mirror of
https://github.com/nilaoda/N_m3u8DL-RE.git
synced 2025-04-29 22:24:34 +02:00
271 lines
8.8 KiB
C#
271 lines
8.8 KiB
C#
using System.Text;
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using System.Text.RegularExpressions;
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namespace N_m3u8DL_RE.Common.Entity;
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public partial class WebVttSub
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{
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[GeneratedRegex("X-TIMESTAMP-MAP.*")]
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private static partial Regex TSMapRegex();
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[GeneratedRegex("MPEGTS:(\\d+)")]
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private static partial Regex TSValueRegex();
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[GeneratedRegex("\\s")]
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private static partial Regex SplitRegex();
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[GeneratedRegex("<c\\..*?>([\\s\\S]*?)<\\/c>")]
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private static partial Regex VttClassRegex();
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public List<SubCue> Cues { get; set; } = new List<SubCue>();
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public long MpegtsTimestamp { get; set; } = 0L;
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/// <summary>
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/// 从字节数组解析WEBVTT
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/// </summary>
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/// <param name="textBytes"></param>
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/// <returns></returns>
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public static WebVttSub Parse(byte[] textBytes, long BaseTimestamp = 0L)
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{
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return Parse(Encoding.UTF8.GetString(textBytes), BaseTimestamp);
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}
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/// <summary>
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/// 从字节数组解析WEBVTT
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/// </summary>
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/// <param name="textBytes"></param>
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/// <param name="encoding"></param>
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/// <returns></returns>
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public static WebVttSub Parse(byte[] textBytes, Encoding encoding, long BaseTimestamp = 0L)
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{
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return Parse(encoding.GetString(textBytes), BaseTimestamp);
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}
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/// <summary>
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/// 从字符串解析WEBVTT
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/// </summary>
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/// <param name="text"></param>
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/// <returns></returns>
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public static WebVttSub Parse(string text, long BaseTimestamp = 0L)
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{
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if (!text.Trim().StartsWith("WEBVTT"))
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throw new Exception("Bad vtt!");
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text += Environment.NewLine;
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var webSub = new WebVttSub();
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var needPayload = false;
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var timeLine = "";
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var regex1 = TSMapRegex();
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if (regex1.IsMatch(text))
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{
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var timestamp = TSValueRegex().Match(regex1.Match(text).Value).Groups[1].Value;
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webSub.MpegtsTimestamp = Convert.ToInt64(timestamp);
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}
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var payloads = new List<string>();
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foreach (var line in text.Split('\n'))
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{
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if (line.Contains(" --> "))
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{
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needPayload = true;
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timeLine = line.Trim();
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continue;
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}
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if (needPayload)
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{
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if (string.IsNullOrEmpty(line.Trim()))
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{
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var payload = string.Join(Environment.NewLine, payloads);
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if (string.IsNullOrEmpty(payload.Trim())) continue; // 没获取到payload 跳过添加
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var arr = SplitRegex().Split(timeLine.Replace("-->", "")).Where(s => !string.IsNullOrEmpty(s)).ToList();
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var startTime = ConvertToTS(arr[0]);
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var endTime = ConvertToTS(arr[1]);
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var style = arr.Count > 2 ? string.Join(" ", arr.Skip(2)) : "";
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webSub.Cues.Add(new SubCue()
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{
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StartTime = startTime,
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EndTime = endTime,
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Payload = RemoveClassTag(string.Join("", payload.Where(c => c != 8203))), // Remove Zero Width Space!
