diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8bba6c4..754f741 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,11 @@ CHANGELOG
 
 * 0.4.0 (xx-xx-xxxx)
 
+* 0.3.3 (xx-xx-2013)
+
+  * Add convenient Stream::getDimensions method to extract video dimension.
+  * Add DisplayRatioFixer Frame filter.
+
 * 0.3.2 (08-08-2013)
 
   * Fix A/V synchronization over flash and HTML5 players.
diff --git a/src/FFMpeg/Exception/LogicException.php b/src/FFMpeg/Exception/LogicException.php
new file mode 100644
index 0000000..b73b567
--- /dev/null
+++ b/src/FFMpeg/Exception/LogicException.php
@@ -0,0 +1,16 @@
+<?php
+
+/*
+ * This file is part of PHP-FFmpeg.
+ *
+ * (c) Alchemy <info@alchemy.fr>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace FFMpeg\Exception;
+
+class LogicException extends \LogicException implements ExceptionInterface
+{
+}
diff --git a/src/FFMpeg/FFProbe/DataMapping/Stream.php b/src/FFMpeg/FFProbe/DataMapping/Stream.php
index 9b0d170..e74503e 100644
--- a/src/FFMpeg/FFProbe/DataMapping/Stream.php
+++ b/src/FFMpeg/FFProbe/DataMapping/Stream.php
@@ -11,6 +11,10 @@
 
 namespace FFMpeg\FFProbe\DataMapping;
 
+use FFMpeg\Exception\LogicException;
+use FFMpeg\Exception\RuntimeException;
+use FFMpeg\Coordinate\Dimension;
+
 class Stream extends AbstractData
 {
     /**
@@ -32,4 +36,63 @@ class Stream extends AbstractData
     {
         return $this->has('codec_type') ? 'video' === $this->get('codec_type') : false;
     }
+
+    /**
+     * Returns the dimension of the video stream.
+     *
+     * @return Dimension
+     *
+     * @throws LogicException   In case the stream is not a video stream.
+     * @throws RuntimeException In case the dimensions can not be extracted.
+     */
+    public function getDimensions()
+    {
+        if (!$this->isVideo()) {
+            throw new LogicException('Dimensions can only be retrieved from video streams.');
+        }
+
+        $width = $height = $sampleRatio = $displayRatio = null;
+
+        if ($this->has('width')) {
+            $width = $this->get('width');
+        }
+        if ($this->has('height')) {
+            $height = $this->get('height');
+        }
+        if (null !== $ratio = $this->extractRatio($this, 'sample_aspect_ratio')) {
+            $sampleRatio = $ratio;
+        }
+        if (null !== $ratio = $this->extractRatio($this, 'display_aspect_ratio')) {
+            $displayRatio = $ratio;
+        }
+
+        if (null === $height || null === $width) {
+            throw new RuntimeException('Unable to extract dimensions.');
+        }
+
+        if (null !== $displayRatio && null !== $sampleRatio) {
+            $width = round($width / $sampleRatio[0] * $sampleRatio[1] * $displayRatio[0] / $displayRatio[1]);
+        }
+
+        return new Dimension($width, $height);
+    }
+
+    /**
+     * Extracts a ratio from a string in a \d+:\d+ format given a key name.
+     *
+     * @param  Stream     $stream The stream where to look for the ratio.
+     * @param  string     $name   the name of the key.
+     * @return null|array An array containing the width and the height, null if not found.
+     */
+    private function extractRatio(Stream $stream, $name)
+    {
+        if ($stream->has($name)) {
+            $ratio = $stream->get($name);
+            if (preg_match('/\d+:\d+/', $ratio)) {
+                return array_map(function ($int) { return (int) $int; }, explode(':', $ratio));
+            }
+        }
+
+        return null;
+    }
 }
diff --git a/src/FFMpeg/Filters/FiltersCollection.php b/src/FFMpeg/Filters/FiltersCollection.php
index d44a880..c91241a 100644
--- a/src/FFMpeg/Filters/FiltersCollection.php
+++ b/src/FFMpeg/Filters/FiltersCollection.php
@@ -47,8 +47,12 @@ class FiltersCollection implements \Countable, \IteratorAggregate
     public function getIterator()
     {
         if (null === $this->sorted) {
-            krsort($this->filters);
-            $this->sorted = call_user_func_array('array_merge', $this->filters);
+            if (0 === count($this->filters)) {
+                $this->sorted = $this->filters;
+            } else {
+                krsort($this->filters);
+                $this->sorted = call_user_func_array('array_merge', $this->filters);
+            }
         }
 
