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• Set the time according to the image height

  5 août 2019, par Võ Nhân

  I am creating video from the image using ffmpeg, I have some problems with image height and video length, I want to set the time automatically according to the image length.Is it possible to set the time -t to the automatic value ?

  ffmpeg -y -loop 1 -i "{output}_cut1.jpg" -ss 0 -t 25 -r 1 -loop 1 -i 01.png -ss 0 -t 25 -filter_complex " [1:v] scale=w=1:h=1[fg]; [0:v] scale=w=-2:h=3*ih, crop=w=3*1988:h=3*1600/1.2:y=t*(in_h-out_h)/25 , scale=w=1920:h=1080,  setsar=1 [bg] ; [bg][fg]overlay=shortest=1[v] " -map "[v]" -c:v h264 -crf 18 -preset ultrafast "{output}_cut1.mp4"

• Why when using ffmpeg to create in real time avi video file from images the avi file is playing with purple noisy color ?

  30 juin 2015, par Brubaker Haim

  This is my Ffmpeg class i did some time ago

  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 Manager
  
  {
  
      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 yuv420p -video_size 1920x1080 -i \\.\pipe\mytestpipe -map 0 -c:v mpeg4 -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 i’m using it in form1 in a button click event :

  private void button1_Click(object sender, EventArgs e)
  
          {
  
              timer1.Start();
  
          }

  the directroy screenshots is where i’m taking a screenshot every 100ms in the timer1 tick event :

      ScreenShot shot = new ScreenShot();
  
      public static int counter = 0;
  
      private void timer1_Tick(object sender, EventArgs e)
  
      {
  
          counter++;
  
          shot.GetScreenShot(@"e:\screenshots\", "screenshot");
  
          if (counter == 1200)
  
          {
  
              timer1.Stop();
  
          }
  
      }

  I’m calling the method PushFrame from inside the ScreenShot class where i save the screenshots.

  Ffmpeg fmpeg;

  Then :

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

  And :

  public Bitmap GetScreenShot(string folder, string name)
  
      {
  
          _screenShot = new Bitmap(GetScreen());
  
          System.GC.Collect();
  
          System.GC.WaitForPendingFinalizers();
  
          string ingName = folder + name + Elgato_Video_Capture.counter.ToString("D6") + ".bmp";
  
          _screenShot.Save(ingName);
  
          fmpeg.PushFrame(_screenShot);
  
          _screenShot.Dispose();
  
  
  
          return _screenShot;
  
      }

  All the images on the hard disk are fine i can edit/open them and watch them no problems.
  They are also same size.

  The result in the end is one big avi file 1.08 GB size.
  But when i play it i see many windows running inside very fast and all painted with noisy purple color.

  Here a screenshot from the video file when playing it :

  avi file playing screenshot

  I think the problem is somewhere in the Ffmpeg class where i give parameters to the ffmpeg.exe

  psi.Arguments = @"-f rawvideo -pix_fmt yuv420p -video_size 1920x1080 -i \\.\pipe\mytestpipe -map 0 -c:v mpeg4 -r " + BitmapRate + " " + outPath;

  Not sure what make this avi file to look like that.

  This is the video file the result i got : https://www.youtube.com/watch?v=fdxPus-Xv1k&feature=youtu.be

• How can I overlay a video ontop of background image ?

  19 août 2019, par user11588722

  I have a command which creates waves ontop of a background image :

  ffmpeg -y -i "Assets/Screens/new.png" -i "Temp/video.mp4" -i "Temp/audio.mp3" -filter_complex "[2:a]showwaves=mode=cline:s=255x81:scale=sqrt:colors=0x222222,colorkey=0x000000:0.01:0.1,format=yuva420p[w];[v][w]overlay=240:594,scale=1920:1080[outv]" -map "[outv]" -map 2:a -movflags +faststart -c:v libx264 -c:a aac -preset veryfast -shortest "output.mp4"

  How can I also overlay a 1024x576px video at position 756:252 ?

  I have already included the video file as the second (1:v) input, but I can’t seem to get the filters to play nicely.

  Thanks for any help.