Below is a PHP function that takes in youtube embed code, a desired width and height. It returns the embed code with width and height resized to the desired dimensions.

This is very useful when uploading youtube videos using a CMS or allowing users to upload youtube videos as user generated content.

function resizeYoutubeEmbeddedVideo($embedCode, $width, $height) {
$patterns = array();
$patterns[0] = '/width="(.*?)"/';
$patterns[1] = '/height="(.*?)"/';
$replacements = array();
$replacements[0] = 'width="' . $width . '"';
$replacements[1] = 'height="' . $height . '"';

return preg_replace($patterns, $replacements, $embedCode);
}