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• Is it possible for FFMPEG built-in command line api to achieve below batch command ?

  24 janvier 2017, par BOBO

  My scenario is listed below :

  1. use ffmpeg to grab videos from their live raw urls and directly convert them into (480px * 480px) .mp4 custom video format with white background if uncovered after resize, disregarding the input video url source might be different in original dimensions, square or rectangular or vertical rectangular etcs.

  code sample is like : (prefer running on local machine, cause faster less costly than run it on server under same hardware spec )

   ffmpeg -i "[raw http video url]"  -vf "scale=iw*min(480/iw\,480/ih):ih*min(480/iw\,480/ih),pad=480:480:(480-iw)/2:(480-ih)/2:color=white" [target_path_and_filename].mp4

  2. when video finished step 1 and saved onto the hard-disk,
     I need to calculate duration of it and retrive information of three frame timestamp in seconds, such as store in an array
     [0, duration/2, duration] using ffprobe

  3. using ffmpeg api command to extract 3 jpeg files
     at the

     0sec frame firstframe.jpg,
     duration/2 (sec) middleframe.jpg,
     and last frame = duration (sec).jpg

  Final step I would like to combine all three steps into one combined task of ffmpeg command line and for loop it in a windows command line batch file.

  so final result of the single batch file, I would like to see if i run :

  loop_ffmpeg_urlvideos_into_3_jpegsets_task.bat video_urls.txt

  output are all those 3 image sets extracted from every row of the url array under one folder if there are [n] lines of vidoes in the video_urls.txt :

  video1_firstframe.jpg video1_middleframe.jpg video1_lastframe.jpg
  video2_firstframe.jpg video2_middleframe.jpg video3_lastframe.jpg
  ......
  video[n]_firstframe.jpg video[n]_middleframe.jpg video[n]_lastframe.jpg

  I’m able to go through the second and third step by using php-ffmpeg library,

  $ffmpeg = FFMpeg\FFMpeg::create();
  
  $video = $ffmpeg->open($video_url);    
  
  $duration = $ffmpeg->getFFProbe()->format($video_url)->get('duration');
  
  
  
  $breakpoints = [0,$duration/2,$duration];
  
  
  
  foreach( $breakpoints as $key=>$breakpoint ):
  
        $jpgfname ="video[$key].jpg"; 
  
        $video
  
         ->frame(FFMpeg\Coordinate\TimeCode::fromSeconds($breakpoint))
  
        ->save( $yoursavepath.'/'.$jpgfname );          
  
  endforeach; 

  but I think it would be greater if all these can be achieved via ffmpeg command line doing 3 steps together.
  so just to loop video_urls from single txt file, and
  run windows bat file at background one time to extract all image sets i wanted without using other 3rd party libraries which might introduce more dependencies on the configuration of [local/remote] server + switching interface from command line CMD.exe to web browser.

• Place attribute_deprecated in the right position for struct declarations

  22 février 2017, par Diego Biurrun

  Place attribute_deprecated in the right position for struct declarations
  libavcodec/vaapi.h:58:1 : warning : attribute ’deprecated’ is ignored, place it after "struct" to apply attribute to type declaration [-Wignored-attributes]
  

  • [DBH] libavcodec/vaapi.h
  • [DBH] libavcodec/xvmc.h

• EXTRACT SUBTITLES POSITION ONLY ON SRT FILE OR SIMILAR

  20 septembre 2019, par user3449922

  I have some mkv files with subtitles inside in PGS format.

  So I need to extract a text file like :

  //
  1
  00:00:05,569 —> 00:00:07,569

  2
  00:00:07,820 —> 00:00:11,940
  //

  or another format that include when start and finish a dialogue (subtitle).

  I don’t need the words but only the exact positions.

  Is not possbile save it in srt file becouse PGS is a image file.

  There is some command line utility (ffmpeg or other) that can do it ?

  Best Regards