file);
                    string targetSubFileName = filename.Replace(ext, ".srt");

                    if (subFiles.Contains(targetSubFileName))
                    {
                        //m.Log("INFO " + DateTime.Now.ToString() + " - Subtitle: " + filename + " subfile already exists");
                    }
                    else
                    {
                        string subFile =  m.getSubFilePath(filename, subFiles);

                        if (subFile != null)
                        {

                            m.Log("INFO " + DateTime.Now.ToString() + " - Subtitle Video: " + filename + " subfile matched: " + subFile);
                            File.Move(Path.Combine(folderPath, subFile), Path.Combine(folderPath, targetSubFileName));
                            subFile = null;
                        }
                    }
                }
            }
        }