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• ffmpeg : combine two or three audios into one by lowering the volume of the other

  15 juin 2016, par somya bhargava

  Want to combine some audio files eg :

  1) one long audio file which will act as a background audio
  2) some audio files which will be replaced at specific intervals
  like at 10 sec of the first one

  So final output required is
  audio-1 60 sec
  audio-2 starting from 10 sec to 20 sec with audio-1 at 0.1 volume

• Append two videos without duplicating FFMPEG

  10 septembre 2021, par Hasindu Lanka

  Let's say we have 2 video files (X,Y) in the same format, codec and dimensions.

  


  X is a longer video with several gigabytes in size. Y is a short 10 second video. I want to append Y to the end of X without creating another copy of X (Because it's big in size)

  


  I have to repeat this process for hours with many 10 second videos arriving one after another.

  


  Currently, I'm concatenating files using ffmpeg.

  


  ffmpeg -f concat -safe 0 -i chunk.list -c copy final-video.mkv

  


  chunk.list contains file names of X and several 10 second videos. After this, X will be deleted and replaced by final-video.mkv. Then, repeat.

  


  But this needs twice the storage capacity and I/O operations. How to do this without creating duplicates ?

  


  It's okay to duplicate these 10 second videos. But duplicating that bigger file X really hurts performance.

  


  Additional info :

  


  All these videos will be encoded with H264, H265, VP8 or VP9 and contained in MKV or MP4 as they are codec copy friendly. Only one of these formats will be used.

  


  This is for a special case screen recorder that's supposed to run on cloud and preemptive remote desktops (Linux).
HTML/JS browser front-end captures the screen and sends to the back-end (Golang) as chunks through HTTP. Network route is undefined and unreliable as there can be firewalls/proxies between the front-end and the back-end. Therefore, we can't use connections like UDP. So the only option is to send video chunks using HTTP.

  


  It's FOSS on https://github.com/HasinduLanka/screencorder

  


• FFMpeg command in android tutorial

  25 novembre 2013, par Azhagiri

  I want to write a android app that concats two videos

  i tried the following code

      InputStream in=null;
  
      OutputStream os=null;
  
      String appFileDirectory = getFilesDir().getPath();
  
      final String executableFilePath = appFileDirectory + "/ffmpeg";
  
      final String input ="concat:/mnt/sdcard/input1.mpg|/mnt/sdcrad/input2.mpg";
  
      File executable=new File(executableFilePath);
  
      try {
  
          in = getAssets().open("ffmpeg");
  
          os = new FileOutputStream(executable);
  
          int read = 0;
  
          byte[] bytes = new byte[1024];
  
  
  
          while ((read = in.read(bytes)) != -1) {
  
              os.write(bytes, 0, read);
  
          }
  
  
  
  
  
      } catch (IOException e) {
  
          // TODO Auto-generated catch block
  
          e.printStackTrace();
  
      }finally {
  
          if (in != null) {
  
              try {
  
                  in.close();
  
              } catch (IOException e) {
  
                  e.printStackTrace();
  
              }
  
          }
  
          if (os != null) {
  
              try {
  
                  // outputStream.flush();
  
                  os.close();
  
              } catch (IOException e) {
  
                  e.printStackTrace();
  
              }
  
          }
  
      }
  
      executable.setExecutable(true);
  
      Button b = (Button)findViewById(R.id.button);
  
      b.setOnClickListener(new View.OnClickListener() {
  
          @Override
  
          public void onClick(View view) {
  
              try {
  
                  Process p = Runtime.getRuntime().exec(executableFilePath + "-i \""+ input + "\" -c copy /mnt/sdcrd/output.mpg");
  
              } catch (IOException e) {
  
                  // TODO Auto-generated catch block
  
                  e.printStackTrace();
  
              }
  
          }
  
      });
  
  
  
  }

  this code doesn't give any error or it is not crashing but nothing happens when i click the button. I created the ffmpeg build that is compatible with android. So can anyone help me out how to run the command from android java code.