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• How to speed up thumbnail generation for video files using FFMPEG on MIPS

  6 juillet 2012, par Spottsworth

  I'm using the following command to get a thumbnail from a video file. It uses the seek option to grab a thumbnail. The problem is that this command takes up quite some time especially with certain containers such as MPEG-2 TS. (As much as 40 seconds). If I vary the point (duration) at which I want to grab the thumbnail , it does not seem to have an impact on the time taken. Of course when I run this on my Linux workstation, it hardly takes 2 seconds to produce the thumbnail. Any suggestions to speed up the process on my MIPS board ?

  ./ffmpeg -ss 18 -i input.ts -vf select='eq(pict_type\,PICT_TYPE_I)' -vframes 1 -an -s 150x100 thumb.jpg

• php stream any mp4

  3 avril 2012, par GRaecuS

  I'm developing a web app that converts videos and allows to play them through Flowplayer.

  On the current status, I use ffmpeg to convert the videos to mp4 and qtfaststart to fix their metadata for streaming. Everything is working smoothly as I can download any converted mp4 and view it correctly.

  For serving the videos to Flowplayer, I use a php file which contains the following (summarized) code :

  header("Content-Type: {$mediatype}");
  
  
  
  if ( empty($_SERVER['HTTP_RANGE']) )
  
  {
  
      if ( $filetype == 'flv' && $seekPos != 0 )
  
      {
  
          header("Content-Length: " . ($filesize + 13));
  
          print('FLV');
  
          print(pack('C', 1));
  
          print(pack('C', 1));
  
          print(pack('N', 9));
  
          print(pack('N', 9));
  
      }
  
      else
  
      {           
  
          header("Content-Length: {$filesize}");
  
      }
  
  
  
      $fh = fopen($filepath, "rb") or die("Could not open file: {$filepath}");
  
  
  
      # seek to requested file position
  
      fseek($fh, $seekPos);
  
  
  
      # output file
  
      while(!feof($fh))
  
      {
  
          # output file without bandwidth limiting
  
          echo fread($fh, $filesize);
  
      }
  
      fclose($fh);
  
  }
  
  else //violes rfc2616, which requires ignoring  the header if it's invalid
  
  {   
  
      $fp = @fopen($file, 'rb');
  
  
  
      $size   = filesize($file); // File size
  
      $length = $size;           // Content length
  
      $start  = 0;               // Start byte
  
      $end    = $size - 1;       // End byte
  
      // Now that we've gotten so far without errors we send the accept range header
  
      /* At the moment we only support single ranges.
  
       * Multiple ranges requires some more work to ensure it works correctly
  
       * and comply with the spesifications: http://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html#sec19.2
  
       *
  
       * Multirange support annouces itself with:
  
       * header('Accept-Ranges: bytes');
  
       *
  
       * Multirange content must be sent with multipart/byteranges mediatype,
  
       * (mediatype = mimetype)
  
       * as well as a boundry header to indicate the various chunks of data.
  
       */
  
      header("Accept-Ranges: 0-$length");
  
      // header('Accept-Ranges: bytes');
  
      // multipart/byteranges
  
      // http://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html#sec19.2
  
      if (isset($_SERVER['HTTP_RANGE']))
  
      {
  
          $c_start = $start;
  
          $c_end   = $end;
  
          // Extract the range string
  
          list(, $range) = explode('=', $_SERVER['HTTP_RANGE'], 2);
  
          // Make sure the client hasn't sent us a multibyte range
  
          if (strpos($range, ',') !== false)
  
          {
  
              // (?) Shoud this be issued here, or should the first
  
              // range be used? Or should the header be ignored and
  
              // we output the whole content?
  
              header('HTTP/1.1 416 Requested Range Not Satisfiable');
  
              header("Content-Range: bytes $start-$end/$size");
  
              // (?) Echo some info to the client?
  
              exit;
  
          }
  
          // If the range starts with an '-' we start from the beginning
  
          // If not, we forward the file pointer
  
          // And make sure to get the end byte if spesified
  
          if ($range0 == '-')
  
          {
  
  
  
              // The n-number of the last bytes is requested
  
              $c_start = $size - substr($range, 1);
  
          }
  
          else
  
          {
  
              $range  = explode('-', $range);
  
              $c_start = $range[0];
  
              $c_end   = (isset($range[1]) && is_numeric($range[1])) ? $range[1] : $size;
  
          }
  
          /* Check the range and make sure it's treated according to the specs.
  
           * http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
  
           */
  
          // End bytes can not be larger than $end.
  
          $c_end = ($c_end > $end) ? $end : $c_end;
  
          // Validate the requested range and return an error if it's not correct.
  
          if ($c_start > $c_end || $c_start > $size - 1 || $c_end >= $size)
  
          {
  
              header('HTTP/1.1 416 Requested Range Not Satisfiable');
  
              header("Content-Range: bytes $start-$end/$size");
  
              // (?) Echo some info to the client?
  
              exit;
  
          }
  
          $start  = $c_start;
  
          $end    = $c_end;
  
          $length = $end - $start + 1; // Calculate new content length
  
          fseek($fp, $start);
  
          header('HTTP/1.1 206 Partial Content');
  
      }
  
  
  
      // Notify the client the byte range we'll be outputting
  
      header("Content-Range: bytes $start-$end/$size");
  
      header("Content-Length: $length");
  
  
  
      // Start buffered download
  
      $buffer = 1024 * 8;
  
      while(!feof($fp) && ($p = ftell($fp)) <= $end)
  
      {
  
          if ($p + $buffer > $end)
  
          {
  
              // In case we're only outputtin a chunk, make sure we don't
  
              // read past the length
  
              $buffer = $end - $p + 1;
  
          }
  
          set_time_limit(0); // Reset time limit for big files
  
          echo fread($fp, $buffer);
  
          flush(); // Free up memory. Otherwise large files will trigger PHP's memory limit.
  
      }
  
  
  
      fclose($fp);
  
  }

  Unfortunately, it is working only for the majority of the videos. For some of them, Flowplayer keeps returning Error 200, even though they were encoded correctly.

  How can I fix this ? Is it a coding problem or those videos are faulty ?

• creating thumbnail on mips using FFMPEG is quite slow for some containers

  6 juillet 2012, par Spottsworth

  I'm using the following command to get a thumbnail from a video file. It uses the seek option to grab a thumbnail. The problem is that this command takes up quite some time especially with certain containers such as MPEG-2 TS. (As much as 40 seconds). If I vary the point (duration) at which I want to grab the thumbnail , it does not seem to have an impact on the time taken. Of course when I run this on my Linux workstation, it hardly takes 2 seconds to produce the thumbnail. Any suggestions to speed up the process on my MIPS board ?

  ./ffmpeg -ss 18 -i input.ts -vf select='eq(pict_type\,PICT_TYPE_I)' -vframes 1 -an -s 150x100 thumb.jpg