diff --git a/README.md b/README.md
index 41c9433..af59a56 100644
--- a/README.md
+++ b/README.md
@@ -178,8 +178,8 @@ $video = $ffmpeg->open( 'video.mp4' );
 // Set an audio format
 $audio_format = new FFMpeg\Format\Audio\Mp3();
 
-// Extract the audio into a new file
-$video->save('audio.mp3');
+// Extract the audio into a new file as mp3
+$video->save($audio_format, 'audio.mp3');
 
 // Set the audio file
 $audio = $ffmpeg->open( 'audio.mp3' );
diff --git a/src/FFMpeg/Coordinate/Point.php b/src/FFMpeg/Coordinate/Point.php
index c0688e8..710216c 100644
--- a/src/FFMpeg/Coordinate/Point.php
+++ b/src/FFMpeg/Coordinate/Point.php
@@ -16,10 +16,15 @@ class Point
     private $x;
     private $y;
 
-    public function __construct($x, $y)
+    public function __construct($x, $y, $dynamic = false)
     {
-        $this->x = (int) $x;
-        $this->y = (int) $y;
+        if ($dynamic) {
+            $this->x = $x;
+            $this->y = $y;
+        } else {
+            $this->x = (int)$x;
+            $this->y = (int)$y;
+        }
     }
 
     /**
diff --git a/src/FFMpeg/FFProbe.php b/src/FFMpeg/FFProbe.php
index 7e25b0d..a1a0ba3 100644
--- a/src/FFMpeg/FFProbe.php
+++ b/src/FFMpeg/FFProbe.php
@@ -170,6 +170,25 @@ class FFProbe
         return $this->probe($pathfile, '-show_format', static::TYPE_FORMAT);
     }
 
+    /**
+     * @api
+     *
+     * Checks wether the given `$pathfile` is considered a valid media file.
+     *
+     * @param string $pathfile
+     * @return bool
+     * @since 0.10.0
+     */
+    public function isValid($pathfile)
+    {
+        try {
+            return $this->format($pathfile)->get('duration') > 0;
+        } catch(\Exception $e) {
+            // complete invalid data
+            return false;
+        }
+    }
+
     /**
      * @api
      *
diff --git a/tests/Functional/FFProbeTest.php b/tests/Functional/FFProbeTest.php
index 10a98c0..b183e08 100644
--- a/tests/Functional/FFProbeTest.php
+++ b/tests/Functional/FFProbeTest.php
@@ -12,10 +12,23 @@ class FFProbeTest extends FunctionalTestCase
         $this->assertGreaterThan(0, count($ffprobe->streams(__DIR__ . '/../files/Audio.mp3')));
     }
 
+    public function testValidateExistingFile()
+    {
+        $ffprobe = FFProbe::create();
+        $this->assertTrue($ffprobe->isValid(__DIR__ . '/../files/sample.3gp'));
+    }
+
+
+    public function testValidateNonExistingFile()
+    {
+        $ffprobe = FFProbe::create();
+        $this->assertFalse($ffprobe->isValid(__DIR__ . '/../files/WrongFile.mp4'));
+    }
+
     /**
      * @expectedException FFMpeg\Exception\RuntimeException
      */
-    public function testProbeOnUnexistantFile()
+    public function testProbeOnNonExistantFile()
     {
         $ffprobe = FFProbe::create();
         $ffprobe->streams('/path/to/no/file');
diff --git a/tests/Unit/Coordinate/PointTest.php b/tests/Unit/Coordinate/PointTest.php
index 09bd22e..4d633ce 100644
--- a/tests/Unit/Coordinate/PointTest.php
+++ b/tests/Unit/Coordinate/PointTest.php
@@ -13,4 +13,11 @@ class PointTest extends TestCase
         $this->assertEquals(4, $point->getX());
         $this->assertEquals(25, $point->getY());
     }
+
+    public function testDynamicPointGetters()
+    {
+        $point = new Point("t*100", "t", true);
+        $this->assertEquals("t*100", $point->getX());
+        $this->assertEquals("t", $point->getY());
+    }
 }