Sdcb.FFmpeg

FFmpeg auto generated unsafe bindings for C#/.NET, forked from https://github.com/Ruslan-B/FFmpeg.AutoGen.

Compared to original version, For low-level APIs, Sdcb.FFmpeg optimized for:

• Using standard [DllImport] instead of LoadLibrary
• Deleted common prefix or enums, for example it emited AVCodecID.H264 instead of AVCodecID.AV_CODEC_ID_H264
• Combined same prefix macros into a enum, for example AV_DICT_READ.MatchCase instead of AV_DICT_MATCH_CASE
• Other optimization and fixs...

Sdcb.FFmpeg also provided some high level APIs:

• wrapper of class-like APIs like FormatContext/CodecContext/MediaDictionary
• helper of wrapping existing APIs like FramesExtensions.ApplyFilters
• some source generators like VideoFrameGenerator.Yuv420pSequence

For code generations, Sdcb.FFmpeg have benifits from:

• Minimized repository size, removed all ffmpeg *.dll binaries using bfg
• Auto download FFmpeg binaries from known existing sources

NuGet Packages

• FFmpeg 4.4.x:

  Package	Link
  Sdcb.FFmpeg
  Sdcb.FFmpeg.runtime.windows-x64

• FFmpeg 5.x:

  Package	Link
  Sdcb.FFmpeg
  Sdcb.FFmpeg.runtime.windows-x64

Install

Install the Native asset nuget package:

• https://www.nuget.org/packages/Sdcb.FFmpeg

Note:

• some API isn't stable enough and subjected to change at any time, please try install the specific version and keep a eye on latest updates.

You also need to install FFmpeg binaries native assets or related nuget packages:

• Windows:
  Install NuGet package:

  • For FFmpeg 4.4.3: https://www.nuget.org/packages/Sdcb.FFmpeg.runtime.windows-x64/4.4.3
  • For FFmpeg 5.1.2: https://www.nuget.org/packages/Sdcb.FFmpeg.runtime.windows-x64/5.1.2

  Note: these packages is under published under GPL license, you can also download/compile your own native assets, Sdcb.FFmpeg will link to specific ffmpeg native dynamic libraries automatically according your environment variable.

• Linux:
  Use your package manager of choice, in Ubuntu 22.04 & ffmpeg 4.4.2 specificly, you can write following commands:

  apt update
  apt install software-properties-common
  add-apt-repository ppa:savoury1/ffmpeg4 -y
  apt update
  apt install ffmpeg -y

  For ffmpeg 5.x, you can write following commands:

  apt update
  apt install software-properties-common
  add-apt-repository ppa:savoury1/ffmpeg4 -y
  add-apt-repository ppa:savoury1/ffmpeg5 -y
  apt update
  apt install ffmpeg -y

• Mac OS X:
  Install ffmpeg via Homebrew:

  brew install ffmpeg

For the more sophisticated operations please refer to offical ffmpeg Documentation expecially API section of it.

Tutorial and examples

You can refer to Examples.cs for multiple tutorial and examples.

Featured examples

Example 1: Generate a video from code:

// this example is based on Sdcb.FFmpeg 5.1.2
FFmpegLogger.LogWriter = (level, msg) => Console.Write(msg);

using FormatContext fc = FormatContext.AllocOutput(formatName: "mp4");
fc.VideoCodec = Codec.CommonEncoders.Libx264;
MediaStream vstream = fc.NewStream(fc.VideoCodec);
using CodecContext vcodec = new CodecContext(fc.VideoCodec)
{
	Width = 800,
	Height = 600,
	TimeBase = new AVRational(1, 30),
	PixelFormat = AVPixelFormat.Yuv420p,
	Flags = AV_CODEC_FLAG.GlobalHeader, 
};
vcodec.Open(fc.VideoCodec);
vstream.Codecpar!.CopyFrom(vcodec);
vstream.TimeBase = vcodec.TimeBase;

string outputPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "muxing.mp4");
fc.DumpFormat(streamIndex: 0, outputPath, isOutput: true);

using IOContext io = IOContext.OpenWrite(outputPath);
fc.Pb = io;
fc.WriteHeader();
VideoFrameGenerator.Yuv420pSequence(vcodec.Width, vcodec.Height, 600)
	.ConvertFrames(vcodec)
	.EncodeAllFrames(fc, null, vcodec)
	.WriteAll(fc);
fc.WriteTrailer();

