315 lines
11 KiB
C#
315 lines
11 KiB
C#
using System.Drawing.Imaging;
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using System.Runtime.InteropServices;
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using System.Text;
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using anjianjingling.Vision;
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namespace anjianjingling.Capture
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{
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/// <summary>
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/// 屏幕录像：GDI 抓帧 → JPEG 编码 → 手写 AVI(MJPG) 封装，无需 ffmpeg。
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/// </summary>
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public sealed class ScreenRecorder : IDisposable
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{
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private readonly ScreenCapture _capture = new();
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private Thread? _thread;
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private volatile bool _running;
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private AviWriter? _writer;
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public bool IsRecording => _running;
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public string? OutputPath { get; private set; }
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public long FrameCount { get; private set; }
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public event Action<string, long>? Finished;
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public int Fps { get; set; } = 15;
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public bool DrawCursor { get; set; } = true;
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public int Quality { get; set; } = 70;
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public void Start(string path, Rectangle region)
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{
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if (_running) return;
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int w = region.Width & ~1; // 编码器要求偶数宽高更稳
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int h = region.Height & ~1;
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if (w < 16 || h < 16) throw new ArgumentException("录制区域太小");
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Directory.CreateDirectory(Path.GetDirectoryName(Path.GetFullPath(path))!);
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OutputPath = path;
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FrameCount = 0;
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_writer = new AviWriter(path, w, h, Math.Clamp(Fps, 1, 60));
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_running = true;
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var rect = new Rectangle(region.X, region.Y, w, h);
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var codec = GetJpegCodec();
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var ep = new EncoderParameters(1);
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ep.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, (long)Math.Clamp(Quality, 20, 95));
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_thread = new Thread(() =>
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{
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var sw = System.Diagnostics.Stopwatch.StartNew();
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int frameInterval = Math.Max(1, 1000 / Math.Clamp(Fps, 1, 60));
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long frameIdx = 0;
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while (_running)
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{
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// 固定帧率：按理论时间点抓帧，抓不动就丢帧，保证 AVI 时长等于真实时长
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long target = frameIdx * frameInterval;
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long now = sw.ElapsedMilliseconds;
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if (now < target)
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{
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Thread.Sleep((int)Math.Min(30, target - now));
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continue;
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}
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try
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{
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using var bmp = _capture.CaptureRegion(rect.X, rect.Y, rect.Width, rect.Height);
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if (DrawCursor)
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{
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using var g = Graphics.FromImage(bmp);
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DrawCursorOn(g, rect.X, rect.Y);
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}
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using var ms = new MemoryStream();
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bmp.Save(ms, codec, ep);
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_writer!.AddFrame(ms.ToArray());
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FrameCount++;
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}
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catch
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{
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Thread.Sleep(frameInterval);
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}
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frameIdx = Math.Max(frameIdx + 1, now / frameInterval + 1);
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}
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})
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{ IsBackground = true, Name = "ScreenRecorder" };
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_thread.Start();
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}
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public void Stop()
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{
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if (!_running) return;
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_running = false;
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_thread?.Join(3000);
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_thread = null;
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_writer?.Complete();
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_writer?.Dispose();
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_writer = null;
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if (OutputPath != null) Finished?.Invoke(OutputPath, FrameCount);
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}
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public void Dispose()
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{
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Stop();
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}
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private static ImageCodecInfo GetJpegCodec()
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=> ImageCodecInfo.GetImageEncoders().First(c => c.FormatID == ImageFormat.Jpeg.Guid);
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// ===================== 光标 =====================
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[StructLayout(LayoutKind.Sequential)]
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private struct CURSORINFO
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{
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public int cbSize;
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public int flags;
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public IntPtr hCursor;
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public POINT ptScreenPos;
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}
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[StructLayout(LayoutKind.Sequential)]
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private struct POINT { public int X, Y; }
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[StructLayout(LayoutKind.Sequential)]
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private struct ICONINFO
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{
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public bool fIcon;
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public int xHotspot;
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public int yHotspot;
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public IntPtr hbmMask;
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public IntPtr hbmColor;
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}
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private const int CURSOR_SHOWING = 0x00000001;
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private const int DI_NORMAL = 0x0003;
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[DllImport("user32.dll")]
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private static extern bool GetCursorInfo(ref CURSORINFO pci);
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[DllImport("user32.dll")]
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private static extern bool GetIconInfo(IntPtr hIcon, out ICONINFO piconinfo);
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[DllImport("user32.dll")]
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private static extern bool DrawIconEx(IntPtr hdc, int xLeft, int yTop, IntPtr hIcon,
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int cxWidth, int cyWidth, int istepIfAniCur, IntPtr hbrFlickerFreeDraw, int diFlags);
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[DllImport("gdi32.dll")]
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private static extern bool DeleteObject(IntPtr hObject);
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private static void DrawCursorOn(Graphics g, int offsetX, int offsetY)
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{
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var ci = new CURSORINFO { cbSize = Marshal.SizeOf<CURSORINFO>() };
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if (!GetCursorInfo(ref ci) || (ci.flags & CURSOR_SHOWING) == 0) return;
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int hx = 0, hy = 0;
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if (GetIconInfo(ci.hCursor, out var ii))
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{
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hx = ii.xHotspot;
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hy = ii.yHotspot;
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if (ii.hbmMask != IntPtr.Zero) DeleteObject(ii.hbmMask);
