TYPO3 Core

The Vimeorenderer checks if

if ($autoplay !== null) {
                $options['autoplay'] = $autoplay;
            }

But in $autoplay there is always a value. That´s why an autoplay function cannot be set via fluid, as shown in the example (<f:media file="{file}" width="400" height="375" additionalConfig="{autoplay: '1'}" />).

Solution:

if (!empty($autoplay)) {
                $options['autoplay'] = $autoplay;
            }