Example 2: Decode and remuxing mp4:

// this example is based on Sdcb.FFmpeg 4.4.2
void A7r3VideoToWechat(string mp4Path)
{
	using FormatContext inFc = FormatContext.OpenInputUrl(mp4Path);
	inFc.LoadStreamInfo();

	// prepare input stream/codec
	MediaStream inAudioStream = inFc.GetAudioStream();
	using CodecContext audioDecoder = new(Codec.FindDecoderById(inAudioStream.Codecpar!.CodecId));
	audioDecoder.FillParameters(inAudioStream.Codecpar);
	audioDecoder.Open();
	audioDecoder.ChannelLayout = (ulong)ffmpeg.av_get_default_channel_layout(audioDecoder.Channels);

	MediaStream inVideoStream = inFc.GetVideoStream();
	using CodecContext videoDecoder = new(Codec.FindDecoderByName("h264_qsv"));
	videoDecoder.FillParameters(inVideoStream.Codecpar!);
	videoDecoder.Open();

	// dest file
	string destFile = Path.Combine(Path.GetDirectoryName(mp4Path)!, Path.GetFileNameWithoutExtension(mp4Path) + "_wechat.mp4");
	using FormatContext outFc = FormatContext.AllocOutput(fileName: destFile);

	// dest encoder and streams
	outFc.AudioCodec = Codec.CommonEncoders.AAC;
	MediaStream outAudioStream = outFc.NewStream(outFc.AudioCodec);
	using CodecContext audioEncoder = new(outFc.AudioCodec)
	{
		Channels = 1,
		SampleFormat = outFc.AudioCodec.Value.NegociateSampleFormat(AVSampleFormat.Fltp),
		SampleRate = outFc.AudioCodec.Value.NegociateSampleRates(48000),
		BitRate = 48000
	};
	audioEncoder.ChannelLayout = (ulong)ffmpeg.av_get_default_channel_layout(audioEncoder.Channels);
	audioEncoder.TimeBase = new AVRational(1, audioEncoder.SampleRate);
	audioEncoder.Open(outFc.AudioCodec);
	outAudioStream.Codecpar!.CopyFrom(audioEncoder);

	outFc.VideoCodec = Codec.FindEncoderByName("libx264");
	MediaStream outVideoStream = outFc.NewStream(outFc.VideoCodec);
	using VideoFilterContext vfilter = VideoFilterContext.Create(inVideoStream, "scale=1024:-1");
	using CodecContext videoEncoder = new(outFc.VideoCodec)
	{
		Flags = AV_CODEC_FLAG.GlobalHeader,
		ThreadCount = Environment.ProcessorCount, 
		ThreadType = ffmpeg.FF_THREAD_FRAME,
	};
	vfilter.ConfigureEncoder(videoEncoder);
	var dict = new MediaDictionary
	{
		["crf"] = "30",
		["preset"] = "veryslow"
	};
	videoEncoder.Open(outFc.VideoCodec, dict);
	dict.Dump();
	outVideoStream.Codecpar!.CopyFrom(videoEncoder);
	outVideoStream.TimeBase = videoEncoder.TimeBase;

	// begin write
	using IOContext io = IOContext.OpenWrite(destFile);
	outFc.Pb = io;
	outFc.WriteHeader();

	MediaThreadQueue<Frame> decodingQueue = inFc
		.ReadPackets(inVideoStream.Index, inAudioStream.Index)
		.DecodeAllPackets(inFc, audioDecoder, videoDecoder)
		.ToThreadQueue(cancellationToken: QueryCancelToken, boundedCapacity: 64);

