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• Python get Audio/Video frames separately from video file

  3 juillet 2016, par AlvaroAV

  What i’m trying to do :

  Hi !

  I’m trying to store the Video and Audio information from a video file. I would like to store video frames and audio frames separately in different variables.

  My intention is to manage video/files and do some actions with the audio and video frame list, but to do what I’m plannign to do I need to store this audio/video frames separately. I’ve read a lot of questions in StackOverflow about python and audio/video managing.

  Most people recommend to use OpenCV or ffmpeg to manage videos. I saw some scripts using these libraries to get video(only video) frames, but none of them are getting audio, most of them are just getting video frames and save them as RGB images. I also check some scripts where people get audio frames from a mp3 file, but I’m not sure if you can do that in a video file

  Most important thing to me is to know the best way to manage video and audio separately. I’m not looking for people to do my code, just asking to point me in a good direction.

  One of the things I’m trying to do is to send this information via socket, but as I said I need the audio and video frames to be in separated variables (yes, i’m wondering about an stream app, but that’s not the only thing I’m trying to do)

  I know I should give more information, and maybe show some code, but I don’t have any concret code I tried some things, but I’ve never been capable to separate audio and video. I know that each format has his own encryption, and at the end I decided to use "mp4" as video format but I don’t know neither if this is the best format for what I’m trying to do.

  Resume :

  Is openCV the best way to manage video and audio separately ?

  Wich is the easiest way to separate video and audio frames ? Is it possible ?

  Wich is the best documentation I should read to learn about video/audio management ?

  I would like to do the things with my own code, and use in the less way possible openCV or other libraries.

  My "basic" idea is to get a "list" of audio and video frames, and then I would like to do some operations, but right now I can’t find the best way for me to manage a vide using python. I even wonder if could be possible to manage a video as raw data

  I need to know wich is the best library to manage videos using python, for me the best library, will be the one that allows me to manage the videos more "freely"

  I’ve already checked :

  I’ve read too many questions on this theme, the most recent are :

  How to extract audio from video file

  Split audio video separately from given video using MLT

  Embed audio video in python gui

• PHP FFmpeg video aspect ratio problem [SOLVED]

  29 août 2011, par Herr Kaleun

  i compiled the new version of FFMPEG and the padding commands have been deprecated.
  As i try to get familiar with the new -vf pad= commands, i want to ask, how can i
  convert a video without changing it's aspect ratio.

  I've checked numerous solutions from stackoverflow, nothing seemed to work.
  Can someone, please post a working PHP example or cmd line. I would be VERY happy.

  Please note that the videos in question, could be 4:3 and also be 16:9

  Let's say, i convert a 16:9 video to 640x480 format. It will need some bars at
  the top and at the bottom. That is what i want to do.

  Thanks

  EDIT :
  I solved the problem on my own. The FFmpeg documentation is a little bit weird so
  you have to experiment yourself a little bit.
  The padding formula is like :

      $pad_horizontal = $target_width     + $pad_left + $pad_right;
  
      $pad_vertical   = $target_height;
  
      // blah
  
      $command .= " -vf pad=$pad_horizontal:$pad_vertical:". $pad_left .":". $pad_top  .":black";

  Pay special attention at the $pad_vertical part since the paddings there are better
  not added so that the padding calculation of ffmpeg is not broken.

  Here is the full source code to the demo

  <?
  
  
  
      /***********************************************************************************
  
      get_dimensions()
  
  
  
      Takes in a set of video dimensions - original and target - and returns the optimal conversion
  
      dimensions.  It will always return the smaller of the original or target dimensions.
  
      For example: original dimensions of 320x240 and target dimensions of 640x480.
  
      The result will be 320x240 because converting to 640x480 would be a waste of disk
  
      space, processing, and bandwidth (assuming these videos are to be downloaded).
  
  
  
      @param $original_width:     The actual width of the original video file which is to be converted.
  
      @param $original_height:    The actual height of the original video file which is to be converted.
  
      @param $target_width:       The width of the video file which we will be converting to.
  
      @param $target_height:      The height of the video file which we will be converting to.
  
      @param $force_aspect:       Boolean value of whether or not to force conversion to the target's
  
                            aspect ratio using padding (so the video isn't stretched).  If false, the
  
                            conversion dimensions will retain the aspect ratio of the original.
  
                            Optional parameter.  Defaults to true.
  
      @return: An array containing the size and padding information to be used for conversion.
  
