diff --git a/src/FFMpeg/FFMpeg.php b/src/FFMpeg/FFMpeg.php
index 822e495..4cb35e1 100644
--- a/src/FFMpeg/FFMpeg.php
+++ b/src/FFMpeg/FFMpeg.php
@@ -63,6 +63,45 @@ class FFMpeg extends Binary
 
         $threads = max(min($threads, 64), 1);
 
+        switch (true)
+        {
+            case $format instanceof Format\VideoFormat:
+                return $this->encodeVideo($format, $outputPathfile, $threads);
+                break;
+            default:
+            case $format instanceof Format\AudioFormat:
+                return $this->encodeAudio($format, $outputPathfile, $threads);
+                break;
+        }
+
+        return false;
+    }
+
+    protected function encodeAudio(Format\AudioFormat $format, $outputPathfile, $threads)
+    {
+        $cmd = $this->binary
+          . ' -y -i '
+          . escapeshellarg($this->pathfile)
+          . ' ' . $format->getExtraParams()
+          . ' -threads ' . $threads
+          . ' -acodec ' . $format->getAudioCodec()
+          . ' -ab ' . $format->getKiloBitrate() . 'k '
+          . ' -ac 2 -ar ' . $format->getAudioSampleRate()
+          . ' ' . escapeshellarg($outputPathfile);
+
+        $process = new \Symfony\Component\Process\Process($cmd);
+        $process->run();
+
+        if ( ! $process->isSuccessful())
+        {
+            throw new \RuntimeException(sprintf('Encoding failed : %s', $process->getErrorOutput()));
+        }
+
+        return true;
+    }
+
+    protected function encodeVideo(Format\VideoFormat $format, $outputPathfile, $threads)
+    {
         $cmd_part1 = $this->binary
           . ' -y -i '
           . escapeshellarg($this->pathfile) . ' '
diff --git a/src/FFMpeg/Format/Audio/Flac.php b/src/FFMpeg/Format/Audio/Flac.php
new file mode 100644
index 0000000..1e220d1
--- /dev/null
+++ b/src/FFMpeg/Format/Audio/Flac.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace FFMpeg\Format\Audio;
+
+use FFMpeg\Format\DefaultAudioFormat;
+
+class Flac extends DefaultAudioFormat
+{
+
+    protected $audioCodec = 'flac';
+
+    protected function getAvailableAudioCodecs()
+    {
+        return array('flac');
+    }
+
+}
\ No newline at end of file
diff --git a/src/FFMpeg/Format/Audio/Mp3.php b/src/FFMpeg/Format/Audio/Mp3.php
new file mode 100644
index 0000000..6470232
--- /dev/null
+++ b/src/FFMpeg/Format/Audio/Mp3.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace FFMpeg\Format\Audio;
+
+use FFMpeg\Format\DefaultAudioFormat;
+
+class Mp3 extends DefaultAudioFormat
+{
+
+    protected $audioCodec = 'libmp3lame';
+
+    protected function getAvailableAudioCodecs()
+    {
+        return array('libmp3lame');
+    }
+
+}
\ No newline at end of file
diff --git a/src/FFMpeg/Format/DefaultAudioFormat.php b/src/FFMpeg/Format/DefaultAudioFormat.php
index d983be5..7ee176d 100644
--- a/src/FFMpeg/Format/DefaultAudioFormat.php
+++ b/src/FFMpeg/Format/DefaultAudioFormat.php
@@ -7,7 +7,7 @@ abstract class DefaultAudioFormat implements AudioFormat
 
     protected $audioCodec;
     protected $audioSampleRate = 44100;
-    protected $kiloBitrate     = 1000;
+    protected $kiloBitrate     = 128;
 
     public function getExtraParams()
     {
diff --git a/src/FFMpeg/Format/DefaultVideoFormat.php b/src/FFMpeg/Format/DefaultVideoFormat.php
index 5654a58..115d985 100644
--- a/src/FFMpeg/Format/DefaultVideoFormat.php
+++ b/src/FFMpeg/Format/DefaultVideoFormat.php
@@ -7,9 +7,10 @@ abstract class DefaultVideoFormat extends DefaultAudioFormat implements VideoFor
 
     protected $width;
     protected $height;
-    protected $frameRate = 25;
+    protected $frameRate   = 25;
     protected $videoCodec;
-    protected $GOPsize   = 25;
+    protected $GOPsize     = 25;
+    protected $kiloBitrate = 1000;
 
     public function __construct($width, $height)
     {
diff --git a/src/FFMpeg/Format/VideoFormat.php b/src/FFMpeg/Format/VideoFormat.php
index 0e6c991..11b7e06 100644
--- a/src/FFMpeg/Format/VideoFormat.php
+++ b/src/FFMpeg/Format/VideoFormat.php
@@ -2,7 +2,7 @@
 
 namespace FFMpeg\Format;
 
