887 lines
39 KiB
C#
887 lines
39 KiB
C#
using System.Diagnostics;
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using System.Net.Http;
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using System.Text;
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using System.Text.Json;
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using System.Text.RegularExpressions;
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namespace WinFormsApp3
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{
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/// <summary>
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/// 下载进度：文字说明 + 可选的百分比（0~1）。
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/// </summary>
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public record DownloadProgress(string Message, double? Ratio);
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/// <summary>
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/// 下载结果。
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/// </summary>
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/// <param name="FilePath">最终落盘的文件路径（HLS 转封装后可能改变扩展名）。</param>
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/// <param name="Bytes">写出的字节数。</param>
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/// <param name="Converted">是否由 ffmpeg 把 ts 转封装为 mp4。</param>
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public record DownloadResult(string FilePath, long Bytes, bool Converted);
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/// <summary>
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/// 视频下载器：支持直链（mp4/flv/ts…）与 HLS（m3u8）分片合并下载。
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/// 请求时带上当前页面 Referer，抖音等站点校验 Referer 后才允许访问播放地址。
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/// </summary>
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public class VideoDownloader
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{
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private const string UserAgent =
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"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36 Edg/126.0.0.0";
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private static readonly Regex CharsetRx = new(@"charset\s*=\s*""?([\w-]+)""?", RegexOptions.IgnoreCase);
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private static readonly string[] MediaExtensions =
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[".mp4", ".flv", ".m3u8", ".mpd", ".mkv", ".mov", ".m4v", ".webm", ".f4v", ".3gp", ".ts", ".mpg", ".mpeg"];
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/// <summary>
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/// 整片容器格式。这些后缀永远不能当作 HLS 分片，否则 /video/xxx.flv 这类地址会被误删。
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/// </summary>
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private static readonly string[] WholeVideoExtensions =
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[".mp4", ".flv", ".mkv", ".mov", ".webm", ".m4v", ".f4v", ".3gp", ".avi", ".rmvb", ".mpg", ".mpeg", ".m3u8", ".mpd"];
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private readonly string? _referer;
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private readonly string? _cookie;
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/// <param name="referer">播放器所在页面的地址，不是顶层页面地址（播放器常在跨域 iframe 里）。</param>
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/// <param name="cookie">从 WebView2 配置文件里取出的 Cookie，部分站点没 Cookie 直接给空文件。</param>
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public VideoDownloader(string? referer, string? cookie = null)
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{
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if (!string.IsNullOrWhiteSpace(referer) && Uri.TryCreate(referer, UriKind.Absolute, out var u)
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&& !string.IsNullOrEmpty(u.Host))
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{
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// 防盗链一般只校来源站点，保留完整路径反而更容易被判定为非法来源；
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// 用 Authority 而不是 Host，带端口的站点把端口去掉后来源就对不上了
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_referer = $"{u.Scheme}://{u.Authority}/";
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}
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if (!string.IsNullOrWhiteSpace(cookie)) _cookie = cookie;
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}
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public static bool IsHlsUrl(string url) =>
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!string.IsNullOrEmpty(url) && Regex.IsMatch(url, @"\.m3u8(\?|#|$)", RegexOptions.IgnoreCase);
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/// <summary>
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/// 判断是否是 DASH 纯音频轨地址（抖音 .../media-audio-xxx/...）。
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/// 这种地址单独下载出来没有画面，必须和视频轨合并。
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/// </summary>
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public static bool IsDashAudioOnly(string? url) =>
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!string.IsNullOrEmpty(url) && Regex.IsMatch(url, @"/media-audio[/-]", RegexOptions.IgnoreCase);
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/// <summary>
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/// 判断是否是 DASH 纯视频轨地址（抖音 .../media-video-xxx/...）。
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/// 这种地址单独下载出来没有声音，需要配音频轨。
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/// </summary>
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public static bool IsDashVideoOnly(string? url) =>
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!string.IsNullOrEmpty(url) && Regex.IsMatch(url, @"/media-video[/-]", RegexOptions.IgnoreCase);