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if (ii.hbmColor != IntPtr.Zero) DeleteObject(ii.hbmColor);
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}
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IntPtr hdc = g.GetHdc();
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try
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{
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DrawIconEx(hdc, ci.ptScreenPos.X - offsetX - hx, ci.ptScreenPos.Y - offsetY - hy,
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ci.hCursor, 0, 0, 0, IntPtr.Zero, DI_NORMAL);
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}
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finally { g.ReleaseHdc(hdc); }
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}
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}
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/// <summary>
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/// 最小可用 AVI(MJPG) 封装：RIFF/hdrl(avih+strl)/movi/idx1。
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/// </summary>
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internal sealed class AviWriter : IDisposable
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{
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private readonly FileStream _fs;
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private readonly int _w, _h, _fps;
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private readonly List<(long Offset, int Size)> _index = new();
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private long _riffSizePos, _moviSizePos, _moviDataStart;
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private long _avihFramesPos, _strhLengthPos, _avihMaxBytesPos, _avihBufPos, _strhBufPos;
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private int _frames;
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private long _maxBytes;
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public AviWriter(string path, int width, int height, int fps)
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{
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_w = width; _h = height; _fps = fps;
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_fs = new FileStream(path, FileMode.Create, FileAccess.ReadWrite, FileShare.Read);
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WriteHeader();
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}
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private void W(string s) => _fs.Write(Encoding.ASCII.GetBytes(s));
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private void W(int v) => _fs.Write(BitConverter.GetBytes(v));
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private void W(uint v) => _fs.Write(BitConverter.GetBytes(v));
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private void W(short v) => _fs.Write(BitConverter.GetBytes(v));
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private void WriteHeader()
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{
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W("RIFF");
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_riffSizePos = _fs.Position; W(0);
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W("AVI ");
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// ---- LIST hdrl ----（size = 'hdrl' + avih块 + strl整块）
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const int strlContent = 4 + (8 + 56) + (8 + 40); // 'strl' + strh + strf = 116
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const int strlList = 8 + strlContent; // 124
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const int hdrlContent = 4 + (8 + 56) + strlList; // 192
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W("LIST");
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W(hdrlContent);
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W("hdrl");
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// avih
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W("avih"); W(56);
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long avihStart = _fs.Position;
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W(1_000_000 / _fps); // dwMicroSecPerFrame
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_avihMaxBytesPos = _fs.Position; W(0); // dwMaxBytesPerSec
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W(0); // dwPaddingGranularity
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W(0x10); // dwFlags: AVIF_HASINDEX
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_avihFramesPos = _fs.Position; W(0); // dwTotalFrames
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W(0); // dwInitialFrames
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W(1); // dwStreams
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_avihBufPos = _fs.Position; W(0); // dwSuggestedBufferSize
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W(_w); W(_h);
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W(0); W(0); W(0); W(0); // reserved
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// ---- LIST strl ----
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W("LIST");
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W(strlContent);
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W("strl");
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W("strh"); W(56);
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W("vids"); W("MJPG");
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W(0); // dwFlags
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W((short)0); // wPriority
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W((short)0); // wLanguage
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W(0); // dwInitialFrames
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W(1); // dwScale
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W(_fps); // dwRate
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W(0); // dwStart
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_strhLengthPos = _fs.Position; W(0); // dwLength
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_strhBufPos = _fs.Position; W(0); // dwSuggestedBufferSize
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W(-1); // dwQuality
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W(0); // dwSampleSize
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W((short)0); W((short)0); W((short)_w); W((short)_h); // rcFrame
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W("strf"); W(40);
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W(40); // biSize
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W(_w); W(_h);
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W((short)1); // biPlanes
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W((short)24); // biBitCount
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W("MJPG"); // biCompression
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W(_w * _h * 3); // biSizeImage
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W(0); W(0); W(0); W(0);
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// ---- LIST movi ----
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W("LIST");
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_moviSizePos = _fs.Position; W(0);
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W("movi");
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_moviDataStart = _fs.Position;
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}
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public void AddFrame(byte[] jpeg)
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{
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long chunkStart = _fs.Position;
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W("00dc");
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W(jpeg.Length);
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_fs.Write(jpeg);
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if ((jpeg.Length & 1) == 1) _fs.WriteByte(0);
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_index.Add((chunkStart - _moviDataStart, jpeg.Length));
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_frames++;
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if (jpeg.Length > _maxBytes) _maxBytes = jpeg.Length;
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}
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public void Complete()
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{
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long moviEnd = _fs.Position;
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long moviSize = moviEnd - _moviSizePos - 4; // 不含 'movi' 四字符
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// idx1
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W("idx1");
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W(_index.Count * 16);
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foreach (var (off, size) in _index)
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{
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W("00dc");
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W((uint)0x10);
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W((int)off);
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W(size);
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}
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long fileEnd = _fs.Position;
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// 回填各长度字段
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void Patch(long pos, int val)
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{
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long save = _fs.Position;
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_fs.Position = pos;
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_fs.Write(BitConverter.GetBytes(val));
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_fs.Position = save;
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}
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Patch(_riffSizePos, (int)(fileEnd - 8));
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Patch(_moviSizePos, (int)moviSize);
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Patch(_avihFramesPos, _frames);
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Patch(_strhLengthPos, _frames);
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Patch(_avihMaxBytesPos, (int)(_maxBytes * _fps));
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Patch(_avihBufPos, (int)_maxBytes);
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Patch(_strhBufPos, (int)_maxBytes);
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_fs.Flush();
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}
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public void Dispose() => _fs.Dispose();
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}
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}
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