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• How can i capture a screenshots from pictureBox1 every X milliseconds ?

  9 avril 2016, par Brubaker Haim

  The way it is now it’s capturing screenshots depending on on what screen I am in.
  For example if i’m in my desktop it will take screenshots of my desktop if I move to the form1 and see the pictureBox1 it will take screenshots of the pictureBox1.

  But how can I get directly screenshots from the pictureBox1 no matter on what screen I am ?

  Bitmap bmp1;
  
          public static int counter = 0;
  
          private void timer1_Tick(object sender, EventArgs e)
  
          {
  
              counter++;
  
  
  
              Rectangle rect = new Rectangle(0, 0, pictureBox1.ClientSize.Width, pictureBox1.ClientSize.Height);
  
              bmp1 = new Bitmap(rect.Width, rect.Height, PixelFormat.Format32bppArgb);
  
              Graphics g = Graphics.FromImage(bmp1);
  
              g.CopyFromScreen(rect.Left, rect.Top, 0, 0, bmp1.Size, CopyPixelOperation.SourceCopy);
  
              bmp1.Save(@"e:\screenshots\" + "screenshot" + counter.ToString("D6") + ".bmp", ImageFormat.Bmp);
  
              bmp1.Dispose();
  
              g.Dispose();
  
              if (counter == 500)//1200)
  
              {
  
                  timer1.Stop();
  
                  this.Close();
  
              }
  
          }

  The timer1 is set now to 100ms interval in the designer.
  But what is a reasonable speed to take screenshots from animation in the pictureBox1 ? In this case I have a game I show in the pictureBox1 and I want to take a screenshots of each frame from the pictureBox1 and in real time to create mp4 video file on the hard disk from each frame I took.

  So instead saving the bmp1 to the hard disk I need somehow to save each frame I capture in memory and build mp4 video file in real time.

  I created a ffmpeg class for that :

  using System;
  
  using System.Windows.Forms;
  
  using System.Collections.Generic;
  
  using System.Linq;
  
  using System.Text;
  
  using System.Threading.Tasks;
  
  using System.Drawing;
  
  using System.IO.Pipes;
  
  using System.Runtime.InteropServices;
  
  using System.Diagnostics;
  
  using System.IO;
  
  using DannyGeneral;
  
  
  
  namespace ffmpeg
  
  {
  
      public class Ffmpeg
  
      {
  
          NamedPipeServerStream p;
  
          String pipename = "mytestpipe";
  
          System.Diagnostics.Process process;
  
          string ffmpegFileName = "ffmpeg.exe";
  
          string workingDirectory;
  
  
  
          public Ffmpeg()
  
          {
  
              workingDirectory = Path.GetDirectoryName(Application.ExecutablePath);
  
              Logger.Write("workingDirectory: " + workingDirectory);
  
              if (!Directory.Exists(workingDirectory))
  
              {
  
                  Directory.CreateDirectory(workingDirectory);
  
              }
  
              ffmpegFileName = Path.Combine(workingDirectory, ffmpegFileName);
  
              Logger.Write("FfmpegFilename: " + ffmpegFileName);
  
          }
  
  
  
          public void Start(string pathFileName, int BitmapRate)
  
          {
  
              try
  
              {
  
  
  
                  string outPath = pathFileName;
  
                  p = new NamedPipeServerStream(pipename, PipeDirection.Out, 1, PipeTransmissionMode.Byte);
  
                  ProcessStartInfo psi = new ProcessStartInfo();
  
                  psi.WindowStyle = ProcessWindowStyle.Hidden;
  
                  psi.UseShellExecute = false;
  
                  psi.CreateNoWindow = false;
  
                  psi.FileName = ffmpegFileName;
  
                  psi.WorkingDirectory = workingDirectory;
  
                  psi.Arguments = @"-f rawvideo -pix_fmt bgra -video_size 1920x1080 -i \\.\pipe\mytestpipe -c:v mpeg2video -crf 20 -r " + BitmapRate + " " + outPath;
  
                  process = Process.Start(psi);
  
                  process.EnableRaisingEvents = false;
  
                  psi.RedirectStandardError = true;
  
                  p.WaitForConnection();
  
              }
  
              catch (Exception err)
  
              {
  
                  Logger.Write("Exception Error: " + err.ToString());
  
              }
  
          }
  
  
  
          public void PushFrame(Bitmap bmp)
  
          {
  
              try
  
              {
  
                  int length;
  
                  // Lock the bitmap's bits.
  