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/// <summary>
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/// 判断是否是 HLS 分片（合并播放列表可用，但单独下载没有意义）。
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/// 只认分片特有的后缀与编号形式，不能拿路径里的 video / seg 字样当依据，
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/// 否则 /video/xxx.flv 这种整片地址会被当成分片删掉。
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/// </summary>
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public static bool IsSegmentUrl(string url)
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{
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if (string.IsNullOrEmpty(url)) return false;
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var path = Uri.TryCreate(url, UriKind.Absolute, out var u) ? u.AbsolutePath.ToLowerInvariant() : url.ToLowerInvariant();
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var extension = Path.GetExtension(path);
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// 没有扩展名的地址多为接口型直链（如抖音），当作整片
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if (extension.Length == 0) return false;
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if (WholeVideoExtensions.Any(e => extension == e)) return false;
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return extension is ".ts" or ".m4s" or ".init" or ".m2ts" or ".aac" or ".mp3"
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|| Regex.IsMatch(path, @"(seg|chunk|part|fragment|f)[-_.]?\d+");
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}
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public static bool LooksLikeMedia(string? url)
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{
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if (string.IsNullOrWhiteSpace(url)) return false;
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if (url.StartsWith("blob:", StringComparison.OrdinalIgnoreCase) ||
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url.StartsWith("data:", StringComparison.OrdinalIgnoreCase)) return false;
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if (!Uri.TryCreate(url, UriKind.Absolute, out var u)) return false;
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if (u.Scheme != Uri.UriSchemeHttp && u.Scheme != Uri.UriSchemeHttps) return false;
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var path = u.AbsolutePath.ToLowerInvariant();
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if (Regex.IsMatch(path, @"\.(jpg|jpeg|png|gif|webp|ico|svg|css|js|json|woff2?|ttf|map)$")) return false;
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if (MediaExtensions.Any(e => path.EndsWith(e))) return true;
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return Regex.IsMatch(path, @"/(video|vod|playback|media)[/-]");
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}
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/// <summary>
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/// 根据地址推断保存扩展名；m3u8 会合并成单个文件，有 ffmpeg 时转 mp4，否则输出 ts。
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/// </summary>
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public static string ExtensionFor(string url)
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{
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var raw = RawExtension(url);
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if (raw == ".m3u8" || (raw.Length == 0 && IsHlsUrl(url))) return HasFfmpeg() ? ".mp4" : ".ts";
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if (raw.Length == 0) return ".mp4";
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return raw;
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}
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public static string RawExtension(string url)
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{
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try
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{
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return Path.GetExtension(new Uri(url).AbsolutePath).ToLowerInvariant();
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}
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catch
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{
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return "";
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}
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}
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/// <summary>
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/// 生成建议的文件名：优先用页面标题，其次用地址末段。
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/// </summary>
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public string SuggestedFileName(string url, string? title)
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{
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var name = CleanFileName(title);
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if (string.IsNullOrWhiteSpace(name))
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{
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try
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{
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name = CleanFileName(Path.GetFileNameWithoutExtension(new Uri(url).AbsolutePath));
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}
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catch
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{
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// 忽略，使用兜底名
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}
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}
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if (string.IsNullOrWhiteSpace(name)) name = "video";
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if (name.Length > 60) name = name[..60];
