Added configuration for audio channels

src/FFMpeg/Format/Audio/DefaultAudio.php

@@ -27,6 +27,9 @@ abstract class DefaultAudio extends EventEmitter implements AudioInterface, Prog
     /** @var integer */
     protected $audioKiloBitrate = 128;
 
+    /** @var integer */
+    protected $audioChannels = null;
+
     /**
      * {@inheritdoc}
      */
@@ -90,6 +93,31 @@ abstract class DefaultAudio extends EventEmitter implements AudioInterface, Prog
         return $this;
     }
 
+	/**
+	 * {@inheritdoc}
+	 */
+	public function getAudioChannels()
+	{
+		return $this->audioChannels;
+	}
+
+	/**
+     * Sets the channels value.
+     *
+     * @param  integer                  $channels
+     * @throws InvalidArgumentException
+     */
+    public function setAudioChannels($channels)
+    {
+        if ($channels < 1) {
+            throw new InvalidArgumentException('Wrong channels value');
+        }
+
+        $this->audioChannels = (int) $channels;
+
+        return $this;
+    }
+
     /**
      * {@inheritdoc}
      */

src/FFMpeg/Format/AudioInterface.php

@@ -19,6 +19,13 @@ interface AudioInterface extends FormatInterface
      */
     public function getAudioKiloBitrate();
 
+    /**
+     * Gets the audio channels value.
+     *
+     * @return integer
+     */
+    public function getAudioChannels();
+
     /**
      * Returns the audio codec.
      *

src/FFMpeg/Media/Audio.php

@@ -87,6 +87,10 @@ class Audio extends AbstractStreamableMedia
             $commands[] = '-b:a';
             $commands[] = $format->getAudioKiloBitrate() . 'k';
         }
+        if (null !== $format->getAudioChannels()) {
+            $commands[] = '-ac';
+            $commands[] = $format->getAudioChannels();
+        }
         $commands[] = $outputPathfile;
 
         try {

src/FFMpeg/Media/Video.php

@@ -114,6 +114,10 @@ class Video extends Audio
                 $commands[] = '-b:a';
                 $commands[] = $format->getAudioKiloBitrate() . 'k';
             }
+	        if (null !== $format->getAudioChannels()) {
+		        $commands[] = '-ac';
+		        $commands[] = $format->getAudioChannels();
+	        }
         }
 
         $fs = FsManager::create();