	MediaThreadQueue<Packet> encodingQueue = decodingQueue.GetConsumingEnumerable()
		.ApplyVideoFilters(vfilter)
		.ConvertAllFrames(audioEncoder, videoEncoder)
		.AudioFifo(audioEncoder)
		.EncodeAllFrames(outFc, audioEncoder, videoEncoder)
		.ToThreadQueue(cancellationToken: QueryCancelToken);

	CancellationTokenSource end = new();
	QueryCancelToken.Register(() => end.Cancel());
	Dictionary<int, PtsDts> ptsDts = new();
	Task.Run(async () =>
	{
		double totalDuration = Math.Max(inVideoStream.GetDurationInSeconds(), inAudioStream.GetDurationInSeconds());
		try
		{
			while (!end.IsCancellationRequested)
			{
				Log();
				await Task.Delay(1000, end.Token);
			}
		}
		finally
		{
			Log();
		}

		void Log() => Console.WriteLine($"{GetStatusText()}, dec/enc queue: {decodingQueue.Count}/{encodingQueue.Count}");
		string GetStatusText() => $"{(outVideoStream.TimeBase * ptsDts.GetValueOrDefault(outVideoStream.Index, PtsDts.Default).Dts).ToDouble():F2} of {totalDuration:F2}";
	});
	encodingQueue.GetConsumingEnumerable()
		.RecordPtsDts(ptsDts)
		.WriteAll(outFc);
	end.Cancel();
	outFc.WriteTrailer();
}

Example 3: Create gif emoji based on video

This demo is also avaiable here: https://ffmpeg-sorry-demo.starworks.cc:88/

This demo Visual Studio source code is also available here: https://github.com/sdcb/ffmpeg-wjz-sorry-generator

// This example is initially written based on Sdcb.FFmpeg 4.4.3 + Vortice.Direct2D1
#nullable enable

void Main()
{
	FFmpegLogger.LogWriter = (level, msg) => Console.Write(msg);
	byte[] videoBytes = CreateGif(239, 239, timebase: new AVRational(1, 30), duration: new AVRational(1, 1), RenderOneFrame);
	File.WriteAllBytes(Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "muxing.gif"), videoBytes);
	Util.Image(videoBytes, Util.ScaleMode.Unscaled).Dump(videoBytes.Length.ToString());
}

static void RenderOneFrame(VideoTime time, ID2D1RenderTarget ctx, DxRes res)
{
	using IDWriteTextFormat font = res.DWriteFactory.CreateTextFormat("Consolas", 40.0f);
	ctx.Clear(Colors.Transparent);
	ctx.Transform = Matrix3x2.CreateRotation(time.Percent * MathF.PI * 2, new Vector2(ctx.Size.Width / 2, ctx.Size.Height / 2));
	using var layout = res.DWriteFactory.CreateTextLayout("Test1234!", font, int.MaxValue, int.MaxValue);
	ctx.DrawTextLayout(new Vector2(ctx.Size.Width / 2 - layout.Metrics.Width / 2, ctx.Size.Height / 2 - layout.Metrics.Height / 2), layout, res.GetColor(Colors.Red));
}

public static byte[] CreateGif(int width, int height, AVRational timebase, AVRational duration, FrameRendererDelegate frameRenderer)
{
    using FormatContext fc = FormatContext.AllocOutput(formatName: "gif");
    fc.VideoCodec = Codec.FindEncoderById(AVCodecID.Gif);
    MediaStream vstream = fc.NewStream(fc.VideoCodec);
    using CodecContext vcodec = new CodecContext(fc.VideoCodec)
    {
        Width = width,
        Height = height,
        TimeBase = timebase,
        PixelFormat = AVPixelFormat.Pal8,
    };
    vcodec.Open(fc.VideoCodec);
    vstream.Codecpar!.CopyFrom(vcodec);
    vstream.TimeBase = vcodec.TimeBase;