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return name + ExtensionFor(url);
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}
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private static string? CleanFileName(string? text)
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{
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if (string.IsNullOrWhiteSpace(text)) return null;
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var cleaned = Regex.Replace(text, @"[\\/:*?""<>|\r\n\t]", " ").Trim();
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cleaned = Regex.Replace(cleaned, @"\s+", " ");
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return string.IsNullOrWhiteSpace(cleaned) ? null : cleaned;
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}
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/// <summary>
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/// 下载视频。m3u8 会自动挑选最高清晰度并顺序合并分片。
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/// </summary>
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public async Task<DownloadResult> DownloadAsync(string url, string filePath, IProgress<DownloadProgress>? progress, CancellationToken ct)
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{
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using var client = CreateClient();
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if (IsHlsUrl(url))
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{
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progress?.Report(new DownloadProgress("解析播放列表…", null));
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var playlist = await ResolvePlaylistAsync(client, url, ct);
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return await WriteHlsAsync(client, playlist, filePath, progress, ct);
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}
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return await DownloadSingleAsync(client, url, filePath, progress, ct);
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}
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/// <summary>
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/// 站点只用 MSE 播放、抓不到 m3u8 地址时，直接拿页面里嗅探到的播放列表文本下载。
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/// </summary>
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public async Task<DownloadResult> DownloadFromPlaylistTextAsync(string playlistText, string baseUrl, string filePath, IProgress<DownloadProgress>? progress, CancellationToken ct)
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{
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using var client = CreateClient();
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progress?.Report(new DownloadProgress("解析播放列表…", null));
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var playlist = await ParsePlaylistAsync(playlistText, baseUrl, client, ct, 0);
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return await WriteHlsAsync(client, playlist, filePath, progress, ct);
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}
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/// <summary>
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/// 下载 DASH 分离的视频轨和音频轨，再用 ffmpeg 合并成单个 mp4。
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/// 抖音等站点把视频和音频分成两个独立的 mp4 轨道返回，必须合并才能有声有画。
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/// </summary>
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public async Task<DownloadResult> DownloadDashPairAsync(string videoUrl, string audioUrl, string filePath, IProgress<DownloadProgress>? progress, CancellationToken ct)
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{
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var ffmpeg = FindFfmpeg();
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if (ffmpeg == null)
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{
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throw new NotSupportedException("下载抖音 DASH 分离视频轨需要 ffmpeg 合并音视频，但未找到 ffmpeg.exe。请把 ffmpeg.exe 放到程序目录下。");
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}
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using var client = CreateClient();
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// 临时文件
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var tmpDir = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString("N"));
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Directory.CreateDirectory(tmpDir);
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var videoTmp = Path.Combine(tmpDir, "video.mp4");
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var audioTmp = Path.Combine(tmpDir, "audio.mp4");
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try
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{
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// 下载视频轨（占总进度 0~50%）
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progress?.Report(new DownloadProgress("下载视频轨…", 0));
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await DownloadSingleToFileAsync(client, videoUrl, videoTmp, ct,
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p => progress?.Report(new DownloadProgress($"下载视频轨 {FormatSize(p)}", null)));
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var videoSize = new FileInfo(videoTmp).Length;
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// 下载音频轨（占总进度 50~100%）
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progress?.Report(new DownloadProgress("下载音频轨…", 0.5));
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await DownloadSingleToFileAsync(client, audioUrl, audioTmp, ct,
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p => progress?.Report(new DownloadProgress($"下载音频轨 {FormatSize(p)}", null)));
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var audioSize = new FileInfo(audioTmp).Length;
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// 合并