         return new \ArrayIterator($this->sorted);
diff --git a/src/FFMpeg/Filters/Frame/DisplayRatioFixerFilter.php b/src/FFMpeg/Filters/Frame/DisplayRatioFixerFilter.php
new file mode 100644
index 0000000..0cc3cea
--- /dev/null
+++ b/src/FFMpeg/Filters/Frame/DisplayRatioFixerFilter.php
@@ -0,0 +1,58 @@
+<?php
+
+/*
+ * This file is part of PHP-FFmpeg.
+ *
+ * (c) Alchemy <dev.team@alchemy.fr>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace FFMpeg\Filters\Frame;
+
+use FFMpeg\Exception\RuntimeException;
+use FFMpeg\Media\Frame;
+
+class DisplayRatioFixerFilter implements FrameFilterInterface
+{
+    /** @var integer */
+    private $priority;
+
+    public function __construct($priority = 0)
+    {
+        $this->priority = $priority;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getPriority()
+    {
+        return $this->priority;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function apply(Frame $frame)
+    {
+        $dimensions = null;
+        $commands = array();
+
+        foreach ($frame->getVideo()->getStreams() as $stream) {
+            if ($stream->isVideo()) {
+                try {
+                    $dimensions = $stream->getDimensions();
+                    $commands[] = '-s';
+                    $commands[] = $dimensions->getWidth() . 'x' . $dimensions->getHeight();
+                    break;
+                } catch (RuntimeException $e) {
+
+                }
+            }
+        }
+
+        return $commands;
+    }
+}
diff --git a/src/FFMpeg/Filters/Frame/FrameFilterInterface.php b/src/FFMpeg/Filters/Frame/FrameFilterInterface.php
index db4fdac..d9df0e4 100644
--- a/src/FFMpeg/Filters/Frame/FrameFilterInterface.php
+++ b/src/FFMpeg/Filters/Frame/FrameFilterInterface.php
@@ -13,9 +13,8 @@ namespace FFMpeg\Filters\Frame;
 
 use FFMpeg\Filters\FilterInterface;
 use FFMpeg\Media\Frame;
-use FFMpeg\Format\FrameInterface;
 
 interface FrameFilterInterface extends FilterInterface
 {
-    public function apply(Frame $frame, FrameInterface $format);
+    public function apply(Frame $frame);
 }
diff --git a/src/FFMpeg/Filters/Frame/FrameFilters.php b/src/FFMpeg/Filters/Frame/FrameFilters.php
index 85bfde9..255da0c 100644
--- a/src/FFMpeg/Filters/Frame/FrameFilters.php
+++ b/src/FFMpeg/Filters/Frame/FrameFilters.php
@@ -21,4 +21,19 @@ class FrameFilters
     {
         $this->frame = $frame;
     }
+
+    /**
+     * Fixes the display ratio of the output frame.
+     * 
+     * In case the sample ratio and display ratio are different, image may be
+     * anamorphozed. This filter fixes this by specifying the output size.
+     * 
+     * @return FrameFilters
+     */
+    public function fixDisplayRatio()
+    {
+        $this->frame->addFilter(new DisplayRatioFixerFilter());
+
+        return $this;
+    }
 }
diff --git a/src/FFMpeg/Filters/Video/ResizeFilter.php b/src/FFMpeg/Filters/Video/ResizeFilter.php
index a3e407d..c5f96cb 100644
--- a/src/FFMpeg/Filters/Video/ResizeFilter.php
+++ b/src/FFMpeg/Filters/Video/ResizeFilter.php
@@ -12,6 +12,7 @@
 namespace FFMpeg\Filters\Video;
 
 use FFMpeg\Coordinate\Dimension;
+use FFMpeg\Exception\RuntimeException;
 use FFMpeg\Media\Video;
 use FFMpeg\Format\VideoInterface;
 
@@ -80,23 +81,22 @@ class ResizeFilter implements VideoFilterInterface
      */
     public function apply(Video $video, VideoInterface $format)
     {
-        $originalWidth = $originalHeight = null;
+        $dimensions = null;
+        $commands = array();
 
         foreach ($video->getStreams() as $stream) {
             if ($stream->isVideo()) {
-                if ($stream->has('width')) {
-                    $originalWidth = $stream->get('width');
-                }
-                if ($stream->has('height')) {
-                    $originalHeight = $stream->get('height');
+                try {
+                    $dimensions = $stream->getDimensions();
+                    break;
+                } catch (RuntimeException $e) {
+
                 }
             }
         }
 
