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• Accord.Video.FFMPEG.VideoFileWriter writes different data from the input data

  14 novembre 2017, par Rasool Ahmed

  I’m working on project that encrypting video frames using RC4 algorithm and save these frames in playable video file.

  I used a package named Accord.Video.FFMPEG. This package has a classes (VideoFileReader, & VideoFileWriter) that reads and writes video frames.

  The first step is reads the video :

  VideoHandler v = new VideoHandler();
  
  OpenFileDialog newimag = new OpenFileDialog();
  
          if (newimag.ShowDialog() == DialogResult.OK)
  
          {
  
              textfile = newimag.FileName;
  
              picbox.ImageLocation = textfile;
  
              status1.Text = "loaded";
  
              //MessageBox.Show("your video file have been loaded seccufly"); // is an idea for viwing message 
  
  
  
          }
  
      bytedata = v.ReadAllFrameBytes(textfile);

  The second step is encrypting the frames of video :

  byte[] bn = new byte[bytedata.Length];// new array to hold the encryptred file
  
  
  
          bn = Encrypt(bytedata, ba);

  The last step is saving the encrypted frames :

  v.WriteFramesData(newfilepath, bn);

  My encrypting algorithm is encrypting and decrypting the cipher with same algorithm and key.

  These stpes works on Text, and Images files, but when I use it on video I can’t restore the encrypted video. After some testings, I found that VideoFileWriter dosn’t write the same input frames. Whyyyyyyy ?

  Here is my VideoFileHandler I made it :

   using System;
  
   using System.Collections.Generic;
  
   using System.Drawing;
  
   using System.Linq;
  
   using System.Text;
  
   using System.Drawing.Imaging;
  
   using System.IO;
  
   using Accord.Video.FFMPEG;
  
   namespace imgtobyt_1_in_c
  
   {
  
  class VideoHandler
  
  {
  
      public List data;
  
      public byte[] imagedata;
  
      public int Height, Width;
  
      public byte[] ReadAllFrameBytes(string FileName)
  
      {
  
          // create instance of video reader
  
          VideoFileReader reader = new VideoFileReader();
  
          // open video file
  
          reader.Open(FileName);
  
          Height = reader.Height;
  
          Width = reader.Width;
  
  
  
          data = new List();
  
          // read video frames
  
          for (int i = 0; i < 100; i++) //change 100 to reader.FrameCount
  
          {
  
              Bitmap videoFrame = reader.ReadVideoFrame();
  
              byte[] framebytes = GetBytesFromFrame(videoFrame);
  
              data.Add(framebytes);
  
              // dispose the frame when it is no longer required
  
              videoFrame.Dispose();
  
          }
  
          reader.Close();
  
          imagedata = new byte[data.Count * data[0].Length];
  
          int c = 0;
  
          for (int i = 0; i < data.Count; i++)
  
          {
  
              byte[] d = data[i];
  
              for (int x = 0; x < d.Length; x++)
  
              {
  
                  imagedata[c] = d[x];
  
                  c++;
  
              }
  
          }
  
          return imagedata;
  
      }
  
  
  
      public byte[] GetBytesFromFrame(Bitmap Frame)
  
      {
  
          LockBitmap lockBitmap = new LockBitmap(Frame);
  
          lockBitmap.LockBits();
  
  
  
          byte[] framebytes = new byte[Frame.Width * Frame.Height * 3];
  
          int z = 0;
  
          for (int x = 0; x < lockBitmap.Height; x++)
  
              for (int y = 0; y < lockBitmap.Width; y++)
  
              {
  
                  Color Pixel = lockBitmap.GetPixel(y, x);
  
                  framebytes[z] = Pixel.R;
  
                  z++;
  
                  framebytes[z] = Pixel.G;
  
                  z++;
  
                  framebytes[z] = Pixel.B;
  
                  z++;
  
              }
  
  
  
          lockBitmap.UnlockBits();
  
          return framebytes;
  
          //using (var stream = new MemoryStream())
  
          //{
  
          //    Frame.Save(stream, System.Drawing.Imaging.ImageFormat.Png);
  
          //    return stream.ToArray();
  
          //}
  
      }
  
  
  
      public Bitmap GetFrameFromBytes(byte[] Framebytes, ref int offset, int Width, int Height)
  
      {
  
          Bitmap Frame = new Bitmap(Width, Height, PixelFormat.Format24bppRgb);
  
          LockBitmap lockBitmap = new LockBitmap(Frame);
  
          lockBitmap.LockBits();
  
          for (int x = 0; x < Height; x++)
  
              for (int y = 0; y < Width; y++)
  
              {
  
                  Color Pixel = Color.FromArgb(Framebytes[offset], Framebytes[offset + 1], Framebytes[offset + 2]); offset += 3;
  
                  lockBitmap.SetPixel(y, x, Pixel);
  
              }
  
  
  
          lockBitmap.UnlockBits();
  
  
  
          return Frame;
  
          //Bitmap bmp;
  
          //using (var ms = new MemoryStream(Framebytes))
  
          //{
  
          //    bmp = new Bitmap(ms);
  
          //}
  
          //return bmp;
  
      }
  
  
  
      public void WriteFramesData(string FileName, byte[] data)
  
      {
  
          // create instance of video writer
  
          VideoFileWriter writer = new VideoFileWriter();
  
          // create new video file
  
          writer.Open(FileName, Width, Height);
  
  
  
          int offset = 0;
  
          // write video frames
  
          for (int i = 0; i < 100; i++)
  
          {
  
              // create a bitmap to save into the video file
  
              Bitmap Frame = GetFrameFromBytes(data, ref offset, Width, Height);
  
              writer.WriteVideoFrame(Frame);
  
          }
  
          writer.Close();
  
      }
  
  }
  
   }

  Please, I need to make this works.

• Revision 65043 : Accord au singulier

  20 août 2012, par real3t@… — Log

  Accord au singulier

• Revision 101409 : chaînes de langue plus précise (avec accord de proximité)

  11 juin 2018, par maieul@… — Log

  chaînes de langue plus précise (avec accord de proximité)