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• Revision e890c2579b : add a context tree structure to encoder This patch sets up a quad_tree structur

  17 avril 2014, par Jim Bankoski

  Changed Paths :
   Modify /vp9/encoder/vp9_block.h

  
   Add /vp9/encoder/vp9_context_tree.c

  
   Add /vp9/encoder/vp9_context_tree.h

  
   Modify /vp9/encoder/vp9_encodeframe.c

  
   Modify /vp9/encoder/vp9_firstpass.c

  
   Modify /vp9/encoder/vp9_onyx_if.c

  
   Modify /vp9/vp9cx.mk

  
  
  add a context tree structure to encoder

  This patch sets up a quad_tree structure (pc_tree) for holding all of
  pick_mode_context data we use at any square block size during encoding
  or picking modes. That includes contexts for 2 horizontal and 2 vertical
  splits, one none, and pointers to 4 sub pc_tree nodes corresponding
  to split. It also includes a pointer to the current chosen partitioning.

  This replaces code that held an index for every level in the pick
  modes array including : sb_index, mb_index,
  b_index, ab_index.

  These were used as stateful indexes that pointed to the current pick mode
  contexts you had at each level stored in the following arrays

  array ab4x4_context[][][],
  sb8x4_context[][][], sb4x8_context[][][], sb8x8_context[][][],
  sb8x16_context[][][], sb16x8_context[][][], mb_context[][], sb32x16[][],
  sb16x32[], sb32_context[], sb32x64_context[], sb64x32_context[],
  sb64_context

  and the partitioning that had been stored in the following :
  b_partitioning, mb_partitioning, sb_partitioning, and sb64_partitioning.

  Prior to this patch before doing an encode you had to set the appropriate
  index for your block size ( switch statement), update it ( up to 3
  lookups for the index array value) and then make your call into a recursive
  function at which point you'd have to call get_context which then
  had to do a switch statement based on the blocksize, and then up to 3
  lookups based upon the block size to find the context to use.

  With the new code the context for the block size is passed around directly
  avoiding the extraneous switch statements and multi dimensional array
  look ups that were listed above. At any level in the search all of the
  contexts are local to the pc_tree you are working on (in ?).

  In addition in most places code that used to call sub functions and
  then check if the block size was 4x4 and index was > 0 and return
  now don't preferring instead to call the right none function on the inside.

  Change-Id : I06e39318269d9af2ce37961b3f95e181b57f5ed9

• php rename of ffmpeg deleted/reduced my video files to 20Kb

  29 octobre 2018, par ax.falcon

  I’m not sure what I did but somehow when I ran my code it deleted my video files, that is, it reduced each video file to a mere 20-40Kb.

  I’m using a directory tree iterator to go through the selected folder and iterate all the files and subfolders in there, with commands for each. I’m only doing the files at this stage, and the code simply

  1. renames the video file so that it has no spaces in it’s name
  2. extracts a thumbnail using ffmpeg and places it in the videos directory
  3. inserts data in to database for displaying on a website.

  Now I was able to use it once, and it worked save for 2 video files that I had been using for testing. For some reason those files were deleted. I tried running it again and it deleted all the videos.

  What might be the problem ?

  $mysqli = new mysqli("localhost", "refit_2_admin", "asd123", "refit_2");
  
  if($mysqli->connect_error)
  
  {
  
      exit('Error db');
  
  }
  
  mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
  
  $mysqli->set_charset("utf8mb4");
  
  $_SESSION['mysqli'] = $mysqli;
  
  
  
  // DIRECTORY
  
  
  
  $dir = 'videos';
  
  
  
  $it = new RecursiveTreeIterator(new RecursiveDirectoryIterator($dir, RecursiveDirectoryIterator::SKIP_DOTS)); 
  
  foreach($it as $path => $branch)
  
  {
  
      if(is_dir($path)) // if is a directory
  
      {
  
          // echo something
  
      }
  
      if(is_file($path)) // if is a file
  
      {
  
          $schism = pathinfo($path);
  
