Network Programming in .NET

If you are still using Visual Studio 2013, you may notice that today, the Package Manager Console will have stopped working, any attempt to install a new package will give an error like

The source at nuget.org [https://www.nuget.org/api/v2/] is unreachable. Falling back to NuGet Local Cache at C:\Users\you\AppData\Local\NuGet\Cache

This is because NUGET has withdrawn support for TLS 1.1, and VS 2013 will use TLS 1.1 by default.

To Fix this, type this into the PM console:

[Net.ServicePointManager]::SecurityProtocol=[Net.ServicePointManager]::SecurityProtocol-bOR [Net.SecurityProtocolType]::Tls12

If you’ve written a Windows service, and you need to update it, perhaps with a bug fix, you’ll find that the process is very cumbersome, you need to stop the service, uninstall it, pull your changes, install it again, configure the service, then start the service.

This procedure, although not difficult, can eat away 15 minutes of development time on every update, and slows the fix/release cycle.

This is where I created a windows batch file, that does these steps in sequence, to save lots of time.

@echo off
REM – ADMIN ACCESS IS REQUIRED
REM – MAKE SURE LATEST CHANGES ARE CHECKED IN TO GIT, THIS CODE WILL UNDO UNCOMMITTED CHANGES.
net stop “My Service”
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\installutil /u MyService.exe
git stash save –keep-index –include-untracked
git pull
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\installutil MyService.exe
SC failure “My Service” actions=restart/60000/restart/60000/restart/60000 reset=86400
net start “My Service”

The SC command may not be applicable to you, but this tells the service to restart in the event of a failure.

Hope this helps someone!

You want to create a dynamic video, from a collection of images – Here is where FFMpeg is a great tool to use with C#

So, as a pre-requisite, you’ll need to download FFMpeg and put it in a folder, I’m calling it “C:\FFmpeg\” – but you can put it anywhere. I’m also assuming you have a collection of images in c:\input, and you want the output video in C:\out-video\out.mp4 – all these paths can be changed.

If you’ve seem my earlier example of capturing video from a webcam and saving to a video, this approach is more elegant, since it doesn’t involve chopping the header off the bitmap array, and swapping the red and blue channels, however, this solution is for Windows only, it’s not cross platform.

I used the FFMediaToolkit Nuget package, and also System.Drawing.Common

FFmpegLoader.FFmpegPath =
	@"C:\FFmpeg\";

var settings = new VideoEncoderSettings(width: 960, height: 544, framerate: 30, codec: VideoCodec.H264);
settings.EncoderPreset = EncoderPreset.Fast;
settings.CRF = 17;
var file = MediaBuilder.CreateContainer(@"C:\out-video\out.mp4").WithVideo(settings).Create();
var files = Directory.GetFiles(@"C:\Input\");
foreach (var inputFile in files)
{
	var binInputFile = File.ReadAllBytes(inputFile);
	var memInput = new MemoryStream(binInputFile);
	var bitmap = Bitmap.FromStream(memInput) as Bitmap;
	var rect = new System.Drawing.Rectangle(System.Drawing.Point.Empty, bitmap.Size);
	var bitLock = bitmap.LockBits(rect, ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
	var bitmapData = ImageData.FromPointer(bitLock.Scan0, ImagePixelFormat.Bgr24, bitmap.Size);
	file.Video.AddFrame(bitmapData); // Encode the frame
	bitmap.UnlockBits(bitLock);

	
}

file.Dispose();

So, what this does, is create a container video of a given size and framerate, and codec. (H264), then adds the images one by one. The container is hard-coded to 960×544, but you should base this on the maximum size of the images in your image folder instead.

The images need to be decompressed, from jpeg to Bitmap, then from Bitmap to ImageData, which is an array of BGR24 structures.

Hope this helps someone!