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• ffmpeg transcoding one input video stream and multiple output video streams in the same file

  28 janvier 2020, par user2165262

  I am trying to transcode a single video file with 1 video stream and several audio streams to the file having same video stream in different bitrates/sizes with correct padding at the same time.

  the command I use is :

      ffmpeg -y -ss 600 -t 600 -i "INPUT.mkv" -map_chapters -1 -map 0:0 -c:v libx264 -keyint_min 48 -g 96 -bufsize 350k -b:v 350k -minrate 300k -maxrate 400k -profile:v baseline -level 3.0 -preset slow -vf "scale=iw*min(480/iw\,272/ih):ih*min(480/iw\,272/ih),pad=480:272 :(480-iw)/2 :(272-ih)/2" -map 0:0 -c:v libx264 -keyint_min 48 -g 96 -bufsize 650k -b:v 650k -minrate 500k -maxrate 800k -profile:v baseline -level 3.1 -preset slow -vf "scale=iw*min(640/iw\,360/ih):ih*min(640/iw\,360/ih),pad=640:360 :(640-iw)/2 :(360-ih)/2" -map 0:1 -c:a libfaac -b:a 32k -ar 44100 -f mpegts OUTPUT.m2ts
  

  ffmpeg creates two video streams, however the bitrate and resolution for all of them are taken from the last video arguments - i.e. both streams are 640x360 :

      Output #0, mpegts, to ’OUTPUT.m2ts’ :
      Stream #0:0(eng) : Video : h264, yuv420p, 640x360 [SAR 559:560 DAR 559:315], q=-1—1, 650 kb/s,     Stream #0:1(eng) : Video : h264, yuv420p, 640x360 [SAR 559:560 DAR 559:315], q=-1—1, 650 kb/s, 90k tbn, 23.98 tbc (default)
      Stream #0:2(rus) : Audio : aac, 44100 Hz, 5.1, s16, 32 kb/s (default)
      Stream mapping :
      Stream #0:0 -> #0:0 (h264 -> libx264)
      Stream #0:0 -> #0:1 (h264 -> libx264)
      Stream #0:1 -> #0:2 (aac -> libfaac)
      Press [q] to stop, [?] for help
  

  Is it practically possible to make transcoding to several bitrates to the same file ?

• How to get better video quality using Accord.Video.FFMPEG.DLL

  31 juillet 2023, par HighwayRob

  I have developed a Visual Studio Winapp that produces a video file utilizing Accord.Video.FFMPEG.DLL.

  


  The quality the video is less than the original images.
Here is the code and then a sample original image and snapshot of the resulting video.

  


  What can I change to improve the video image ?

  


              VideoFileWriter writer = new VideoFileWriter();
            writer.Open(outfile, width, height, 1, VideoCodec.Mpeg4);
            for (int i = firstrow; i <= testframes; i++)
            {
                Bitmap bitmap = new Bitmap(ffiles[i, 0].ToString());
                writer.WriteVideoFrame(bitmap);
                bitmap.Dispose();
            }


  


  I tried Bitmap image = new Bitmap(width, height, PixelFormat.Format64bppArgb) ;

  


  

  


• ffmpeg overlay video on image and remove video black background

  15 septembre 2021, par Moslem Aslani

  Im using this ffmpeg command to overlay a video on image (with remove black background) :

  


  ffmpeg -loop 1 -i image.png -i video.mp4 -filter_complex [1:v]colorkey=0x000000:0.1:0.1[ckout];[0:v][ckout]overlay[out] -map [out] -t 5 -c:a copy -c:v libx264 -y result.mp4


  


  

  


  But as you can see in the picture, the black parts of the ball have also disappeared. How can I solve this problem ?