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• Repeating video frame sequences without iterating each frame

  4 juillet 2015, par Raheel Khan

  I have an application that generates a video from a given number of files. A total frame count and sequence is provided and the generated video should loop the given sequence until the total number of frames have been written.

  At the moment, I’m using FFMPEG.VideoFileWriter from AForge.

  var frameIndex = 0;
  
  var frameCount = 300;
  
  
  
  var writer = new AForge.Video.FFMPEG.VideoFileWriter();
  
  writer.Open(filename: "Video.mp4", width: 10000, height: 10000, fps: 30, code: VideoCodec.MPEG4, bitrate: 1024 * 1024 * 2);
  
  
  
  using (var imageCanvas = new Bitmap(width, height))
  
  {
  
      do
  
      {
  
          foreach (var file in this._Files)
  
          {
  
              frameIndex++;
  
              if (frameIndex > frameCount) { break; }
  
  
  
              using (var graphicsCanvas = Graphics.FromImage(imageCanvas))
  
              {
  
                  graphicsCanvas.Clear(Color.Black);
  
  
  
                  using (var imageFile = Image.FromFile(file.FullName))
  
                  {
  
                      graphicsCanvas.DrawImage(imageFile, 0, 0, imageCanvas.Width, imageCanvas.Height);
  
                  }
  
              }
  
  
  
              writer.WriteVideoFrame(imageCanvas);
  
          }
  
      }
  
      while (true);
  
  }

  the bottlenecks are :

  • The call to writer.WriteVideoFrame(imageCanvas).
  • The source images in question are massive (more than 10Kx10K 32bpp) so keeping them all in memory is not an option.

  The only thing I can think of is to create an uncompressed AVI file and somehow copy entire sequences in bulk. although transcoding back to MP4 would still take a while, it may same some overall.

  Any general optimization suggestions or clues on how to write multiple frames at once would be appreciated.

• First Frame of SaveVideo playing longer, and last frame playing shortly

  19 décembre 2018, par Ricardo Alonso Esparza Gamez

  I’m using SaveVideo to create an animation based on different ggplots.
  Here’s what I am doing :

  saveVideo({for(i in 1:12){p <- ggplot()+...etc,video.name = "months.mp4")

  And these are my animation options :

  ani.options(interval=1.5,ani.width=1280,ani.dev = function(...){png(res=75*2.5,...)},ani.height=720, other.opts = '-analyzeduration 2M -probesize 1M')

  On the published video, the first frame lasts for like 5 seconds, then the other frames play normally, until the last frame which goes really quickly (less than 1 second). I have played around with different analyzeduration and probesize options with no results. Any idea how to solve this ?
  Thanks !

• How to get each frame of the video and do some modifications to the frame in android

  4 décembre 2014, par Naresh Sharma

  I need to get the frames a video and do some modification on it like drawing something on it or write some text. Then on saving I need that video with that modifications.

  Please suggest me the best way to do that. Any help is appreciated.

  Please see the below app for to understand my problem

  https://play.google.com/store/apps/details?id=com.techsmith.apps.coachseye.free