diff --git a/classes/VideoDownload.php b/classes/VideoDownload.php
index 39fa401..188432d 100644
--- a/classes/VideoDownload.php
+++ b/classes/VideoDownload.php
@@ -12,7 +12,18 @@ use Symfony\Component\Process\ProcessBuilder;
  */
 class VideoDownload
 {
+    /**
+     * Config instance.
+     *
+     * @var Config
+     */
     private $config;
+
+    /**
+     * ProcessBuilder instance used to call Python.
+     *
+     * @var ProcessBuilder
+     */
     private $procBuilder;
 
     /**
@@ -48,6 +59,15 @@ class VideoDownload
         return explode(PHP_EOL, trim($process->getOutput()));
     }
 
+    /**
+     * Get a property from youtube-dl.
+     *
+     * @param string $url    URL to parse
+     * @param string $format Format
+     * @param string $prop   Property
+     *
+     * @return string
+     */
     private function getProp($url, $format = null, $prop = 'dump-json')
     {
         $this->procBuilder->setArguments(