For this tip, you’ll need mencoder, ffmpeg and php installed. Only tested on Linux.

I’ve a load of videos, because I don’t like deleting anything in case I want to watch it again later (hoarding!).

I’ve three 1TB drives stuffed full of what I’ve collected over the last 20 years, but still I keep running out of room.

So, choice – buy more drives, or shrink what I have? I chose to shrink what I have, because I’m totally happy with VHS-quality video in stereo – I don’t need to watch fan-subbed Bleach in HD in 5.1 surround sound!

So, I wrote a script which will search the current directory (and its sub-directories) for all videos, will figure out their bit-rates, and will shrink them if they’re too large.

The script also reduces the videos so they match a maximum width and height.

It’s written in such a way that it will start with the most wasteful files (those that are taking up the most room), and work from that to the least wasteful.

It’s also written to only do 100 videos in a run. There’s no point shrinking absolutely every video you have, as most will probably save only a few kilobytes. The script does 100 of the most wasteful ones.

Of course, you could always run it again and again afterwards, and it should choose different videos each time to shrink.

How to use: copy the file into the root directory of your video repository. Go to that directory. Type “php shrink.php” into the console. Now go do something for a few days. Simple as that!

<?php

$maxwidth=624;
$maxheight=352;

function list_files($dir, $list) {
  $files=new DirectoryIterator($dir);
  foreach ($files as $f) {
    if ($f->isDot()) {
      continue;
    }
    $fname=$f->getPathname();
    if (is_dir($fname)) {
      $list=list_files($fname, $list);
      continue;
    }
    if (in_array(
      strtolower(preg_replace('/.*\./', '', $fname)),
      array('avi', 'mpg', 'mp4')
    )) {
      if (preg_match('/-shrink.avi$/', $fname)) {
        unlink($fname);
        continue;
      }
      $arr2=array();
      // { get duration of video
        exec('ffmpeg -i "'.$fname.'" 2>&1 | grep Duration', $arr2);
        $bits=explode(':', preg_replace('/.*Duration: ([^,]*),.*/', '\1', $arr2[0]));
        if (count($bits)!=3) {
          echo 'failed to get duration of "'.$fname.'"'."\n";
        }
        $duration=(int)preg_replace('/^0/', '', $bits[2])
          +((int)preg_replace('/^0/', '', $bits[1]))*60
          +((int)preg_replace('/^0/', '', $bits[0]))*3600;
      // }
      // { get width/height of video
        exec('ffmpeg -i "'.$fname.'" 2>&1 | grep "Video:"', $arr2);
        $bits=explode('x', preg_replace('/.*\s([0-9]+x[0-9]+)[\s,].*/', '\1', $arr2[1]));
        if (count($bits)!=2) {
          echo 'failed to get dimensions of "'.$fname.'"'."\n";
          continue;
        }
        $width=$bits[0];
        $height=$bits[1];
      // }
      $fsize=filesize($fname);
      $bps=$fsize/$duration;
      echo '.';
      $list[]=array($bps, $fsize, $width, $height, $duration, $fname);
    }
  }
  return $list;
}

echo "\ngetting file details\n";
$list=list_files('.', array());

echo "\nsorting by bits per second\n";
for ($i=0; $i<count($list)-1; ++$i) {
  echo '.';
  for ($j=$i+1; $j<count($list); ++$j) {
    if ($list[$j][0]>$list[$i][0]) {
      $tmp=$list[$j];
      $list[$j]=$list[$i];
      $list[$i]=$tmp;
    }
  }
}

echo "\nshrinking\n";
for ($i=0; $i<100&&$i<count($list); ++$i) {
  $fname=$list[$i][5];
  echo $fname."\nold size: ".$list[$i][1]."\n";
  @unlink('divx2pass.log');
  $resize='';
  if ($list[$i][2]>$maxwidth || $list[$i][3]>$maxheight) {
    $rx=$maxwidth/$list[$i][2];
    $ry=$maxheight/$list[$i][3];
    $ratio=$rx<$ry?$rx:$ry;
    $width=(int)($list[$i][2]*$ratio);
    $height=(int)($list[$i][3]*$ratio);
    $resize='-vf scale='.$width.':'.$height;
  }
  exec('mencoder "'.$fname.'" -ovc xvid -xvidencopts bvhq=1:chroma_opt:quan'
    .'t_type=mpeg:bitrate=400:pass=1 '.$resize.' -alang en -oac copy -o "'
    .$fname.'-shrink.avi" 2>&1');
  exec('mencoder "'.$fname.'" -ovc xvid -xvidencopts bvhq=1:chroma_opt:quan'
    .'t_type=mpeg:bitrate=400:pass=2 '.$resize.' -alang en -oac mp3lame '
    .' -o "'.$fname.'-shrink.avi" 2>&1');
  echo 'new size: '.filesize($fname.'-shrink.avi')."\n\n";
  if (filesize($fname.'-shrink.avi')<$list[$i][1]) {
    unlink($fname);
    rename($fname.'-shrink.avi', preg_replace('/\.[^\.]*$/', '.avi', $fname));
  }
  else {
    unlink($fname.'-shrink.avi');
  }
}

I tend to keep a log tailing in one console while working in another.

tail is a Linux program that displays the last few lines of a file. If you run tail -f /var/log/httpd/error_log as root, or as your normal user if you’ve set the right permissions, then you will see any errors as they are added to the log.

However, I also tend to get immersed in my coding and not notice any errors until they cause a visual problem.

What I needed was a program that would watch my log, and beep to get my attention if an error was added.

This article explains how to set that up in Fedora.

First, install the program swatch:

[root@ryuk ~]# yum install swatch

Now create /etc/init.d/swatch, which is the startup/shutdown script for the logger:

#!/bin/sh

case "$1" in
'start')
                /usr/bin/swatch --daemon --config-file=/etc/swatch-httpd-errors --tail-file=/var/log/httpd/error_log --pid-file=/var/run/swatch-httpd-errors.pid
                ;;
'stop')
                PID=`cat /var/run/swatch-httpd-errors.pid`
                kill -9 $PID
                ;;
*)
                echo "Usage: $0 { start | stop }"
                ;;
esac
exit 0

Notice the two file locations in the /usr/bin/swatch command – the configuration file location, and the log file to be tailed.

Make the file executable:

[root@ryuk ~]# chmod +x /etc/init.d/swatch

Now create the configuration file, /etc/swatch-httpd-errors:

watchfor /PHP Parse error|PHP Fatal error/
        exec mplayer /home/kae/sounds/beep-8.wav > /dev/null 2> /dev/null

You can have swatch do basically anything, from sending an email, to flashing lights in your face if you have them connected to the computer. All I wanted was a little beep.

Change the exec command to whatever your want.

I started experimenting by having Arnold Schwarzenegger yell “What the hell are you doing??” at me, but that could get annoying for other people. In the end, I changed it to a beep – a very /short/ beep. More of a tick than a beep.

Now start up the daemon:

[root@ryuk ~]# /etc/init.d/swatch start

Create a php script with an error in it, and view it in your browser. You should get a satisfying beep.

If you want to have this run automatically when the laptop boots, add the above command to the /etc/rc.local file.