-interface VideoFormat
+interface VideoFormat extends AudioFormat
 {
 
     public function getWidth();
diff --git a/tests/src/FFMpeg/FFMpegTest.php b/tests/src/FFMpeg/FFMpegTest.php
index 39f9453..daab063 100644
--- a/tests/src/FFMpeg/FFMpegTest.php
+++ b/tests/src/FFMpeg/FFMpegTest.php
@@ -71,6 +71,7 @@ class FFMpegTest extends \PHPUnit_Framework_TestCase
         $this->object->encode(new Format\Video\WebM(32, 32), './invalid.file');
     }
 
+
     /**
      * @covers FFMpeg\FFMpeg::encode
      * @expectedException \RuntimeException
@@ -87,6 +88,39 @@ class FFMpegTest extends \PHPUnit_Framework_TestCase
 
     /**
      * @covers FFMpeg\FFMpeg::encode
+     * @covers FFMpeg\FFMpeg::encodeAudio
+     */
+    public function testEncodeMp3()
+    {
+        $dest = __DIR__ . '/../../files/encode_test.mp3';
+
+        $this->object->open(__DIR__ . '/../../files/Audio.mp3');
+        $this->object->encode(new Format\Audio\Mp3(), $dest);
+
+        $this->probe->probeFormat($dest);
+
+        unlink($dest);
+    }
+
+    /**
+     * @covers FFMpeg\FFMpeg::encode
+     * @covers FFMpeg\FFMpeg::encodeAudio
+     */
+    public function testEncodeFlac()
+    {
+        $dest = __DIR__ . '/../../files/encode_test.flac';
+
+        $this->object->open(__DIR__ . '/../../files/Audio.mp3');
+        $this->object->encode(new Format\Audio\Flac(), $dest);
+
+        $this->probe->probeFormat($dest);
+
+        unlink($dest);
+    }
+
+    /**
+     * @covers FFMpeg\FFMpeg::encode
+     * @covers FFMpeg\FFMpeg::encodeVideo
      */
     public function testEncodeWebm()
     {
@@ -102,6 +136,7 @@ class FFMpegTest extends \PHPUnit_Framework_TestCase
 
     /**
      * @covers FFMpeg\FFMpeg::encode
+     * @covers FFMpeg\FFMpeg::encodeVideo
      */
     public function testEncodeOgg()
     {
@@ -117,6 +152,7 @@ class FFMpegTest extends \PHPUnit_Framework_TestCase
 
     /**
      * @covers FFMpeg\FFMpeg::encode
+     * @covers FFMpeg\FFMpeg::encodeVideo
      */
     public function testEncodeX264()
     {
diff --git a/tests/src/FFMpeg/Format/DefaultAudioFormatTest.php b/tests/src/FFMpeg/Format/DefaultAudioFormatTest.php
index 2a27cf0..6f03675 100644
--- a/tests/src/FFMpeg/Format/DefaultAudioFormatTest.php
+++ b/tests/src/FFMpeg/Format/DefaultAudioFormatTest.php
@@ -107,7 +107,7 @@ class DefaultAudioFormatTest extends \PHPUnit_Framework_TestCase
      */
     public function testGetKiloBitrate()
     {
-        $this->assertEquals(1000, $this->object->getKiloBitrate());
+        $this->assertEquals(128, $this->object->getKiloBitrate());
     }
 
     /**
diff --git a/tests/src/FFMpeg/Format/DefaultVideoFormatTest.php b/tests/src/FFMpeg/Format/DefaultVideoFormatTest.php
index bc010b2..29479b8 100644
--- a/tests/src/FFMpeg/Format/DefaultVideoFormatTest.php
+++ b/tests/src/FFMpeg/Format/DefaultVideoFormatTest.php
@@ -187,6 +187,14 @@ class DefaultVideoFormatTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals(16, $this->object->getMultiple(8, 16));
     }
 
+    /**
+     * @covers FFMpeg\Format\DefaultVideoFormat::getKiloBitrate
+     */
+    public function testGetKiloBitrate()
+    {
+        $this->assertEquals(1000, $this->object->getKiloBitrate());
+    }
+
 }
 
 class DefaultVideoFormatTester extends DefaultVideoFormat