    ﻿using System;
    using System.Collections.Generic;
    using System.Text;

    namespace Nikse.SubtitleEdit.Core.SubtitleFormats
    {
        public class Wsb : SubtitleFormat
        {
            public override string Extension => ".WSB";

            public override string Name => "WSB";

            public override string ToText(Subtitle subtitle, string title)
            {
                var sb = new StringBuilder();
                int index = 0;
                foreach (Paragraph p in subtitle.Paragraphs)
                {
                    sb.AppendLine($"{index + 1:0000} : {EncodeTimeCode(p.StartTime)},{EncodeTimeCode(p.EndTime)},10");
                    sb.AppendLine("80 80 80");
                    foreach (string line in p.Text.SplitToLines())
                        sb.AppendLine("C1Y00 " + line.Trim());
                    sb.AppendLine();
                    index++;
                }
                return sb.ToString();
            }

            private static string EncodeTimeCode(TimeCode time)
            {
                //00:03:15:22 (last is frame)
                return $"{time.Hours:00}{time.Minutes:00}{time.Seconds:00}{MillisecondsToFramesMaxFrameRate(time.Milliseconds):00}";
            }

            public override void LoadSubtitle(Subtitle subtitle, List<string> lines, string fileName)
            {
                //01072508010729007
                _errorCount = 0;
                Paragraph p = null;
                subtitle.Paragraphs.Clear();
                subtitle.Header = null;
                foreach (string line in lines)
                {
                    if (string.IsNullOrWhiteSpace(line))
                    {
                        continue;
                    }

                    var indexOf7001 = line.IndexOf("7\x01\x01\0", StringComparison.Ordinal);
                    var indexOfTen = line.IndexOf("     10     ", StringComparison.Ordinal);
                    if (indexOf7001 >= 0 && indexOfTen > 0)
                    {
                        try
                        {
                            string text = line.Substring(0, indexOfTen).Trim();
                            string time = line.Substring(indexOf7001 - 16, 16);

                            var starTime = time.Substring(0, 8);
                            var endTime = time.Substring(8);

                            string[] startTimeParts = { starTime.Substring(0, 2), starTime.Substring(2, 2), starTime.Substring(4, 2), starTime.Substring(6, 2) };
                            string[] endTimeParts = { endTime.Substring(0, 2), endTime.Substring(2, 2), endTime.Substring(4, 2), endTime.Substring(6, 2) };

                            p = new Paragraph(DecodeTimeCodeFramesFourParts(startTimeParts), DecodeTimeCodeFramesFourParts(endTimeParts), text);
                            subtitle.Paragraphs.Add(p);
                        }
                        catch (Exception exception)
                        {
                            System.Diagnostics.Debug.WriteLine(exception.Message);
                            _errorCount++;
                        }
                    }
                    else if (p != null)
                    {
                        _errorCount++;
                    }
                }
                if (p != null && !string.IsNullOrEmpty(p.Text))
                    subtitle.Paragraphs.Add(p);

                subtitle.Renumber();
            }

        }
    }

↑ V3057 The 'Substring' function could receive the '-16' value while non-negative value is expected. Inspect the first argument.