    using DynamicIOContext io = IOContext.OpenDynamic();
    fc.Pb = io;
    fc.WriteHeader();
	int frameCount = (int)Math.Ceiling(duration.ToDouble() / timebase.ToDouble());
    RenderAll(vcodec, frameRenderer, frameCount: frameCount)
		//.ConvertFrames(vcodec)
		.ApplyVideoFilters(timebase, AVPixelFormat.Pal8, $"scale=flags=lanczos,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse")
        .EncodeAllFrames(fc, null, vcodec)
        .WriteAll(fc);
    fc.WriteTrailer();
    return io.GetBuffer().ToArray();

	static IEnumerable<Frame> RenderAll(CodecContext codecCtx, FrameRendererDelegate frameRenderer, int frameCount)
	{
		using DxRes basic = new(codecCtx.Width, codecCtx.Height);
		using VideoFrameConverter frameConverter = new();
		using Frame rgbFrame = new Frame()
		{
			Width = codecCtx.Width,
			Height = codecCtx.Height,
			Format = (int)AVPixelFormat.Bgra
		};
		using Frame refFrame = new();

		for (int i = 0; i < frameCount; ++i)
		{
			ID2D1RenderTarget ctx = basic.RenderTarget;
			VideoTime time = new(i, TimeSpan.FromSeconds(1.0 * i * codecCtx.TimeBase.Num / codecCtx.TimeBase.Den), frameCount);
			ctx.BeginDraw();
			frameRenderer(time, ctx, basic);
			ctx.EndDraw();

			using (IWICBitmapLock bmpLock = basic.WicBmp.Lock(BitmapLockFlags.Read))
			{
				rgbFrame.Data._0 = bmpLock.Data.DataPointer;
				rgbFrame.Linesize[0] = bmpLock.Data.Pitch;
				refFrame.Ref(rgbFrame);
				yield return refFrame;
			}
		}
	}
}

public delegate void FrameRendererDelegate(VideoTime time, ID2D1RenderTarget ctx, DxRes res);

public record struct VideoTime(int Frame, TimeSpan Elapsed, int TotalFrame)
{
	public float Percent => 1.0f * Frame / TotalFrame;
}

public class DxRes : IDisposable
{
    public readonly IWICImagingFactory WicFactory = new IWICImagingFactory();
    public readonly ID2D1Factory2 D2dFactory = D2D1.D2D1CreateFactory<ID2D1Factory2>();
    public readonly IWICBitmap WicBmp;
    public readonly ID2D1RenderTarget RenderTarget;
    private readonly ID2D1SolidColorBrush DefaultColor;
    public readonly IDWriteFactory DWriteFactory = DWrite.DWriteCreateFactory<IDWriteFactory>();

    public DxRes(int width, int height)
    {
        WicBmp = WicFactory.CreateBitmap(width, height, Vortice.WIC.PixelFormat.Format32bppPBGRA, BitmapCreateCacheOption.CacheOnLoad);
        RenderTarget = D2dFactory.CreateWicBitmapRenderTarget(WicBmp, new RenderTargetProperties(new Vortice.DCommon.PixelFormat(Format.B8G8R8A8_UNorm, Vortice.DCommon.AlphaMode.Premultiplied)));
        DefaultColor = RenderTarget.CreateSolidColorBrush(Colors.CornflowerBlue);
    }

    public ID2D1SolidColorBrush GetColor(Color4 color)
	{
		DefaultColor.Color = color;
		return DefaultColor;
	}

	public void Dispose()
	{
		DefaultColor.Dispose();
		RenderTarget.Dispose();
		WicBmp.Dispose();
		D2dFactory.Dispose();
		WicFactory.Dispose();
		DWriteFactory.Dispose();
	}
}

Example 4: Streaming screen and transfer via network

Server side code:

