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

    namespace Nikse.SubtitleEdit.Core.SubtitleFormats
    {
        public class PinnacleImpression : SubtitleFormat
        {
            private static readonly Regex RegexTimeCodes = new Regex(@"^\d\d:\d\d:\d\d:\d\d \d\d:\d\d:\d\d:\d\d ", RegexOptions.Compiled);

            public override string Extension => ".txt";

            public override string Name => "Pinnacle Impression";

            public override bool IsMine(List<string> lines, string fileName)
            {
                var sb = new StringBuilder();
                foreach (string line in lines)
                    sb.AppendLine(line);
                if (sb.ToString().Contains("#INPOINT OUTPOINT PATH"))
                {
                    return base.IsMine(lines, fileName);
                }
                return false;
            }

            public override string ToText(Subtitle subtitle, string title)
            {
                var sb = new StringBuilder();
                sb.AppendLine(@"-------------------------------------------------
    #INPOINT OUTPOINT PATH
    -------------------------------------------------");
                foreach (Paragraph p in subtitle.Paragraphs)
                {
                    //00:03:15:22 00:03:23:10 This is line one.
                    //This is line two.
                    sb.AppendLine($"{EncodeTimeCode(p.StartTime)} {EncodeTimeCode(p.EndTime)} {HtmlUtil.RemoveHtmlTags(p.Text)}");
                }
                sb.AppendLine(@"-------------------------------------------------");

                return sb.ToString();
            }

            private static string EncodeTimeCode(TimeCode time)
            {
                //00:03:15:22 (last is frame)
                int frames = time.Milliseconds / (1000 / 30);
                return $"{time.Hours:00}:{time.Minutes:00}:{time.Seconds:00}:{frames:00}";
            }

            public override void LoadSubtitle(Subtitle subtitle, List<string> lines, string fileName)
            {
                //00:03:15:22 00:03:23:10 This is line one.
                //This is line two.
                Paragraph p = null;
                subtitle.Paragraphs.Clear();
                _errorCount = 0;
                foreach (string line in lines)
                {
                    if (RegexTimeCodes.IsMatch(line))
                    {
                        string temp = line.Substring(0, RegexTimeCodes.Match(line).Length);
                        string start = temp.Substring(0, 11);
                        string end = temp.Substring(12, 11);

                        string[] startParts = start.Split(SplitCharColon, StringSplitOptions.RemoveEmptyEntries);
                        string[] endParts = end.Split(SplitCharColon, StringSplitOptions.RemoveEmptyEntries);
                        if (startParts.Length == 4 && endParts.Length == 4)
                        {
                            string text = line.Remove(0, RegexTimeCodes.Match(line).Length - 1).Trim();
                            p = new Paragraph(DecodeTimeCode(startParts), DecodeTimeCode(endParts), text);
                            subtitle.Paragraphs.Add(p);
                        }
                    }
                    else if (string.IsNullOrWhiteSpace(line.Trim('-')))
                    {
                        // skip these lines
                    }
                    else if (!string.IsNullOrWhiteSpace(line) && p != null)
                    {
                        if (string.IsNullOrEmpty(p.Text))
                            p.Text = line;
                        else
                            p.Text = p.Text + Environment.NewLine + line;
                    }
                }

                subtitle.Renumber();
            }

            private static TimeCode DecodeTimeCode(string[] parts)
            {
                //00:00:07:12
                string hour = parts[0];
                string minutes = parts[1];
                string seconds = parts[2];
                string frames = parts[3];

                int milliseconds = (int)Math.Round(1000.0 / 30.0 * int.Parse(frames));
                if (milliseconds > 999)
                    milliseconds = 999;

                return new TimeCode(int.Parse(hour), int.Parse(minutes), int.Parse(seconds), milliseconds);
            }

        }
    }

↑ V3095 The 'line' object was used before it was verified against null. Check lines: 76, 80.