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progress?.Report(new DownloadProgress("合并音视频…", 0.95));
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Directory.CreateDirectory(Path.GetDirectoryName(Path.GetFullPath(filePath))!);
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var ok = await MuxDashAsync(ffmpeg, videoTmp, audioTmp, filePath, ct);
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if (!ok)
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throw new InvalidOperationException("ffmpeg 合并音视频失败");
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var finalSize = new FileInfo(filePath).Length;
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progress?.Report(new DownloadProgress($"完成 {FormatSize(finalSize)}", 1));
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return new DownloadResult(filePath, finalSize, true);
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}
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finally
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{
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try { Directory.Delete(tmpDir, true); } catch { /* 临时目录删不掉不影响结果 */ }
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}
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}
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/// <summary>
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/// 下载单个文件到指定路径（不做 .part 重命名，内部用）。
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/// </summary>
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private async Task DownloadSingleToFileAsync(HttpClient client, string url, string filePath, CancellationToken ct, Action<long>? onBytes = null)
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{
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using var resp = await GetFollowRedirectAsync(client, url, ct);
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EnsureVideoResponse(resp);
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await using var input = await resp.Content.ReadAsStreamAsync(ct);
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await using var output = new FileStream(filePath, FileMode.Create, FileAccess.Write, FileShare.None, 1024 * 64, true);
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var buffer = new byte[1024 * 64];
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long total = 0;
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int read;
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while ((read = await input.ReadAsync(buffer, ct)) > 0)
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{
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await output.WriteAsync(buffer.AsMemory(0, read), ct);
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total += read;
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onBytes?.Invoke(total);
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}
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}
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/// <summary>
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/// 用 ffmpeg 把 DASH 视频轨和音频轨合并成 mp4。
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/// 优先两条流直接 copy：不重编码、时间戳原样保留，音画对齐最准确；
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/// 只有音频轨格式装不进 mp4 容器时才回退到 AAC 转码。
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/// </summary>
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private static async Task<bool> MuxDashAsync(string ffmpeg, string videoFile, string audioFile, string outputFile, CancellationToken ct)
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{
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// 只取视频轨的视频流 + 音频轨的音频流（没音频流也照常出片），-shortest 把两条轨截齐到同一时长
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var copyArgs = $"-hide_banner -loglevel error -y -fflags +genpts -i \"{videoFile}\" -i \"{audioFile}\" -map 0:v:0 -map 1:a:0? -c copy -shortest -movflags +faststart \"{outputFile}\"";
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if (await RunFfmpegAsync(ffmpeg, copyArgs, outputFile, ct)) return true;
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TryDelete(outputFile);
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var aacArgs = $"-hide_banner -loglevel error -y -fflags +genpts -i \"{videoFile}\" -i \"{audioFile}\" -map 0:v:0 -map 1:a:0? -c:v copy -c:a aac -strict experimental -shortest -movflags +faststart \"{outputFile}\"";
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return await RunFfmpegAsync(ffmpeg, aacArgs, outputFile, ct);
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}
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private static async Task<bool> RunFfmpegAsync(string ffmpeg, string args, string outputFile, CancellationToken ct)
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{
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var psi = new ProcessStartInfo
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{
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FileName = ffmpeg,
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Arguments = args,
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UseShellExecute = false,
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CreateNoWindow = true,
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RedirectStandardError = true,
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RedirectStandardOutput = true
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};
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using var proc = Process.Start(psi);
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if (proc == null) return false;
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using (ct.Register(() => { try { if (!proc.HasExited) proc.Kill(true); } catch { } }))
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{
