Do you have some library to capture a screen to be a compressed video file or some solution that can do it?
This code uses SharpAvi available on NuGet.
using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;
using System.Threading;
using System.Threading.Tasks;
using SharpAvi;
using SharpAvi.Codecs;
using SharpAvi.Output;
using System.Windows.Forms;
namespace Captura
{
// Used to Configure the Recorder
public class RecorderParams
{
public RecorderParams(string filename, int FrameRate, FourCC Encoder, int Quality)
{
FileName = filename;
FramesPerSecond = FrameRate;
Codec = Encoder;
this.Quality = Quality;
Height = Screen.PrimaryScreen.Bounds.Height;
Width = Screen.PrimaryScreen.Bounds.Width;
}
string FileName;
public int FramesPerSecond, Quality;
FourCC Codec;
public int Height { get; private set; }
public int Width { get; private set; }
public AviWriter CreateAviWriter()
{
return new AviWriter(FileName)
{
FramesPerSecond = FramesPerSecond,
EmitIndex1 = true,
};
}
public IAviVideoStream CreateVideoStream(AviWriter writer)
{
// Select encoder type based on FOURCC of codec
if (Codec == KnownFourCCs.Codecs.Uncompressed)
return writer.AddUncompressedVideoStream(Width, Height);
else if (Codec == KnownFourCCs.Codecs.MotionJpeg)
return writer.AddMotionJpegVideoStream(Width, Height, Quality);
else
{
return writer.AddMpeg4VideoStream(Width, Height, (double)writer.FramesPerSecond,
// It seems that all tested MPEG-4 VfW codecs ignore the quality affecting parameters passed through VfW API
// They only respect the settings from their own configuration dialogs, and Mpeg4VideoEncoder currently has no support for this
quality: Quality,
codec: Codec,
// Most of VfW codecs expect single-threaded use, so we wrap this encoder to special wrapper
// Thus all calls to the encoder (including its instantiation) will be invoked on a single thread although encoding (and writing) is performed asynchronously
forceSingleThreadedAccess: true);
}
}
}
public class Recorder : IDisposable
{
#region Fields
AviWriter writer;
RecorderParams Params;
IAviVideoStream videoStream;
Thread screenThread;
ManualResetEvent stopThread = new ManualResetEvent(false);
#endregion
public Recorder(RecorderParams Params)
{
this.Params = Params;
// Create AVI writer and specify FPS
writer = Params.CreateAviWriter();
// Create video stream
videoStream = Params.CreateVideoStream(writer);
// Set only name. Other properties were when creating stream,
// either explicitly by arguments or implicitly by the encoder used
videoStream.Name = "Captura";
screenThread = new Thread(RecordScreen)
{
Name = typeof(Recorder).Name + ".RecordScreen",
IsBackground = true
};
screenThread.Start();
}
public void Dispose()
{
stopThread.Set();
screenThread.Join();
// Close writer: the remaining data is written to a file and file is closed
writer.Close();
stopThread.Dispose();
}
void RecordScreen()
{
var frameInterval = TimeSpan.FromSeconds(1 / (double)writer.FramesPerSecond);
var buffer = new byte[Params.Width * Params.Height * 4];
Task videoWriteTask = null;
var timeTillNextFrame = TimeSpan.Zero;
while (!stopThread.WaitOne(timeTillNextFrame))
{
var timestamp = DateTime.Now;
Screenshot(buffer);
// Wait for the previous frame is written
videoWriteTask?.Wait();
// Start asynchronous (encoding and) writing of the new frame
videoWriteTask = videoStream.WriteFrameAsync(true, buffer, 0, buffer.Length);
timeTillNextFrame = timestamp + frameInterval - DateTime.Now;
if (timeTillNextFrame < TimeSpan.Zero)
timeTillNextFrame = TimeSpan.Zero;
}
// Wait for the last frame is written
videoWriteTask?.Wait();
}
public void Screenshot(byte[] Buffer)
{
using (var BMP = new Bitmap(Params.Width, Params.Height))
{
using (var g = Graphics.FromImage(BMP))
{
g.CopyFromScreen(Point.Empty, Point.Empty, new Size(Params.Width, Params.Height), CopyPixelOperation.SourceCopy);
g.Flush();
var bits = BMP.LockBits(new Rectangle(0, 0, Params.Width, Params.Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppRgb);
Marshal.Copy(bits.Scan0, Buffer, 0, Buffer.Length);
BMP.UnlockBits(bits);
}
}
}
}
}
System.Drawing
and System.Windows.Forms
. (The usage of System.Windows.Forms
can be avoided if you modify the code).Code:
using Captura;
using System;
namespace ConsoleApp
{
class Program
{
static void Main(string[] args)
{
// Using MotionJpeg as Avi encoder,
// output to 'out.avi' at 10 Frames per second, 70% quality
var rec = new Recorder(new RecorderParams("out.avi", 10, SharpAvi.KnownFourCCs.Codecs.MotionJpeg, 70));
Console.WriteLine("Press any key to Stop...");
Console.ReadKey();
// Finish Writing
rec.Dispose();
}
}
}