WordPress allows you to embed videos so easily using oEmbed. You can easily add videos to your post just pasting their URL to your post. WordPress handles all the object and embed HTML for you. But this code is missing wmode parameter which is necessary for CSS z-index to work.
Embedding videos from video sites to your posts is a very simple task in WordPress. You can easily embed videos just pasting URL of the video to your posts. It automatically displays the video depending on your media settings. What if you wanted a different video size in single posts?