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await proc.WaitForExitAsync(ct);
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}
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return proc.ExitCode == 0 && File.Exists(outputFile) && new FileInfo(outputFile).Length > 0;
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}
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/// <summary>
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/// 抽帧结果：成功时 Frames 非空；失败时 Error 给界面显示原因，不让用户干等。
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/// </summary>
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public record FrameExtraction(List<byte[]> Frames, string? Error);
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/// <summary>
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/// 抽取预览截图：每 intervalSeconds 秒取一张、共取 frameCount 张（默认 5 秒 3 张），
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/// 供下载列表肉眼对比哪个是当前视频。用 ffmpeg 直接读远端地址，带 Referer/Cookie 过防盗链。
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/// 单次尝试限 25 秒，超时不再重试第二次，避免地址失效时列表长时间卡在“生成中”。
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/// </summary>
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public async Task<FrameExtraction> ExtractFramesAsync(string url, CancellationToken ct, int intervalSeconds = 5, int frameCount = 3)
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{
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var ffmpeg = FindFfmpeg();
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if (ffmpeg == null)
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{
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return new FrameExtraction(new List<byte[]>(), "未找到 ffmpeg，无法生成截图");
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}
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if (!Uri.TryCreate(url, UriKind.Absolute, out var uri)
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|| (uri.Scheme != Uri.UriSchemeHttp && uri.Scheme != Uri.UriSchemeHttps))
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{
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return new FrameExtraction(new List<byte[]>(), "该地址无法直接抽帧");
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}
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var tmpDir = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString("N"));
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Directory.CreateDirectory(tmpDir);
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try
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{
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string? lastError = null;
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// 先试从第 2 秒开始抽（片头常有黑帧），只有上一次正常退出且没拿到帧才退回 0 秒再试
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foreach (var startAt in new[] { 2, 0 })
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{
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ct.ThrowIfCancellationRequested();
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var args = new List<string>
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{
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"-hide_banner", "-loglevel", "error", "-nostdin", "-y",
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// 远端卡住时快速失败：单次 I/O 12 秒，探测上限 2MB/2秒，不靠外部杀进程兑底
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"-rw_timeout", "12000000",
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"-probesize", "2000000", "-analyzeduration", "2000000",
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"-reconnect", "1", "-reconnect_streamed", "1", "-reconnect_delay_max", "2"
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};
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var headers = BuildFfmpegHeaders();
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if (headers.Length > 0)
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{
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args.Add("-headers");
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args.Add(headers);
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}
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if (IsHlsUrl(url))
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{
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args.Add("-protocol_whitelist");
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args.Add("file,http,https,tcp,tls,crypto");
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}
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args.AddRange(new[]
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{
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"-ss", startAt.ToString(), "-i", url,
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"-t", (intervalSeconds * frameCount).ToString(),
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"-vf", $"fps=1/{intervalSeconds},scale=160:-2",
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"-frames:v", frameCount.ToString(), "-an",
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Path.Combine(tmpDir, "f_%d.jpg")
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});
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var run = await RunFfmpegArgsAsync(ffmpeg, args, ct);
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var files = Directory.GetFiles(tmpDir, "f_*.jpg").OrderBy(f => f, StringComparer.Ordinal).ToList();
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if (files.Count > 0)
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{
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return new FrameExtraction(files.Select(File.ReadAllBytes).ToList(), null);
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}
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lastError = run.Error ?? "没抽到帧";
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if (run.TimedOut)
