Displaying mp4s problem

hello,
i want to pull mp4 video to my template with this code:

 <?php $vids = $uebung->documents()->filterBy('extension', 'mp4');
                     
                    if ($vids->isNotEmpty()) : ?>
                         <?php foreach($vids as $vid): ?>
                                  <div class="videoplayer"> <video controls><source src="<?= $vid->url() ?>" type="<?= $vid->mime() ?>">
                         </video></div>
                         <?php endforeach ?>
                    <?php endif ?>

but $vids seems to be empty.
the same code works when pulling .pdfs. also pulling the mp4 manually into the textarea in the panel also works. so i’m clueless right now.

tnx
fusi

Videos are not documents, use videos instead