diff --git a/src/MPEG/Audio.php b/src/MPEG/Audio.php
index 05e4ac8..7c92889 100644
--- a/src/MPEG/Audio.php
+++ b/src/MPEG/Audio.php
@@ -271,7 +271,7 @@ final class MPEG_Audio extends MPEG_Audio_Object
    */
   public function getFormattedLengthEstimate()
   {
-    return $this->_formatTime($this->getLengthEstimate());
+    return $this->formatTime($this->getLengthEstimate());
   }
   
   /**
@@ -285,28 +285,7 @@ final class MPEG_Audio extends MPEG_Audio_Object
    */
   public function getFormattedLength()
   {
-    return $this->_formatTime($this->getLength());
-  }
-  
-  /**
-   * Formats given time in seconds into the form of
-   * [hours]:minutes:seconds.milliseconds.
-   * 
-   * @param integer $seconds The time to format, in seconds
-   * @return string
-   */
-  private function _formatTime($seconds)
-  {
-    $milliseconds = round(($seconds - floor($seconds)) * 1000);
-    $seconds = floor($seconds);
-    $minutes = floor($seconds / 60);
-    $hours = floor($minutes / 60);
-    return
-      ($minutes > 0 ?
-       ($hours > 0 ? $hours . ":" .
-        str_pad($minutes % 60, 2, "0", STR_PAD_LEFT) : $minutes % 60) . ":" .
-        str_pad($seconds % 60, 2, "0", STR_PAD_LEFT) : $seconds % 60) . "." .
-        str_pad($milliseconds, 3, "0", STR_PAD_LEFT);
+    return $this->formatTime($this->getLength());
   }
   
   /**
diff --git a/src/MPEG/Object.php b/src/MPEG/Object.php
index 1e4889c..86968ce 100644
--- a/src/MPEG/Object.php
+++ b/src/MPEG/Object.php
@@ -195,6 +195,27 @@ abstract class MPEG_Object
     return 0;
   }
   
