diff --git a/src/FFMpeg/FFMpeg.php b/src/FFMpeg/FFMpeg.php
index 9caeff3..fd0a4e2 100644
--- a/src/FFMpeg/FFMpeg.php
+++ b/src/FFMpeg/FFMpeg.php
@@ -332,9 +332,8 @@ class FFMpeg extends Binary
 
             if ($originalHeight !== null && $originalWidth !== null) {
                 $dimensions = $format->getComputedDimensions($originalWidth, $originalHeight);
-
-                $width = $this->getMultiple($dimensions->getWidth(), 16);
-                $height = $this->getMultiple($dimensions->getHeight(), 16);
+                $width = $this->getMultiple($dimensions->getWidth(), $format->getModulus());
+                $height = $this->getMultiple($dimensions->getHeight(), $format->getModulus());
 
                 $builder->add('-s')->add($width . 'x' . $height);
             }
@@ -455,31 +454,15 @@ class FFMpeg extends Binary
      */
     protected function getMultiple($value, $multiple)
     {
-        $modulo = $value % $multiple;
-
-        $ret = (int) $multiple;
-
-        $halfDistance = $multiple / 2;
-        if ($modulo <= $halfDistance)
-            $bound = 'bottom';
-        else
-            $bound = 'top';
-
-        switch ($bound) {
-            default:
-            case 'top':
-                $ret = $value + $multiple - $modulo;
-                break;
-            case 'bottom':
-                $ret = $value - $modulo;
-                break;
+        if (($value % $multiple) === 0){
+            return $value;
         }
 
-        if ($ret < $multiple) {
-            $ret = (int) $multiple;
-        }
+        do {
+            $value++;
+        } while (($value % $multiple) != 0);
 
-        return (int) $ret;
+        return $value;
     }
 
     /**
diff --git a/src/FFMpeg/Format/Video/DefaultVideo.php b/src/FFMpeg/Format/Video/DefaultVideo.php
index 3df5d73..47b0210 100644
--- a/src/FFMpeg/Format/Video/DefaultVideo.php
+++ b/src/FFMpeg/Format/Video/DefaultVideo.php
@@ -24,6 +24,8 @@ abstract class DefaultVideo extends DefaultAudio implements Interactive, Resampl
 {
     const RESIZEMODE_FIT = 'fit';
     const RESIZEMODE_INSET = 'inset';
+    const RESIZEMODE_SCALE_WIDTH = 'width';
+    const RESIZEMODE_SCALE_HEIGHT = 'height';
 
     protected $width;
     protected $height;
@@ -32,6 +34,7 @@ abstract class DefaultVideo extends DefaultAudio implements Interactive, Resampl
     protected $videoCodec;
     protected $GOPsize = 25;
     protected $kiloBitrate = 1000;
+    protected $modulus = 16;
 
     /**
      * Returns the width setting.
@@ -82,9 +85,18 @@ abstract class DefaultVideo extends DefaultAudio implements Interactive, Resampl
      */
     public function getComputedDimensions($originalWidth, $originalHeight)
     {
+        $originalRatio = $originalWidth / $originalHeight;
+
         switch ($this->getResizeMode()) {
+            case self::RESIZEMODE_SCALE_WIDTH:
+                $height = $this->height;
+                $width = round($originalRatio * $this->height);
+                break;
+            case self::RESIZEMODE_SCALE_HEIGHT:
+                $width = $this->width;
+                $height = round($this->width / $originalRatio);
+                break;
             case self::RESIZEMODE_INSET:
-                $originalRatio = $originalWidth / $originalHeight;
                 $targetRatio = $this->width / $this->height;
 
                 if ($targetRatio > $originalRatio) {
@@ -119,11 +131,11 @@ abstract class DefaultVideo extends DefaultAudio implements Interactive, Resampl
      */
     public function setResizeMode($mode)
     {
-        if ( ! in_array($mode, array(self::RESIZEMODE_FIT, self::RESIZEMODE_INSET))) {
+        if ( ! in_array($mode, array(self::RESIZEMODE_FIT, self::RESIZEMODE_INSET, self::RESIZEMODE_SCALE_WIDTH, self::RESIZEMODE_SCALE_HEIGHT))) {
             throw new InvalidArgumentException(
                 'Resize mode `%s` is not valid , avalaible values are %s',
                 $mode,
-                implode(', ', array(self::RESIZEMODE_FIT, self::RESIZEMODE_INSET))
+                implode(', ', array(self::RESIZEMODE_FIT, self::RESIZEMODE_INSET, self::RESIZEMODE_SCALE_WIDTH, self::RESIZEMODE_SCALE_HEIGHT))
             );
         }
 
@@ -230,4 +242,26 @@ abstract class DefaultVideo extends DefaultAudio implements Interactive, Resampl
     {
         return 1;
     }
+
+    /**
+     * Used to determine what resolutions sizes are valid.
+     *
+     * @param int $value
+     */
+    public function setModulus($value)
+    {
+        if(!in_array($value, array(2, 4, 8, 16))){
+            throw new InvalidArgumentException('Wrong modulus division value. Valid values are 2, 4, 8 or 16');
+        }
+
+        $this->modulus = $value;
+    }
+
+    /**
+     * @return int
+     */
+    public function getModulus()
+    {
+        return $this->modulus;
+    }
 }
diff --git a/src/FFMpeg/Format/Video/Resizable.php b/src/FFMpeg/Format/Video/Resizable.php
index 63289d6..aabedd9 100644
--- a/src/FFMpeg/Format/Video/Resizable.php
+++ b/src/FFMpeg/Format/Video/Resizable.php
@@ -33,4 +33,6 @@ interface Resizable extends VideoInterface
      * @return Dimension A dimension
      */
     public function getComputedDimensions($originalWidth, $originalHeight);
+
+    public function getModulus();
 }
diff --git a/src/FFMpeg/Format/Video/X264.php b/src/FFMpeg/Format/Video/X264.php
index fd57231..f2d4018 100644
--- a/src/FFMpeg/Format/Video/X264.php
+++ b/src/FFMpeg/Format/Video/X264.php
@@ -52,4 +52,9 @@ class X264 extends DefaultVideo
     {
         return 2;
     }
+
+    public function getModulus()
+    {
+        return 2;
+    }
 }