// This example was initially written based on Sdcb.FFmpeg 4.4.3 & Sdcb.ScreenCapture
void Main()
{
	StartService(QueryCancelToken);
}

void StartService(CancellationToken cancellationToken = default)
{
	var tcpListener = new TcpListener(IPAddress.Any, 5555);
	cancellationToken.Register(() => tcpListener.Stop());
	tcpListener.Start();

	while (!cancellationToken.IsCancellationRequested)
	{
		TcpClient client = tcpListener.AcceptTcpClient();
		Task.Run(() => ServeClient(client, cancellationToken));
	}
}

void ServeClient(TcpClient tcpClient, CancellationToken cancellationToken = default)
{
	try
	{
		using var _ = tcpClient;
		using NetworkStream stream = tcpClient.GetStream();
		using BinaryWriter writer = new(stream);
		RectI screenSize = ScreenCapture.GetScreenSize(screenId: 0);
		RdpCodecParameter rcp = new(AVCodecID.H264, screenSize.Width, screenSize.Height, AVPixelFormat.Bgr0);

		using CodecContext cc = new(Codec.CommonEncoders.Libx264RGB)
		{
			Width = rcp.Width,
			Height = rcp.Height,
			PixelFormat = rcp.PixelFormat,
			TimeBase = new AVRational(1, 20),
		};
		cc.Open(null, new MediaDictionary
		{
			["crf"] = "30",
			["tune"] = "zerolatency",
			["preset"] = "veryfast"
		});

		writer.Write(rcp.ToArray());
		using Frame source = new();
		foreach (Packet packet in ScreenCapture
			.CaptureScreenFrames(screenId: 0)
			.ToBgraFrame()
			.ConvertFrames(cc)
			.EncodeFrames(cc))
		{
			if (cancellationToken.IsCancellationRequested)
			{
				break;
			}
			writer.Write(packet.Data.Length);
			writer.Write(packet.Data.AsSpan());
		}
	}
	catch (IOException ex)
	{
		// Unable to write data to the transport connection: 远程主机强迫关闭了一个现有的连接。.
		// Unable to write data to the transport connection: 你的主机中的软件中止了一个已建立的连接。
		ex.Dump();
	}
}

public class Filo<T> : IDisposable
{
	private T? Item { get; set; }
	private ManualResetEventSlim Notify { get; } = new ManualResetEventSlim();

	public void Update(T item)
	{
		Item = item;
		Notify.Set();
	}

	public IEnumerable<T> Consume(CancellationToken cancellationToken = default)
	{
		while (!cancellationToken.IsCancellationRequested)
		{
			Notify.Wait(cancellationToken);
			yield return Item!;
		}
	}

	public void Dispose() => Notify.Dispose();
}

public static class BgraFrameExtensions
{
	public static IEnumerable<Frame> ToBgraFrame(this IEnumerable<LockedBgraFrame> bgras)
	{
		using Frame frame = new Frame();
		foreach (LockedBgraFrame bgra in bgras)
		{
			frame.Width = bgra.Width;
			frame.Height = bgra.Height;
			frame.Format = (int)AVPixelFormat.Bgra;
			frame.Data[0] = bgra.DataPointer;
			frame.Linesize[0] = bgra.RowPitch;
			yield return frame;
		}
	}
}

record RdpCodecParameter(AVCodecID CodecId, int Width, int Height, AVPixelFormat PixelFormat)
{
	public byte[] ToArray()
	{
		byte[] data = new byte[16];
		Span<byte> span = data.AsSpan();
		BinaryPrimitives.WriteInt32LittleEndian(span, (int)CodecId);
		BinaryPrimitives.WriteInt32LittleEndian(span[4..], Width);
		BinaryPrimitives.WriteInt32LittleEndian(span[8..], Height);
		BinaryPrimitives.WriteInt32LittleEndian(span[12..], (int)PixelFormat);
		return data;
	}
}

Client side code:

// This example was initially written based on Sdcb.FFmpeg 4.4.3 & FlysEngine.Desktop
#nullable enable

