Sulu\Bundle\MediaBundle\Collection\Manager\CollectionManager::getPreviewsFromFileVersion PHP Method

    protected function getPreviewsFromFileVersion($mediaId, $fileVersion, $locale)
    {
        $title = '';
        /*
         * @var FileVersionMeta
         */
        foreach ($fileVersion->getMeta() as $key => $meta) {
            if ($meta->getLocale() == $locale) {
                $title = $meta->getTitle();
                break;
            } elseif ($key == 0) {
                // fallback title
                $title = $meta->getTitle();
            }
        }
        $mediaFormats = $this->formatManager->getFormats($mediaId, $fileVersion->getName(), $fileVersion->getStorageOptions(), $fileVersion->getVersion(), $fileVersion->getSubVersion(), $fileVersion->getMimeType());
        foreach ($mediaFormats as $formatName => $formatUrl) {
            if ($formatName == $this->collectionPreviewFormat) {
                return ['url' => $formatUrl, 'title' => $title];
                break;
            }
        }
        return [];
    }