                  Format:
  
                  Array
  
                  (
  
                      [width] => int
  
                      [height] => int
  
                      [padtop] => int // top padding (if applicable)
  
                      [padbottom] => int // bottom padding (if applicable)
  
                      [padleft] => int // left padding (if applicable)
  
                      [padright] => int // right padding (if applicable)
  
                  )
  
      ***********************************************************************************/
  
      function get_dimensions($original_width,$original_height,$target_width,$target_height,$force_aspect)
  
      {
  
          if(!isset($force_aspect))
  
          {
  
              $force_aspect = true;
  
          }
  
          // Array to be returned by this function
  
          $target = array();
  
          $target['padleft'] = 0;
  
          $target['padright'] = 0;
  
          $target['padbottom'] = 0;
  
          $target['padtop'] = 0;
  
  
  
  
  
  
  
          // Target aspect ratio (width / height)
  
          $aspect = $target_width / $target_height;
  
          // Target reciprocal aspect ratio (height / width)
  
          $raspect = $target_height / $target_width;
  
  
  
          if($original_width/$original_height !== $aspect)
  
          {
  
              // Aspect ratio is different
  
              if($original_width/$original_height > $aspect)
  
              {
  
                  // Width is the greater of the two dimensions relative to the target dimensions
  
                  if($original_width < $target_width)
  
                  {
  
                      // Original video is smaller.  Scale down dimensions for conversion
  
                      $target_width = $original_width;
  
                      $target_height = round($raspect * $target_width);
  
                  }
  
                  // Calculate height from width
  
                  $original_height = round($original_height / $original_width * $target_width);
  
                  $original_width = $target_width;
  
                  if($force_aspect)
  
                  {
  
                      // Pad top and bottom
  
                      $dif = round(($target_height - $original_height) / 2);
  
                      $target['padtop'] = $dif;
  
                      $target['padbottom'] = $dif;
  
                  }
  
              }
  
              else
  
              {
  
                  // Height is the greater of the two dimensions relative to the target dimensions
  
                  if($original_height < $target_height)
  
                  {
  
                      // Original video is smaller.  Scale down dimensions for conversion
  
                      $target_height = $original_height;
  
                      $target_width = round($aspect * $target_height);
  
                  }
  
                  //Calculate width from height
  
                  $original_width = round($original_width / $original_height * $target_height);
  
                  $original_height = $target_height;
  
                  if($force_aspect)
  
                  {
  
                      // Pad left and right
  
                      $dif = round(($target_width - $original_width) / 2);
  
                      $target['padleft'] = $dif;
  
                      $target['padright'] = $dif;
  
                  }
  
              }
  
          }
  
          else
  
          {
  
              // The aspect ratio is the same
  
              if($original_width !== $target_width)
  
              {
  
                  if($original_width < $target_width)
  
                  {
  
                      // The original video is smaller.  Use its resolution for conversion
  
                      $target_width = $original_width;
  
                      $target_height = $original_height;
  
                  }
  
                  else
  
                  {
  
                      // The original video is larger,  Use the target dimensions for conversion
  
                      $original_width = $target_width;
  
                      $original_height = $target_height;
  
                  }
  
              }
  
          }
  
          if($force_aspect)
  
          {
  
              // Use the target_ vars because they contain dimensions relative to the target aspect ratio
  
              $target['width'] = $target_width;
  
              $target['height'] = $target_height;
  
          }
  
          else
  
          {
  
              // Use the original_ vars because they contain dimensions relative to the original's aspect ratio
  
              $target['width'] = $original_width;
  
              $target['height'] = $original_height;
  
          }
  
          return $target;
  
      }
  
  
  
      function get_vid_dim($file)
  
      {
  
          $command = '/usr/bin/ffmpeg -i ' . escapeshellarg($file) . ' 2>&1';
  
          $dimensions = array();
  
          exec($command,$output,$status);
  
          if (!preg_match(&#39;/Stream #(?:[0-9\.]+)(?:.*)\: Video: (?P<videocodec>.*) (?P<width>[0-9]*)x(?P<height>[0-9]*)/&#39;,implode("\n",$output),$matches))
  
          {
  
              preg_match(&#39;/Could not find codec parameters \(Video: (?P<videocodec>.*) (?P<width>[0-9]*)x(?P<height>[0-9]*)\)/&#39;,implode("\n",$output),$matches);
  
          }
  
          if(!empty($matches[&#39;width&#39;]) &amp;&amp; !empty($matches[&#39;height&#39;]))
  
          {
  
              $dimensions[&#39;width&#39;] = $matches[&#39;width&#39;];
  
