if ( ! empty( $thumb_id ) ) {
                list( $src, $width, $height ) = wp_get_attachment_image_src( $thumb_id, 'full' );
                $track['image']               = compact( 'src', 'width', 'height' );
                list( $src, $width, $height ) = wp_get_attachment_image_src( $thumb_id, 'thumbnail' );
                $track['thumb']               = compact( 'src', 'width', 'height' );