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• Compress video like whatsapp

  10 juillet 2021, par user1079425

  I'm not an expert in Video Editing but what I want to understand the logic of Whatsapp video processing.

  



  First of all I have noticed that whatever the file is, Whatsapp sets the limit of Uploaded videos to 16MB, after which whatsapp crops the video to not exceed the limit. is this a convention or it's a personal choice ?

  



  Secondly, When a video is recorded using the Camera it's not compressed by default, so whatsapp compresses it using FFMPEG I guess, and it takes no time. (tried for a video of 1min 1920x1080 with 125MB of size, becomes 640x360 with 5MB of size in no time, and the upload starts automatically).. how may they do this ? and why the choice of 640x360, It seems to me very fast for 2 asynchronous tasks : Compression + Upload.

  



  When I run the compression command ffmpeg -y -i in.mp4 -codec:v libx264 -crf 23 -preset medium -codec:a libfdk_aac -vbr 4 -vf scale=-1:640,format=yuv420p out.mp4 it takes approximatively 1 min and the video is being rotated !! :D

  



  Finally, when we download a video from Youtube it's already compressed (I guess) and whatsapp doesn't even try to compress it. So I think that it automatically detects thats the video is compressed. How can we detect this ?

  



  Thank you.

  


• What are the commands for FFmpeg extract images binary command

  19 juillet 2017, par Tix

  My ffmpeg for android studio is compiled using this :

  compile ’com.writingminds:FFmpegAndroid:0.3.2’

  In the code below i have this line of code :

  String[] complexCommand = "-i", yourRealPath, "-c:v", "libx264",
  "-crf", "22", "-map", "0", "-segment_time", "6", "-g", "9",
  "-sc_threshold", "0", "-force_key_frames", "expr:gte(t,n_forced*6)",
  "-f", "segment", dest.getAbsolutePath() ;

  Things i want to know :

  1. I’d like to know what those inputs(i.e. "-sc_threshold", "-g", "-crf") are, and what are their functions.
  2. If a video has 30fps and is 5 seconds long, are there 150 frames, if so is ffmpeg able to extact all 150 ?

  This is my code :

       /**
  
       * Command for extracting images from video
  
       */
  
      private void extractImagesVideo(int startMs, int endMs) {
  
          File moviesDir = Environment.getExternalStoragePublicDirectory(
  
                  Environment.DIRECTORY_PICTURES
  
          );
  
  
  
          String filePrefix = "extract_picture";
  
          String fileExtn = ".jpg";
  
          String yourRealPath = getPath(MainActivity.this, selectedVideoUri);
  
  
  
          File dir = new File(moviesDir, "VideoEditor");
  
          int fileNo = 0;
  
          while (dir.exists()) {
  
              fileNo++;
  
              dir = new File(moviesDir, "VideoEditor" + fileNo);
  
  
  
          }
  
          dir.mkdir();
  
          filePath = dir.getAbsolutePath();
  
          File dest = new File(dir, filePrefix + "%03d" + fileExtn);
  
  
  
  
  
          Log.d(TAG, "startTrim: src: " + yourRealPath);
  
          Log.d(TAG, "startTrim: dest: " + dest.getAbsolutePath());
  
  
  
          String[] complexCommand = {"-y", "-i", yourRealPath, "-an", "-r", "1/2", "-ss", "" + startMs / 1000, "-t", "" + (endMs - startMs) / 1000, dest.getAbsolutePath()};
  
  
  
          execFFmpegBinary(complexCommand);
  
  
  
      }
  
  
  
   /**
  
       * Executing ffmpeg binary
  
       */
  
      private void execFFmpegBinary(final String[] command) {
  
          try {
  
              ffmpeg.execute(command, new ExecuteBinaryResponseHandler() {
  
                  @Override
  
                  public void onFailure(String s) {
  
                      Log.d(TAG, "FAILED with output : " + s);
  
                  }
  
  
  
                  @Override
  
                  public void onSuccess(String s) {
  
                      Log.d(TAG, "SUCCESS with output : " + s);
  
                      if (choice == 1 || choice == 2 || choice == 5 || choice == 6 || choice == 7) {
  
                          Intent intent = new Intent(MainActivity.this, PreviewActivity.class);
  
                          intent.putExtra(FILEPATH, filePath);
  
                          startActivity(intent);
  
                      } else if (choice == 3) {
  
                          Intent intent = new Intent(MainActivity.this, PreviewImageActivity.class);
  
                          intent.putExtra(FILEPATH, filePath);
  
                          startActivity(intent);
  
                      } else if (choice == 4) {
  
                          Intent intent = new Intent(MainActivity.this, AudioPreviewActivity.class);
  
                          intent.putExtra(FILEPATH, filePath);
  
                          startActivity(intent);
  
                      } else if (choice == 8) {
  
                          choice = 9;
  
                          reverseVideoCommand();
  
                      } else if (Arrays.equals(command, lastReverseCommand)) {
  
                          choice = 10;
  
                          concatVideoCommand();
  
                      } else if (choice == 10) {
  
                          File moviesDir = Environment.getExternalStoragePublicDirectory(
  
                                  Environment.DIRECTORY_MOVIES
  
                          );
  
                          File destDir = new File(moviesDir, ".VideoPartsReverse");
  
                          File dir = new File(moviesDir, ".VideoSplit");
  
                          if (dir.exists())
  
                              deleteDir(dir);
  
                          if (destDir.exists())
  
                              deleteDir(destDir);
  
                          choice = 11;
  
                          Intent intent = new Intent(MainActivity.this, PreviewActivity.class);
  
                          intent.putExtra(FILEPATH, filePath);
  
                          startActivity(intent);
  
                      }
  
                  }

  Code downloaded from :

  https://github.com/bhuvnesh123/FFmpeg-Video-Editor-Android

• avfilter/pthread : use slice threading from avutil

  12 juillet 2017, par Muhammad Faiz

  avfilter/pthread : use slice threading from avutil
  Benchmark (with 2 cpus) :
  
  ./ffmpeg -f rawvideo -s 1280x720 -t 1000 -i /dev/zero \
  
      -filter_threads $threads -vf transpose=clock -f null null
  
  threads=2 :
  
    old : 31.129s 31.446s 31.574s
  
    new : 29.602s 29.636s 29.656s
  
  threads=3 (nb_threads = nb_cpus + 1 is bad choice at this situation) :
  
    old : 40.132s 40.279s 40.279s
  
    new : 39.308s 39.570s 39.693s
  
  threads=4 :
  
    old : 31.306s 31.366s 31.654s
  
    new : 30.231s 30.360s 30.451s
  Signed-off-by : Muhammad Faiz <mfcc64@gmail.com>
  

  • [DH] libavfilter/pthread.c