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• Why i'm getting strange video file when using ffmpeg and pipes to create video file in real time ?

  30 juin 2015, par Brubaker Haim

  The goal here is to create a compressed mp4 video file in real time.
  I’m saving screenshots as bitmaps type on my hard disk.
  And i want to create mp4 file and compress the mp4 video file in real time.

  The problem is the end the video file i get looks very strange.
  This is the result : Strange Video File

  The class that i’m using the ffmpeg with arguments.

  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 Youtube_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;
  
                  //psi.Arguments = @"-framerate 1/5 -i -c:v libx264 -r 30 -pix_fmt yuv420p \\.\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();
  
          }
  
      }
  
  }

  Then i’m using the method PushFrame here in this class :

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

  The Bitmaps on the hard disk are fine i can edit/open see them.
  When using command prompt and manually type ffmpeg command it does compress and create a mp4 video file.

  But when using the Ffmpeg class i did with the PushFrame method it’s creating this strange video file.

  This is a link for my OneDrive with 10 screenshots images files for testing :

  screenshots rar

  Sample screenshot from the video file when playing the video file :
  Looks very choppy. The Bitmaps on the hard disk each one is 1920x1080 and Bit depth 32

  But it dosen’t look like that in the video file :

  

  This is the arguments i’m using :

  psi.Arguments = @"-f rawvideo -vcodec rawvideo -pix_fmt rgb24 -video_size 1920x1080 -i \\.\pipe\mytestpipe -map 0 -c:v mpeg4 -r " + BitmapRate + " " + outPath;

  The video size is very small 1.24 MB

• how to make ffmpeg process large files faster ?

  12 octobre 2019, par Hakim Douib

  I am using ffmpeg to view video for dash player. But the videos used are more than 1GB, and the server has
  60 GB of RAM
  Ten cores

  The server takes more than 50 hours to process a video.
  The method I use is by separating each operation thread to make it faster ,
  and the files in the end have size between 2 to 5 GB

  dash params variable

  VP9_DASH_PARAMS="-tile-columns 4 -frame-parallel 1"

  cmd :

  ffmpeg  -i  vid_origenal.mp4 -c:v libx265  -s 1920x1080 -b:v 3000k -keyint_min 150 -g 150 ${VP9_DASH_PARAMS} -an -f webm -dash 1  1080.webm >/dev/null 2>&1 &

  I use this for all qualities

  thanks

• Is there any way to provide different video qualities in my web application without converting each video to each format ?

  15 octobre 2019, par Dheeraj Arora

  i am building a web application which will handle thousand of videos. Currently, I am using ffmpeg to convert each video to 4 formats(1080,720,480,340px). It consumes lot of memory and time to upload for each video. Is there any best way that allows user to stream my videos in different video quality without converting each video ?