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Settings = style
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});
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payloads.Clear();
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needPayload = false;
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}
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else
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{
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payloads.Add(line.Trim());
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}
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}
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}
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if (BaseTimestamp != 0)
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{
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foreach (var item in webSub.Cues)
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{
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if (item.StartTime.TotalMilliseconds - BaseTimestamp >= 0)
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{
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item.StartTime = TimeSpan.FromMilliseconds(item.StartTime.TotalMilliseconds - BaseTimestamp);
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item.EndTime = TimeSpan.FromMilliseconds(item.EndTime.TotalMilliseconds - BaseTimestamp);
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}
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else
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{
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break;
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}
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}
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}
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return webSub;
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}
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private static string RemoveClassTag(string text)
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{
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if (VttClassRegex().IsMatch(text))
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{
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return string.Join(Environment.NewLine, text.Split('\n').Select(line => line.TrimEnd()).Select(line =>
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{
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return string.Concat(VttClassRegex().Matches(line).Select(x => x.Groups[1].Value + " "));
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})).TrimEnd();
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}
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else return text;
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}
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/// <summary>
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/// 从另一个字幕中获取所有Cue，并加载此字幕中，且自动修正偏移
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/// </summary>
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/// <param name="webSub"></param>
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/// <returns></returns>
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public WebVttSub AddCuesFromOne(WebVttSub webSub)
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{
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FixTimestamp(webSub, this.MpegtsTimestamp);
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foreach (var item in webSub.Cues)
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{
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if (!this.Cues.Contains(item))
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{
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// 如果相差只有1ms，且payload相同，则拼接
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var last = this.Cues.LastOrDefault();
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if (last != null && this.Cues.Count > 0 && (item.StartTime - last.EndTime).TotalMilliseconds <= 1 && item.Payload == last.Payload)
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{
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last.EndTime = item.EndTime;
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}
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else
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{
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this.Cues.Add(item);
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}
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}
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}
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return this;
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}
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private void FixTimestamp(WebVttSub sub, long baseTimestamp)
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{
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if (sub.MpegtsTimestamp == 0)
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{
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return;
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}
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// 确实存在时间轴错误的情况，才修复
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if ((this.Cues.Count > 0 && sub.Cues.Count > 0 && sub.Cues.First().StartTime < this.Cues.Last().EndTime && sub.Cues.First().EndTime != this.Cues.Last().EndTime) || this.Cues.Count == 0)
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{
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// The MPEG2 transport stream clocks (PCR, PTS, DTS) all have units of 1/90000 second
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var seconds = (sub.MpegtsTimestamp - baseTimestamp) / 90000;
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var offset = TimeSpan.FromSeconds(seconds);
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// 当前预添加的字幕的起始时间小于实际上已经走过的时间(如offset已经是100秒，而字幕起始却是2秒)，才修复
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if (sub.Cues.Count > 0 && sub.Cues.First().StartTime < offset)
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{
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for (int i = 0; i < sub.Cues.Count; i++)
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{
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sub.Cues[i].StartTime += offset;
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sub.Cues[i].EndTime += offset;
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}
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}
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}
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}
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private IEnumerable<SubCue> GetCues()
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{
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return this.Cues.Where(c => !string.IsNullOrEmpty(c.Payload));
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}
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private static TimeSpan ConvertToTS(string str)
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{
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// 17.0s
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if (str.EndsWith('s'))
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{
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double sec = Convert.ToDouble(str[..^1]);
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return TimeSpan.FromSeconds(sec);
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}
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str = str.Replace(',', '.');
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long time = 0;
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string[] parts = str.Split('.');
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if (parts.Length > 1)
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{
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time += Convert.ToInt32(parts.Last().PadRight(3, '0'));
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str = parts.First();
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}
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var t = str.Split(':').Reverse().ToList();
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for (int i = 0; i < t.Count(); i++)
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{
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time += (long)Math.Pow(60, i) * Convert.ToInt32(t[i]) * 1000;
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}
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return TimeSpan.FromMilliseconds(time);
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}
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public override string ToString()
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{
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StringBuilder sb = new StringBuilder();
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foreach (var c in GetCues()) // 输出时去除空串
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{
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sb.AppendLine(c.StartTime.ToString(@"hh\:mm\:ss\.fff") + " --> " + c.EndTime.ToString(@"hh\:mm\:ss\.fff") + " " + c.Settings);
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sb.AppendLine(c.Payload);
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sb.AppendLine();
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}
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sb.AppendLine();
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return sb.ToString();
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}
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/// <summary>
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/// 字幕向前平移指定时间
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/// </summary>
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/// <param name="time"></param>
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public void LeftShiftTime(TimeSpan time)
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{
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foreach (var cue in this.Cues)
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{
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if (cue.StartTime.TotalSeconds - time.TotalSeconds > 0) cue.StartTime -= time;
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else cue.StartTime = TimeSpan.FromSeconds(0);
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if (cue.EndTime.TotalSeconds - time.TotalSeconds > 0) cue.EndTime -= time;
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else cue.EndTime = TimeSpan.FromSeconds(0);
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}
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}
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public string ToVtt()
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{
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return "WEBVTT" + Environment.NewLine + Environment.NewLine + ToString();
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}
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public string ToSrt()
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{
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StringBuilder sb = new StringBuilder();
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int index = 1;
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foreach (var c in GetCues())
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{
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sb.AppendLine($"{index++}");
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sb.AppendLine(c.StartTime.ToString(@"hh\:mm\:ss\,fff") + " --> " + c.EndTime.ToString(@"hh\:mm\:ss\,fff"));
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sb.AppendLine(c.Payload);
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sb.AppendLine();
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}
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sb.AppendLine();
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var srt = sb.ToString();
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if (string.IsNullOrEmpty(srt.Trim()))
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{
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srt = "1\r\n00:00:00,000 --> 00:00:01,000"; // 空字幕
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}
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return srt;
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}
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} |