public function getMediaType()
    {
        $contentType = $this->getContentType();
        if (is_string($contentType)) {
            $contentTypeParts = preg_split('/\s*[;,]\s*/', $contentType);

            return isset($contentTypeParts[0]) ? strtolower($contentTypeParts[0]) : null;
        }

        return null;
    }