Is it possible to insert iFrames or better yet shortcodes

Is it possible to insert iFrames or better yet shortcodes into a unit? I have some content (training videos) that I want to make available as part of our courses, but this content is stored in a html wrapper. My hope is to allow the authors to insert these training materials via a shortcode in the unit. I have written the following shortcode function in the functions.php, but the text editor in the Unit is not parsing it. It is only displaying it as raw text. And if I type the iframe directly into the editor it is stripped out.

function iframe_shortcode($params, $content) {
    if(!$atts['width']) {
        $atts['width'] = 1500;
    }
    if(!$atts['height']) {
        $atts['height'] = 790;
    }

    $html = '<iframe border="0" class="shortcode_iframe" src="'.$atts['src'].'" width="'.$atts['width'].'" height="'.$atts['height'].'"></iframe>';
    return $html;
}
add_shortcode('iframe', 'iframe_shortcode');