+  /**
+   * Formats given time in seconds into the form of
+   * [hours]:minutes:seconds.milliseconds.
+   * 
+   * @param integer $seconds The time to format, in seconds
+   * @return string
+   */
+  protected function formatTime($seconds)
+  {
+    $milliseconds = round(($seconds - floor($seconds)) * 1000);
+    $seconds = floor($seconds);
+    $minutes = floor($seconds / 60);
+    $hours = floor($minutes / 60);
+    return
+      ($minutes > 0 ?
+       ($hours > 0 ? $hours . ":" .
+        str_pad($minutes % 60, 2, "0", STR_PAD_LEFT) : $minutes % 60) . ":" .
+        str_pad($seconds % 60, 2, "0", STR_PAD_LEFT) : $seconds % 60) . "." .
+        str_pad($milliseconds, 3, "0", STR_PAD_LEFT);
+  }
+  
   /**
    * Magic function so that $obj->value will work.
    *
diff --git a/src/MPEG/ProgramStream.php b/src/MPEG/ProgramStream.php
new file mode 100644
index 0000000..453d8b6
--- /dev/null
+++ b/src/MPEG/ProgramStream.php
@@ -0,0 +1,145 @@
+<?php
+/**
+ * PHP Reader Library
+ *
+ * Copyright (c) 2008 The PHP Reader Project Workgroup. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  - Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *  - Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *  - Neither the name of the project workgroup nor the names of its
+ *    contributors may be used to endorse or promote products derived from this
+ *    software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * @package    php-reader
+ * @subpackage MPEG
+ * @copyright  Copyright (c) 2008 The PHP Reader Project Workgroup
+ * @license    http://code.google.com/p/php-reader/wiki/License New BSD License
+ * @version    $Id: MPEG.php 1 2008-07-06 10:43:41Z rbutterfield $
+ */
+
+/**#@+ @ignore */
+require_once("Twiddling.php");
+require_once("MPEG/Object.php");
+/**#@-*/
+
+/**
+ * This class represents a MPEG Program Stream encoded file as described in
+ * ISO/IEC 13818-1 Systems standard.
+ * 
+ * The Program Stream is a stream definition which is tailored for communicating
+ * or storing one program of coded data and other data in environments where
+ * errors are very unlikely, and where processing of system coding, e.g. by
+ * software, is a major consideration.
+ * 
+ * This class only supports the parsing of the play duration.
+ * 
+ * @package    php-reader
+ * @subpackage MPEG
+ * @author     Sven Vollbehr <svollbehr@gmail.com>
+ * @copyright  Copyright (c) 2008 The PHP Reader Project Workgroup
+ * @license    http://code.google.com/p/php-reader/wiki/License New BSD License
+ * @version    $Rev: 1 $
+ * @todo       Full implementation
+ */
+final class MPEG_ProgramStream extends MPEG_Object
+{
+  /** @var integer */
+  private $_length;
+  
+  /**
+   * Constructs the MPEG_ProgramStream class with given file and options.
+   *
+   * @param string|Reader $filename The path to the file, file descriptor of an
+   *                                opened file, or {@link Reader} instance.
+   * @param Array         $options  The options array.
+   */
+  public function __construct($filename, $options = array())
+  {
+    if ($filename instanceof Reader)
+      $reader = &$filename;
+    else
+      $reader = new Reader($filename);
+    
+    parent::__construct($reader, $options);
+    
+    $startCode = 0; $startTime = 0;
+    $pictureCount = 0; $pictureRate = 0;
+    $rates = array ( 0, 23.976, 24, 25, 29.97, 30, 50, 59.94, 60 );
+    $foundSeqHdr = false; $foundGOP = false;
+    
+    do {
+      do {
+        $startCode = $this->nextStartCode();
+      } while ($startCode != 0x1b3 && $startCode != 0x1b8);
+      if ($startCode == 0x1b3 /* sequence_header_code */ && $pictureRate == 0) {
+        $i1 = $this->_reader->readUInt32BE();
+        $i2 = $this->_reader->readUInt32BE();
+        if (!Twiddling::testAllBits($i2, 0x2000))
+          throw new RuntimeException("Invalid mark");
+        $pictureRate = $rates[Twiddling::getValue($i1, 4, 8)];
+        $foundSeqHdr = true;
+      }
+      if ($startCode == 0x1b8 /* group_start_code */) {
+        $tmp = $this->_reader->readUInt32BE();
+        $startTime = (($tmp >> 26) & 0x1f) * 60 * 60 * 1000 /* hours */ +
+                (($tmp >> 20) & 0x3f) * 60 * 1000 /* minutes */ +
+                (($tmp >> 13) & 0x3f) * 1000 /* seconds */ +
+                (int)(1 / $pictureRate * (($tmp >> 7) & 0x3f) * 1000);
+        $foundGOP = true;
+      }
+    } while (!$foundSeqHdr || !$foundGOP);
+    
+    $this->_reader->setOffset($this->_reader->getSize());
+    
+    do {
+      if (($startCode = $this->prevStartCode()) == 0x100)
+        $pictureCount++;
+    } while ($startCode != 0x1b8);
+    
+    $this->_reader->skip(4);
+    $tmp = $this->_reader->readUInt32BE();
+    $this->_length =
+      (((($tmp >> 26) & 0x1f) * 60 * 60 * 1000 /* hours */ +
+        (($tmp >> 20) & 0x3f) * 60 * 1000 /* minutes */ +
+        (($tmp >> 13) & 0x3f) * 1000 /* seconds */ +
+        (int)(1 / $pictureRate * (($tmp >> 7) & 0x3f) * 1000)) - $startTime +
+       (int)(1 / $pictureRate * $pictureCount * 1000)) / 1000;
+  }
+  
+  /**
+   * Returns the exact playtime in seconds.
+   *
+   * @return integer
+   */
+  public function getLength() { return $this->_length; }
+  
+  /**
+   * Returns the exact playtime given in seconds as a string in the form of
+   * [hours]:minutes:seconds.milliseconds.
+   *
+   * @param integer $seconds The playtime in seconds.
+   * @return string
+   */
+  public function getFormattedLength()
+  {
+    return $this->formatTime($this->getLength());
+  }
+}