          $string = str_replace(' ', '_', $schism['filename']);
  
  
  
          //$string = str_replace($replace, $with, $string);
  
          rename($path, $dir.'\\'.$string.'.mp4');
  
  
  
          $ffmpeg = 'ffmpeg.exe';
  
  
  
          $video = dirname(__FILE__) . '\\'.$dir.'\\'.$string.'.mp4';
  
          //echo ''.$video.'<br />';
  
  
  
          $image = dirname(__FILE__) . '\\'.$dir.'\\'.$string.'.jpg';
  
          //echo ''.$image.'<br />';
  
  
  
          $second = 1;
  
  
  
          /*$cmd = "$ffmpeg -i $video 2>&amp;1";
  
          if (preg_match('/Duration: ((\d+):(\d+):(\d+))/s', `$cmd`, $time)) {
  
              $total = ($time[2] * 3600) + ($time[3] * 60) + $time[4];
  
              $second = rand(1, ($total - 1));
  
          }*/
  
  
  
          $cmd = "$ffmpeg -i $video -deinterlace -an -ss $second -t 00:00:01 -r 1 -y -vcodec mjpeg -f mjpeg $image 2>&amp;1";
  
          $return = `$cmd`;
  
  
  
          $video_title = substr($schism['filename'], 0, -5);
  
          $video_filename = $schism['filename'].'.mp4';
  
          $video_thumbnail = $schism['filename'].'.jpg';
  
          $video_include = basename(__DIR__);
  
          // Insert
  
          $stmt = $mysqli->prepare("INSERT INTO videos (video_title, video_filename, video_include, video_tags, video_thumbnail) VALUES (?, ?, ?, ?, ?)");
  
          $stmt->bind_param("sssss", $video_title, $video_filename, $dir, $video_title, $video_thumbnail);
  
          $stmt->execute();
  
          $stmt->close();
  
      }
  
  
  
  }

• Can FFMPEG be used to change the transparency of a single PNG ?

  19 juillet 2020, par Chameleon

  I know that FFMPEG can manipulate transparency using fade in/fade out over a series of frames. I just haven't found a way to generate a png with a specified transparency setting.

  


  I am in the process of creating a lot (20 in first set) of procedurally-generated videos. Each video requires several starts and stops, where with each stop, a png overlay describing what is seen will be displayed for several (actual number TBD, and may vary) frames. I'd like each overlay to fade in over x frames, display for y frames at full opacity and then fade out over y frames. The documentation on FFMPEG really sucks at explaining fade effects, and no one I've found showing usage actually explains what all of the parameters do.

  


  The original sources for the videos are CGI png frames with a transparent background. I will be making the descriptive overlays with transparent backgrounds (same resolution as the CGI frames) - I'm really hoping to not have to manually save each overlay (8 overlays per video at a minimum) with 4 to 6 (or more) transparency settings - The company is being real indecisive as to the length of the fade in/out or the "hang time" of the descriptive overlays.

  


  I have already created a Python script that uses FFMPEG to place overlays on specific frames, then uses FFMPEG to stitch all frames into a single video, adds a background to the video and then places the company's watermark on the video. It already manages the key frames and what images should be overlaid (and for how many frames). It is working well, but the company doesn't like the lack of fade. I already have the framework in place to manage the fade in/out duration (I'm just missing the answer to this question). I created the script because I have no doubt that I'll have to generate the final output on the first couple of videos a number of times to appease the stakeholders.

  


  I'm really hoping to find a fairly easy way to hand FFMPEG a png with a transparent background and have FFMPEG hand me a copy of the image whose non-transparent part is now "x percent" transparent (or "y percent" opaque). I know from failed attempts that FFMPEG doesn't choke trying to make a region more than 100% transparent.

  


  It's a real pain to get approval to install new software on the workstation, so I'm not actually interested in any suggestion that doesn't use FFMPEG or a pretty vanilla Python installation. - It's not that the other software might not be useful, it just means that if other software is needed, I'll have to manually create the frames.