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{
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break; // 地址多半已失效或被防盗链卡住，再试一次只会多等半分钟
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}
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}
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return new FrameExtraction(new List<byte[]>(), lastError ?? "没抽到帧");
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}
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finally
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{
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try { Directory.Delete(tmpDir, true); } catch { /* 临时目录删不掉不影响结果 */ }
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}
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}
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/// <summary>
|
||
/// ffmpeg 走网络也要过防盗链：把下载器身上的 UA / Referer / Cookie 拼成 -headers 参数。
|
||
/// </summary>
|
||
private string BuildFfmpegHeaders()
|
||
{
|
||
var sb = new StringBuilder();
|
||
sb.Append($"User-Agent: {UserAgent}\r\n");
|
||
if (_referer != null) sb.Append($"Referer: {_referer}\r\n");
|
||
if (_cookie != null) sb.Append($"Cookie: {_cookie}\r\n");
|
||
return sb.ToString();
|
||
}
|
||
|
||
/// <summary>ffmpeg 单次运行结果：TimedOut 表示被外部杀掉，Error 给界面显示原因。</summary>
|
||
private record FfmpegRun(bool TimedOut, string? Error);
|
||
|
||
private static async Task<FfmpegRun> RunFfmpegArgsAsync(string ffmpeg, List<string> args, CancellationToken ct)
|
||
{
|
||
var psi = new ProcessStartInfo
|
||
{
|
||
FileName = ffmpeg,
|
||
UseShellExecute = false,
|
||
CreateNoWindow = true,
|
||
RedirectStandardError = true,
|
||
RedirectStandardOutput = true
|
||
};
|
||
foreach (var a in args) psi.ArgumentList.Add(a);
|
||
|
||
using var proc = Process.Start(psi);
|
||
if (proc == null) return new FfmpegRun(false, "ffmpeg 启动失败");
|
||
|
||
// 就算 -rw_timeout 失效（DNS 卡住、TLS 握手挂起等），25 秒也必须杀掉
|
||
using var timeout = CancellationTokenSource.CreateLinkedTokenSource(ct);
|
||
timeout.CancelAfter(TimeSpan.FromSeconds(25));
|
||
|
||
var errRead = proc.StandardError.ReadToEndAsync(); // 不读干 stderr 会把进程堵死
|
||
bool timedOut = false;
|
||
using (timeout.Token.Register(() => { try { if (!proc.HasExited) proc.Kill(true); } catch { } }))
|
||
{
|
||
try
|
||
{
|
||
await proc.WaitForExitAsync(timeout.Token);
|
||
}
|
||
catch (OperationCanceledException) when (ct.IsCancellationRequested)
|
||
{
|
||
throw; // 用户取消要往上抛，超时杀掉进程则返回原因
|
||
}
|
||
catch (OperationCanceledException)
|
||
{
|
||
timedOut = true;
|
||
}
|
||
}
|
||
|
||
string stderr = string.Empty;
|
||
try { stderr = await errRead; } catch { /* 进程被杀时读流可能报错，不影响判断 */ }
|
||
|
||
if (timedOut)
|
||
{
|
||
return new FfmpegRun(true, "抽帧超时（25秒）：地址可能已失效或被防盗链卡住");
|
||
}
|
||
if (proc.ExitCode != 0)
|
||
{
|
||
return new FfmpegRun(false, SummarizeFfmpegError(stderr));
|
||
}
|
||
return new FfmpegRun(false, null);
|
||
}
|
||
|
||
/// <summary>取 ffmpeg 报错里最有信息量的一行，太长截断，直接丢给界面显示。</summary>
|
||
private static string SummarizeFfmpegError(string stderr)
|
||
{
|
||
var line = (stderr ?? string.Empty)
|
||
.Split('\n')
|
||
.Select(l => l.Trim('\r', ' '))
|
||
.FirstOrDefault(l => l.Length > 0 && !l.StartsWith("[h264", StringComparison.OrdinalIgnoreCase)
|
||
&& !l.StartsWith("[aac", StringComparison.OrdinalIgnoreCase));
|
||
if (string.IsNullOrEmpty(line)) return "ffmpeg 抽帧失败";
|
||
return line.Length > 90 ? line[..90] + "…" : line;
|
||
}
|
||
|
||
private HttpClient CreateClient()
|
||
{
|
||
var client = new HttpClient(new HttpClientHandler { AllowAutoRedirect = false })
|
||
{
|
||
Timeout = TimeSpan.FromMinutes(15)
|
||
};
|
||
client.DefaultRequestHeaders.UserAgent.ParseAdd(UserAgent);
|
||
client.DefaultRequestHeaders.Accept.ParseAdd("*/*");
|
||
client.DefaultRequestHeaders.AcceptLanguage.ParseAdd("zh-CN,zh;q=0.9,en;q=0.8");
|
||
if (_referer != null) client.DefaultRequestHeaders.Referrer = new Uri(_referer);
|
||
if (_cookie != null) client.DefaultRequestHeaders.TryAddWithoutValidation("Cookie", _cookie);
|
||
return client;
|
||
}
|
||
|
||
private async Task<DownloadResult> DownloadSingleAsync(HttpClient client, string url, string filePath, IProgress<DownloadProgress>? progress, CancellationToken ct)
|
||
{
|
||
using var resp = await GetFollowRedirectAsync(client, url, ct);
|
||
EnsureVideoResponse(resp);
|
||
|
||
var total = resp.Content.Headers.ContentLength ?? -1L;
|
||
var part = filePath + ".part";
|
||
Directory.CreateDirectory(Path.GetDirectoryName(Path.GetFullPath(filePath))!);
|
||
|
||
long done = 0;
|
||
long lastReport = 0;
|
||
|
||
await using var input = await resp.Content.ReadAsStreamAsync(ct);
|
||
|
||
try
|
||
{
|
||
var buffer = new byte[1024 * 64];
|
||
|
||
// 先读一小块验货：防盗链站点经常不报 403，而是给一段 200 的 HTML 错误页
|
||
int read = await input.ReadAsync(buffer.AsMemory(0, 4096), ct);
|
||
if (read > 0) EnsureRealVideoContent(buffer, read, resp, url);
|
||
|
||
await using var output = new FileStream(part, FileMode.Create, FileAccess.Write, FileShare.None, 1024 * 64, true);
|
||
while (read > 0)
|
||
{
|
||
await output.WriteAsync(buffer.AsMemory(0, read), ct);
|
||
done += read;
|
||
|
||
if (done - lastReport >= 256 * 1024)
|
||
{
|
||
lastReport = done;
|
||
progress?.Report(total > 0
|
||
? new DownloadProgress($"下载中 {FormatSize(done)} / {FormatSize(total)}", done / (double)total)
|
||
: new DownloadProgress($"下载中 {FormatSize(done)}（总大小未知，可点取消结束）", null));
|
||
}
|
||
|
||
read = await input.ReadAsync(buffer, ct);
|
||
}
|
||
}
|
||
catch
|
||
{
|
||
TryDelete(part);
|
||
throw;
|
||
}
|
||
|
||
MoveIntoPlace(part, filePath);
|
||
progress?.Report(new DownloadProgress($"完成 {FormatSize(done)}", 1));
|
||
return new DownloadResult(filePath, done, false);
|
||
}
|
||
|
||
/// <summary>
|
||
/// 把常见 HTTP 错误码翻译成能行动的原因，只说“403”用户不知道下一步该做什么。
|
||
/// </summary>
|
||
private static void EnsureVideoResponse(HttpResponseMessage resp)