-        $commands = array();
-
-        if ($originalHeight !== null && $originalWidth !== null) {
-            $dimensions = $this->getComputedDimensions(new Dimension($originalWidth, $originalHeight), $format->getModulus());
+        if (null !== $dimensions) {
+            $dimensions = $this->getComputedDimensions($dimensions, $format->getModulus());
 
             $commands[] = '-s';
             $commands[] = $dimensions->getWidth() . 'x' . $dimensions->getHeight();
diff --git a/src/FFMpeg/Media/Frame.php b/src/FFMpeg/Media/Frame.php
index bfbed8f..a48c50e 100644
--- a/src/FFMpeg/Media/Frame.php
+++ b/src/FFMpeg/Media/Frame.php
@@ -18,16 +18,30 @@ use FFMpeg\Driver\FFMpegDriver;
 use FFMpeg\FFProbe;
 use FFMpeg\Exception\RuntimeException;
 use FFMpeg\Coordinate\TimeCode;
+use FFMpeg\Media\Video;
 
 class Frame extends AbstractMediaType
 {
     /** @var TimeCode */
     private $timecode;
+    /** @var Video */
+    private $video;
 
-    public function __construct($pathfile, FFMpegDriver $driver, FFProbe $ffprobe, TimeCode $timecode)
+    public function __construct(Video $video, FFMpegDriver $driver, FFProbe $ffprobe, TimeCode $timecode)
     {
-        parent::__construct($pathfile, $driver, $ffprobe);
+        parent::__construct($video->getPathfile(), $driver, $ffprobe);
         $this->timecode = $timecode;
+        $this->video = $video;
+    }
+
+    /**
+     * Returns the video related to the frame.
+     *
+     * @return Video
+     */
+    public function getVideo()
+    {
+        return $this->video;
     }
 
     /**
@@ -83,16 +97,22 @@ class Frame extends AbstractMediaType
                 '-y', '-ss', (string) $this->timecode,
                 '-i', $this->pathfile,
                 '-vframes', '1',
-                '-f', 'image2', $pathfile
+                '-f', 'image2'
             );
         } else {
             $commands = array(
                 '-y', '-i', $this->pathfile,
                 '-vframes', '1', '-ss', (string) $this->timecode,
-                '-f', 'image2', $pathfile
+                '-f', 'image2'
             );
         }
 
+        foreach ($this->filters as $filter) {
+            $commands = array_merge($commands, $filter->apply($this));
+        }
+        
+        $commands = array_merge($commands, array($pathfile));
+
         try {
             $this->driver->command($commands);
         } catch (ExecutionFailureException $e) {
diff --git a/src/FFMpeg/Media/Video.php b/src/FFMpeg/Media/Video.php
index 77da940..006e346 100644
--- a/src/FFMpeg/Media/Video.php
+++ b/src/FFMpeg/Media/Video.php
@@ -159,6 +159,6 @@ class Video extends Audio
      */
     public function frame(TimeCode $at)
     {
-        return new Frame($this->pathfile, $this->driver, $this->ffprobe, $at);
+        return new Frame($this, $this->driver, $this->ffprobe, $at);
     }
 }
diff --git a/tests/FFMpeg/Tests/FFProbe/DataMapping/StreamTest.php b/tests/FFMpeg/Tests/FFProbe/DataMapping/StreamTest.php
index e1ea7b6..c9f9c19 100644
--- a/tests/FFMpeg/Tests/FFProbe/DataMapping/StreamTest.php
+++ b/tests/FFMpeg/Tests/FFProbe/DataMapping/StreamTest.php
@@ -2,6 +2,7 @@
 
 namespace FFMpeg\Tests\FFProbe\DataMapping;
 
+use FFMpeg\Coordinate\Dimension;
 use FFMpeg\Tests\TestCase;
 use FFMpeg\FFProbe\DataMapping\Stream;
 