ManagedBgraFrame? managedFrame = null;
bool cancel = false;

unsafe void Main()
{
	using RenderWindow w = new();
	w.FormClosed += delegate { cancel = true; };
	Task decodingTask = Task.Run(() => DecodeThread(() => (3840, 2160)));

	w.Draw += (_, ctx) =>
	{
		ctx.Clear(Colors.CornflowerBlue);
		if (managedFrame == null) return;

		ManagedBgraFrame frame = managedFrame.Value;

		fixed (byte* ptr = frame.Data)
		{
			//new System.Drawing.Bitmap(frame.Width, frame.Height, frame.RowPitch, System.Drawing.Imaging.PixelFormat.Format32bppPArgb, (IntPtr)ptr).DumpUnscaled();
			BitmapProperties1 props = new(new PixelFormat(Format.B8G8R8A8_UNorm, Vortice.DCommon.AlphaMode.Premultiplied));
			using ID2D1Bitmap bmp = ctx.CreateBitmap(new SizeI(frame.Width, frame.Height), (IntPtr)ptr, frame.RowPitch, props);
			ctx.UnitMode = UnitMode.Dips;
			ctx.DrawBitmap(bmp, 1.0f, InterpolationMode.NearestNeighbor);
		}
	};
	RenderLoop.Run(w, () => w.Render(1, Vortice.DXGI.PresentFlags.None));
}

async Task DecodeThread(Func<(int width, int height)> sizeAccessor)
{
	using TcpClient client = new TcpClient();
	await client.ConnectAsync(IPAddress.Loopback, 5555);
	using NetworkStream stream = client.GetStream();

	using BinaryReader reader = new(stream);
	RdpCodecParameter rcp = RdpCodecParameter.FromSpan(reader.ReadBytes(16));

	using CodecContext cc = new(Codec.FindDecoderById(rcp.CodecId))
	{
		Width = rcp.Width,
		Height = rcp.Height,
		PixelFormat = rcp.PixelFormat,
	};
	cc.Open(null);

	foreach (var frame in reader
		.ReadPackets()
		.DecodePackets(cc)
		.ConvertVideoFrames(sizeAccessor, AVPixelFormat.Bgra)
		.ToManaged()
		)
	{
		if (cancel) break;
		managedFrame = frame;
	}
}


public static class FramesExtensions
{
	public static IEnumerable<ManagedBgraFrame> ToManaged(this IEnumerable<Frame> bgraFrames, bool unref = true)
	{
		foreach (Frame frame in bgraFrames)
		{
			int rowPitch = frame.Linesize[0];
			int length = rowPitch * frame.Height;
			byte[] buffer = new byte[length];
			Marshal.Copy(frame.Data._0, buffer, 0, length);
			ManagedBgraFrame managed = new(buffer, length, length / frame.Height);
			if (unref) frame.Unref();
			yield return managed;
		}
	}
}

public record struct ManagedBgraFrame(byte[] Data, int Length, int RowPitch)
{
	public int Width => RowPitch / BytePerPixel;
	public int Height => Length / RowPitch;

	public const int BytePerPixel = 4;
}


public static class ReadPacketExtensions
{
	public static IEnumerable<Packet> ReadPackets(this BinaryReader reader)
	{
		using Packet packet = new();
		while (true)
		{
			int packetSize = reader.ReadInt32();
			if (packetSize == 0) yield break;

			byte[] data = reader.ReadBytes(packetSize);
			GCHandle dataHandle = GCHandle.Alloc(data, GCHandleType.Pinned);
			try
			{
				packet.Data = new DataPointer(dataHandle.AddrOfPinnedObject(), packetSize);
				yield return packet;
			}
			finally
			{
				dataHandle.Free();
			}
		}
	}
}

record RdpCodecParameter(AVCodecID CodecId, int Width, int Height, AVPixelFormat PixelFormat)
{
	public static RdpCodecParameter FromSpan(ReadOnlySpan<byte> data)
	{
		return new RdpCodecParameter(
			CodecId: (AVCodecID)BinaryPrimitives.ReadInt32LittleEndian(data),
			Width: BinaryPrimitives.ReadInt32LittleEndian(data[4..]),
			Height: BinaryPrimitives.ReadInt32LittleEndian(data[8..]),
			PixelFormat: (AVPixelFormat)BinaryPrimitives.ReadInt32LittleEndian(data[12..]));
	}
}

