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• how to pass glob string to ffmpeg from a bash function ? [duplicate]

  20 novembre 2017, par Timothy W. Hilton

  This question already has an answer here :

  • Using a glob expression passed as a bash script argument
    
    1 answer
    

  I’m trying to create an animation from a group of png
  files prefix_XXXX.png in a directory (where X is a digit 0-9). This creates the file foo.mp4 :

  ffmpeg -nostdin -r 2 -pattern_type glob  -i './prefix_*.png' -c:v libx264 -pix_fmt yuv420p foo.mp4

  I want to place my command in a bash function so I don’t have to
  dig all the ffmpeg args out of my bash history everytime. I suspect I’m
  not quoting the glob string correctly :

  function wrf_animate()  {
  
      # usage: wrf_animate files_to_animate_glob_string name_of_output.mp4
  
      echo "running in $PWD"
  
      echo " ==== "
  
      ls -lh $1
  
      echo " ==== "
  
      ffmpeg -nostdin -r 2 -pattern_type glob  -i "$1" -c:v libx264 -pix_fmt yuv420p $2
  
  }

  The echo and ls lines in the above function show I’m running in
  the right place and the args are making it in.

  $1, "$1", \’"$1"\’ all result in : "File ’prefix_0100.png’ already exists. Exiting."

  "\’$1\’" results in : \’prefix_0000.png\’ : No such file or directory

  \’$1\’ results in : ’prefix_0000.png’ : No such file or directory

• Finding a string with AWK before or after an iteration of a repeated sequence

  9 novembre 2017, par dne202

  So I’ve got a text document that looks like this (truncated)

  [FRAME]
  
  pkt_pts_time=0.000000
  
  pict_type=I
  
  [/FRAME]
  
  [FRAME]
  
  pkt_pts_time=0.250250
  
  pict_type=B
  
  [/FRAME]
  
  [FRAME]
  
  pkt_pts_time=0.500500
  
  pict_type=P
  
  [/FRAME]
  
  [FRAME]
  
  pkt_pts_time=0.750750
  
  pict_type=B
  
  [/FRAME]
  
  [FRAME]
  
  pkt_pts_time=0.959292
  
  pict_type=I
  
  [/FRAME]

  This text was created with this command :

  ffprobe -select_streams v -show_frames -show_entries frame=pkt_pts_time,pict_type,frame_number -v quiet input.mp4

  As you can see, the [Frame] to [/Frame] sequence is repeated. So this is a way for me to count the frames and find which frame is an I frame. In each sequence the "pict_type=" value changes. I was wondering if there was a way for me to use AWK to input an iteration number and output the preceding pkt_pts_time value where the pict_type value equals I.

  For instance, if my frame number is 3. I would be able to enter the number 3 and the awk expression would go to the third [Frame] to [/Frame] sequence and then look back from there till it found a "pict_type=I" string. Then it would see that the pkt_pts_time for that sequence iteration was "pkt_pts_time=0.00000" and it would output 0.0000

• String command for text-watermarking a video using FFmpeg in Android Studio

  11 octobre 2017, par djac

  Following is the ffmpeg function which accepts string command, coded in Android Studio. Can you give Sample/Reference string command for text-watermarking a video for this function (in Android Studio) ?

  For example :
  Input video file absolute path is "inputvideo".
  Watermark text is "stackoverflow".
  Output video file absolute path is "outputvideo".

  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);
  
  //Perform action on success
  
  }
  
  }
  
  
  
  @Override
  
  public void onProgress(String s) {
  
  Log.d(TAG, “progress : ” + s);
  
  }
  
  
  
  @Override
  
  public void onStart() {
  
  Log.d(TAG, “Started command : ffmpeg ” + command);
  
  }
  
  
  
  @Override
  
  public void onFinish() {
  
  Log.d(TAG, “Finished command : ffmpeg ” + command);
  
  
  
  }
  
  });
  
  } catch (FFmpegCommandAlreadyRunningException e) {
  
  
  
  }
  
  }