@@ -40,4 +41,45 @@ class StreamTest extends TestCase
             array(false, array('codec_type' => 'audio')),
         );
     }
+
+    /**
+     * @expectedException FFMpeg\Exception\LogicException
+     * @expectedExceptionMessage Dimensions can only be retrieved from video streams.
+     */
+    public function testGetDimensionsFromAudio()
+    {
+        $stream = new Stream(array('codec_type' => 'audio'));
+        $stream->getDimensions();
+    }
+
+    public function testGetDimensionsFromVideo()
+    {
+        $stream = new Stream(array('codec_type' => 'video', 'width' => 960, 'height' => 720));
+        $this->assertEquals(new Dimension(960, 720), $stream->getDimensions());
+    }
+
+    /**
+     * @dataProvider provideInvalidPropertiesForDimensionsExtraction
+     * @expectedException FFMpeg\Exception\RuntimeException
+     * @expectedExceptionMessage Unable to extract dimensions.
+     */
+    public function testUnableToGetDimensionsFromVideo($properties)
+    {
+        $stream = new Stream(array('codec_type' => 'video', 'width' => 960));
+        $stream->getDimensions();
+    }
+
+    public function provideInvalidPropertiesForDimensionsExtraction()
+    {
+        return array(
+            array('codec_type' => 'video', 'width' => 960),
+            array('codec_type' => 'video', 'height' => 960),
+        );
+    }
+
+    public function testGetDimensionsFromVideoWithDisplayRatio()
+    {
+        $stream = new Stream(array('codec_type' => 'video', 'width' => 960, 'height' => 720, 'sample_aspect_ratio' => '4:3', 'display_aspect_ratio' => '16:9'));
+        $this->assertEquals(new Dimension(1280, 720), $stream->getDimensions());
+    }
 }
diff --git a/tests/FFMpeg/Tests/Filters/FiltersCollectionTest.php b/tests/FFMpeg/Tests/Filters/FiltersCollectionTest.php
index 52a1395..5a29008 100644
--- a/tests/FFMpeg/Tests/Filters/FiltersCollectionTest.php
+++ b/tests/FFMpeg/Tests/Filters/FiltersCollectionTest.php
@@ -30,6 +30,12 @@ class FiltersCollectionTest extends TestCase
         $this->assertCount(2, $coll->getIterator());
     }
 
+    public function testEmptyIterator()
+    {
+        $coll = new FiltersCollection();
+        $this->assertInstanceOf('\ArrayIterator', $coll->getIterator());
+    }
+
     public function testIteratorSort()
     {
         $coll = new FiltersCollection();
diff --git a/tests/FFMpeg/Tests/Filters/Frame/DisplayRatioFixerFilterTest.php b/tests/FFMpeg/Tests/Filters/Frame/DisplayRatioFixerFilterTest.php
new file mode 100644
index 0000000..bb642b4
--- /dev/null
+++ b/tests/FFMpeg/Tests/Filters/Frame/DisplayRatioFixerFilterTest.php
@@ -0,0 +1,28 @@
+<?php
+
+namespace FFMpeg\Tests\Filters\Frame;
+
+use FFMpeg\Tests\TestCase;
+use FFMpeg\Filters\Frame\DisplayRatioFixerFilter;
+use FFMpeg\Media\Frame;
+use FFMpeg\Coordinate\TimeCode;
+use FFMpeg\FFProbe\DataMapping\StreamCollection;
+use FFMpeg\FFProbe\DataMapping\Stream;
+
+class DisplayRatioFixerFilterTest extends TestCase
+{
+    public function testApply()
+    {
+        $stream = new Stream(array('codec_type' => 'video', 'width' => 960, 'height' => 720));
+        $streams = new StreamCollection(array($stream));
+        
+        $video = $this->getVideoMock(__FILE__);
+        $video->expects($this->once())
+                ->method('getStreams')
+                ->will($this->returnValue($streams));
+        
+        $frame = new Frame($video, $this->getFFMpegDriverMock(), $this->getFFProbeMock(), new TimeCode(0, 0, 0, 0));
+        $filter = new DisplayRatioFixerFilter();
+        $this->assertEquals(array('-s', '960x720'), $filter->apply($frame));
+    }
+}
diff --git a/tests/FFMpeg/Tests/Filters/Frame/FrameFiltersTest.php b/tests/FFMpeg/Tests/Filters/Frame/FrameFiltersTest.php
new file mode 100644
index 0000000..a0e6434
--- /dev/null
+++ b/tests/FFMpeg/Tests/Filters/Frame/FrameFiltersTest.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace FFMpeg\Tests\Filters\Frame;
+
+use FFMpeg\Tests\TestCase;
+use FFMpeg\Filters\Frame\FrameFilters;
+
+class FrameFiltersTest extends TestCase
+{
+    public function testResize()
+    {
+        $frame = $this->getFrameMock();
+        $filters = new FrameFilters($frame);
+
+        $frame->expects($this->once())
+            ->method('addFilter')
+            ->with($this->isInstanceOf('FFMpeg\Filters\Frame\DisplayRatioFixerFilter'));
+
+        $filters->fixDisplayRatio();
+    }
+}
diff --git a/tests/FFMpeg/Tests/Media/FrameTest.php b/tests/FFMpeg/Tests/Media/FrameTest.php
index a95df2b..b64d6e9 100644
--- a/tests/FFMpeg/Tests/Media/FrameTest.php
+++ b/tests/FFMpeg/Tests/Media/FrameTest.php
@@ -11,7 +11,7 @@ class FrameTest extends AbstractMediaTestCase
      */
     public function testWithInvalidFile()
     {
-        new Frame('/No/file', $this->getFFMpegDriverMock(), $this->getFFProbeMock(), $this->getTimeCodeMock());
+        new Frame($this->getVideoMock('/No/file'), $this->getFFMpegDriverMock(), $this->getFFProbeMock(), $this->getTimeCodeMock());
     }
 