Example 5: Decode RTSP camera stream and show

// This example was initially written using Sdcb.FFmpeg 4.4.3 & Vortice.Direct2D1
#nullable enable

FFmpegBmp? ffBmp = null;
FFmpegBmp? lastFFbmp = null;
FFmpegLogger.LogWriter = (level, msg) => Util.FixedFont(msg).Dump();
CancellationTokenSource cts = new ();

using RenderWindow w = new();
Task.Run(() => DecodeRTSP(Util.GetPassword("home-rtsp-ipc"), cts.Token));
w.Draw += (_, ctx) =>
{
	if (ffBmp == null) return;
	if (lastFFbmp == ffBmp) return;

	GCHandle handle = GCHandle.Alloc(ffBmp.Data, GCHandleType.Pinned);
	try
	{
		using ID2D1Bitmap bmp = ctx.CreateBitmap(new SizeI(ffBmp.Width, ffBmp.Height), handle.AddrOfPinnedObject(), ffBmp.RowPitch, new BitmapProperties(new Vortice.DCommon.PixelFormat(Format.B8G8R8A8_UNorm, Vortice.DCommon.AlphaMode.Premultiplied)));
		lastFFbmp = ffBmp;
		Size clientSize = ctx.Size;
		float top = (clientSize.Height - ffBmp.Height) / 2;
		ctx.Transform = Matrix3x2.CreateTranslation(0, top);
		ctx.DrawBitmap(bmp, 1.0f, InterpolationMode.Linear);
	}
	finally
	{
		handle.Free();
	}
};
w.FormClosing += delegate { cts.Cancel(); };
RenderLoop.Run(w, () => w.Render(1, Vortice.DXGI.PresentFlags.None));

void DecodeRTSP(string url, CancellationToken cancellationToken = default)
{
	using FormatContext fc = FormatContext.OpenInputUrl(url);
	fc.LoadStreamInfo();
	MediaStream videoStream = fc.GetVideoStream();
	
	using CodecContext videoDecoder = new CodecContext(Codec.FindDecoderByName("hevc_qsv"));
	videoDecoder.FillParameters(videoStream.Codecpar!);
	videoDecoder.Open();
	
	var dc = new DumpContainer().Dump();
	foreach (Frame frame in fc
		.ReadPackets(videoStream.Index)
		.DecodePackets(videoDecoder)
		.ConvertVideoFrames(() => new (w.ClientSize.Width, w.ClientSize.Width * videoDecoder.Height / videoDecoder.Width), AVPixelFormat.Bgr0))
	{
		if (cancellationToken.IsCancellationRequested) break;
		
		try
		{
			byte[] data = new byte[frame.Linesize[0] * frame.Height];
			Marshal.Copy(frame.Data._0, data, 0, data.Length);
			ffBmp = new FFmpegBmp(frame.Width, frame.Height, frame.Linesize[0], data);
		}
		finally
		{
			frame.Unref();
		}
	}
}

public record FFmpegBmp(int Width, int Height, int RowPitch, byte[] Data);

