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• ffmpeg2.4 transcoding.c avfilter

  18 novembre 2014, par rosen

  编译时：

  --enable-avfilter \
  
  --enable-nonfree \
  
  --disable-filters \
  
  --enable-filter=movie \
  
  --enable-filter=overlay \
  
  --enable-filter=null \
  
  --enable-filter=anull \
  
  --enable-filter=scale \
  
  --enable-filter=rotate \

  运行例子的

  filter_spec = "null"; /* passthrough (dummy) filter for video */

  可以编码出视频
  但是使用

  filter_spec = "movie=/storage/emulated/0/image.png [wm]; [in][wm] overlay=10:10 [out]";

  执行到例子transcoding.c的

  if ((ret = avfilter_graph_parse_ptr(filter_graph, filter_spec,

  &inputs, &outputs, NULL)) < 0)
  goto end ;

  就报错：
  Invalid data found when processing input
  @bbcallen
  求你帮我看一下，这个就是我想实现的一个加水印的demo。

• FFmpegPHP get thumbnail from external URL

  22 janvier 2013, par jValdron

  I'm trying to create thumbnails from external videos, mostly MP4s and FLVs. I'm using FFmpegPHP. I already have the thumbnail generation working fine, however, I need to load the video entirely on my server first. Would it be possible to stream only a small part of the video then extract the thumbnail from that ?

  Here's the code I have so far :

  require_once PRIV . 'Vendor/FFmpegPHP/FFmpegAutoloader.php';
  
  
  
  // Download the whole video.
  
  $video = file_get_contents($_PUT['video']);
  
  $file = 'path_to_cache';
  
  file_put_contents($file, $video);
  
  
  
  $movie = new FFmpegMovie($file);
  
  
  
  // Generate the thumbnail.
  
  $thumb = $movie->getFrame($movie->getFrameCount() / 2);
  
  $thumb->resize(320, 240);
  
  imagejpeg($thumb->toGDImage(), 'path_to_thumb');

  Anyone has a suggestion ?

  EDIT

  As Brad suggested, here is the updated code :

  $file = CACHE . 'moodboard_video_' . rand();
  
  $fh = fopen($file, 'w');
  
  $size = 0;
  
  
  
  curl_setopt($ch, CURLOPT_URL, $_PUT['video']);
  
  curl_setopt($ch, CURLOPT_HEADER, 0);
  
  curl_setopt($ch, CURLOPT_WRITEFUNCTION, function($ch, $data) use($fh, &$size){
  
      $length = fwrite($fh, $data);
  
  
  
      if($length === FALSE) {
  
          return 0;
  
      } else {
  
          $size += $length;
  
      }
  
  
  
      // Downloads 1MB.
  
      return $size < 1024 * 1024 * XXXXXX ? $length : 0;
  
  });
  
  
  
  curl_exec($ch);
  
  
  
  fclose($fh);
  
  curl_close($ch);
  
  
  
  // Create the thumbnail.
  
  $thumb = $movie->getFrame(XXXXXX);
  
  $thumb->resize(static::DEFAULT_THUMBNAIL_WIDTH, $thumb->getHeight() / $thumb->getWidth() * static::DEFAULT_THUMBNAIL_WIDTH);
  
  $image = $thumb->toGDImage();
  
  imagejpeg($image, PRIV . static::THUMBNAILS_PATH . $item->getLastInsertIdentifier() . '_' . static::DEFAULT_THUMBNAIL_WIDTH);

• how to determine the average biterate and peak bitrate of a video using ffmpeg ?

  14 février 2018, par loki

  I don’t understand, when in ffmpeg i do ffmpeg -i <input /> i have :

  Video : hevc (Main) (hev1 / 0x31766568), yuv420p(tv), 1920x1080, 4997 kb/s, 30 fps, 30 tbr, 998795.00 tbn, 30 tbc (default)

  it’s show bitrate : 4997 kb/s BUT the size of the file is 114915563 bytes for a duration of 179 secondes. when i do math i have 114915563 / 179 = 641986 bytes/s = 642 kb/s :(

  What did i miss ? how to retrieve the average bitrate of a movie and the peak bitrate of a movie ?