Add support for .dtc subs - thx wesskywalker :)

work on #5218

src/libse/SubtitleFormats/Drtic.cs

@@ -0,0 +1,85 @@
+using Nikse.SubtitleEdit.Core.Common;
+using System;
+using System.Collections.Generic;
+
+namespace Nikse.SubtitleEdit.Core.SubtitleFormats
+{
+    public class Drtic : MicroDvd
+    {
+        public override string Extension => ".dtc";
+
+        public override string Name => "Drtic";
+
+        public override bool IsTimeBased => false;
+
+        public override bool IsMine(List<string> lines, string fileName)
+        {
+            var headerFound = false;
+            var trimmedLines = new List<string>();
+            int errors = 0;
+            foreach (string line in lines)
+            {
+                if (!string.IsNullOrWhiteSpace(line))
+                {
+                    if (line.StartsWith("[JRT2:", StringComparison.Ordinal))
+                    {
+                        headerFound = true;
+                    }
+                    else if (line.Contains('{'))
+                    {
+                        string s = RemoveIllegalSpacesAndFixEmptyCodes(line);
+                        if (RegexMicroDvdLine.IsMatch(s))
+                        {
+                            trimmedLines.Add(s);
+                        }
+                        else
+                        {
+                            errors++;
+                        }
+                    }
+                    else
+                    {
+                        errors++;
+                    }
+                }
+            }
+
+            return headerFound && trimmedLines.Count > errors;
+        }
+
+        private static string RemoveIllegalSpacesAndFixEmptyCodes(string line)
+        {
+            if (string.IsNullOrEmpty(line) || line.Length > 2000)
+            {
+                return line;
+            }
+
+            int index = line.IndexOf('}');
+            if (index >= 0 && index + 1 < line.Length)
+            {
+                index = line.IndexOf('}', index + 1);
+                if (index >= 0 && index + 1 < line.Length)
+                {
+                    var indexOfBrackets = line.IndexOf("{}", StringComparison.Ordinal);
+                    if (indexOfBrackets >= 0 && indexOfBrackets < index)
+                    {
+                        line = line.Insert(indexOfBrackets + 1, "0"); // set empty time codes to zero
+                        index++;
+                    }
+
+                    while (line.Contains(' ') && line.IndexOf(' ') < index)
+                    {
+                        line = line.Remove(line.IndexOf(' '), 1);
+                        index--;
+                    }
+                }
+            }
+            return line;
+        }
+
+        public override string ToText(Subtitle subtitle, string title)
+        {
+            return $"[JRT2: {subtitle.Paragraphs.Count} 0 ]{Environment.NewLine}{base.ToText(subtitle, title)}{Environment.NewLine}";
+        }
+    }
+}

src/libse/SubtitleFormats/MicroDvd.cs

@@ -8,7 +8,7 @@ namespace Nikse.SubtitleEdit.Core.SubtitleFormats
 {
     public class MicroDvd : SubtitleFormat
     {
-        private static readonly Regex RegexMicroDvdLine = new Regex(@"^\{-?\d+}\{-?\d+}.*$", RegexOptions.Compiled);
+        internal static readonly Regex RegexMicroDvdLine = new Regex(@"^\{-?\d+}\{-?\d+}.*$", RegexOptions.Compiled);
         public string Errors { get; private set; }
         private StringBuilder _errors;
         private int _lineNumber;
@@ -39,12 +39,17 @@ namespace Nikse.SubtitleEdit.Core.SubtitleFormats
                             errors++;
                         }
                     }
+                    else if (line.StartsWith("[JRT2:", StringComparison.Ordinal))
+                    {
+                        return false;
+                    }
                     else
                     {
                         errors++;
                     }
                 }
             }
+
             Errors = null;
             return trimmedLines.Count > errors;
         }

src/libse/SubtitleFormats/SubtitleFormat.cs

@@ -69,6 +69,7 @@ namespace Nikse.SubtitleEdit.Core.SubtitleFormats
                     new DCinemaSmpte2014(),
                     new DfxpBasic(),
                     new DigiBeta(),
+                    new Drtic(),
                     new DvdStudioPro(),
                     new DvdStudioProSpaceOne(),
                     new DvdStudioProSpaceOneSemicolon(),