public int InsertPaddingChapters() { int chCount = Chapters.Count; if (chCount == 0) { return(0); } var ch = Chapters.First(); if (ch.Time.Begin > TimeSpan.Zero && !ch.IsPaddingChapter) { var preChapter = new Chapter(ch.Time.Begin) { IsPaddingChapter = true }; Chapters.Insert(0, preChapter); } ch = Chapters.Last(); if (ch.Time.End < this.Duration && !ch.IsPaddingChapter) { var postChapter = new Chapter(ch.Time.End, this.Duration) { IsPaddingChapter = true }; Chapters.Add(postChapter); } return(Chapters.Count - chCount); }