SRTVideoEncoding.InProcess 1.0.0

SRTVideoEncoding - FFmpeg In-Process Video Encoder for .NET

Description

SRTVideoEncoding is a high-performance .NET library that wraps FFmpeg.AutoGen to provide in-memory (In-Process) video encoding without the need to launch external processes (ffmpeg.exe) or use standard input/output pipes (stdin/stdout).

Designed specifically for ultra-low latency video streaming applications, such as custom SRT (Secure Reliable Transport) or UDP implementations. It transforms raw memory buffers (for example, originating from OpenCV BGR matrices) into network-compatible MPEG-TS containers, compressed using libx264 or libx265.

Features

• 100% In-Process: Executes entirely in RAM. Avoids bottlenecks caused by disk I/O operations or IPC pipes.

• Native MPEG-TS: Direct output in multiplexed Transport Stream format, ready to be dispatched to network sockets.

• Zero External Configuration: Internally configured for maximum speed (preset=ultrafast, tune=zerolatency).

• Direct Integration: Ideal for consuming the Data / Stride output of an OpenCvSharp Mat object or a standard .NET Bitmap.

Environment Requirements

1. Unsafe Compilation: This library operates directly with the memory pointers of the FFmpeg C API. Your project consuming this code must enable the use of unsafe blocks.

   • In Visual Studio: Right-click the project → Properties → Build → Allow unsafe code.

2. FFmpeg Shared Binaries: The host machine (or container) must have the shared FFmpeg binaries available (avcodec-.dll, avutil-.dll, avformat-.dll, swscale-.dll on Windows, or .so on Linux). You can set the path dynamically in your code before initialization: ffmpeg.RootPath = "path/to/your/ffmpeg/binaries";

Usage Examples

Example in VB.NET

Imports SRTVideoEncoding
Imports OpenCvSharp

' 1. Instantiate and initialize (1920x1080 at 60 FPS, 5000 kbps, H.264)
Dim encoder As IVideoEncoder = New FFmpegInProcessEncoder()
encoder.Initialize(1920, 1080, 60, 5000, "libx264")

' 2. Inside your rendering / capture loop:
Dim frameMat As Mat = CaptureFrame() ' Assumes a 3-channel BGR Mat

' Pass the raw Data pointer and the Stride to the C# library
Dim mpegTsBytes As Byte() = encoder.EncodeFrame(frameMat.Data, CInt(frameMat.Step()))

' 3. Transmit directly to the network
If mpegTsBytes IsNot Nothing AndAlso mpegTsBytes.Length > 0 Then
    ' Assuming mySrtSocket is your active SRT connection
    mySrtSocket.Send(mpegTsBytes, 0, mpegTsBytes.Length)
End If

' 4. Final cleanup when streaming stops
encoder.Dispose()

Example in C#

using SRTVideoEncoding;
using OpenCvSharp;

// 1. Instantiate and initialize (1920x1080 at 60 FPS, 5000 kbps, H.264)
IVideoEncoder encoder = new FFmpegInProcessEncoder();
encoder.Initialize(1920, 1080, 60, 5000, "libx264");

// 2. Inside your rendering / capture loop:
Mat frameMat = CaptureFrame(); // Assumes a 3-channel BGR Mat

// Pass the raw Data pointer and the Stride to the library
byte[] mpegTsBytes = encoder.EncodeFrame(frameMat.Data, (int)frameMat.Step());

// 3. Transmit directly to the network
if (mpegTsBytes != null && mpegTsBytes.Length > 0) 
{
    // Assuming mySrtSocket is your active SRT connection
    mySrtSocket.Send(mpegTsBytes, 0, mpegTsBytes.Length);
}

// 4. Final cleanup when streaming stops
encoder.Dispose();

Maintenance and Extensibility

This library uses avio_alloc_context with a native delegate redirected to a .NET MemoryStream, meaning the multiplexer packages the data without touching a hard drive. If you need to modify complex encoder parameters (such as main or high profiles, chroma subsampling, or GOP_Size), you should adapt the Initialize() method inside FFmpegInProcessEncoder.cs.