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• How to compare/show the difference between 2 videos in ffmpeg ?

  25 janvier 2016, par polarka

  I am a newbie at encoding. I have read and tried x264 in lossless mode (-qp 0), however I’d like to make sure that in my new video, every single pixel contains the same information as the source file (which is in YUV 420 so the loss of color conversion is avoidable, as far as I know). I want to be able to check that, because I don’t believe in that if someone just says its lossless.

  I welcome answers suggesting other codecs for lossless encoding, my only requirements for codecs are having one of the best compression rate and let me to pick different calculation times (such as the range from placebo to veryfast in x264) in order to adjust the compression level and calc time to my needs. But keep in mind that the original question is about how can I calculate the differences frame by frame of two videos and export it to a 3rd file, so I can watch it myself. I think that knowledge (if its possible and doesnt have serious limitations) will be useful for me in the future too.

• avformat/segafilmenc : Remove redundant checks

  14 janvier 2020, par Andreas Rheinhardt

  avformat/segafilmenc : Remove redundant checks
  If an audio stream is present, the Sega FILM muxer checks for its
  
  compability with the container during init, so that the very same check
  
  needn't be repeated during writing the trailer.
  Essentially the same is true for the presence of a video stream : It has
  
  already been checked during init. Furthermore, after the check for the
  
  presence of a video stream succeeded, a pointer is set to point to the
  
  video stream. Yet said pointer (which was NULL before) will be
  
  derefenced anyway regardless of the result of the check. Coverity thus
  
  complained about this in CID 1434155 and removing this pointless check
  
  will also fix this issue.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/segafilmenc.c

• create thumbnail from video URL in C#

  23 mai 2016, par Hashem Aboonajmi

  I want to generate thumbnail from a video URL in C#. I have searched a lot to find a neat way but no success. I have used Nreco and MediaToolKit but none of them extract thumbnail image. using ffmpeg also has mumbo jumbos which didn’t worked !

  using NReco :

  var ffMpeg = new NReco.VideoConverter.FFMpegConverter();
  
  string thumbnailJPEGpath = "http://localhost:81882/content/hashem.jpeg";
  
  ffMpeg.GetVideoThumbnail(videoUrl,thumbnailJPEGpath);

  using ffmpeg :

  try
  
          {
  
              System.Diagnostics.Process ffmpeg;
  
  
  
              string video;
  
              string thumb;
  
  
  
              video = Server.MapPath("~/Content/Movies/bye.mp4");
  
              thumb = Server.MapPath("~/Content/frame.jpg");
  
  
  
              ffmpeg = new System.Diagnostics.Process();
  
  
  
              ffmpeg.StartInfo.Arguments = " -i " + video + " -ss 00:00:07 -vframes 1 -f image2 -vcodec mjpeg " + thumb;
  
              ffmpeg.StartInfo.FileName = Server.MapPath("~/Content/ffmpeg.exe");
  
              ffmpeg.Start();
  
              ffmpeg.WaitForExit();
  
              ffmpeg.Close();
  
          }
  
          catch (Exception ex)
  
          {
  
              Response.Write("Error: " + ex.Message);
  
          }

  to consider video files are not local and I have only a direct link to the file :
  e.g. :http://phytonord.com/Film-Series/hana/26.mp4

  does anyone has any solution ? any sample code that works ?