|
||
{
|
||
if (resp.IsSuccessStatusCode) return;
|
||
|
||
string hint = (int)resp.StatusCode switch
|
||
{
|
||
403 or 401 => "，防盗链或需要登录：先在页面里把视频播起来再点下载，或换一条线路",
|
||
404 => "，地址已失效（这类直链通常只有特别短的有效期）",
|
||
416 => "，服务器不接受当前请求范围，重试即可",
|
||
_ => string.Empty
|
||
};
|
||
|
||
throw new HttpRequestException($"服务器返回 {(int)resp.StatusCode} {resp.StatusCode}{hint}");
|
||
}
|
||
|
||
/// <summary>
|
||
/// 真正的视频容器不会以 "<" 或 "{" 开头；m3u8 / mpd 本身是文本，不参与检查。
|
||
/// </summary>
|
||
private static void EnsureRealVideoContent(byte[] head, int length, HttpResponseMessage resp, string url)
|
||
{
|
||
if (IsHlsUrl(url) || RawExtension(url) == ".mpd") return;
|
||
|
||
var type = resp.Content.Headers.ContentType?.MediaType ?? string.Empty;
|
||
if (type.StartsWith("text/html", StringComparison.OrdinalIgnoreCase)
|
||
|| type.StartsWith("text/plain", StringComparison.OrdinalIgnoreCase)
|
||
|| type.Contains("json", StringComparison.OrdinalIgnoreCase))
|
||
{
|
||
throw new NotSupportedException($"站点返回的是 {type} 而不是视频，多半是防盗链或需要先登录/先播放");
|
||
}
|
||
|
||
int i = 0;
|
||
while (i < length && (head[i] is 0xEF or 0xBB or 0xBF or 0x20 or 0x0D or 0x0A or 0x09)) i++;
|
||
|
||
if (i < length && (head[i] == (byte)'<' || head[i] == (byte)'{'))
|
||
{
|
||
throw new NotSupportedException("站点返回的是网页内容而不是视频（防盗链或地址已过期），换一条线路重试");
|
||
}
|
||
}
|
||
|
||
private static void TryDelete(string path)
|
||
{
|
||
try { if (File.Exists(path)) File.Delete(path); } catch { /* 删不掉不影响报错 */ }
|
||
}
|
||
|
||
private async Task<DownloadResult> WriteHlsAsync(HttpClient client, HlsPlaylist playlist, string filePath, IProgress<DownloadProgress>? progress, CancellationToken ct)
|
||
{
|
||
if (playlist.Segments.Count == 0)
|
||
throw new InvalidOperationException("播放列表里没有解析到视频分片，可能还在加载中，请稍后重试");
|
||
|
||
if (playlist.KeyLine != null && playlist.KeyLine.Contains("METHOD=", StringComparison.OrdinalIgnoreCase)
|
||
&& !playlist.KeyLine.Contains("METHOD=NONE", StringComparison.OrdinalIgnoreCase))
|
||
{
|
||
throw new NotSupportedException($"该视频是加密 HLS（{playlist.KeyLine}），需要解密 Key，暂不支持自动下载");
|
||
}
|
||
|
||
// 分片直接拼接出来的是 .ts；装了 ffmpeg 时顺手无损转封装成 mp4，播放更通用
|
||
var wantsMp4 = string.Equals(Path.GetExtension(filePath), ".mp4", StringComparison.OrdinalIgnoreCase);
|
||
var ffmpeg = wantsMp4 ? FindFfmpeg() : null;
|
||
|
||
if (wantsMp4 && ffmpeg == null)
|
||
{
|
||
// 没有 ffmpeg 就不能把 ts 流写成 .mp4 后缀，否则很多播放器认不出来
|
||
filePath = Path.ChangeExtension(filePath, ".ts");
|
||
progress?.Report(new DownloadProgress("未找到 ffmpeg，改存为 .ts（播放器可以直接播）", null));
|
||
}
|
||
|
||
var mergedPath = ffmpeg != null
|
||
? Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString("N") + ".ts")
|
||
: filePath;
|
||
|
||
Directory.CreateDirectory(Path.GetDirectoryName(Path.GetFullPath(mergedPath))!);
|
||
|
||
long total = 0;
|
||
int index = 0;
|
||
var part = mergedPath + ".part";
|
||
|
||
await using (var output = new FileStream(part, FileMode.Create, FileAccess.Write, FileShare.None, 1024 * 1024, true))
|
||
{
|
||
foreach (var segment in playlist.Segments)
|
||
{
|
||
ct.ThrowIfCancellationRequested();
|
||
|
||
using var resp = await GetFollowRedirectAsync(client, segment, ct);
|
||
resp.EnsureSuccessStatusCode();
|
||
|
||
await using var input = await resp.Content.ReadAsStreamAsync(ct);
|
||
await input.CopyToAsync(output, ct);
|
||
|
||
total += resp.Content.Headers.ContentLength ?? 0;
|
||
index++;
|
||
|
||
if (index % 5 == 0 || index == playlist.Segments.Count)
|
||
progress?.Report(new DownloadProgress($"下载分片 {index}/{playlist.Segments.Count}，已下载 {FormatSize(total)}", index / (double)playlist.Segments.Count));
|
||
}
|
||
}
|
||
|
||
if (ffmpeg == null)
|
||
{
|
||
MoveIntoPlace(part, mergedPath);
|
||
progress?.Report(new DownloadProgress($"完成 {FormatSize(total)}", 1));
|
||
return new DownloadResult(mergedPath, new FileInfo(mergedPath).Length, false);
|
||
}
|
||
|
||
progress?.Report(new DownloadProgress("用 ffmpeg 转封装为 mp4…", null));
|
||
MoveIntoPlace(part, mergedPath);
|
||
|
||
try
|
||
{
|
||
var ok = await ConvertToMp4Async(ffmpeg, mergedPath, filePath, ct);
|
||
if (ok)
|
||
{
|
||
try { File.Delete(mergedPath); } catch { /* 临时文件删不掉不影响结果 */ }
|
||
var size = new FileInfo(filePath).Length;
|
||
progress?.Report(new DownloadProgress($"完成 {FormatSize(size)}", 1));
|
||
return new DownloadResult(filePath, size, true);
|
||
}
|
||
}
|
||
catch
|
||
{
|
||
// 转封装失败时保留 ts 文件，避免用户什么都拿不到
|
||
}
|
||
|
||
var tsSize = new FileInfo(mergedPath).Length;
|
||
progress?.Report(new DownloadProgress($"完成（未能转成 mp4，已保存 ts）{FormatSize(tsSize)}", 1));
|
||
return new DownloadResult(mergedPath, tsSize, false);
|
||
}
|
||
|
||
private record HlsPlaylist(List<string> Segments, string? KeyLine);
|
||
|
||
/// <summary>
|
||
/// 解析 m3u8：主播放列表按带宽挑最高清晰度，最后返回绝对地址的分片列表。
|
||
/// </summary>
|
||
private async Task<HlsPlaylist> ResolvePlaylistAsync(HttpClient client, string url, CancellationToken ct, int depth = 0)
|
||
{
|
||
if (depth > 3) throw new InvalidOperationException("播放列表嵌套层级过深");
|
||
|
||
using var resp = await GetFollowRedirectAsync(client, url, ct);
|
||
resp.EnsureSuccessStatusCode();
|
||
|
||
var text = await ReadTextAsync(resp, ct);
|
||
return await ParsePlaylistAsync(text, url, client, ct, depth);
|
||
}
|
||
|
||
private async Task<HlsPlaylist> ParsePlaylistAsync(string text, string url, HttpClient client, CancellationToken ct, int depth)
|
||
{
|
||
if (!text.Contains("#EXTM3U"))
|
||
throw new InvalidOperationException("返回的内容不是 m3u8 播放列表，请改用列表里的 mp4 直链下载");
|
||
|
||
var lines = text.Split('\n').Select(l => l.Trim('\r', ' ', '\t')).ToList();
|
||
|
||
// 主播放列表：#EXT-X-STREAM-INF 后面紧跟子列表地址
|
||
var variants = new List<(string Uri, int Bandwidth)>();
|
||
for (int i = 0; i < lines.Count; i++)
|
||
{
|
||
if (!lines[i].StartsWith("#EXT-X-STREAM-INF", StringComparison.OrdinalIgnoreCase)) continue;
|
||
|
||
var bandwidth = 0;
|
||
