Poster image for video

The following code works, but it would be reassuring if someone could confirm it is okay.

I’d like to be able to add a poster image to videos (that will be displayed before the video starts).

In my Blueprint I have a field to upload the poster image:

fields:
	poster:
		label: Poster for video
		type: files

Then in my snippet I have the following:

<video autoplay controls loop poster="<?php echo ( $poster = $file->poster()->toFile() ) ? $poster->url() : ''; ?>" class="border">
	<source src="<?= $file->url() ?>">
</video>
<?php if ($file->caption()->isNotEmpty()): ?>
	<p class="caption"><?= $file->caption() ?></p>
<?php endif ?>

LGTM :+1: (and some more chars)