                  //bmp = new Bitmap(1920, 1080);
  
                  Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
  
                  //Rectangle rect = new Rectangle(0, 0, 1280, 720);
  
                  System.Drawing.Imaging.BitmapData bmpData =
  
                      bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadOnly,
  
                      bmp.PixelFormat);
  
  
  
                  int absStride = Math.Abs(bmpData.Stride);
  
                  // Get the address of the first line.
  
                  IntPtr ptr = bmpData.Scan0;
  
  
  
                  // Declare an array to hold the bytes of the bitmap.
  
                  //length = 3 * bmp.Width * bmp.Height;
  
                  length = absStride * bmpData.Height;
  
                  byte[] rgbValues = new byte[length];
  
  
  
                  //Marshal.Copy(ptr, rgbValues, 0, length);
  
                  int j = bmp.Height - 1;
  
                  for (int i = 0; i < bmp.Height; i++)
  
                  {
  
                      IntPtr pointer = new IntPtr(bmpData.Scan0.ToInt32() + (bmpData.Stride * j));
  
                      System.Runtime.InteropServices.Marshal.Copy(pointer, rgbValues, absStride * (bmp.Height - i - 1), absStride);
  
                      j--;
  
                  }
  
                  p.Write(rgbValues, 0, length);
  
                  bmp.UnlockBits(bmpData);
  
              }
  
              catch(Exception err)
  
              {
  
                  Logger.Write("Error: " + err.ToString());
  
              }
  
  
  
          }
  
  
  
          public void Close()
  
          {
  
              p.Close();
  
          }
  
      }
  
  }

  And using the ffmpeg class like this :

  public static Ffmpeg fmpeg;

  Then

  fmpeg = new Ffmpeg();
  
  fmpeg.Start(@"e:\screenshots\test.mp4", 25);

  And

  fmpeg.PushFrame(_screenShot);

  My main question is first how to get the screenshots(frames) from the pictureBox1 directly no matter what screen i’m in now ?

  And how to use on each frame with the fmpeg to get a fine mp4 speed video file I mean that I will not miss a frame to capture all frames and also that the mp4 video file will when I play it later will not display a fast video or too slow ?

• FFMPEG - Scaling video to squash it horizontally doesn't work. How can I tell FFMPEG to switch the aspect ration here ? [duplicate]

  30 mars 2021, par schuelermine

  I have a video in 1920×1080. I want to squash it horizontally, producing a 608×1080 video.

  


  I'm trying to do this with ffmpeg -i i.mp4 -vf scale=608:1080 o.mp4. I've tried switching the arguments to be sure.
  
No matter the argument order, or whether or not I include force_original_aspect_ration, or use x or :,
  
the output video is always (so far) in 1080×608 instead of 608×1080.

  


  How the hell do I get FFMPEG to not switch the axes back ?

  


• FFmpeg hevc_nvenc encoder B Frame problem

  16 mai 2023, par ramondq

  I'm using the latest FFmpeg windows Build (2022-12-02 12:44) from BtbN.
I'm trying to encode a video into HEVC codec using hevc_nvenc encoder. But it says [hevc_nvenc @ 00000263983f4280] B frames as references are not supported. Cause my GPU GTX1060 (GP106) doesn't support hardware accelerate encode HEVC of B frames.
command line

  


  I tried to disable the B frames by adding the parameter -bf 0, but it doesn't work.
Then I tried to use the latest build from gyan.dev and it is the same. But when I tried to use an older build (2021-02-28 12:32) of BtbN, it doesn't have the problem.
Is there a workaround to bypass this B frame problem ? Cause I don't want to switch to an older build. Thanks.