              $dimensions[&#39;height&#39;] = $matches[&#39;height&#39;];
  
          }
  
          return $dimensions;
  
      }
  
  
  
  
  
      $command    = &#39;/usr/bin/ffmpeg -i &#39; . $src . &#39; -ab 96k -b 700k -ar 44100 -f flv -s &#39; . &#39;640x480 -acodec mp3 &#39;. $video_output_dir . $video_filename . &#39; 2>&amp;1&#39;;
  
  
  
  
  
      define( &#39;VIDEO_WIDTH&#39;,      &#39;640&#39; );
  
      define( &#39;VIDEO_HEIGHT&#39;,     &#39;480&#39; );
  
  
  
      $src_1              = getcwd() .&#39;/&#39;. &#39;test_video1.mpeg&#39;;
  
      $video_filename1    = &#39;video1.flv&#39;;
  
  
  
      $src_2              = getcwd() .&#39;/&#39;. &#39;test_video2.mp4&#39;;
  
      $video_filename2    = &#39;video2.flv&#39;;
  
  
  
      $src_3              = getcwd() .&#39;/&#39;. &#39;test_video3.mp4&#39;;
  
      $video_filename3    = &#39;video3.flv&#39;;
  
  
  
      convert_video( $src_1, $video_filename1 );
  
      convert_video( $src_2, $video_filename2 );
  
      convert_video( $src_3, $video_filename3 );
  
  
  
      function convert_video( $src = &#39;&#39;, $video_filename = &#39;&#39; )
  
      {
  
  
  
          $video_output_dir   = getcwd() .&#39;/&#39;;
  
  
  
          @unlink ( $video_output_dir . $video_filename );
  
  
  
          $original   = get_vid_dim($src);
  
          $target     = get_dimensions( $original[&#39;width&#39;], $original[&#39;height&#39;], VIDEO_WIDTH, VIDEO_HEIGHT, TRUE );
  
  
  
          echo &#39;<pre>&#39;;
  
          print_r( $original );
  
          echo &#39;</pre>&#39;;
  
          echo &#39;<pre>&#39;;
  
          print_r( $target );
  
          echo &#39;</pre>&#39;;
  
  
  
  
  
  
  
          $target_width   = $target[&#39;width&#39;];
  
          $target_height  = $target[&#39;height&#39;];
  
  
  
          $pad_left       = $target[&#39;padleft&#39;];
  
          $pad_right      = $target[&#39;padright&#39;];
  
          $pad_bottom     = $target[&#39;padbottom&#39;];
  
          $pad_top        = $target[&#39;padtop&#39;];
  
  
  
          $pad_horizontal = $target_width     + $pad_left + $pad_right;
  
          $pad_vertical   = $target_height; //    + $pad_top + $pad_bottom;
  
  
  
  
  
          $command = &#39;/usr/bin/ffmpeg -i &#39; . $src;
  
  
  
          // $command .= " -s {$target_width}x{$target_height} ";
  
  
  
          $command .= " -vf pad=$pad_horizontal:$pad_vertical:". $pad_left .":". $pad_top  .":black";
  
  
  
          $command .= &#39; -ab 96k -b 700k -ar 44100&#39;;
  
          $command .= &#39; -f flv &#39;;
  
          $command .= &#39; -qscale 4&#39;;
  
  
  
          $command .= &#39; -ss 30&#39;;
  
          $command .= &#39; -t 5&#39;;
  
  
  
          $command .= &#39; -ac 2 -ab 128k -qscale 5 &#39;;
  
          $command .= &#39; &#39; . $video_output_dir . $video_filename;
  
  
  
  
  
          exec( $command, $output, $status );
  
  
  
          echo &#39;<pre>&#39;;
  
          print_r( $command );
  
          echo &#39;</pre>&#39;;
  
  
  
          if ( $status == 0 ) 
  
          {
  
              echo &#39;<br />Convert OK. <br />&#39;;
  
          }
  
          else
  
          {
  
              echo &#39;<pre>&#39;;
  
              print_r( $output );
  
              echo &#39;</pre>&#39;;
  
          }
  
  
  
          echo &#39;<br />&#39;;
  
          echo &#39;<br />&#39;;
  
  
  
      }
  
  
  
  
  
  
  
  
  
  
  
  ?>
  
  </height></width></videocodec></height></width></videocodec>

  Thank you and have fun :)

• ffplay : fix a crash caused by aborting the video queue

  25 août 2011, par Marton Balint

  ffplay : fix a crash caused by aborting the video queue