WordPress Search return wrong results

i limit the search in my WP blog to be within post only by adding this line

<?php if (is_search() && ($post->post_type==’page’)) continue; ?>

So any results from static pages will be excluded , that fine but i have a problem if i have a post and it has the below content

Test POST

[video width="320" height="240" mp4="http://localhost/blog/wp-content/uploads/2015/01/a1.mp4" poster="1.jpg"][/video]

and if i try to search by this keyword ” post ” it return this post which has video tag and “poster” attribute , which not make sense so how i can exclude the attribute of media tags in search results .