Copy paste from my answer here but with iframe/video mime type added:
Alter image output in content
function WPSE_80145_Mime($html, $id) {
//fetching attachment by post $id
$attachment = get_post($id);
$mime_type = $attachment->post_mime_type;
//get an valid array of video types, add any extra ones you need
$image_exts = array( 'video/mpeg', 'video/mp4', 'video/quicktime' );
//checking the above mime-type
if (in_array($mime_type, $image_exts)) {
// the image link would be great
$src = wp_get_attachment_url( $id );
// enter you custom output here,
//you will want to change this to what you want in the iframe
$html="<iframe><a href="" . $src . '"></a></iframe>';
return $html; // return new iframe wrapped video via $html
}
return $html;
}
add_filter('media_send_to_editor', 'WPSE_80145_Mime', 20, 2);