     public function testGetTimeCode()
@@ -20,7 +20,7 @@ class FrameTest extends AbstractMediaTestCase
         $ffprobe = $this->getFFProbeMock();
         $timecode = $this->getTimeCodeMock();
 
-        $frame = new Frame(__FILE__, $driver, $ffprobe, $timecode);
+        $frame = new Frame($this->getVideoMock(__FILE__), $driver, $ffprobe, $timecode);
         $this->assertSame($timecode, $frame->getTimeCode());
     }
 
@@ -30,7 +30,7 @@ class FrameTest extends AbstractMediaTestCase
         $ffprobe = $this->getFFProbeMock();
         $timecode = $this->getTimeCodeMock();
 
-        $frame = new Frame(__FILE__, $driver, $ffprobe, $timecode);
+        $frame = new Frame($this->getVideoMock(__FILE__), $driver, $ffprobe, $timecode);
         $this->assertInstanceOf('FFMpeg\Filters\Frame\FrameFilters', $frame->filters());
     }
 
@@ -50,7 +50,7 @@ class FrameTest extends AbstractMediaTestCase
             ->method('add')
             ->with($filter);
 
-        $frame = new Frame(__FILE__, $driver, $ffprobe, $timecode);
+        $frame = new Frame($this->getVideoMock(__FILE__), $driver, $ffprobe, $timecode);
         $frame->setFiltersCollection($filters);
         $frame->addFilter($filter);
     }
@@ -75,7 +75,7 @@ class FrameTest extends AbstractMediaTestCase
             ->method('command')
             ->with($commands);
 
-        $frame = new Frame(__FILE__, $driver, $ffprobe, $timecode);
+        $frame = new Frame($this->getVideoMock(__FILE__), $driver, $ffprobe, $timecode);
         $this->assertSame($frame, $frame->save($pathfile, $accurate));
     }
 
diff --git a/tests/FFMpeg/Tests/TestCase.php b/tests/FFMpeg/Tests/TestCase.php
index d347acd..4757f95 100644
--- a/tests/FFMpeg/Tests/TestCase.php
+++ b/tests/FFMpeg/Tests/TestCase.php
@@ -40,6 +40,13 @@ class TestCase extends \PHPUnit_Framework_TestCase
             ->getMock();
     }
 
+    public function getFrameMock()
+    {
+        return $this->getMockBuilder('FFMpeg\Media\Frame')
+            ->disableOriginalConstructor()
+            ->getMock();
+    }
+
     public function getFFMpegDriverMock()
     {
         return $this->getMockBuilder('FFMpeg\Driver\FFMpegDriver')
@@ -122,10 +129,16 @@ class TestCase extends \PHPUnit_Framework_TestCase
             ->getMock();
     }
 
-    protected function getVideoMock()
+    protected function getVideoMock($filename = null)
     {
-        return $this->getMockBuilder('FFMpeg\Media\Video')
+        $video = $this->getMockBuilder('FFMpeg\Media\Video')
             ->disableOriginalConstructor()
             ->getMock();
+
+        $video->expects($this->any())
+            ->method('getPathfile')
+            ->will($this->returnValue($filename));
+
+        return $video;
     }
 }