How do I modify the output of iframes generated by Media oEmbed module?
The HTML is being generated by the YouTube oEmbed API.

If you inspect the themes/media-oembed.tpl.php template &amp; the theme preprocess include themes/media_oembed.theme.inc, you can see that  media_oembed_get_data() looks up the plugin which pulls the data from the API. In the returned data, the html element is used to fill the $content variable in the template.

The module provides a few different means to hook into retrieval/process/display of the data:


hook_media_oembed_request_alter($parameters, $plugin, $url) can be evoked to alter data before plugin retrieval.
hook_media_oembed_response_alter($embed) can be evoked to alter data after plugin retrieval.
hook_preprocess_media_oembed(&amp;$variables) can be evoked before processing the template for display.


Whatever means you use, it looks like you'll need to manipulate the HTML string directly to add the title element to your output.