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• Merge videos in c# asp.net using ffmpeg

  3 juillet 2012, par Arun Kumar

  Is it possible to merge the two videos by c# asp.net with the help of ffmpeg. In the ffmpeg documentation they gave us cat command. But it wont works in asp.net. I thought it only for linux.

  cat intermediate1.mpg intermediate2.mpg > intermediate_all.mpg

  asp.net execute this command but there is no output. Help me.

  namespace demo
  
  {
  
      public partial class Default : System.Web.UI.Page
  
      {
  
          protected void Button2_Click(object sender, EventArgs e)
  
          {
  
              string strFile = "cars1.flv";
  
              MergeFiles(strFile);
  
          }
  
  
  
          public void MergeFiles(string strFile)
  
          {
  
              string strParam;
  
              string Path_FFMPEG = Server.MapPath("~/ffmpeg/bin/ffmpeg.exe");
  
  
  
              //Converting a video into mp4 format
  
              string strOrginal = Server.MapPath("~/Videos/");
  
              strOrginal = strOrginal + strFile;
  
              string strConvert = Server.MapPath("~/Videos/ConvertedFiles/");
  
              string strExtn = Path.GetExtension(strOrginal);
  
              if (strExtn != ".mp4")
  
              {
  
                  strConvert = strConvert + strFile.Replace(strExtn, ".mp4");
  
                  strParam  = "-i " + strOrginal + " " + strConvert;
  
                  //strParam = "-i " + strOrginal + " -same_quant " + strConvert;
  
                  process(Path_FFMPEG, strParam);
  
              }
  
  
  
              //Merging two videos               
  
              String video1 = Server.MapPath("~/Videos/Cars1.mp4");
  
              String video2 = Server.MapPath("~/Videos/ConvertedFiles/Cars2.mp4");
  
              String strResult = Server.MapPath("~/Videos/ConvertedFiles/Merge.mp4");
  
              //strParam = "-loop_input -shortest -y -i " + video1 + " -i " + video2 + " -acodec copy -vcodec mjpeg " + strResult;
  
  
  
              strParam = " -i " + video1 + " -i " + video2 + " -acodec copy -vcodec mjpeg " + strResult;
  
  
  
              process(Path_FFMPEG, strParam);
  
          }
  
  
  
          public void process(string Path_FFMPEG, string strParam)
  
          {
  
              try
  
              {
  
                  Process ffmpeg = new Process();
  
                  ProcessStartInfo ffmpeg_StartInfo = new ProcessStartInfo(Path_FFMPEG, strParam);
  
                  ffmpeg_StartInfo.UseShellExecute = false;
  
                  ffmpeg_StartInfo.RedirectStandardError = true;
  
                  ffmpeg_StartInfo.RedirectStandardOutput = true;
  
                  ffmpeg.StartInfo = ffmpeg_StartInfo;
  
                  ffmpeg_StartInfo.CreateNoWindow = true;
  
                  ffmpeg.EnableRaisingEvents = true;
  
                  ffmpeg.Start();
  
                  ffmpeg.WaitForExit();
  
                  ffmpeg.Close();
  
                  ffmpeg.Dispose();
  
                  ffmpeg = null;
  
              }
  
              catch (Exception ex)
  
              {
  
  
  
              }
  
          }
  
  
  
      }
  
  }

• Compressing videos from a smartphone

  21 septembre 2019, par fejesjoco

  I have a Nexus 6p with the stock camera. It’s set to record at 1080p, 30fps. Here’s a 5 second sample (11 MB).

  Videos from this phone come out at about 17 Mbps on average. I tried to compress it with ffmpeg with -c:v libx264 -crf 23 -preset veryslow, the result comes out at about 5.5 MB, which is about 9 Mbps.

  I think this bitrate is a bit too much. When I look at torrent file listings, I can see high quality videos at 3 GB in size on average, and if such a movie is 90 minutes long on average, that is about 4-5 Mbps which sounds okay.

  I’m wondering, why the big difference ? I can notice that my video is noisy/grainy (which is expected from a phone), and that might reduce compressibility. I tried a few ffmpeg filters, like hqdn3d and atadenoise, but the noise mostly remained (maybe I didn’t play with it enough). Then I figured, the video is also shaky (which is also expected), and that might reduce compressibility too (and even makes temporal noise filtering less effective). I tried to stabilize it with the deshake filter, but that didn’t help either.

  I know I could just limit the bandwidth to whatever I like, but there must be a reason why ffmpeg thinks it needs a high bandwidth to maintain a certain quality, and a lower bandwidth would just decrease the quality.

  Why do these videos have such a high bitrate ? What’s the best way to compress them more while keeping or even increasing their quality ?

• FFMPEG merge two .mp4 videos - resolution distorted

  9 juin 2016, par Misha Moryachok

  I am trying to merge two .mp4 videos, and in some cases the seconds video part is distorted in the output video. Providing an example below :
  https://www.youtube.com/watch?v=wWMNTBWJ37A

  The real video is : https://www.youtube.com/watch?v=ASio-j-Epi8

  As you can see, we added intro before the real content, however, the real content is stretched.
  In my opinion it happens because first video is 1280x720 and the second is 460x720.

  Providing commands for merging videos :

  *1st step (convert the videos from .mp4 to .ts)

   ffmpeg -i videoPathMP4 -c copy -bsf:v h264_mp4toannexb -f mpegts videoPathTS

  *2nd step (merge videos)

  ffmpeg -i "concat:$video1 | $video2" -c copy -bsf:a aac_adtstoasc $meagePathMP4

  Video output is like you saw in provided videolink on youtube.
  I also tried to change the first video resolution to be like the second video :

  ffmpeg -i inputVideo.mp4 -s 460x720 outputVideo.mp4

  However it doesn’t helped.
  Is anyone know how to solve this ?
  Thanks