Question

I want to build a Screen Sharing program in C#.(with TCP)

I sniffed around the web and found out that the most efficient way to do it is by sending alot of screenshots from the client to the server.

The point is – how can I compress a Bitmap to Jpeg – receive it on the server and decompress again to Bitmap (so I can show it in a form) ?

I’ve tried using the JpegBitmapEncoder with no luck, here’s my code:

        Bitmap screen = TakeScreenshot();
        MemoryStream ms = new MemoryStream();
        byte[] Bytes = BmpToBytes_Unsafe(screen);
        ms.Write(Bytes, 0, Bytes.Length);
        Jpeg = new JpegBitmapEncoder();
        Jpeg.Frames.Add(BitmapFrame.Create(ms));
        Jpeg.QualityLevel = 40;
        Jpeg.Save(ms);
        BinaryReader br = new BinaryReader(ms);
        SendMessage(br.ReadBytes((int)ms.Length));

It throws an NotSupportedException at Jpeg.Frames.Add(BitmapFrame.Create(ms));

No imaging component suitable to complete this operation was found.

So I need a way to convert a Bitmap to Jpeg, then to byte[], then send it over TCP.

And on the other end, do the exact opposite. Any suggestions ?

Thank you.

Answer 1

JPEG was designed for photographs, not for screen captures. Also, most of the screen doesn’t change so better to just send the changed portions and only a full screen when much of the screen has changed.

Unless you’re just doing this for fun, you are going about this all wrong. VNC has been doing this for years and the source code is free so you could look to see how that’s done.