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• DirectShowLib library is not working with .MP4

  4 novembre 2015, par Ragesh Puthiyedath

  I am a newbie in using DirectShowLib for create image thumbnails from video.

  Now i try to use this library for make a thumbnail of my .mp4 video.

  Please see my code below.

  public static bool CreateThumb(string videoFilename, string thumbFilename, double positionPercent)
  
      {
  
          //Logger.ReportInfo("Creating thumb for " + videoFilename);
  
          bool rval = false;
  
          try
  
          {
  
  
  
              IMediaDet m = new MediaDet() as IMediaDet;
  
              m.put_Filename(videoFilename);
  
  
  
              int streamCount;
  
              m.get_OutputStreams(out streamCount);
  
  
  
              AMMediaType media_type = new AMMediaType();
  
  
  
              for (int i = 0; i < streamCount; i++)
  
              {
  
                  m.get_StreamMediaType(media_type);
  
  
  
                  VideoInfoHeader vih = (VideoInfoHeader)Marshal.PtrToStructure(media_type.formatPtr, typeof(VideoInfoHeader));
  
  
  
                  if (vih == null)
  
                  {
  
                      continue;
  
                  }
  
  
  
                  double pos;
  
                  m.get_StreamLength(out pos);
  
                  pos = (int)(pos * positionPercent);
  
  
  
                  int width = vih.BmiHeader.Width;
  
                  int height = vih.BmiHeader.Height;
  
  
  
                  if (height < 10 || width < 10)
  
                  {
  
                      continue;
  
                  }
  
  
  
                  string tempfile = Path.GetTempFileName() + ".bmp";
  
  
  
                  m.WriteBitmapBits(pos, width, height, tempfile);
  
  
  
                  if (File.Exists(tempfile))
  
                  {
  
                      using (var bitmap = new Bitmap(tempfile))
  
                      {
  
                          bitmap.Save(thumbFilename, ImageFormat.Png);
  
                      }
  
  
  
                      File.Delete(tempfile);
  
                      rval = true;
  
                  }
  
  
  
                  break;
  
              }
  
  
  
              Marshal.ReleaseComObject(m);
  
  
  
          }
  
          catch (Exception ex)
  
          {
  
  
  
              throw ex;
  
          }
  
          return rval;
  
  
  
      }

  But this method is skiped after this line code execution.

  m.get_OutputStreams(out streamCount) ;

  streamCount is always ’0’. Is this library is not supported the .mp4 format.

  Please give me a advice.

  Thanks

• How to extract attachment from mkv file with ffmpeg (dump_attachment command not working)

  31 octobre 2015, par Anna K.

  This is the command that I’m running through nwjs :

  ffmpeg -dump_attachment:t:4 C:\nw\files/test.jpg -i E:\video/test.mkv

  From their docs here http://ffmpeg.org/ffmpeg.html#Main-options looks like it’s right

  But I get the error "At least one output file must be specified". I don’t understand why because It’s clearly specified in the command :(

  Any help please ?

  I tried running the same command in the Windows command line and the same error appears...

  ---

  I found out that this command :

  ffmpeg -i E:\video/test.mkv -map 0:4 -c copy C:\nw\files/test.jpg

  does extract the attachment, but the ffmpeg process does not close !

  If I run the same command in the Windows shell it prints to the screen "press [q] to quit" or something, which doesn’t work because I have to press ctrl+c twice to quit, and then I get some error about reading from the mkv. But when I look in the files directory I see the attachment there

• ffmpeg -pattern_type glob not working in Google Colab

  22 février 2023, par John Jannone

  I'm trying to combine images into video using ffmpeg in a Google Colab Notebook ; I'm getting errors but don't see what I'm doing wrong.

  


  !ffmpeg -pattern_type glob  -i 2023021522* -c:v libx264 video2.mp4

  


  returns : Option pattern_type not found.

  


  !ffmpeg -pattern_type glob  -i '2023021522*' -c:v libx264 video2.mp4 or
!ffmpeg -pattern_type glob  -i "2023021522*" -c:v libx264 video2.mp4

  


  return : 2023021522* : No such file or directory

  


  I also tried adding from glob import glob and just import glob