Example 6: Read RTSP stream and save to multiple mp4/mov

// The example was initially written using Sdcb.FFmpeg 4.4.3
FFmpegLogger.LogWriter = (level, msg) => Console.Write(Util.FixedFont(msg));

using FormatContext inFc = FormatContext.OpenInputUrl(Util.GetPassword("home-rtsp-ipc"));
inFc.LoadStreamInfo();
MediaStream inAudioStream = inFc.GetAudioStream();
MediaStream inVideoStream = inFc.GetVideoStream();
long gpts_v = 0, gpts_a = 0, gdts_v = 0, gdts_a = 0;

while (!QueryCancelToken.IsCancellationRequested)
{
	using FormatContext outFc = FormatContext.AllocOutput(formatName: "mov");
	string dir = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "rtsp", DateTime.Now.ToString("yyyy-MM-dd"));
	Directory.CreateDirectory(dir.Dump());
	using IOContext io = IOContext.OpenWrite(Path.Combine(dir, $"{DateTime.Now:HHmmss}.mov"));
	outFc.Pb = io;

	MediaStream videoStream = outFc.NewStream(Codec.FindEncoderById(inVideoStream.Codecpar!.CodecId));
	videoStream.Codecpar!.CopyFrom(inVideoStream.Codecpar);
	videoStream.TimeBase = inVideoStream.RFrameRate.Inverse();
	videoStream.SampleAspectRatio = inVideoStream.SampleAspectRatio;

	MediaStream audioStream = outFc.NewStream(Codec.FindEncoderById(inAudioStream.Codecpar!.CodecId));
	audioStream.Codecpar!.CopyFrom(inAudioStream.Codecpar);
	audioStream.TimeBase = inAudioStream.TimeBase;
	audioStream.Codecpar.ChannelLayout = (ulong)ffmpeg.av_get_default_channel_layout(inAudioStream.Codecpar.Channels);

	outFc.WriteHeader();
	
	FilterPackets(inFc.ReadPackets(inAudioStream.Index, inVideoStream.Index), videoFrameCount: 60 * 20)
		.WriteAll(outFc);
	outFc.WriteTrailer();

	IEnumerable<Packet> FilterPackets(IEnumerable<Packet> packets, int videoFrameCount)
	{
		long pts_v = gpts_v, pts_a = gpts_a, dts_v = gdts_v, dts_a = gdts_a;
		long[] buffer = new long[200];
		long ithreshold = -1;
		int videoFrame = 0;

		foreach (Packet pkt in packets)
		{
			pkt.StreamIndex = pkt.StreamIndex == inAudioStream.Index ?
					audioStream.Index :
					videoStream.Index;
			if (pkt.StreamIndex == inAudioStream.Index)
			{
				// audio
				(gpts_a, gdts_a, pkt.Pts, pkt.Dts) = (pkt.Pts, pkt.Dts, pkt.Pts - pts_a, pkt.Dts - dts_a);
				pkt.RescaleTimestamp(inAudioStream.TimeBase, audioStream.TimeBase);
			}
			else
			{
				// video
				if (videoFrame < buffer.Length)
				{
					buffer[videoFrame] = pkt.Data.Length;
					ithreshold = -1;
				}
				else if (videoFrame == buffer.Length)
				{
					ithreshold = buffer.Order().ToArray()[buffer.Length / 2] * 4;
				}
				
				if (videoFrame >= videoFrameCount && pkt.Data.Length > ithreshold)
				{
					break;
				}

				(gpts_v, gdts_v, pkt.Pts, pkt.Dts) = (pkt.Pts, pkt.Dts, pkt.Pts - pts_v, pkt.Dts - dts_v);
				pkt.RescaleTimestamp(inVideoStream.TimeBase, videoStream.TimeBase);
				videoFrame++;
			}
			yield return pkt;
		}
	}
}

Build & Generation

The bindings generator uses CppSharp.

Prerequisites:

• Visual Studio 2022 with C# and C++ desktop development workloads and Windows SDK for desktop.

Steps to generate:

• Run Sdcb.FFmpeg.AutoGen
• All files with extension *.g.cs in Sdcb.FFmpeg project will be regenerated.

License

Copyright © Sdcb, Ruslan Balanukhin 2022 All rights reserved.

Distributed under the GNU Lesser General Public License (LGPL) version 3.
http://www.gnu.org/licenses/lgpl.html