protected static function define_properties() {
        return array(
            'sourcefileid' => [
                'type' => PARAM_INT,
            ],
            'targetformat' => [
                'type' => PARAM_ALPHANUMEXT,
            ],
            'status' => [
                'type' => PARAM_INT,
                'choices' => [
                    self::STATUS_PENDING,
                    self::STATUS_IN_PROGRESS,
                    self::STATUS_COMPLETE,
                    self::STATUS_FAILED,
                ],
                'default' => self::STATUS_PENDING,
            ],
            'statusmessage' => [
                'type' => PARAM_RAW,
                'null' => NULL_ALLOWED,
                'default' => null,
            ],
            'converter' => [
                'type' => PARAM_RAW,
                'null' => NULL_ALLOWED,
                'default' => null,
            ],
            'destfileid' => [
                'type' => PARAM_INT,
                'null' => NULL_ALLOWED,
                'default' => null,
            ],
            'data' => [
                'type' => PARAM_RAW,
                'null' => NULL_ALLOWED,
                'default' => null,
            ],
        );
    }