var m = Regex.Match(lines[i], @"BANDWIDTH=(\d+)", RegexOptions.IgnoreCase);
|
||
if (m.Success) bandwidth = int.Parse(m.Groups[1].Value);
|
||
|
||
for (int j = i + 1; j < lines.Count; j++)
|
||
{
|
||
if (lines[j].Length == 0 || lines[j].StartsWith("#")) continue;
|
||
variants.Add((lines[j], bandwidth));
|
||
break;
|
||
}
|
||
}
|
||
|
||
if (variants.Count > 0)
|
||
{
|
||
var best = variants[^1];
|
||
foreach (var v in variants)
|
||
if (v.Bandwidth > best.Bandwidth) best = v;
|
||
|
||
ct.ThrowIfCancellationRequested();
|
||
return await ResolvePlaylistAsync(client, Resolve(url, best.Uri), ct, depth + 1);
|
||
}
|
||
|
||
var segments = lines
|
||
.Where(l => l.Length > 0 && !l.StartsWith("#"))
|
||
.Select(l => Resolve(url, l))
|
||
.ToList();
|
||
|
||
var keyLine = lines.FirstOrDefault(l => l.StartsWith("#EXT-X-KEY", StringComparison.OrdinalIgnoreCase));
|
||
return new HlsPlaylist(segments, keyLine);
|
||
}
|
||
|
||
private static string Resolve(string baseUrl, string relative)
|
||
{
|
||
if (Path.IsPathRooted(relative) || relative.StartsWith("//", StringComparison.Ordinal))
|
||
{
|
||
try
|
||
{
|
||
var u = new Uri(baseUrl);
|
||
return $"{u.Scheme}:{relative}";
|
||
}
|
||
catch
|
||
{
|
||
return relative;
|
||
}
|
||
}
|
||
|
||
if (Uri.TryCreate(relative, UriKind.Absolute, out _)) return relative;
|
||
|
||
try
|
||
{
|
||
return new Uri(new Uri(baseUrl), relative).ToString();
|
||
}
|
||
catch
|
||
{
|
||
return relative;
|
||
}
|
||
}
|
||
|
||
private static async Task<HttpResponseMessage> GetFollowRedirectAsync(HttpClient client, string url, CancellationToken ct)
|
||
{
|
||
var current = url;
|
||
HttpResponseMessage? previous = null;
|
||
|
||
for (int i = 0; i < 6; i++)
|
||
{
|
||
var resp = await client.GetAsync(current, HttpCompletionOption.ResponseHeadersRead, ct);
|
||
|
||
if (resp.IsSuccessStatusCode) return resp;
|
||
|
||
var status = (int)resp.StatusCode;
|
||
var location = resp.Headers.Location;
|
||
if (status < 300 || status > 399 || location == null) return resp;
|
||
|
||
previous?.Dispose();
|
||
previous = resp;
|
||
current = location.IsAbsoluteUri ? location.ToString() : new Uri(new Uri(current), location).ToString();
|
||
}
|
||
|
||
return previous ?? await client.GetAsync(current, HttpCompletionOption.ResponseHeadersRead, ct);
|
||
}
|
||
|
||
/// <summary>
|
||
/// m3u8 常用 GBK 编码，直接按 UTF8 读会让中文路径的分片地址出错。
|
||
/// </summary>
|
||
private static async Task<string> ReadTextAsync(HttpResponseMessage resp, CancellationToken ct)
|
||
{
|
||
using var ms = new MemoryStream();
|
||
await resp.Content.CopyToAsync(ms, ct);
|
||
|
||
var encoding = Encoding.UTF8;
|
||
var match = CharsetRx.Match(resp.Content.Headers.ContentType?.ToString() ?? "");
|
||
if (match.Success)
|
||
{
|
||
try { encoding = Encoding.GetEncoding(match.Groups[1].Value); }
|
||
catch { /* 未知编码退回 UTF8 */ }
|
||
}
|
||
|
||
var text = encoding.GetString(ms.ToArray());
|
||
|
||
// 去掉可能存在的 BOM
|
||
if (text.Length > 0 && text[0] == '\uFEFF') text = text[1..];
|
||
return text;
|
||
}
|
||
|
||
private static async Task<bool> ConvertToMp4Async(string ffmpeg, string tsFile, string mp4File, CancellationToken ct)
|
||
{
|
||
var args = $"-hide_banner -loglevel error -y -fflags +genpts -i \"{tsFile}\" -c copy -bsf:a aac_adtstoasc -movflags +faststart \"{mp4File}\"";
|
||
var psi = new ProcessStartInfo
|
||
{
|
||
FileName = ffmpeg,
|
||
Arguments = args,
|
||
UseShellExecute = false,
|
||
CreateNoWindow = true,
|
||
RedirectStandardError = true,
|
||
RedirectStandardOutput = true
|
||
};
|
||
|
||
using var proc = Process.Start(psi);
|
||
if (proc == null) return false;
|
||
|
||
using (ct.Register(() => { try { if (!proc.HasExited) proc.Kill(true); } catch { } }))
|
||
{
|
||
await proc.WaitForExitAsync(ct);
|
||
}
|
||
|
||
return proc.ExitCode == 0 && File.Exists(mp4File) && new FileInfo(mp4File).Length > 0;
|
||
}
|
||
|
||
/// <summary>
|
||
/// 查找 ffmpeg：顺序为 1) ffmpeg.json 配置文件指定的路径；2) 程序目录 ffmpeg.exe；3) PATH。
|
||
/// 配置文件格式：{"ffmpegPath": "D:\\NET8\\Exe\\ffmpeg\\bin\\ffmpeg.exe"}
|
||
/// </summary>
|
||
public static string? FindFfmpeg()
|
||
{
|
||
// 1. 配置文件指定的路径（优先级最高）
|
||
var configPath = Path.Combine(AppContext.BaseDirectory, "ffmpeg.json");
|
||
if (File.Exists(configPath))
|
||
{
|
||
try
|
||
{
|
||
var json = File.ReadAllText(configPath);
|
||
using var doc = JsonDocument.Parse(json);
|
||
if (doc.RootElement.TryGetProperty("ffmpegPath", out var prop) &&
|
||
prop.ValueKind == JsonValueKind.String)
|
||
{
|
||
var configured = prop.GetString();
|
||
if (!string.IsNullOrWhiteSpace(configured) && File.Exists(configured))
|
||
return configured;
|
||
}
|
||
}
|
||
catch { /* 配置文件损坏就跳过，继续找别的 */ }
|
||
}
|
||
|
||
// 2. 程序目录
|
||
var local = Path.Combine(AppContext.BaseDirectory, "ffmpeg.exe");
|
||
if (File.Exists(local)) return local;
|
||
|
||
// 3. PATH
|
||
foreach (var dir in (Environment.GetEnvironmentVariable("PATH") ?? "").Split(Path.PathSeparator))
|
||
{
|
||
if (string.IsNullOrWhiteSpace(dir)) continue;
|
||
try
|
||
{
|
||
var candidate = Path.Combine(dir.Trim().Trim('"'), "ffmpeg.exe");
|
||
if (File.Exists(candidate)) return candidate;
|
||
}
|
||
catch
|
||
{
|
||
// PATH 里存在非法字符时跳过该项
|
||
}
|
||
}
|
||
|
||
return null;
|
||
}
|
||
|
||
public static bool HasFfmpeg() => FindFfmpeg() != null;
|
||
|
||
private static void MoveIntoPlace(string partFile, string targetFile)
|
||
{
|
||
if (File.Exists(targetFile)) File.Delete(targetFile);
|
||
File.Move(partFile, targetFile);
|
||
}
|
||
|
||
public static string FormatSize(long bytes)
|
||
{
|
||
if (bytes <= 0) return "0 B";
|
||
if (bytes >= 1L << 30) return $"{bytes / (double)(1L << 30):0.00} GB";
|
||
if (bytes >= 1L << 20) return $"{bytes / (double)(1L << 20):0.0} MB";
|
||
if (bytes >= 1L << 10) return $"{bytes / (double)(1L << 10):0.0} KB";
|
||
return $"{bytes} B";
|
||
}
|
||
}
|
||
}
|